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PubMed1974

Inhibition of DNA synthesis and cell division in Salmonella typhimurium by azide.

Evidence has been obtained that sodium azide is an inhibitor of cell division in wild-type and aziA strains of Salmonella typhimurium. The bacteria grown in media containing sodium azide and glucose formed long filaments. It has been found that sodium azide had a stronger inhibitory effect on DNA synthesis than on cell mass increase. When filaments produced by azide action were transferred to azide-free medium very rapid increase in DNA content was observed during the first 45 min. After this time, when relative DNA content was increased the rate of DNA synthesis was reduced and cell divisions reappeared. Inhibitory effect of azide on DNA biosynthesis in vitro was observed with toluenized cells of S typhimurium. Only ATP-dependent radioactive dTMP incorporation into DNA was affected by sodium azide. It had no effect on the incorporation in the absence of ATP. Mutant aziC was isolated in S. typhimurium by scoring for clones with normal cell division in the presence of sodium azide. Azide had much less effect on DNA biosynthesis in vivo and in vitro in aziC cells as compared with isogenic controls.

Azides↗
PubMed1994

Systemic or local administration of azide produces striatal lesions by an energy impairment-induced excitotoxic mechanism.

Sodium azide is an inhibitor of cytochrome oxidase which produces selective striatal lesions in both rodents and primates. In the present study we investigated the neurochemical and histologic effects of both intrastriatal and systemic administration of sodium azide, as well as the age dependence and mechanism of the lesions. Intrastriatal administration of sodium azide produced dose-dependent lesions. Neurochemical and histologic evaluation showed that markers of both spiny projection neurons (GABA, substance P) and aspiny interneurons (somatostatin, neuropeptide Y, NADPH-diaphorase) were equally affected. Subacute systemic administration of sodium azide resulted in lesions with a similar neurochemical profile; however, in contrast to intrastriatal injections there was sparing of dopaminergic striatal afferents. Prior decortication significantly attenuated lesions produced by intrastriatal administration of sodium azide, consistent with an excitotoxic process. Chronic administration of sodium azide for 1 month lead to striatal neuropathological changes. Lesions produced by intrastriatal administration of sodium azide in 1-, 4-, and 12-month-old animals showed age dependence. Both freeze-clamp measurements and chemical-shift magnetic resonance spectroscopy confirmed that sodium azide impairs oxidative phosphorylation in the striatum following either intrastriatal or systemic administration. These results show that the striatum is particularly vulnerable to oxidative stress produced by sodium azide, and that it produces striatal lesions by a secondary excitotoxic mechanism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2003

Protective effect of benidipine against sodium azide-induced cell death in cultured neonatal rat cardiac myocytes.

We investigated the effect of benidipine, a calcium antagonist, against sodium azide (NaN(3))-induced cell death in cultured neonatal rat cardiac myocytes with increase of LDH release, depletion of cellular ATP contents, and collapse of mitochondrial membrane potential (DeltaPsi) as indicators. Cells were treated with 1 mmol/L NaN(3) for 18 h. Benidipine concentration-dependently inhibited NaN(3)-induced cell death. The protective effect of benidipine was compared with those of amlodipine, nifedipine, candesartan, and captopril. Calcium antagonists exhibited a protective effect and the IC(50) values of benidipine, amlodipine, and nifedipine were 0.65, 90, and 65 nmol/L, respectively. NaN(3)-induced cell death was inhibited completely with the calpain inhibitor. It was considered that the sustained elevation of [Ca(2+)](i) might be implicated in NaN(3)-induced cell death. Benidipine, moreover, concentration-dependently preserved cellular ATP contents and maintained DeltaPsi the extent of the control level. In conclusion, benidipine exhibited the protective effect at an approximately 100-fold lower concentration than those of amlodipine and nifedipine in the NaN(3)-induced cardiac cell death model. It was considered that both the inhibition of Ca(2+) influx and the preservation of cellular ATP contents might play an important role in the protective effect of benidipine.

Adenosine Triphosphate↗
PubMed1986

A versatile transition metal salt reaction for a wide range of common biochemical reagents: an instantaneous and quantifiable color test.

A rapid and sensitive spot test amenable to visual or spectrophotometric quantitation has been developed for a wide variety of biochemical reagents by utilizing the transition metal salt cupric chloride and its large number of related colored compounds. This assay is potentially a widely applicable multipurpose test for rapidly detecting the presence of unknown substances. Combination of the test sample with the working reagent results in the immediate formation of a distinctive colored product that may be precipitable. Some compounds require the further addition of sodium hydroxide in order to generate the distinctively colored product. Distinctive reactions occur with the following reagents, and their limit of visual detection is indicated in parentheses: ammonium bicarbonate (12.5 mM), ammonium acetate (25 mM), ammonium hydroxide (0.1%), ammonium sulfate (2%), ammonium persulfate (0.02 mM), L-(+)-cysteine (0.07 mM), dithiothreitol (DTT) (1.25 mM), EDTA (0.6 mM), ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid (5 mM), D-glucose (6 mM), glycerol (0.3%), imidazol (12.5 mM), DL-methionine (100 mM), mercaptoethanol (0.05%), sodium azide (19 mM, 0.1%), sodium dithionite (0.25%), sodium metabisulfite (25 mM), sodium nitrite (6.2 mM), sodium periodate (3.1 mM), sodium sulfite (12.5 mM), sodium thiosulfite (12.5 mM), sucrose (6 mM), and N,N,N',N'-tetramethylethylenediamine (0.05%). A distinctive exothermic reaction occurs with hydrogen peroxide, but without color change. Compounds reacting insignificantly include 50 mM Tris buffer, urea, N,N'-methylene bisacrylamide, sodium dodecyl sulfate, isopropyl alcohol, sodium fluoride, trichloroacetic acid, phenol, mannose, K2HPO4, guanidine HCl, chloramine-T, magnesium chloride, and boric acid, where the solids were tested at approximately 10 mg/ml. Spectrophotometric standard curves were developed for DTT and sodium azide utilizing the clear supernatants resulting from these reactions. Combinations of at least four reagents could be discriminated, as demonstrated with mixtures of glucose, sodium azide, EDTA, and DTT. In addition ammonium sulfate could be detected to a limit of 4% in the presence of protein, DTT, and EDTA in a 50 mM Tris buffer. Spot tests were developed which utilized reagent-impregnated filter paper and gave distinctive colored products on addition of 5 microliter of test sample.

Centrifugation↗
PubMed1986

Microcalorimetric investigation of metabolism in rat hepatocytes cultured on microplates and in cell suspensions.

In the present work, heat production rate in rat hepatocytes has been measured by use of thermopile heat conduction calorimeters. Both hepatocytes cultured in monolayers on microplates and hepatocytes in suspensions were used for microcalorimetric measurements. The highest heat production rate was found in newly cultured cells; thereafter, a gradual decrease was noted. After 1 day of culture, metabolic activity had reached a steady state that lasted about 4 days. A cell-density dependence of heat production was found, both in cell suspensions and in cultured hepatocytes on microplates. Higher cell concentration in the calorimeter ampoule was accompanied by decreasing heat production per cell. The heat output recorded for hepatocytes cultured on microplates (25 X 10(3) cells) was found to be 0.327 +/- 0.13 nW per cell after 24-48 h. Addition of sodium azide and sodium fluoride to tissue culture medium reduced heat production rate in cultured hepatocytes by 60 and 20%, respectively. Recording of heat production with the present calorimetric technique is relatively simple and fast, and offers the possibility to perform measurements in small samples of cultured hepatocytes on microplates, thus allowing long-term as well as repeated measurements on the same cell population.

Animals↗
PubMed2000

Metabolic and K(ATP) channel-independent actions of keto acid initiators of insulin secretion.

Insulin-releasing effects of 2-ketobutyric acid (KB), 2-ketoisocaproic acid (KIC), 2-keto-3-methylvaleric acid (KMV), and 3-phenylpyruvic acid (PP) were examined by using clonal beta cells. Whereas KIC, KMV, and PP dose-dependently initiated insulin secretion and potentiated the effects of 4.2-16.7 mM glucose, equimolar KB was without effect. Transport inhibition by using 10 mM valine, isoleucine, 2-cyano-3 hydroxycinnamate or 2-cyano-4 hydroxycinnamate, or metabolic inhibition by 15 mM mannoheptulose, 5 mM sodium azide, 5 mM sodium cyanide, or removal of HCO3 reduced the secretory effects of KIC, KMV, and PP. Whereas K+ depletion reduced keto acid-induced insulin output, depolarizing concentrations of L-leucine and L-arginine potentiated the keto acid-induced effects. Under depolarizing conditions (25 mM KCI and 16.7 mM glucose), 10 mM KIC, KMV, or PP induced insulin secretion, suggesting K(ATP) channel-independent actions. Furthermore, the K(ATP) channel opener diazoxide reduced, but did not abolish, the keto acid-induced effects. However, voltage-dependent Ca2+ channel blockade with verapamil or removal of extracellular Ca2+ abolished keto acid-induced insulin release. Collectively, these results indicate that KIC, KMV, and PP initiate insulin secretion at least partially independently of K(ATP) channel activity, through both mitochondrial metabolism and regulation of Ca2+ influx.

Animals↗
PubMedDate not supplied

Peroxidase-release associated with phagocytosis in Mytilus galloprovincialis haemocytes.

Fluorescence spectra of the supernatant of adherent haemocyte monolayers from Mytilus galloprovincialis, supplemented with homovanillic acid or with a tyrosyl peptide glycylglycyltyrosine (GGY), were recorded before and after stimulation by zymosan. The formation of fluorescent derivatives was observed to have spectral characteristics similar to those of fluorescent compounds generated by the exposure of homovanillic acid or GGY to a horseradish peroxidase/hydrogen peroxide system in vitro. Lucigenine-enhanced chemiluminescence (CLluc) of M. galloprovincialis haemocytes stimulated by zymosan or by phorbol ester (PMA) was measured in the presence and absence of sodium azide, a peroxidase inhibitor. Sodium azide inhibited the CLluc of haemocytes stimulated by zymosan, an effective stimulus for myeloperoxidase secretion in human polymorphonuclear leukocytes, but not the CLluc of haemocytes stimulated by PMA, indicating the presence of peroxidases with some properties of myeloperoxidase, in adherent haemocytes from M. galloprovincialis.

Animals↗
PubMed2000

Determination of the phospholipid precursor of anandamide and other N-acylethanolamine phospholipids before and after sodium azide-induced toxicity in cultured neocortical neurons.

Phospholipase D-mediated hydrolysis of N-acylethanolamine phospholipids (NAPEs) releases anandamide and other N-acylethanolamines, resulting in different actions at cellular targets in the CNS. Recently, we have demonstrated that these N-acyl lipids accumulate in cultured neocortical neurons subjected to sodium azide-induced cell injury. We here extend the information on the NAPE response, reporting on the composition of N-acylspecies of NAPE, employing a new methodological approach of HPLC-coupled electrospray ionization mass spectrometry. Exposure to sodium azide (5 mM) increased the total amount of NAPE threefold over control levels; however, no alteration of the relative composition of NAPE species was detected. The anandamide precursor (20 : 4-NAPE) constituted only 0.1% of all NAPEs detected in the neurons. Total NAPE species in control cells amounted to 956-1,060 pmol/10(7) cells. Moreover, we detected the presence of an unknown NAPE species with molecular weight identical to 20 : 4-NAPE. This may suggest the presence of a putative stereoisomer of the anandamide precursor with at least one trans-configured double bond in the N-arachidonoyl moiety. These results show that with the present method, neuronal NAPE species can be identified and quantified with respect to N-acyl composition, including a trans-isomer of the anandamide precursor. The anandamide precursor is up-regulated to the same extent as other NAPEs upon neuronal injury.

Animals↗
PubMed1985

Cyanide and sulfide interact with nitrogenous compounds to influence the relaxation of various smooth muscles.

Sodium nitroprusside relaxed guinea pig ileum after the segment had been submaximally contracted by either histamine or acetylcholine, intact isolated rabbit gall bladder after submaximal contraction by either acetylcholine or cholecystokinin octapeptide, and rat pulmonary artery helical strips after submaximal contraction with norepinephrine. In each of these cases the relaxation produced by nitroprusside was at least partially reversed by the subsequent addition of excess sodium cyanide. Cyanide, however, in nontoxic concentrations did not reverse the spasmolytic effects of hydroxylamine hydrochloride, sodium azide, nitroglycerin, sodium nitrite, or nitric oxide hemoglobin on guinea pig ileum, nor did cyanide alone in the same concentrations have any effect. The similar interaction between nitroprusside and cyanide on rabbit aortic strips is not dependent on the presence of an intact endothelial cell layer. Also, on rabbit aortic strips and like cyanide, sodium sulfide reversed the spasmolytic effects of azide and hydroxylamine, but it had little or no effect on the relaxation induced by papaverine. Unlike cyanide, however, sulfide augmented the relaxation induced by nitroprusside, and it reversed the effects of nitric oxide hemoglobin, nitroglycerin, and nitrite. A direct chemical reaction between sulfide and nitroprusside may account for the difference between it and cyanide. Although evidence was obtained also for a direct chemical reaction between sulfide and norepinephrine, that reaction does not seem to have played a role in these results. These observations suggest the existence of at least three distinct subclasses of so-called nitric oxide vasodilators. At least in some cases cyanide and sulfide cannot be acting by the same mechanism in their modifications of the responses to the agonists.

Acetylcholine↗
PubMed2004

Catalase inhibition in the Arcuate nucleus blocks ethanol effects on the locomotor activity of rats.

Previous studies have demonstrated that there is a bidirectional modulation of ethanol-induced locomotion produced by drugs that regulate brain catalase activity. In the present study we have assessed the effect in rats of intraperitoneal, intraventricular or intracraneal administration of the catalase inhibitor sodium azide in the locomotor changes observed after ethanol (1 g/kg) administration. Our results show that sodium azide prevents the effects of ethanol in rats locomotion not only when sodium azide was systemically administered but also when it was intraventricularly injected, then confirming that the interaction between catalase and ethanol takes place in Central Nervous System (CNS). Even more interestingly, the same results were observed when sodium azide administration was restricted to the hypothalamic Arcuate nucleus (ARC), a brain region which has one of the highest levels of expression of catalase. Therefore, the results of the present study not only confirm a role for brain catalase in the mediation of ethanol-induced locomotor changes in rodents but also point to the ARC as a major neuroanatomical location for this interaction. These results are in agreement with our reports showing that ethanol-induced locomotor changes are clearly dependent of the ARC integrity and, especially of the POMc-synthesising neurons of this nucleus. According to these data we propose a model in which ethanol oxidation via catalase could produce acetaldehyde into the ARC and to promote a release of beta-endorphins that would activate opioid receptors to produce locomotion and other ethanol-induced neurobehavioural changes.

Analysis of Variance↗
PubMed2005

Effects of chemical ischemia in cerebral cortex slices. Focus on nitric oxide.

Superfused rat cerebral cortex slices were submitted to a continuous electrical (5 Hz) stimulation and treated with sodium azide (1-10 mM) in the presence of 2 mM 2-deoxyglucose ("chemical ischemia"). Presynaptic cholinergic activity, evaluated as acetylcholine release, was inhibited depending on the sodium azide concentrations and on the length of application (5-30 min). Following a 5-min treatment with 10 mM sodium azide, acetylcholine release was reduced to 45+/-2.3%; simultaneously, there was a 15- and 10-fold increase in glutamate and nitric oxide effluxes, respectively. After restoring normal superfusion conditions, acetylcholine release recovered to 70+/-3.1% of the controls; the N-methyl-D-aspartate receptor antagonist MK-801 (10 microM) as well as the nitric oxide scavengers, haemoglobin (20 microM) and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide (150 microM), improved the recovery in presynaptic activity, showing that both glutamate and nitric oxide play detrimental roles in chemical ischemia. On the other hand, the post-ischemic recovery was worsened by the guanylylcyclase inhibitor 1H-[l,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (10 microM), suggesting that the activation of such a pathway plays a neuroprotective role and that the nitric oxide-induced harmful effects depend on different mechanisms. Chemical ischemia-evoked nitric oxide efflux partly derived from its calcium-dependent endogenous synthesis, since both the intracellular calcium chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (1 mM), and the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methyl ester (100 microM), substantially prevented sodium azide effects. Nitric oxide efflux was only weakly reduced by MK-801 and was not modified by either the L-type calcium channel blocker, nifedipine (10 microM) or the N-type calcium channel blocker omega-conotoxin (0.5 microM), thus suggesting a prevailing intracellular calcium-dependence of nitric oxide production, although a partial extracellular calcium source cannot be ruled out. These findings show that sodium azide plus 2-deoxyglucose treatment is a useful protocol to induce brain ischemia in vitro and underline the involvement of nitric oxide in the complex events following the ischemic insult.

Acetylcholine↗
PubMed1990

Azide-resistant mutants of Escherichia coli alter the SecA protein, an azide-sensitive component of the protein export machinery.

Escherichia coli azi mutants, whose growth is resistant to millimolar concentrations of sodium azide, were among the earliest E. coli mutants isolated. Genetic complementation, mapping, and DNA sequence analysis now show that these mutations are alleles of the secA gene, which is essential for protein export across the E. coli plasma membrane. We have found that sodium azide is an extremely rapid and potent inhibitor of protein export in vivo and that azi mutants are more resistant to such inhibition. Furthermore, SecA-dependent in vitro protein translocation and ATPase activities are inhibited by sodium azide, and SecA protein prepared from an azi mutant strain is more resistant to such inhibition. These studies point to the utility of specific inhibitors of protein export, such as sodium azide, in facilitating the dissection of the function of individual components of the protein export machinery.

Adenosine Triphosphatases↗
PubMed1993

Giardiavirus enters Giardia lamblia WB trophozoite via endocytosis.

As part of our continuing effort in the study of Giardiavirus life cycle, the early events of Giardia lamblia virus (GLV) infection in the trophozoites of G. lamblia WB strain were examined. Electron microscopy showed that GLV particles were initially localized on plasma membrane. As time progresses, GLV was translocated to the peripheral vacuole and then spread to the cytoplasm. Inhibitors of endocytosis such as sodium azide, chloroquine, or ammonium chloride disrupted viral infection when the drug was added simultaneously with the infecting GLV. The inhibitory effect was reduced when sodium azide or chloroquine was added at various intervals after infection. When cells infected for 1 hr were examined by immunofluorescence staining, sodium azide greatly reduced GLV staining signal in general while chloroquine restricted the staining signal to a few bright spots. Significantly more GLV was found in the peripheral vacuoles of chloroquine-treated cells than untreated controls by semiquantitative electron microscopy. In contrast, only a reduced amount of GLV was found in the peripheral vacuoles of sodium azide-treated cells. These results suggest that sodium azide reduces the internalization of infecting GLV, while chloroquine confines the virus in the peripheral vacuoles and, consequently, leads to nonproductive infection. We conclude from these observations that the entry of GLV into the susceptible WB cells in the event of infection is most likely mediated by endocytosis.

Ammonium Chloride↗
PubMed1980

Cold and metabolic inhibitor effects on cytoplasmic microtubules and the Golgi complex in cultured rat epiphyseal chondrocytes.

Previous work has shown that exposure of cultured chondrocytes to colchicine leads to disappearance of microtubules and dispersion of the dictyosomes of the Golgi complex throughout the cytoplasm. Here, the effects of cold and metabolic inhibitors on cultured chondrocytes have been investigated in order to characterize further the relationship between these organelle systems. After incubation of cells for 24h at 4 degrees C most, but not all microtubules disappeared, indicating the existence of cold-resistant microtubules. Dictyosomes remained united in one area, until transfer of cultures to 37 degrees C, when they dispersed throughout the cytoplasm in about one-third of the cells. In cells exposed simultaneously to cold and colchicine, microtubules disappeared completely, but spreading of dictyosomes occurred only in some cells and became generalized first upon warming. Application of the metabolic inhibitors sodium azide or sodium fluoride (10(-2) M) or 2-deoxyglucose (5 X 10(-2) M) together with sodium cyanide (10(-2) M) inhibited microtubule removal by colchicine. Consequently, spreading of the Golgi complex was prevented. These findings support the concept of an important role of microtubules in the organization of the Golgi complex. Moreover, depolymerization of microtubules by colchicine appears to be an energy dependent process.

Animals↗
PubMed1971

Properties of the sarcolemmal calcium ion-stimulated adenosine triphosphatase of hamster skeletal muscle.

1. A sarcolemmal fraction was isolated from hamster hind-leg skeletal muscles by successive treatment with lithium bromide and potassium chloride. The membranous fraction was observed to contain a highly active Ca(2+)-stimulated ATPase (adenosine triphosphatase), a Mg(2+)-stimulated ATPase, and an Na(+)+K(+)-stimulated Mg(2+)-dependent ouabain-sensitive ATPase. 2. The Ca(2+)-stimulated ATPase activity was pH-dependent, the optimum being pH7.6. 3. Optimum activation of this enzyme was obtained with 3-4mm-Ca(2+) when 4mm-ATP was present as a substrate, and was not influenced by Na(+), K(+) or ouabain, whereas 2,4-dinitrophenol, sodium azide, oligomycin, sodium fluoride and ethanedioxybis(ethylamine)tetra-acetate were inhibitory. 4. The Ca(2+)-stimulated ATPase was markedly inhibited by thiol-blocking reagents, and cysteine was able to reverse this inhibition. 5. Various bivalent cations stimulated ATP hydrolysis by the sarcolemmal fraction in the following decreasing order of potency: Mg(2+), Ca(2+), Mn(2+), Co(2+), Sr(2+), Ba(2+), Zn(2+), Cu(2+).

Adenosine Triphosphatases↗
PubMed1976

Sheep erythrocytes binding ability on a mouse renal adenocarcinoma cell line and its hybrid with human lymphocytes.

A mouse renal adenocarcinoma (Rag) cell line, not related to L cells, rosette with erythrocytes from sheep and mice. The Rag-cell rosettes are performed in suspension and on coverslips. Microscopically they rosette like human T cell. No virus-like particles thus far have been found between the rosetted cells. However, the sheep erythrocyte binding ability of Rag cells are very different as compared to human T cells. The former cannot be impaired by trypsin-EDTA treatment nor inhibited by rabbit anti-human thymocyte immunoglobulin, sodium azide or sodium iodoacetate. Two hybrid clones isolated between Rag-human lymphocytes show similar rosette characteristics as the Rag cells.

Adenocarcinoma↗
PubMed2006

Syntheses, crystal structures, and magnetic characterization of five new dimeric manganese(III) tetradentate Schiff base complexes exhibiting single-molecule-magnet behavior.

Tetradentate Schiff base ligands H2L (H2saltmen, H2salen, H2-5-Brsalen, and H2-3,5-Brsalen), derived from the condensation of the corresponding salicylaldehyde or its derivatives with 1,1,2,2-tetramethylethyldiamine or 1, 2-diaminoethane, reacted with Mn(III) acetate or perchlorate salts and sodium azide or sodium cyanate to produce five Mn(III) dimer complexes, [Mn(saltmen)(O2CCH3)]2.2CH3CO2H (1), [Mn(saltmen)(N3)]2 (2), [Mn(salen)(NCO)]2 (3), [Mn(3,5-Brsalen)(3,5-Brsalicylaldehyde)]2 (4), and [Mn(5-Brsalen)(CH3OH)]2(ClO4)2 (5). These new complexes have been characterized by IR, elemental analyses, crystal structural analyses, and magnetic studies. Within these Mn(III) dimeric complexes, two Mn(III) ions are connected by phenolate oxygen atoms with acetate, azide, cyanate, a 3,5-Brsalicyladehyde anion, and a neutral methanol molecule as the axial ligands for complexes 1-5, respectively. Complexes 1-4 exhibit intradimer ferromagnetic exchange and display frequency dependence of ac magnetic susceptibility, possibly showing single-molecule-magnet (SMM) behavior. In contrast, complex 5 shows an intradimer antiferromagnetic coupling probably originating from the relatively shorter Mn-O distance, compared to those of complexes 1-4.

Journal Article↗
PubMed1977

[Energy-dependent 63Ni-uptake by Alcaligenes eutrophus strains H1 and H16 (author's transl)].

Kinetic studies of the uptake of 63Ni were undertaken with two strains of Alcaligenes eutrophus, known to require nickel ions for chemolithotrophic growth. Using carbon dioxide as sole carbon source, growth is stimulated by low concentrations of nickel with optimum concentration for growth stimulation at about 0.3 micron nickel. Higher nickel concentrations were inhibitory. Heterotrophic growth on fructose was not stimulated by nickel ions.--Upon transfer into phosphate buffer freed of heavy metal ions, autotrophically grown cells exhibited rapid uptake of 63Ni which was dependent upon the presence of hydrogen, oxygen and carbon dioxide. Within 60 min nickel was accumulated from the medium, reaching 280-fold concentration in the cells. The observed uptake exhibited a temperature optimum at about 29 degrees C and was markedly inhibited by metabolic inhibitors such as arsenite, iodoacetate, methylene-blue, sodium azide and sodium cyanide. Other heavy metal ions (Zn, Co, Mn and Cu) only slightly inhibited 63Ni-uptake. The efflux of 63Ni from the cells was stimulated by 58NiCl2 and by toluene. These data indicate that nickel ions are accumulated by an energy dependent mechanism in chemolithotrophically grown cells of these strains.

Alcaligenes↗