Aufnahme von Ferrioxamin B durch Tomatenpflanzen

Summary Ferrioxamin B (FOB), an iron chelating cyclopeptide, is shown to be absorbed and translocated in tomato plants from nutrient solution. Chelated iron (FOB) is transported to the upper parts of tomato plants more rapidly than ionic iron (FeCl₃).     

Serum iron level of the common Indian frogRana tigrina Daud.

Summary A study extending over a period of 2 years has been made on serum iron level of common Indian frogR. tigrina. Serum iron averages 99.4 g/100 ml in female and 92.60 g/100 ml in males. The serum iron concentration is relatively high from May to October. Starvation has been found to decrease the serum iron level from the 16th day onwards.Acknowledgment. Thanks are due to Professor Dr M. M. Goil, Head of the Zoology Department for guidance and help in various ways and to Professor Dr R. K. Sharma for valuable suggestions.     

The family of iron responsive RNA structures regulated by changes in cellular iron and oxygen

The life of aerobes is dependent on iron and oxygen for efficient bioenergetics. Due to potential risks associated with iron/oxygen chemistry, iron acquisition, concentration, storage, utilization, and efflux are tightly regulated in the cell. A central role in regulating iron/oxygen chemistry in animals is played by mRNA translation or turnover via the iron responsive element (IRE)/iron regulatory protein (IRP) system. The IRE family is composed of three-dimensional RNA structures located in 3′ or 5′ untranslated regions of mRNA. To date, there are 11 different IRE mRNAs in the family, regulated through translation initiation or mRNA stability. Iron or oxidant stimuli induce a set of graded responses related to mRNA-specific IRE substructures, indicated by differential responses to iron in vivo and binding IRPs in vitro. Molecular effects of phosphorylation, iron and oxygen remain to be added to the structural information of the IRE-RNA and IRP repressor in the regulatory complex. Received 21 April 2007; received after revision 13 July 2007; accepted 2 August 2007     

High levels of transition metals in dinoflagellate chromosomes

Summary X-ray microanalysis of fixed, sectioned chromosomes of the dinoflagellatesGlenodinium foliaceum, Prorocentrum micans andAmphidinium carterae has revealed high levels of iron, nickel, copper and zinc. We report high levels of these transition metals in association with chromosomes in intact eukaryote cells.L.P.K. gratefully acknowledges the financial support of the SRC.     

Failure of calcium to stimulate Na,K-ATPase in the presence of EDTA

Summary The effect of calcium on Na, K-ATPase activity of rat brain homogenates and its modification by the chelating agent EDTA has been investigated. In the absence of EDTA, free calcium (approximately 10^–6mol/l) stimulates Na,K-ATPase activity; in the presence of EDTA the same concentration of free calcium is without effect on the enzyme. In the absence of EDTA the stimulation by calcium of Na,-K-ATPase activity is enhanced by the additional presence of calmodulin but in the presence of EDTA, even when calmodulin is added to excess, calcium still fails to stimulate the enzyme. The possibility that EDTA interferes with an interaction between a calcium-calmodulin complex and Na,K-ATPase is discussed.The expert technical assistance of Mrs Paula Jarvie is gratefully acknowledged. Thanks are due also to Professor Philip Kuchel for assistance with the calculations to determine the concentrations of metal-ligand complexes in the experimental media.     

Complexing agents from microorganisms

Summary The majority of extracellular complexing ligands produced by microorganisms are summarized as being of low molecular mass (<10,000 daltons) and are usually released as part of metal detoxification processes. These exudates appear to exhibit strong metal-binding characteristics, often reducing metal toxicity. Under certain conditions microbes produce metal-specific compounds of low molecular mass called siderophores; although these are normally specific for iron they also have relatively high affinities for radionuclides such as Pu and facilitate their uptake into cells. The occurrence of specific actinide complexing agents has been recorded.The breakdown of lignins and cellulosic material produces large macromolecular compounds called humates. These contain multiligand sites and display a wide range of complexing abilities. They form both soluble and insoluble complexes with toxic elements with various results. Humates also considerably influence adsorption of metals to substrate surfaces and at high pH may compete with OH-ions for metal binding.As well as with extracellular ligands, metals can interact directly with microorganisms by accumulation in subcellular compartments or by adsorption on bacterial surfaces.     

Supernumerary chromosomes inDrosophila nasuta albomicana

Summary Supernumerary chromosomes have been detected in the karyotype ofD.n. albomicana. Their number varies from one to three. They are the smallest elements in the karyotype. Karyotypes ofD.n. albomicana with and without supernumerary chromosomes have been presented.     

Effect of exogenous iron on the viability of pathogenicNaegleria fowleri in serum

Summary WhenNaegleria fowleri (Lee) was incubated in newborn calf and human serum an amebicidal effect was observed. Heat inactivation of both sera resulted in the recovery of viable amebae after incubation in these sera. Exogenous iron added to non-heat inactivated calf serum improved viability slightly but was without effect when added to human serum not heat inactivated. Exogenous iron greatly enhanced growth and/or viability in heat inactivated calf serum. Viability of amebae also was considerably enhanced in human serum which was heat inactivated when pH was lowered in conjunction with iron supplements.Appreciation is expressed to Dr Ronald R. Weik (Dept. Biochemistry, Louisiana State Univ., New Orleans, LA. 70119) and Dr David T. John (Dept. Microbiology, Medical College of Virginia, Richmond, VA. 23298) for providing theNaegleria fowleri (Lee) used in this investigation.     

Prolyl endopeptidases

This review describes the structure and function of prolyl endopeptidase (PEP) enzymes and how they are being evaluated as drug targets and therapeutic agents. The most well studied PEP family has a two-domain structure whose unique seven-blade β-propeller domain works with the catalytic domain to hydrolyze the peptide bond on the carboxyl side of internal proline residues of an oligopeptide substrate. Structural and functional studies on this protease family have elucidated the mechanism for peptide entry between the two domains. Other structurally unrelated PEPs have been identified, but have not been studied in detail. Human PEP has been evaluated as a pharmacological target for neurological diseases due to its high brain concentration and ability to cleave neuropeptides in vitro. Recently, microbial PEPs have been studied as potential therapeutics for celiac sprue, an inflammatory disease of the small intestine triggered by proline-rich gluten. Received 6 July 2006; received after revision 17 August 2006; accepted 1 November 2006     

Dps-like proteins: structural and functional insights into a versatile protein family

Dps-like proteins are key factors involved in the protection of prokaryotic cells from oxidative damage. They act by either oxidizing iron to prevent the formation of oxidative radicals or by forming Dps-DNA complexes to physically protect DNA. All Dps-like proteins are characterized by a common three-dimensional architecture and are found as spherical dodecamers with a hollow central cavity. Despite their structural similarities, recent biochemical and structural data have suggested different functions among members of the family that range from protection inside the cells in response to various stress signals to adhesion and virulence during bacterial infections. Moreover, the Dps-like proteins have lately attracted considerable interest in the field of nanotechnology owing to their ability to act as protein cages for iron and various other metals. A better understanding of their function and mechanism could therefore lead to novel applications in biotechnology and nanotechnology.     

Verhütung der Hitzekoagulation von Serumproteinen durch Zucker

Summary Sixteen individuals of different types of sugars have been investigated as to their ability of inhibiting the visible heat coagulation of serum. When bovine serum was diluted with an equal amount of water and maintained at 70° C during half an hour, the following sugars were able to prevent coagulation in a minimum concentration of 5% per volume:l-arabinose,d-ribose,l-ascorbic acid, and digitoxose.     

Propriétés antiacétylcholinestérasiques du diiodométhylate debis-(diméthylamino-3-phénoxy)-1-3 propane,de ses dérivés phénoliques et des esters carbamiques correspondants

Summary Thein vitro anti-acetylcholinesterase properties ofbis-(dimethylamino-3-phenoxy)-1-3 propane dimethiodide (2842 CT) of two phenolics derivatives (3443 CT and 3116 CT) and of the two corresponding carbamic esters (3152 CT et 3113 CT) have been compared using human red blood corpuscles as enzyme source; under specified conditions, the Cl-50 are respectively 8 × 10^–7 M for 2842 CT, 3.5 × 10^–9 for the two phenolic compounds, and 1.5 × 10^–9 for the carbamic esters. The potencies of these phenols are very close to those of the carbamates, being a bit higher or lower depending on the concentration of the inhibitor and on the time of the readingThe two phenolic compounds, like 2842 CT, react readily with the enzyme contrarily to the carbamic esters which combine slowly. On the other hand the inhibition by the phenolic derivatives is as stable against washing as that by the carbamates. The carbamates, but not the phenols, show the slow displacement phenomenon.Some of these characteristics are compatible with the hypothesis that carbamic compounds could act through liberated phenolic functions but others indicate that carbamic groups have a role of their own.     

Isatin-3-anils as excystment and cysticidal agents againstSchizopyrenus russelli

Summary A series of isatin-3-anils (with or without a N-piperidino/morpholinomethyl substituent) have been screened for their cysticidal activity againstSchizopyrenus russelli. Their ability to cause excystment has also been studied.     

Failure of calcium to stimulate Na,K-ATPase in the presence of EDTA

The effect of calcium on Na,K-ATPase activity of rat brain homogenates and its modification by the chelating agent EDTA has been investigated. In the absence of EDTA, free calcium (approximately 10(-6) mol/l) stimulates Na,K-ATPase activity; in the presence of EDTA the same concentration of free calcium is without effect on the enzyme. In the absence of EDTA the stimulation by calcium of Na,K-ATPase activity is enhanced by the additional presence of calmodulin but in the presence of EDTA, even when calmodulin is added to excess, calcium still fails to stimulate the enzyme. The possibility that EDTA interferes with an interaction between a calcium-calmodulin complex and Na,K-ATPase is discussed.     

Histidine-induced injury to cultured liver cells,effects of histidine derivatives and of iron chelators

The amino acid histidine is an excellent buffer and is therefore included in several organ preservation solutions used in transplantation medicine. However, when used at concentrations as in these solutions, histidine has a marked injurious potential. Therefore, we here assessed the mechanism of histidine-induced cell injury and searched for ways to use the buffering power of histidine but avoid histidine toxicity. When cultured hepatocytes were incubated in HTK solution or in modified Krebs-Henseleit buffer containing 198 mM L-histidine at 37°C, most cells lost viability within 3 h (LDH release 86 ± 7% and 89 ± 5%, respectively). This injury was accompanied by marked lipid peroxidation, and was strongly inhibited by hypoxia, by the antioxidants trolox, butylated hydroxytoluene and N-acetylcysteine and by the membrane-permeable iron chelators 2,2′-dipyridyl, 1,10-phenanthroline, LK 614, LK 616 and deferoxamine. Thus, histidine-induced cell injury appears to be mediated by an iron-dependent formation of reactive oxygen species. D-Histidine, imidazol and L-histidine methyl ester also elicited marked injury, while the N-substituted derivatives Nα-acetyl-L-histidine and tert-butyl-oxycarbonylhistidine and histidine-containing dipeptides showed almost no toxicity. Histidine toxicity, its iron dependence and the superiority of Nα-acetyl-L-histidine were also evident during/after cold (4°C) incubations. Therefore, we suggest the addition of iron chelators to histidine-containing solutions, and/or replacing histidine with Nα-acetyl-L-histidine in organ preservation solutions. Received 23 October 2006; accepted 21 November 2006     

Distribution of metals in annual rings of the beech (Fagus sylvatica) as an expression of environmental changes

Summary Annual rings of 140–160-year-old beeches (Fagus sylvatica) from St. Ingbert, Saarland (FRG) were prepared and analyzed for 14 metals by atomic absorption spectroscopy. According to the chronological variations of their concentrations, the elements could be divided into three groups: 1) Metals without any tendency for chronological changes. This was established for Na, K, Cu, Cr, Co, Ni, Pb, and Cd. 2) Metals with a recent decrease of their concentrations, appropriate for Ca, Mg, Mn, and Zn. 3) Metals with a recent tendency to increase, e.g. Fe and Al. These variations are discussed in connection with the industrial history of the Saarland region and the influence of acid immissions which may alter the soil and thereby the trace element metabolism of the trees with consequences for the vitality of the plants.     

Über eisenhaltige Wachstumsfaktoren,die Sideramine,und ihre Antagonisten,die eisenhaltigen Antibiotika Sideromycine

Summary A new group of iron-containing metabolites, with growth stimulating properties for a number of microorganisms, has been isolated from streptomycetes and namedferrioxamines. It is proposed to include them, together with some known substances, like ferrichrome, coprogen and the terregens factor, which either contain or bind iron, in a new class of growth factors, thesideramines.The biological property of the sideramines is counteracted by iron-containing antibiotics from streptomycetes, thesideromycins. They comprise, besides known products like grisein and albomycin, two new groups of antibiotics, among them the highly potentferrimycins.

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22. Mitteilung, Stoffwechselprodukte von Actinomyceten; 21. Mitteilung: Helv. chim. acta43, im Druck (1960).     

Ptolemy and the meta-helikôn

In his Harmonics, Ptolemy constructs a complex set of theoretically ‘correct’ forms of musical scale, represented as sequences of ratios, on the basis of mathematical principles and reasoning. But he insists that their credentials will not have been established until they have been submitted to the judgement of the ear. They cannot be audibly instantiated with the necessary accuracy without the help of specially designed instruments, which Ptolemy describes in detail, discussing the uses to which each can be put and cataloguing its limitations. The best known of these instruments is the monochord, but there are several more complex devices. This paper discusses one such instrument which is known from no other source, ancient or modern, whose design was prompted by the geometrical construction known as the helikôn. It has several remarkable peculiarities. I examine its design, its purposes, and the merits and shortcomings which Ptolemy attributes to it. An appendix describes an instrument I have built to Ptolemy’s specifications (possibly the first of its kind since the second century bc), in an attempt to find out how satisfactorily such a bizarre contraption will work; and it explains how various practical problems can be resolved.     

Catechine und Hydroxy-flavandiole als Gerbstoffbildner

Summary From the ranks of the colourless hydroxyflavans, four differenthydroxyflavan-3-ols(catechins and epi-catechins), as well as eight hydroxyflavan-3,4-diols, have so far been encountered in nature. These substances are also procurable by synthesis. On treatment with hot water or dilute acids, they are easily converted into soluble tannins or insoluble phlobaphenes. The mechanism of the self-condensation is explained using catechin via the isolation of a dimerie product. A probable path for the self-condensation of the diols has been indicated. In contrast to the products of their self-condensation, the monomeric polyhydroxyflavans are not real tannins. A particular accumulation of phenolhydroxyl groups in the molecule, the tendency to form supersaturated solutions and low solubility in water in the — generally not attainable — crystalline state are prerequisites for tanning properties. In nature, the self-condensation of polyhydroxyflavans proceeds (e. g. in the wood ofAcacia catechu or in Quebracho Wood) without the assistance of enzymes. Dehydrogenative polymerisation occurs with formation of brown or red phlobaphenes (e.g. in cocoa beam) which are generally insoluble.     

SV40 association with human malignancies and mechanisms of tumor immunity by large tumor antigen

SV40 was discovered as a contaminate of poliovirus vaccine lots distributed to millions of individuals in the United States between 1955 and 1963 while contaminated vaccine batches were later circulated worldwide. After SV40 was observed to cause in vitro animal and human cell transformations and in vivo tumor formations in animals, the search for a connection between the virus and human malignancies has continued to the present day. Different molecular methods have been used to detect SV40 gene products in a variety of human cancers, though SV40 causality in these tumor types has yet to be established. These data, however, are not without controversial issues related to inconclusive SV40 serological and epidemiological evidence alongside tools and methodologies that may contribute to false-positive results in human specimens. This review will also explore how vaccination against SV40 protein products may be used to help prevent and treat individuals with SV40-expressing cancers. Received 19 September 2006; received after revision 8 November 2006; accepted 13 December 2006