Volume 23, Issue 11

Die Spektren im Bereich von 300—600 nm der wäßrigen Lösungen von Prussiaten (II) zeigen in den meisten Fällen drei Banden, denen die Übergänge 1 A 1 → 1 E (1), 1 A 1 → A 2 und 1 A 1 → 1 E(2) zugeordnet werden konnten (C 4v -Symmetrie, Dt < 0). Durch vergleichende Überlegungen im Zusammenhang mit dem Spektrum des [Fe(CN) 5 NO] 2⊖ wurde eine Reihe für die Störwirkung erhalten. Der Komplex [Fe(CN) 5 NO 2 ] 4⊖ zeigt eine sehr geringe Störung der Oh-Symmetrie. Für die Prussiate (III) wurden unter Vernachlässigung der gestörten Oh-Symmetrie nach einer von NAIMAN 6 angeführten Methode für [Fe(CN) 6 ] 3⊖ aus den Werten der Spektren von wäßrigen Lösungen die Dq-Werte abgeschätzt. Dabei zeigte wiederum das [Fe(CN) 5 NO 2 ] 3⊖ mit einem Wert Dq=3350 cm -1 die geringste Abweichung von dem des Hexacyanoferrates(III) (3495 cm -1 ), während die berechneten Werte der anderen Prussiate bei 3200±40 cm -1 lagen. Für die in den Spektren beobachteten Banden bei 17 500, 24 500 und 35 400 cm -1 wurden Zuordnungen getroffen. Die Banden bei 17 500 cm -1 sind bis auf den Fall des [Fe(CN) 5 NH 3 ] 2⊖ durch CT-Banden überlagert.

SiBr 4 , SiCl 4 , (CH 3 ) SiCl 3 , (CH 3 ) 2 SiCl 2 , (CH 3 ) 3 SiCl, C 2 H 3 SiCl 3 , C 6 H 5 SiCl 3 , (C 6 H 5 ) 2 SiCl 2 , (C e H 5 ) 3 SiCl, and (C 6 H 5 ) 4 Si have been γ-irradiated in a matrix of 2-methyltetrahydrofurane at — 196 °C. The reactivity towards the free electron is shown to decrease with increasing number of methyl groups and to increase with increasing number of phenyl groups in these compounds. The results are compared with mass spectrometric appearance potential measurements. The products formed in the electron attack show absorption bands in the near ultraviolet and infrared. Some of the absorptions can easily be bleached by blue light. The observed absorptions are attributed to the following molecular anions or neutral radicals formed by non-dissociative or dissociative electron captures respectively: (C 6 H 5 ) 4 Si⊖, (C 6 H 5 ) 3 SiCl ⊖, (C 6 H 5 ) 2 SiCl, C 6 H 5 SiCl 2 , CH 2 =CHSiCl 2 CH 3 SiCl 2 , SiCl 3 , SiBr 3 .

The unimolecular thermal decomposition of chloroethane-2-d 3 and chloroethane-2-d 1 was studied in a static system at two temperatures and at pressures between 0.1 and 10 mm Hg. The rate constants for the high pressure limit were obtained from these measurements and used to calculate the Arrhenius equations. The decomposition of chloroethane-2-d 3 was also studied at high conversions and yielded almost exclusively (97%) DCl and CD 2 CH 2 as shown by mass spectrometric analysis thus proving a molecular elimination mechanism via a four-centered reaction complex.

Purification of commercially available HCG preparations with DEAE Sephadex A 50 and Sephadex G 100 column chromatography gave homogeneous fractions having specific biological activities four fold those of the starting materials. The purified HCG has ICSH characteristics and, in high doses, a definite FSH effect is present. Chemical analysis of HCG showed it to contain 29% carbohydrates and 69% peptides. The C-terminal amino acid of the peptide chain was found to be serine, but the N-terminal amino acid could not be determined with normal methods. A molecular weight of 22000 — 27000 daltons was obtained by quantitative end group analysis. Ultracentrifugation experiments in 4 m guanidine hydrochloride gave a molecular weight of 27200 daltons, but in neutral saline solutions at HCG concentrations above 2 mg/ml the apparent molecular weight was higher and indicated dimer formation. A dissociation constant of 10 -5 mol/l was estimated for the monomer-dimer equilibrium. Since biological activity is found with 0.1 to 0.5 µg, it was concluded that the HCG monomer is the active entity. The purified HCG is stable from pH 4.5 to pH 10 for 6 hours at 37 °C. At pH 2.5 only 5 to 10% of the original activity is retained. HCG is rapidly inactivated at 100 °C, but a residual activity of 6 — 10% remained after 30 minutes at 80 °C. No activity was lost after 30 minutes incubation at 60 °C.

Bei der Applikation von N-Methylputrescin-[1- 14 C, 15 N-CH 3 ] und von N-Methylputrescin-[1-T] an Nicotiana rustica haben wir einen spezifischen Einbau der Radioaktivität in die Position 5′ des Pyrrolidinringes erhalten. Dieses Ergebnis spricht dafür, daß das N-Methylputrescin unsymmetrisch in das Nicotin eingebaut wird und daß eine Methylierung vor dem Ringschluß zum Pyrrolidin möglich ist.

Base catalysed transesterification of phorbol-12,13,20-tribenzoate yields phorbol-12,13-dibenzoate. By base catalysed transesterification of phorbol-pentaacetate phorbol-9,12,13-triacetate is obtained. This can be re-acetylated to give phorbol-9,12,13,20-tetraacetate which is also obtained by treatment of phorbol-12,13,20-triacetate with acetic anhydride/p-toluene-sulfonic acid. Reduction of phorbol-12,13,20-triacetate with LiAlH 4 yields phorbol-3-ol which reduces Fehling's and Tollen's reagent. Reduction of the 3-keto group alone can be accomplished with sodium borohydride. From all phorbol-esters investigated only in phorbol-pentaacetate an acetyl migration is observed during the sodium borohydride reduction leading to phorbol-3-ol-3,9,12,13,20-pentaacetate. By these findings those two tertiary hydroxyl groups of phorbol which are not acetylated with acetic anhydride/pyridine at room temperature were further characterized. Oxidation of phorbol-12,13-diacetate with activated manganese dioxide yields phorbol-20-al-12,13-diacetate. By evaluation of nmr-spectra of this aldehyde and of some of its derivatives as well as of the epoxide of phorbol-12,13-diacetate and of 6-oxo-7-hydroxy- and 6,7-diacetoxy-20-nor-phorbol-12,13-diacetate the sequence of C-atoms around the allylic alcohol group of phorbol is further characterized.

In phorbol and partial acetates of phorbol the hydroxyl groups in the 20-, 13-, 12- and 4-positions can be etherified with one of the following methods: diazoalkane/Al-i-propylate, tritylchloride/pyridine and methyl-iodide/silveroxide. The investigation of suitable phorbol ethers with Fehling's and Tollens' reagent proves that the tertiary hydroxyl at the cyclopropane ring is solely responsible for the reducing properties of phorbol. Thus, phorbol is the first natural compound in which this reaction of tertiary cyclopropanols was detected.

Oxidation of the secondary hydroxyl in phorbol-13,20-diacetate with chromium-trioxide/pyridine yields the diketone phorbol-12-on-13,20-diacetate. The newly introduced carbonyl group is sterically hindered thus allowing for selective reduction of the α„β-unsaturated ketone to give neophorbol-13,20-diacetate, a positional isomer of phorbol-13,20-diacetate in respect to the carbonyl group. By addition of the circular dichroismus of phorbol-13,20-diacetate and neophorbol-13,20-diacetate the dichroism of phorbol-12-on-13,20-diacetate was calculated, indicating that the electronic system of the two carbonyl functions in the latter do not interact. This excludes the existence of the structural unit of an 1,2-diketone in phorbol-12-on-13,20-diacetate. UV-absorption and circular dichroic spectra of derivatives of phorbol esterified or etherified in the 4-position suggest strongly the presence of a tertiary 1,2-ketol group in phorbol. By investigations of the UV-absorption below 200 nm of tetrahydro-phorbol derivatives, the cyclopropane component in phorbol is confirmed. Circular dichroism and UV-absorption of certain derivatives of phorbol-12-on suggest the presence of an β-cyclopropyl ketone group.

On experimental rat tumors, preferentially on DS-Carcinosarcoma, special glass electrodes were used to measure and to register development of tissue-pH after injection of glucose into the rats. On tumor surface pH-values were lowered more quickly and increased much faster as in tumor depth. The lowest registered pH was about 5,9. High s. c. dosages of Insulin caused a marked decrease of pH-values for nearly one hour too. In metabole effective small tumors tumor acidity could be regulated satisfactory with administered glucose and insulin between pH 7,0 and 6,0. Determination of lactate concentration in tumor tissue, surrounding the electrode, indicated a linear correlation between pH-value und lactate concentration in the range between pH 6,0 and 7,0. Regression coefficient comes to — 40,9 ± 2,2 ×10 -3 mMol/g wet weight and pH-unit. It is emphasized that according to the varying cell supply the compact tumor shows no homogeneity on pH-rates, acidification kinetics, and sensibility against acidotic cell lesion. Results are criticized with reference to other publications and their significance for the theory of tumor lesion by alkylating agents is discussed.

Radiation sterilization of female mice is genetically controlled. After irradiation differences in reproductive performance between F 1 hybrid females from reciprocal crosses are attributable to a maternal factor.

A resolution criterion of general validity is given, and the dependence of autoradiographic resolution on all essential parameters is calculated. The effects of geometric factors (thickness of the emulsion, thickness, size, and number of radioactive objects, and the interspace between the emulsion and the object) and of beta energy on resolution are described first, with the simplifying assumption of linear autoradiographic transfer. The totality of factors influencing resolution can be understood only by considering nonlinear autoradiographic transfer. Here the exposure, the properties of emulsion (sensitivity; maximum number of grains per unit volume of emulsion; diameter of grains; background grain density) and the conditions of observation (autoradiographic “signal-to-noise ratio”; area of measurement) are considered. Increasing the exposure leads to an optimal value of autoradiographic resolution at the beginning of nonlinear transfer; overexposure decreases resolution again. The maximum resolution equals twice the diameter of grains. This parameter is not contained in the basic model and must be considered separately. This theoretical treatment of the resolution problem explains the experimental results quoted in literature in at least a semi-quantitative manner. Possible improvements of the model are discussed.

The amounts of the carotenoids and chlorophylls from the liverwort Sphaerocarpos donnellii have been investigated. Differences in the quantity of pigments in plants grown on earth and in those grown on sterile agar were found. No differences were found for male and female plants grown under the same conditions. Modification of the thin-layer adsorption-system of HAGER and MEYER-BERTENRATH has permitted the separation of two cis-trans-isomers of β-carotene (neo-β-carotene U and neo-β-carotene B, i. e. 3-mono-cis-β-carotene and 3,6-di-cis-β-carotene) from the all-trans components. It is considered as highly probable that neither of these isomers is an artifact.

Since Saccharomyces cells have only a very small uptake of thymine or thymidine, the uptake of labelled samples of these compounds cannot be used to measure the rate of DNA synthesis. Instead two other methods were used for both X-irradiated and unirradiated cells of a series of homozygous isogenic Saccharomyces strains of different ploidy: 1. Yeast cells were incubated with adenine-8-C 14 , the labelled DNA was isolated and completely separated from RNA, and the specific radioactivity of the DNA was determined. The reduction of the specific radioactivity after irradiation as a proportion of the specific radioactivity of unirradiated control cells gave the X-ray induced inhibition in the rate of DNA synthesis. 2. The uptake of thymine-2-C 14 -5′-monophosphate, which is the only thymine compound incorporated into the DNA of Saccharomyces in any appreciable amount, was measured after various incubation times for irradiated and control cells. The results of the two methods are compared and the possibilities for their application are discussed. The dose effect curve for the rate of DNA synthesis after X-irradiation shows two phases: a steep slope at low doses with a shallow slope at high doses. For low doses the proportional decrease with X-irradiation in the rate of DNA synthesis is of the same order of magnitude as that of the colony forming ability, and is considerably greater than that of other metabolic processes such as protein and RNS synthesis, respiration or fermentation. The dependence of this proportional decrease on degree of ploidy is also similar to that dependence shown by colony forming ability and is again different from the dependence shown by RNA or protein synthesis. The reduction in DNA synthesis is greater the greater the time of incubation after irradiation.

An enzyme that oxidizes ᴅ-glutamate and ᴅ-aspartate has been partially purified from the antennal gland of the crayfish. The enzyme is inactivated by dialysis against buffered potassium bromide; the activity is restored by adding FAD, but not by FMN. The enzyme is strictly specific for ᴅ-glutamate and D-aspartate and inactive on all tested ᴅ-amino-monocarboxylic acids and glycine. In pure oxygen the activity is about 20 to 30% higher than in air. The enzyme does not use ferricyanide as acceptor. The pH optimum is reached at pH 9,0 to 9,5. At pH 8,6 the K m for D-glutamate is 15,2·10 -3 Μ, for D-aspartate 5,4·10 -3 Μ. The V max with D-glutamate is 50% higher than with D-aspartate. Accordingly the enzyme should be named D-glutamate: oxygen oxidoreductase (deaminating). Because of the different values of K m the activity on D-aspartate is higher than that on D-glutamate at substrate concentrations below 20 mM. The enzyme is inhibited by Veronal, p-chloromercuribenzoate, iodoacetamide and to a certain degree by ʟ-glutamate and L-aspartate, but not by benzoate, iodoacetate and the dicarboxylic acids α-oxoglutarate, succinate and oxalacetate. The enzyme is compared with the D-glutamate oxidase from Octopus hepatopancreas and the D-aspartate oxidase from rabbit kidney.

Egg cells of the pond snail Lymnaea stagnalis were isolated and reared in an inorganic medium, in which they reached the blastula stage with the same rate and yield as in the egg capsules. Synchrony of cell division was 70—90% depending on temperature and number of cell division. 3 H-leucine incorporation into hot TCA-insoluble material as a function of developmental stage was studied by autoradiography. The rate of leucine incorporation during the metaphase of the first three cell divisions was found to be ca. 30% of the incorporation rate during the corresponding interphases. The interphase rates increased from a very low level before nuclear fusion to a 25 fold value in the third interphase. 3 H-leucine incorporation could be inhibited by 78% by 5 × 10 -3 M puromycin and hence seems to represent protein synthesis.

In search for effective organophosphorus esters against the larva of the cotton leaf worm (Prodenia litura F), some α-hydroxy phosphonic acid dimethyl esters and related compounds have been synthesized. The effect of substitution on the antiesterase activity and toxicity towards Prodenia larvae has been investigated. The infra-red spectra of the prepared phosphorus esters are discussed.

A particulate enzyme preparation from dark grown mung bean shoots incorporates the glucosyl unit from UDP- ( 14 C) -glucose into lipophilic products. These were identified by thin layer chromatography as a mixture of β-sitosterylglucoside and stigmasteryl-glucoside (80%) as well as the acylated forms of these substances (20%). The reaction is almost linear with time up to 10 minutes, optimal at pH values between 6.3 and 6.6 and does not require divalent cations. The acceptor sterols were shown to be present in the particulate preparation; exogenous sterols do not seem to act as acceptors. The same particulate enzyme preparation can also synthesize cellulose from UDPG 15 and lipid intermediates for its biosynthesis have been predicted 20 . It appeared possible, therefore, that the sterylglucosides act as such intermediates. This, however, does not seem to be the case, since dilution of the UDP- ( 14 C) -Glucose with unlabelled UDPG as well as its hydrolysis with phosphodiesterase within the course of an experiment demonstrates that the glucosyl units of the sterylglucosides show no turnover.