PHOTOREACTIVATING ENZYME FROM NEUROSPORA CRASSA*

Abstract— Extracts of Neurospora crassa contain photoreactivating enzyme by the criteria of ability to split thymine-containing dimers and to increase the transforming ability of u.v.-irradiated Hemophilus influenzae DNA. The latter activity is heat-labile and is destroyed by trypsin. The action spectrum of such in vitro photoreactivation is a simple one (with a single maximum at 405 nm in the range 313 to 436 nm), differing from the more complicated in vitro spectra for yeast and Escherichia coli. However, the in vitro Neurospora spectrum coincides closely with the in vivo spectrum for this organism, suggesting that there is little or no “indirect” photoreactivation in Neurospora. It is concluded that the Neurospora photoreactivating enzyme is probably of a different type than those of yeast and Escherichia coli.     

Studies on the solvent extraction of yttrium thenoyltrifluoroacetonate

Studies of extractions of yttrium from aqueous solution into chloroform, benzene, methyl isobutyl ketone, and mixtures of these solvents, containing thenoyltrifluoroacetone are described. The effects of reagent concentration, added n-butylamine, and added fluoride were investigated. Values of pH$\text{1}\text{2}$ and P_e were determined, and identifications of the involved species are suggested.     

Microchemical investigation of medicinal plants. XV

Summary A method is described for the determination of alkaloids in morning glory leaves by means of spectrophotofluorimetry. The total alkaloidal contents found in different batches of leaves ranged from 0.027 to 0.04%.

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Zusammenfassung Ein Verfahren zur Bestimmung der Gesamtalkaloide in den Blättern vonIpomoea violacea wurde angegeben. Spektralfluoreszenzmessungen ergaben für verschiedene Chargen solcher Blätter Gehalte von 0,027 bis 0,04%.

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For part XIV see Mikrochim. Acta [Wien]1976 I, 227.     

Comparison of the structural and chemical composition of giant T-even phage heads.

A study has been made of the structure of the capsids of T4D giant phage produced from mutants in gene 23 and temperature-sensitive mutants in gene 24, and T4D and T2L giant phage formed by the addition of L-canavanine followed by an Larginine chase in the growth medium. All the giant phage capsids have been shown to be built according to the same geometrical architecture. This consists of a near-hexagonal surface net, lattice constant 129.5 A, folded into a left-handed T = 13 prolate icosahedron elongated along one of its fivefold symmetry axes. Their only apparent difference from wild-type T-even phage capsids is their abnormally elongated tubular part. A comparison of the capsomere morphologies and protein compositions of the giant phage capsids showed that all T4D giants are identical but differ from T2L: The T4D capsomere has a complex (6 + 6 + 1)-type morphology, whereas the T2L has a simple 6-type. T2L phage, however, lack two capsid proteins, "soc" and "hoc", present in T4D. The difference in capsomere morphology can therefore be related to the difference in the protein compositions of these two phage. Possible differences between the initiation and means of length regulation of giant phage heads and the aberrant polyheads are discussed.     

Decay of atomic systems in a strong electric field. Negative ion and hydrogen atom

An exact transcendental equation was obtained determining the energy levels of a particle bound by a short-range force and placed in uniform electric field. At high intensities there is a considerable difference between the values of decay probabilities calculated by previous theory and by this one. The results obtained were used to determine the electron binding energy and the polarizability of negative ions by employing experimental data on ion decay during a flight through the field region. Concrete calculations were carried out for the C^? ion.The calculation of the resonance energy E_r and the decay probability 2Γ of the quasistationary state n = S, n₁ = 3, n₂ = 0, and m = 1 of the hydrogen atom in a uniform electric field was performed by means of the direct integration of the time-independent Schrödinger equation for field intensities ranging from 0.8 × 10⁶V/cm to 1.7 × 10⁶V/cm. The calculated values fo E_r perfectly agree with those of the Rayleigh—Schrödinger perturbation energies calculated up to the fourth power in the field strength and differ substantially from the resonance energies obtained earlier by Hirschfelder and Curtiss. Our results concerning the rate of spontaneous ionization also differ substantially from the results of Hirschfelder and Curtiss and agree rather well with the results of Bailey, Hiskes and Riviere who used the general WKB method of Rice and Good.     

Die Bildungsenthalpien einiger Siliciumtetrahalogenid—Pyridin-Addukte

The enthalpies of formation of the addition compounds F₄Si(py)₂, Cl₄Si(py)₂, Br₄Si(py)₂ and I₄Si(py)₄ have been measured calorimetrically by two different ways (see table 1). It was not possible to confirm enthalpy data published in^{7, 8}. The sequence SiF₄4～SiBr₄>SiI₄(?) is proposed for the acceptor power of the silicon tetrahalides towards pyridine.     

Fischer indolization and its related compounds—VII : Development of abnormal fischer indolization of ortho-methoxyphenylhydrazone to provide a synthetic method for useful indole derivatives possessing an active methine group at C6 and novel 3,6′-biindole derivatives

Fischer indolization of ethyl pyruvate 2-methoxyphenylhydrazone (1) with p-toluene-sulfonic acid in benzene in the presence of an enolizable dicarbonyl or an indolic compound gave either an indole product having an active methine group at C₆ or a novel type of 3,6′-biindole compound. Structures of the products were established by NMR spectra and chemical evidence.     

The synthesis of cypridina etioluciferamine and the proof of structure of cypridina luciferin

An unambiguous synthesis of Cypridina etioluciferamine was accomplished in order to prove the structure of this important bioluminescent natural product. Several 2-aminopyrazine 1-oxides were synthesized in order to establish a spectroscopic method for determining the placement of substituents on the pyrazine nucleus of Cypridina etioluciferamine. Titanium tetrachloride was used to improve the yields of these compounds; for example, the yield of 2-amino-3-methyl-5-phenylpyrazine 1-oxide (19) from reaction of phenylglyoxal 1-oxime and α-aminopropionitrile was raised from 3% to 51% by the use of titanium tetrachloride. The pyrazine ring proton is found at τ 1·37 (DMSO-d₆). The isomeric 2-amino-3-methyl-6-phenylpyrazine 1-oxide (22) was similarly prepared and its pyrazine ring proton is found at τ 2·18. This large difference (0·81 ppm) in chemical shift was used to determine whether a 2-aminopyrazine 1-oxide was 5- or 6- substituted. Prepared in an analogous fashion were 2-amino-5-(indol-3-yl)-3-methylpyrazine 1-oxide (23) and 2-amino-5-(indol-3-yl)-3-(3-phthalimidopropyl)pyrazine 1-oxide (16). The structures of these compounds were verified by NMR spectroscopy. By treatment with Raney nickel and hydrogen gas, then 100% hydrazine hydrate, 16 was converted to 2-amino-3-(3-aminopropyl)-5-indol-3-ylpyrazine (5), isolated as the dihydrochloride. This compound, with the indole moiety definitely placed at C-5, is identical with Cypridina etioluciferamine dihydrochloride (IR, UV, TLC). These results show that the structures of Cypridina etioluciferamine and luciferin are correct as published.     

Neutral lipids in the brain of premature and newborn infants

Using already published methods, the authors have determined in eight brains of premature and seven brains of new-born children: dry matter, total lipids, pure lipids, and acid and neutral lipids. The latter have been separated into cerebrosides, sphingomyelines, colamine cephalines, and lecithins.