Cyclization of 13beta-ethyl-3-methoxy-17beta-ol-8,14-seco-1,3,5(10),9-gonatetraen-14-one and its 17 acetate derivative.

13beta-Ethyl-3-methoxy-17beta-ol-8,14-seco-1,3,5(10),8-gonatetraen-14-one (IIIa) was isolated and its participation in the well-known acidic cyclization process was established.     

Genlokalisation auf den larvalen speicheldrüsenchromosomen der stechmücke Culex pipiens L.

Zusammenfassung Die Austauschhäufigkeiten zwischen cytologisch bekannten Bruchkontaktpunkten in den larvalen Speicheldrüsenchromosomen und Mutationen erlauben bei der Stechmücke Culex pipiens L. erstmals die Zuordnung von Genorten zu chromosomalen Strukturen oder Abschnitten. Die vorliegenden Kreuzungsergebnisse stimmen mit der bereits bekannten Zuordnung der drei Koppelungsgruppen zu den cytologisch sichtbaren Chromosomen überein.Um Kreuzungsergebnisse innerhalb eines Chromosoms jedoch sicher miteinander in Bezug setzen zu können, mußte das Problem der unterschiedlichen Austauschhäufigkeiten geklärt werden. Gründe dafür sind weder Alter noch Geschlecht, noch kleine chromosomale Aberrationen der heterozygoten Individuen. Die Höhe des Austausches zwischen zwei Faktoren ist jeweils eine Stamm-spezifische Eigenschaft, die vermutlich faktoriell bedingt ist. Dies konnte durch den Vergleich einer allelen Mutation in zwei Stämmen erarbeitet werden. Es sind deshalb nur solche Austauschwerte vergleichbar, die in ein und demselben Stamm gewonnen wurden, oder bei verschiedenen Stämmen, wenn diese in einen festen Bezug gebracht werden können.Im kleinen Chromosom I ist die Zuordnung des Geschlechts-bestimmenden Allelenpaares M bzw. m zu der heteromorphen Bande 10 C 3 in Arm I L durch Austausch-Analyse mit Bruchkontaktpunkten geschlechtsgekoppelter Translokationen bestätigt. Der Locus der Augenfarbmutation w liegt in unmittelbarer Nähe davon. Der Genort der Augenfarbmutation r ist in Arm I R, in Abschnitt 3 B/C gelegen.Im mittellangen Chromosom II werden zwei Genorte eingegrenzt: die Larvenfarbmutation d ist am distalen Ende des Armes II L gelegen; die Augenfarbmutation ru im zentralen Teil des Armes II R, zwischen den Abschnitten 29 A-21 A. Im langen Chromosom III ist der Genort der Männchen-begrenzten Palpenmutation kps dem Arm III L zugeordnet worden.Eine Zuordnung zu einer distinkten Bande oder Struktur war nur für den Geschlechtsfaktor möglich. Mit den vorliegenden Werten wird für Culex pipiens erstmals eine grobe cytologische Genkarte erstellt.

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Gene mapping on the salivary gland chromosomes of the mosquito Culex pipiens L.

Summary Crossing experiments were done with several mutations and aberrant lines of the mosquito Culex pipiens L. Gene loci and chromosomal structure could be correlated by comparing crossover rates of mutations with breakage points of chromosomal aberrations in the larval salivary gland chromosomes. This confirms linkage groups and their correlated chromosomes.Before comparing crossover rates in one chromosome in different experiments, the problem of different crossover rates between two distinct factors should be solved. The reason for these different rates is not sex, age or small chromosomal aberrations in the heterozygous individuals. It could be interstrain behaviour, characteristic for each strain. This was shown by comparing crossover rates of an allelomorph mutation in two different laboratory strains. Therefore, only results within one pure strain or between two strains with known correlation can be compared. In the small chromosome I, the correlation of the sex-determining allelomorphs M and m with the heteromorphic band 10 C 3 in arm I L was confirmed. This was done by crossover analysis of breakpoints in sex-linked aberrations. The locus of the eye colour mutation w is situated near this band. The eye colour mutation r is located in the segment 3 B/C in arm I R.In chromosome II, two gene loci are narrowed down: the larval colour mutation d is situated on the distal end of arm II L, the eye colour mutation ru in the central part of arm II R. In chromosome III, the male-limited mutation kps is located in arm III L.Hitherto only the sex-factor could be correlated which a distinct structure, i.e. the heteromorphic band 10 C 3 in arm I L. The results of the described experiments made it possible for the first time to establish a cytological gene map of Culex pipiens.

     

A multivibrating switching network in homogeneous kinetics

On the basis of an abstract, simple bistable reaction system (‘homogeneous Eccles-Jordan trigger’) used as anRS flip-flop, an abstract homogeneousastable flip-flop is devised. It can be run also as amonostable flip-flop and as aT flip-flop. The qualitative behavior of the three systems can be understood, in the limiting case, with the aid of Poincaré's notion of bifurcation of steady states. The reaction system is proposed as a paradigm for a specific class of ‘decomposable’ chemical and dynamical systems (so-called DC-type dynamical automata). Two possible biological applications are mentioned.     

Conformation of the common purine (β) ribosides in solution: further evidence for a correlation between N-S state of the ribose moiety and syn-anti equilibrium

The solution conformations of adenosine, guanosine and inosine in liquid ND₃ have been determined by NMR. Comparison of the Karplus analysis of the proton HR spectra of the ribose moiety obtained in this solvent with the data from aqueous solutions of A and I proves that the conformations of the nucleosides are very similar in both liquids. From the analysis of the vicinal coupling constants of the ring protons it has been deduced that the S state C(2′)-endo is slightly preferred. The mole fraction in S approximates 0.6 for all three nucleosides. C-13 relaxation measurements have been applied in the determination of the correlation times for rotational diffusion. Only at temperatures below −40‡ C is the pseudorotation of the furanoside ring slowed down sufficiently for it not to contribute to the measured relaxation rates. From NOE studies and T¹ measurements on the individual protons it is derived that the N, C(3′)-endo, form of the ribose is correlated with an anti conformation of the base (Y≈210‡ to 220‡) and the S, C(2′)-endo, form of the ribose with a syn conformation of the base (Y≈30‡ to 50‡). The glycosyl torsion angles derived for the two conformations of A, G, and I are equal within the limits of accuracy.     

The isolation of Keratinophilic fungi from soils in Israel. A preliminary report

One hundred and fourteen soil samples collected from various areas of Israel were screened for the presence of keratinophilic fungi. Five species were isolated from the 59 positive samples, viz: C. keratinophilum--22 strains, C. evolceanui--18, C. serratus Eidam--10, M. gypseum--T. terrestre--4. Most of the geophilic organisms were recovered from garden soil, road-side and sandy-soil specimens. The importance of these findings is briefly discussed.     

Saprophytic occurrence of Trichophyton mentagrophytes and Microsporum gypseum in the coats of healthy laboratory animals

A group of 199 healthy laboratory animals, comprising 63 guinea pigs; 58 white mice. 47 rats and 31 rabbits, was sampled for the presence of pathogenic dermatophytes. T. mentagrophytes, var. granulare, was isolated in 10% (5-guinea pigs, 6 mice, 6 rats and 2 rabbits) and M. gypseum was found in 7 animals (3 guinea pigs, 3 mice and one rat). No ringworm lesions were observed in the respective animals. This is the first report on such findings in Israel.