ALBERT

Notes: Abstract Fowl plague virus, strain Dutch, was metabolically labeled withd-[2-3H]mannose, or withd-[6-3H]glucosamine, and the small subunit (HA2; 0.8 mg in total) of the viral hemagglutinin was isolated by preparative sodium dodecylsulfate-polyacrylamide gel electrophoresis. After proteolytic digestion, the radioactive oligosaccharides were sequentially liberated from the glycopeptides by treatment with different endo-β-N-acetylglucosaminidases and with peptide:N-glycosidase or, finally, by hydrazinolysis. In this manner, four groups of glycans could be obtained by consecutive gel filtrations and were subfractionated by HPLC. The structures of the individual oligosaccharides were analyzed by micromethylation, by acetolysis or by digestion with exoglycosidases. The major species amongst the high mannose glycans at Ans-406 of the viral glycopolypeptide were found to be Manα1-2Manα1-3(Manα1-2Manα1-6)Manα1-6(Manα1-2Manα1-2Manα1-3)Manβ1-4GlcNacβ1-4GlcNAc and Manα1-3(Manα1-2Manα1-6)Manα1-6(Manα1-2Manα1-2Manα1-3)Manβ1-4GlcNAcβ1-4GlcNAc, while the complex glycans at Asn-478 are predominantly GlcNAcβ1-2Manα1-3(GlcNAcβ1-2Manα1-6)Manβ1-4GlcNAcβ1-4GlcNAc (lacking, in part, one of the outerN-acetylglucosamine residues) and GlcNAcβ1-2Manα1-3(Galβ1-4GlcNAcβ1-2Manα1-6)Manβ1-4GlcNAcβ1-4GlcNAc.

Notes: Abstract This note continues the investigations of Knebusch on algebraic curves over real closed fields and was initiated by reading [3]. Especially we ask for the existence of real algebraic functions with given zeroes and poles, a question going back to Witt [4]. We study the real nature of coverings of real algebraic curves, and if the covering has degree two, we get algebraic proofs for results, which in the classical case have been obtained by topological methods in [2].

Notes: Zusammenfassung In der vorliegenden Arbeit wurde die Wirkung des Ultraschalls auf die Tryptophanase in Escherichia coli untersucht. Es konnte nachgewiesen werden, daß Ultraschall das Tryptophanase-Protein angreift, während das Coenzym Pyridoxalphosphat nicht verändert wird. Weiterhin wurde die Veränderung des Pyridoxalphosphats durch Ultraschall in vitro festgestellt.

Notes: Zusammenfassung Um zu klären, ob der Tod von lebenden Zellen nach Röntgenbestrahlung auf eine Zerstörung des in der Zelle vorhandenen Pyridoxalphosphats und damit auf eine Blockierung der pyridoxalabhängigen Enzyme zurückzuführen ist, wurde in bestrahlten und unbestrahlten Escherichia coli der Pyridoxalphosphat-Gehalt bestimmt. Die Untersuchung wurde an ruhenden und wachsenden Zellen durchgeführt. Durch Bestrahlung mit 10,40 und 80 kr wird der Pyridoxalphosphat-Gehalt der Zelle nicht verändert. Alle Kulturen begannen zur gleichen Zeit am Ende der log-Phase des Wachstums mit der Neubildung von Pyridoxalphosphat.

Notes: Abstract An analytical formulation is developed for the resultant electromagnetic field of an oscillating vertical magnetic dipole located over a thin conductive sheet of infinite extent. The sheet is characterized by a conductivity-thickness product or conductance σd that may be a function of the horizontal coordinates. The system of integral equations arising in the general formulation is simplified greatly when azimuthal symmetry prevails. Numerical results for a Gaussian variation of σd in the radial direction are presented for the case of a symmetrically located source. These results are for the fields at the level of the source dipole over the conductive sheet. It is shown that the quadrature response of the sheet is enhanced when there is rapid variation of the conductance. The null in the resultant wave tilt is also found to be shifted toward the direction of increasing conductance.

Notes: Summary 1. Currently available data on chromosome elimination in Cecidomyiidae are still inadequate to support any definite conclusions regarding its immediate causes. It seems that some evidence on the mechanism of elimination could be obtained from observation of the behavior of E chromosomes in complete absence of spindle. To bring about such absence of spindle, ultraviolet microbeams would appear promising, since they have already been used to destroy spindles in cells of other organisms. 2. For irradiation the embryos of Rhabdophaga batatas Walsh were chosen. It was established that in this species 2 S+E=40 and 2 S (for female)=8. Elimination of 30-odd chromosomes regularly occurs in the fifth cleavage. Embryos were irradiated with 8μ and 16μ heterochromatic ultraviolet microbeams not only in this fifth cleavage but also in the fourth, in which elimination was never observed. The irradiated regions were small parts of somatic cytoplasm or small parts of germ cells. 3. The effects of irradiation were multifold: complete degeneration of nuclei in the vicinity of irradiated cytoplasm; disappearance of spindle and formation of quasi-rosettes; multipolar mitosis. The polar substance present in germ cells was often severely damaged and fragmented. All these effects are evidently indirect. 4. In mitoses thus deprived of spindles, the separation of chromosomes into daughter chromatids was suppressed but some of their active movements persisted. All chromosomes were gathered into a quasirosette, which afterwards divided into two quasi-rosettes. The daughter quasi-rosettes moved apart and formed telophase nuclei. In both irradiated divisions (fourth and fifth) E chromosomes behaved in exactly the same manner as S chromosomes; they showed the same kind of peculiar movement and were incorporated into telophase nuclei. Suppression of elimination of E chromosomes in the fifth division can be regarded as one more indirect effect of irradiation to be added to the list above. 5. These results show that elimination of E chromosomes does not result from failures in chromosomal spindle fibers or from intrinsic morphological defects in the centromeres. The fact that elimination can be suppressed by indirect action of ultraviolet light strongly supports the assumption that elimination occurs because of chemical changes in adjacent cytoplasm that are injurious to the centromeres of E chromosomes. Most probably the indirect action of ultraviolet interferes with the production of some substance that is normally injurious to the centromeres in the fifth division. 6. Since in Cecidomyiidae the general features of the metabolism are known to be stable up to the mid-blastoderm stage, it would appear that the chemical changes involved in elimination cleavage are probably quite specific.

Notes: Summary The extensive genetical analysis of the T-locus in mice, carried out by Dunn and his co-workers, has revealed that the breeding pattern of t-alleles is very peculiar. The complexity of the T-locus indicates that some structural rearrangements are involved here. The purpose of the present work was to gain some informations on the structure of chromosomes in which t-alleles are present. 2. The course of spermatogenesis in the lines of mice of the following genotypes was investigated: +/+; T/+; T/t n — namely T/t 0, T/t12, T/tw1, T/tw6, T/tw18; tn/tx — namely t 0/t12, t0/tw18, t12/tw18, tw1/t12, tw1/t0, tw1/tw6, tw1/tw18, and in heterozygotes for translocations T138 and T190, both involving the fragment of linkage group IX in which some t-alleles are present and used as markers. 3. The alleles T and t w1 are not connected with structural rearrangements, as far as detectable by the methods used. The alleles t 0, tw6 and t w18 are interstitial deficiencies involving different chromosomal regions. The most complete data were obtained for t 0: in T/t 0 heterozygotes a loop corresponding to a big interstitial deficiency was present, in all t 0/tn compounds the aberrant structure of one of the bivalents indicated that an interstitial deficiency is here involved. By analysis of translocation T190 the deficiency loop is localized in the chromosome representing linkage group IX. The identification of t w6 as a small interstitial deficiency is based on the analysis of T/t w6 heterozygotes and its localization in linkage group IX on the presence of this deficiency in translocation T138. The description of tw18 as a small interstitial deficiency stems from the analysis of T/tw18 and t 0/tw18, the localization in linkage group IX is shown by its presence in t 0/tw18 in the same bivalent as t 0. The evidence obtained for t 12 indicates that it is either a big terminal deficiency or a small interstitial one inducing constant asynapsis in adjacent terminal segments of the bivalent. 4. The reasons why loops encountered in genotypes involving t 0, tw6 and t w18 are considered as deficiencies and not as duplications are based on available embryological and genetical data. The possible connections between the mode of action of the investigated t-alleles as embryonic lethals and the cytological results on their structure and localization are discussed. 5. Most of the lethal t-alleles suppress crossing-over in the region T-tf. Factors reducing the frequency of recombination in other organisms are discussed in comparison. It is concluded that the pattern of aberation in meiotic behavior of the bivalent carrying t-alleles is for almost each of the studied alleles rather specific and does not permit for suggesting any general mechanism which could account for the action of investigated lethal t-alleles as crossing-over suppressors. 6. A diagram of the presumable localisation of genetical factors in linkage group IX is presented. It is concluded that the so-called T-locus occupies the main part of the long arm of the chromosome corresponding to linkage group IX and that the investigated t-alleles are not unilocal neither with the gene T nor each with other, but scattered along the chromosome. 7. The possible modes of the origin of new t-alleles are discussed, and the hypothesis is advanced that this event might be connected with mistakes of replication of the strand on which a new t-allele arises.