Strukturelle Grundlagen des Parasitismus beiOrobanche III. Die Differenzierung des Xylemanschlusses beiO. crenata

Zusammenfassung Innerhalb des Wirtsxylems wurden Haustorialzellen des WurzelparasitenOrobanche lichtund elektronenoptisch untersucht. Diese Zellen durchlaufen eine ungewöhnliche Differenzierung bis sie wasserleitendes Xylemanschlu\element sind. Von Haustorialzellen mit stark verdickten FrontwÄnden entwickeln sie sich bei Eintritt in das Wirtsxylem zu einer typischen Transferzelle mit polar zum Holzelement des Wirts angelegtem Wandlabyrinth. Erst durch einen zweiten Differenzierungsschritt wird die Transferzelle zum Wasserleitelement, indem die typischen SekundÄrwandverdickungen des Xylems in der Zelle angelegt werden. Diese entstehen teilweise innerhalb des Wandlabyrinths und sind stets gegenüber denjenigen des Wirtselements angelegt. Zuletzt wird das Labyrinth — bis auf gelegentliche Reststrukturen — abgebaut, der Protoplast degeneriert, und es entsteht ein haustoriales Wasserleitelement, das über kommunizierende Tüpfel an das Wirtselement angeschlossen ist.

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Structural features of parasitism ofOrobanche III. The differentiation of xylem connexion ofO. crenata

Summary Haustorial cells of the root parasiteOrobanche within the xylem of the host tissue were investigated by light- and electronmicroscopy. Coming into contact with the tracheary elements of the host these cells show an unusual differentiation before turning into a water conducting xylem element. From haustorial cells with thickened front walls they develop into typical transfer cells, bearing wall ingrowth in those parts of the wall orientated towards the tracheary elements of the host. During further differentiation the transfer cell changes into a water conducting element by developing the typical secondary wall thickenings of xylem elements within the cell. Partly these wall thickenings are formed inside the labyrinth structures of the transfer cell, always situated opposite those of the tracheary element of the host. Simultaneously the labyrinth disintegrates—some small remnants of wall ingrowths may persist. The protoplast degenerates, and finally a haustorial water conducting element results. Host- und parasitic tracheary elements are connected by pits.

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Wir danken FrauChristl Glockmann für ihre stets verantwortungsvolle Mitarbeit. Den GÄrtnern des Botanischen Gartens in Kiel sei Dank für die oft schwierige Anzucht des Pflanzenmaterials. Die Untersuchungen wurden durch Mittel der Deutschen Forschungsgemeinschaft gefördert.     

Configurational assignments of C-nitromethyl-C-hydroxy branched-chain carbohydrate derivatives by use of a europium shift-reagent in 1 H-N.M.R. spectroscopy

Configurational assignments for the tertiary alcoholic centers of four branched-chain 3-C-nitromethylglycopyranosides, namely, methyl 2-benzamido-4,6-O-benzylidene-2-deoxy-3-C-nitromethyl-α-D-allopyranoside (1), benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-3-C-nitromethyl-α-D-glucopyranoside (4), benzyl 2-acetamido-4,6-O-benzylidene-2-deoxy-3-C-nitromethyl-α-D-allopyranoside (5), and methyl 4,6-O-benzylidene-3-C-nitromethyl-2-O-p-tolylsulfonyl-α-D-glucopyranoside (8), were made on the basis of the downfield chemical shifts of their identifiable protons per molar equivalent of added Eu(fod)₃, as compared with those of model compounds, of known configuration, having a close structural relationship. In some cases, the assignments were corroborated by the position of the acetyl resonances in the unshifted 60-MHz p.m.r. spectra of the corresponding O-acetyl derivatives.     

Zahl und Verteilung antennaler Sensillen bei der Honigbiene (Apis mellifera L.)

Zusammenfassung An Totalpräparaten der Antennengeißel von Arbeiterin und Drohne vonApis mellifera carnica wurden Zahl und Verteilung aller Sensillen und Setae ermittelt. Dabei ließen sich anhand des cuticularen Baues folgende Sensillentypen unterscheiden: S. placodeum, S. ampullaceum, S. coeloconicum, S. campaniforme und 5 Haarsensillen S. trichodeum A, B1, B2, C, D, sowie 4 Setatypen (A 1–3, B), die wahrscheinlich nicht innerviert sind. Die Benennungen der Sensillen wurde den bisher gebrauchten Bezeichnungen gegenübergestellt. Sensillenzahl und -Verteilung, Sinneszellzahl und Funktion der Sensillen wurden anhand von Literaturangaben zusammengestellt und diskutiert. Bemerkenswert ist der starke Dimorphismus zwischen Arbeiterin und Drohne in der relativen Sensillenzahl für die einzelnen Sensillentypen und in der Gesamtzahl der Sinneszellen. So sind bei der Arbeiterin die wahrscheinlich olfaktorischen S. trichodea A und die mechanorezeptorischen S. trichodea B 1 wesentlich stärker vertreten. Die Drohne hat keine S. basiconica und im übrigen wesentlich mehr S. placodea als die Arbeiterin. Insgesamt hat die Drohne eine ca. 2-fach größere Geißeloberfläche und etwa 5-mal soviele Sinneszellen wie die Arbeiterin. Die Arbeiterinnengeißel hat auf ihrer Rückseite eine porenplattenfreie Zone, die dicht mit nichtinnervierten Setae besetzt ist. Bei der Drohne findet man stattdessen eine porenplattenärmere Zone mit einer geringeren Zahl von Setae. Charakteristische Verteilungsmuster bestehen auch für alle anderen Sensillen und Setae.

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Number and distribution of the sensilla on the antennal flagellum of the honeybee (Apis mellifera L.)

Summary Number and distribution of sensilla and setae on the antennal flagellum of the honeybeeApis mellifera carnica were determined on whole antennal preparations. The following types of sensilla were distinguished according to their cuticular structure: Sensillum placodeum, S. ampullaceum, S. coeloconicum, S. basiconicum, S. campaniforme and 5 hair sensilla S.trichodeum A, B1, B2, C, D, as well as 4 types of probably non-innervated setae (A1–3, B). The names used here for the different types were compared with the previously used terms. Number and distribution of sensilla, the number of sensory cells and the function of the sensilla were discussed with respect to the data available from the literature. There is a notable dimorphism between the worker and drone with respect to the relative number of sensilla of each type and to the total number of sensory cells. The worker has far more of the presumably olfactory S. trichodea A and of the mechanoreceptive S. trichodea B1. The drone lacks the S. basiconica and has far more S. placodea than the worker. The flagellum surfarce of the drone is twice as large as that of the worker and has 5 times as many sensory cells. The worker flagellum has a poreplate-free zone on the side facing the head which is densely packed with non-innervated setae. In the corresponding zone the drone has a lower density of poreplates than elsewhere on its antennal flagellum. All other sensilla and setae are also characteristically distributed.

     

A family with a high risk of segregation for an autosomal unbalanced reciprocal translocation

Summary A family with autosomal reciprocal translocation t(4;13) (q25;q31) with a sibship comprising 2 children with unbalanced karyotypes, der(13) partial trisomy 4q, 1 child with the balanced translocation, and 2 abortions were studied. The segregation risk of unbalanced derivation in reciprocal translocations is discussed. The clinical picture of the 2 children with partial trisomy 4q is compared with similar cases.     

Prevalence of Edwards' syndrome. Clustering and seasonal variation?

Summary The incidence of Edwards' syndrome was found to be 1 per 4857 newborn children of 34000 consecutively newborn children in two Danish counties. Six of the 7 cases were born during the months of February through April.The incidence was high compared with the expected incidence of Edwards' syndrome of approximately 1 per 10000. This might be due to clustering in the area studied during the period 1967 to 1973.The finding of variations in incidence of children with Edwards' syndrome in different parts of the world, as well as the finding of seasonal variation in birth of such children, indicates that some of the etiological factors of nondisjunction of chromosome 18 are of an environmental nature.     

Chromosome examination of newborn children

Summary The purpose of making chromosome investigations of newborn children as well as ethical problems in such studies and in follow-up studies of children with chromosome abnormalities is discussed, and a survey of 6 chromosome studies from a total of 47145 newborn children is presented.It is stressed that more chromosome studies of newborn children are needed for several reasons, but one of the main reasons is to study the development of children with different chromosome abnormalities, especially those with sex-chromosome abnormalities and compare them with controls.