Primary neural induction as studied by scanning electron microscopy

Summary Normal primary neural induction has been studied by scanning electron microscopy and the results compared with those obtained by TEM. Mesoderm cells are usually in contact with several other cells, both mesodermal and endodermal in origin. By SEM the ectoderm layer has been shown to be in contact with the underlying mesoderm cells. Tufts of fibrous basement membrane are also present between the two cell types. TEM specimens also show an intermediate basement membrane.Acknowledgments. M. A. E. would like to thank ProfessorF. Beck in whose department this work was conducted. An especial acknowledgment to Mrs.Wendy Nugent for her skilled technical assistance in the preparation of the SEM and TEM specimens. Mr.Duncan Boreham, Electron Microscope Unit, University of Leicester kindly offered assistance and advice.S. V. C. would like to thank ProfessorR. P. Dale in whose department the SEM photographs were prepared.     

A transmission and scanning electron microsope study of primary neural induction.

Normal primary neural induction has been further studied by TEM and SEM. A single mesoderm cell is usually in contact with several ectoderm cells. The mesoderm cells are also contacting other mesoderm cells. It is suggested that ectoderm cells are induced in groups and that induction is synchronized by these contacts. At the points of contact between mesoderm and ectoderm cells cytoplasmic changes are present in the induced tissue.     

Primary neural induction as studied by scanning electron microscopy.

Normal primary neural induction has been studied by scanning electron microscopy and the results compared with those obtained by TEM. Mesoderm cells are usually in contact with several other cells, both mesodermal and endodermal in origin. By SEM the ectoderm layer has been shown to be in contact with the underlying mesoderm cells. Tufts of fibrous basement membrane are also present between the two cell types. TEM specimens also show an intermediate basement membrane.     

How gill surface ofSaccobranchus fossilis facilitates active gas exchange?

Summary The surface morphology of fish gill has been studied by scanning electron microscopy. The surface of gill epithelium shows a pseudoconcentric arrangement of arborizing ridges and channels. Further, at places on gill filaments the surface shows several infoldings labelled as micropits. The role of these morphological adaptations has been correlated with the gas exchange physiology.The author is deeply indebted to Prof.M. Nishiura, Dr.S. Izumi and Mr.O. Fuse for their kind suggestions and help, and to Prof.H. B. Tewari for encouragement. VKR would like to thank Japan Leprosy Mission for excellent facilities.     

Temperature and mutant expression

Zusammenfassung Durch Versuche mit der Mutante ci^D von Drosophila wurde nachgewiesen, dass die temperaturabhängigen Veränderungen in der Ausprägungsweise ausschliesslich durch den Restgenotypus bestimmt werden. Diese Feststellung hat Bedeutung für Genphysiologie, Evolution und quantitative Vererbung.

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I should like to thank Prof.H. Gloor for his critical interest and Prof.H. R. van der Vaart of the Instituut voor Theoretische Biologie, Leiden, for advice in statistical matters.     

Mechanism of teratogenic action of hypoglycin-A

Zusammenfassung Simultane Verabreichung von Riboflavin und Hypoglycin-A reduzierte das Auftreten von foetalen Missbildungen in Ratten. Dagegen haben Carnitin und Leucin keinen Einfluss auf die teratogene Wirkung des Hypoglycins.

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I thank Prof.D. A. N. Hoyte and Prof.B. N. Kropp for helpful discussions, and Prof.C. von Holt for a generous supply of hypoglycin-A.     

Regulation of tryptophan metabolism in the parasitic wasp,Habrobracon juglandis

Zusammenfassung Die Metabolite und 3 Enzyme des Tryptophanstoffwechsels vonHabrobracon weisen während der parasitären Phase sowie während der Puppenruhe und im Imaginalstadium signifikante Konzentrations-bzw. Aktivitätsveränderungen auf. Diese sind das Ergebnis mindestens zweier Regulationsmechanismen.

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I thank Prof.V. Schwartz and Prof.A. Egelhaaf for helpful advice.     

Quantitative determination of amino acids in the 10−14 molar range by scanning microscope photometry

Zusammenfassung Die beschriebene Methode stellt eine Kombination der Mikrochromatographie und der Scanning-Mikroskop-Photometrie dar und ermöglicht eine quantitative Bestimmung von C¹⁴-markierten Dansyl-Aminosäuren in biologischen Material im Bereich von 10^–14 M.

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Supported by the Deutsche Forschungsgemeinschaft.

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We would like to thank Prof. Dr.K. H. Gertz and Priv.-Doz. Dr.H. Stolte for helpful discussion.     

Cell proliferation and cell function of the mesenchymal cells of lathyritic rats,as revealed by the nuclear size

Zusammenfassung Es wurden biometrisch mesenchymale Zellen des Paradontiums als Parameter der Zellproliferation und-funktion untersucht. Durch Verfütterung von Lathyrogen odoratus wurde ein Lathyrismus erzeugt mit Veränderungen der Membranfunktion und des Ionenaustausches. Die Kerne der Versuchstiere waren wesentlich grösser als bei den Kontrollen (Dosisabhängigkeit).

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Acknowledgments. I wish to thank Prof.A. J. Van Amerongen and Prof.C. Jerusalem for consistent help and excellent suggestions.     

Induction of chromosome abnormalities by reversal of colcemid inhibition in leucocyte cultures

Zusammenfassung Menschliche Leukozyten, die vorher 2 resp. 4 h der Wirkung von Colcemid ausgesetzt worden waren, ergaben in Zellkulturen 45 resp. über 50% Zellen mit 45 oder weniger Chromosomen im Vergleich zu 10% in Kontrollkulturen ohne Colcemid.

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This work is supported financially by Schering Chemicals Ltd., Burgess Hill, Sussex. We would like to thank Dr.A. G. Pitchford for advice and MissE. Gristwood for technical assistance.     

Occurence of diploid drones in a neotropical bumblebee

Zusammenfassung Mutter-Sohn-Kreuzung bei der südamerikanischen HummelBombus atratus Franklin ergab diploide Männchen mit normalen Arbeiterinnen im Verhältnis von 3 zu 1. Tur Interpretation des genetischen Mechanismus wurden 2 geschlechtsgebundene Loci angenommen, als bisher angenommen wurde, was für einen älteren Mechanismus bei Apiden spricht.

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This study was made possible by a grant of the State of São Paulo Research Foundation (FAPESP).

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Acknowledgment. I would like to thank Dr.W. E. Kerr, Dr.R. Zucchi and Dr.S. F. Sakagami for their excellent assistance during the course of this investigation as well during the translation. I also would like to thank Dr.R. H. Crozier for his suggestions and comments and I extend my thankfulness to professorsJ. Chaud Netto andZ. Silveira.     

Induction of delayed hypersensitivity by carrageenan

Zusammenfassung Nachweis einer Sensibilisierung des Meerschweinchens durch intradermale Injektion von Carrageenan, was zu «passiv übertragbaren» Spätreaktionen führte.

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The authors wish to thank to MissI. Kawana, MissA. Saito and MissA. Chida for their technical assistance and Prof.Y. Horiuchi for his advice.     

The composition of Taft E s o constants: An application of biased alternatives to least squares

Summary A systematic analysis of the composition of E _s ^o like rate constants clearly revealed that Taft E _s ^o -values depend upon the size of the substituents. Further evidence in favor of this view is adduced even in a case where OLS led to the conclusion that E _s ^o should be completely independent of the size of the substituents, since biased estimators (PCRA, LRRA) showed that this statement is not correct. Furthermore, it seems that the magnitude of the steric effect represented by E _s ^o is a function of the thickness of the substituent along 2 directions perpendicular on its main axis and is not influenced by its length.Acknowledgment. We would like to thank Prof. J.T. Webster, Department of Statistics, Southern Methodist University, Dallas, for sending us s computer program of latent root regression analysis. We also thank the referees whose insightful comments were most helpful in improving the presentation.     

The arrangement of sarcoplasmic reticulum in smooth muscle

Riassunto Nella muscolatura liscia di vari visceri e vasi viene osservato un notevole sviluppo del reticolo endoplasmatico. Esso è costituito da cisterne direttamente sottostanti la membrana plasmatica e le caveolae intracellulares.

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I thank Prof.J. Z. Young and Prof.E. G. Gray for discussion, and the Wellcome Trust for a fellowship.     

The presence of colchicine alkaloids inKreysigia multiflora reichb

Zusammenfassung Die Isolierung der Alkaloide Colchicin und N-Formyl-N-desacetylcolchicin ausKreysigia multiflora wird beschrieben.

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The author wishes to thank Prof.A. R. Battersby, Liverpool, England, for the plant material.     

The role of phenolic acids in the browning, spontaneous heating and deterioration of stored soybeans

Zusammenfassung Beim spontanen Bräunen und Erhitzen von gelagerten Soyabohnen bilden sich Phenolsäuren, welche eine aktive Rolle in Entstehen des Lagerschadens spielen und auch als dessen Frühindikator dienen können.

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The authors wish to express their appreciation to Prof.A. Bondi for helpful suggestions. They also wish to thank MissesFrieda Rabinowitz andMiri Kekun for skilful technical assistance.     

Atypical muscle cells in the wall of the renal calix and pelvis with a note on their possible significance

Zusammenfassung Es werden atypische Muskelzellen beschrieben, welche sich um die Nierenbeckenkelche und die Nierenbecken befinden. Dabei handelt es sich um glatte Muskelfasern, die wahrscheinlich im Nierenbecken-Uretergebiet endigen und deren Einfluss auf die Aktivität des Ureters diskutiert wird.

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I wish to thank Prof. G. A. G.Mitchell for his interest and Mr. A. N.Waas for valuable technical assistance.     

Formation of buds in leaves ofAtropa belladonna L. in the in vitro culture

Zusammenfassung Blattmaterial vonAtropa belladonna vermag unter geeigneten Bedingungen ganze Pflanzen zu regenerieren. Ausgangspunkt der Knospenbildung ist das Pallisadenparenchym.

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Acknowledgements: I wish to thank the head of the Department of General Botany Prof.A. Szweykowska for the facilities and critical reading of this report.     

Modification of visual,auditory, and somatosensory evoked responses in cortical primary receiving areas by nigral stimulation

Zusammenfassung Nachweis einer «unspezifischen» fördernden Wirkung von Stimulation der Substantia nigra auf «evoked potential» in den primären sensorischen Zentren des Grosshirns.

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Supported by a grant from the Japanese Ministry of Education.

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Acknowledgment. We thank Prof.N. Kato, Prof.Y. Iwase, Dr.S. Takahashi, and Dr.N. Tani for their help.     

The exotoxin ofBacillus thuringiensis: A new C-mitotic agent

Summary Thuringiensin A, an exotoxin fromBacillus thuringiensis, a constituent of the microbial insecticide thuricide has been found to inhibit mitotic spindle, condense and scatter chromosomes. It may therefore be a promizing tool in future cell biological studies.We thank Prof.H. Sharatchandra for facilities. CBSR is a National Associate of the University Grants Commission, New Delhi.