Extreme chromosomal polymorphism in a coccinellid beetle

Zusammenfassung Von drei vonChilocorus stigma wies ein Tier eine (A), eines zwei (A, B) und das dritte drei (A, B, C) zentrische Fusionen auf; 2n war 26, 25 und 24. Beim mit 2n = 24 sind mindestens zwei Bivalente heterozygot. Abgesehen vom Unterschied der Geschlechtschromosomen (XX: XO) sind daher 243 verschiedene chromosomale Typen möglich. 2n wird von 21 () zu 28 () variieren. Weitere Fusionen bei den Chromosomen der heterozygoten Paare würden zu 2n = 19 führen, während sich nach andern Fusions-Kombinationen Ringkomplexe bilden müssten.     

A study of DNA synthesis in sea urchin hybrids by the incorporation of H3-thymidine

Zusammenfassung (1) Es wird die DNS-Synthese der letalen SeeigelbastardeParacentrotus ×Arbacia (PA) undParacentrotus ×Sphaerechinus (PS) mit H³-Thymidin untersucht. (2) Dem verschiedenen, der Letalität vorausgehenden Entwicklungstpus (PA ohne, PS mit Chromosomenelimination) entspricht ein verschiedener Verlauf der Hemmung der DNS-Synthese. Parallel dazu wird die Vermehrung in der Anzahl der Kerne verglichen.     

Funktion der Spermien in inkompatiblen Kreuzungen der StechmückeCulex pipiens L.

Summary After irradiating males of the incompatible crossC. pipiens Hamburg ×C. pipiens Paris with X-ray doses between 1 kR and 40 kR, it could be shown that in this cross the sperm has only the function of activating the egg. All the hybrid embryos develop from the haploid female pronucleus.Herrn Professor Dr.H. Laven danke ich für Unterstützung und wertvolle Diskussionen.     

Durch polarisiertes Licht hervorgerufene Optomotorik beiUca tangeri

Summary Optomotor reactions were tested in 10Uca tangeri (5, 5) of intermediate body size, by slowly rotating the plane of polarized light entering the apical ommatidia of the animal; 8 out of 10 animals showed definite optomotor reactions immediately at, or a short time after, the beginning of the rotation. There were no such reactions when the apical ommatidia were stimulated by a rotating black and white disc.     

A γ-globin-chain mutation in the hemoglobin 1 (Hb1) of the domestic chicken

Riassunto Attraverso vari incroci è stato possibile isolare un ceppo di polli domestici portatori di una mutazione a carjco della emoglobina 1 (Hb1). Mediante tecniche cromatografiche ed elettroforetiche si è potuto accertare che la mutazione riguarda la catena globinica della Hb1.     

Sex-specific pheromones in a termite

Résumé La glande sternale des jeunes imagos et secrète une phéromone attractive pour les individus du sexe opposé. Les peuvent prendre une position d'appel indentique à celle connue des . Les imagos, mais pas les nymphes, reconnaissent les phéromones sexuelles de la phéromone de piste sécrétée par la glande sternale des nymphes.     

Unkreaktion mit Befreiungsruf beim Weibchen der KreuzkröteBufo calamita

Summary The release call which is uttered by Bufo in connection with specific movements can also be evoked in the ofBufo calamita. This is indicative of homology of the male release call and the usually silent release movements of the .

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Mit Unterstützung des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung.     

Chromosomal polymorphism in the guinea-pig,Cavia porcellus

Zusammenfassung Bei der karyologischen Analyse von Metaphasen in Knochenmark, Cornea und andern Geweben des indischen Meerschweinchens,Cavia porcellus (7 , 3 ) wurde festgestellt, dass drei männliche Individuen in einem autosomalen Chromosom heterozygot waren. Das Chromosom wird als Marker III bezeichnet.     

Artbastarde in der GattungTilapia (Cichlidae,Teleostei) und ihr Verhalten

Summary The young ofTilapia mossambica (mouth-brooder) show a characteristic contact-behaviour, which is related to the behaviour of the mother fish, who takes them back into the mouth cavity in cases of disturbance. This contacting is lacking in the young ofTilapia tholloni (substrate spawner). Contacting, as studied in our experiments with models, is genetically determined and is dominant over thetholloni pattern in the crossT. mossambica ×T. tholloni .     

Effect of an azo dye on germination and outgrowth ofBacillus megaterium spores

Riassunto È dimostrato che il violetto di genziana non interferisce nella germinazione indotta con inosina di spore diBacillus megaterium, mentre ne inibisce la crescita alle concentrazioni di 1 o più g per ml di cultura. Quando impiegato a concentrazioni comprese fra 0,4 e 0,1 g/ml è possibile mettere in evidenza non solo forme vegetative ma anche protoplasti. Quest'ultima osservazione viene messa in relazione alla attività inibente la sintesi dei precursori del cell wall da parte del violetto di genziana.     

Cytogénétique desLeggada: (1) La formule chromosomique deMus (Leggada)bufo Th., (2) Nouvelles données sur la délétion portant sur le bras court d'unX chezMus (Leggada)triton Th

Summary The author treats 2 topics connected with his studies on the cytogenetics of the African pigmy-mice. (1)Mus (Leggada) bufo Th. shows the primitive complement already detected in other species or subspecies (minutoides ssp ₁,indutus, tenellus, setulosus): 2N=36,N.F.=36, sex chromosomesPR. (2) The deletion of the short arm of oneX-chromosome (X _dc ) was previously observed as heterozygous mutation by 4 in a sample of 7 and 5 . A more important sample (18 , 21 ) gives the following results: 11 X-X, 10 X-X _dc , 18 X-Y. The occurrence of X _dc -X _dc and of X _dc -Y is also very improbable. It is not easy to understand how the chromosomeX _dc may persist in the population if the complementsX _dc -X _dc andX _dc -Y are lethal, which seems to result from these observations.     

W chromosome in the Indian water snake (checkered keel back)Natrix piscator (colubridae)

Zusammenfassung Die diploide Chromosomenzahl beider Geschlechter beträgt 40: 10 Macrochromosomen und 30 Microchromosomen. Die GeschlechtschromosomenZZ () undZW () sind cytologisch erkennbar.     

The synthesis of ecdysone

Zusammenfassung Ecdyson, ein Häutungshormon der Insekten, wurde ausgehend von Ergosterin in 14 Stufen synthetisiert. Wesentliche Zwischenprodukte waren (20S)-2, 3-Diacetoxy-20-formyl-5-pregn-7-en-6-on und (22R)-2, 3-Diacetoxy-14, 22-dihydroxy-25-(tetrahydropyran-2-yloxy)-5-cholest-7-en-6-on.     

Untersuchungen über Bildung und Weitergabe von Drüsensekreten beiFormica (Hymenopt. Formicidae) mit Hilfe der Radioisotopenmethode

Summary Marking experiments with the tracer isotope P³² had the result that food-secretion of ants is mainly formed in the pharyngeal gland, then reaches the crop through the exit channel of the gland, where it is stored and released again, on regurgitation-stimuli, to and and larvae as well as workers.     

Nouvelles contributions à la cytogénétique desMus Africains du sous-genreLeggada

Summary The author describes four new chromosome complements in the African pigmy-mice (Mus, subgenusLeggada). (1) One form from Angola has 18 metacentric chromosomes (N.F.=36) in both sexes. In contrast toMus minutoïdes minutoïdes Smith from South Africa, whose females have the same chromosome complement while the males show an acrocentric and shortY-chromosome, we have here a metacentricY. It is a confirmation of the hypothesis that theY ofM. m. minutoïdes was primarily of translocated type (TR) but lost a big intercalary segment of the autosomic arm. (2) In another species from Angola 2N=34;N.F.=36. It is the first case in the subgenus where a Robertsonian fusion occurs between autosomes before the transformation of the sex-chromosomesPR into sex-chromosomesTR. This observation is a confirmation that the complement 2N=36;N.F.=36 is the primitive one, being found in the three groups of species,minutoïdes, bufo-triton andtenellus. (3) Indeed, from Ghana, I have got specimens ofM. tenellus. We have here to deal with the primitive chromosome complement: 2N=36;N.F.=36. (4) In a sample of 12Leggada from the region of Bukawu (Congo), there are 5 and 7 . 4 show a total deletion of the short arm of theX-chromosome. In spite of the absence of X _dc -Y and of X _dc -X _dc in the sample, it is probable that neither of these complements is lethal.     

Hormone dependency of sex-linked feathering of female hybrid chick embryos (cross new Hampshire ♂ × light sussex ♀)

Zusammenfassung Die rote Daunenpigmentierung der weiblichen F₁ Hybriden der Hühnerrassen Cross New Hampshire × Light Sussex entsteht nicht ohne Ovarialhormone, wie Kastrationsexperimente beweisen. Sie kommt aber zustande, wenn man ganz oder subtotal kastrierten Embryonen Östrogene oder Androgene zuführt oder embryonale Keimdrüsen implantiert.     

On the structure of the natural dipeptide N-acetyl-aspartyl-glutamic acid (NAAGA)

Riassunto Si descrive la sintesi dei due dipeptidi isomeri acido N-acetil--l-aspartil-l-glutammico (I) e acido N-acetil--l-aspartil-l-glutammico (II). Il loro confronto con il NAAGA, dipeptide precedentemente isolato dal tessuto nervoso di alcuni mammiferi, ha dimostrato l'identità del nuovo metabolita con il-dipeptide (II).     

Artificial triploid hybrids by interspecific mating ofOdontophrynus (Amphibia,anura)

Résumé Des hybrides triploïdes ont été obtenus par croisement deOdontophrynus cultripes, amphibien diploïde, avecO. americanus, tétraploide. Les hybrides interspécifiques présentent normalement 33 chromosomes dans les cellules somatiques. Les hybridesO. cultripes ×O. americanus sont plus viables que lesO. americanus ×O. cultripes .

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This work was supported by Public Health Service Research Grant No. GM-14577-02 from the National Institute of General Medical Sciences and by Fundo de Pesquisas do Instituto Butantan.     

Nouvelles données sur la cytogénétique et la spéciation des Leggada (Mammalia-Rodentia-Muridae)

Summary To the 237 pigmy-mice studies in his previous papers, the author brings new data concerning the cytogenetics of 25 Leggada. One first set of 12 mice from Nigeria belongs to the same polymorphic series containing themusculoides from the Ivory Coast and the Central African Republic.A small sample from Ippy (Central African Republic), although the individuals are morphologically all alike and referable tomusculoides, shows an amazing diversity: /259.2N=28, N.F.=36, sex chromosomes of the translocated type (TR). We meet here a new robertsonian combination in the polymorphic series, 34/33/32/31 ... 28/... 22/... 19/18./260.2N=32, N.F.=36, sex chromosomesTR. Both big biarmed autosomes are metacentric — submetacentric with a centromeric index of about 0.25 by the typicalmusculoides having the same diploid number./261.2N=19, N.F.=36, sex chromosomesX/Y ₁ Y ₂. The first occurrence of such sex chromosomes by the Leggada. By themusculoides from Rhodesia we were dealing with the typeX ₁ X ₂ /Y. /262.2N=18, N.F.=36, sex chromosomesX/X. Very likely the female of /261.In the complexminutoides-musculoides, we meet many different caryotypes and it is obvious that the chromosomal mutations play here the part of a primary factor of isolation, previous to the gene mutations which later will allow the taxonomic determination of the species actually in statu nascendi.     

The Kepler Problem from Newton to Johann Bernoulli

Summary Newton solved what was called afterwards for a short time the directKepler problem (le problème direct): given a curve (e.g. an ellipse) and the center of attraction (e.g. the focus), what is the law of this attraction ifKepler's second law holds?The problème inverse (today: the problème direct) was attacked system-atically only later, first byJacob Hermann, then solved completely byJohann Bernoulli in 1710 and followingBernoulli byPierre Varignon. How didBernoulli solve the problem? What method did he use for this purpose and which of his accomplishments do we still follow today?In the second part various questions connected to the first part are dealt with from the point of view, Conflict and Cooperation, suggested byJ. van Maanen to the participants of the Groningen conference.