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  • Springer  (48,717)
  • 1980-1984  (44,784)
  • 1925-1929  (3,933)
  • 1983  (44,784)
  • 1925  (3,933)
  • 1
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Nous avons réalisé une étude expérimentale du développement de grandes larves ayant hiverné, chez 4 espèces deMyrmica. Utilisant une gamme de températures de 15°C à 25°C, nous avons montré que: 1. Il n'y a pas de différences entre les espèces quant à l'effet de la température sur les durées de développement. Toutes suivent le modèle: log. durée de développement =a-b T°C, avec la même valeur pour b. Ceci donne un Q10 effectif d'environ 3,1. Ce résultat est en accord avec les estimations de respirométrie chez les ouvrières de fourmis. 2. Les valeurs de a diffèrent de façon significative entre la plupart des espèces, ce qui confirme la différence intrinsèque que nous avions démontrée à la température constante de 22,5°C dans un précédent travail. Les durées de développement larvaire peuvent être ainsi classées, de la plus rapide à la plus lente:Myrmica ruginodis Nyl.,Myrmica rubra L.,Myrmica scabrinodis Nyl. etMyrmica sabuleti Meinert. A toutes les températures, il faut 1,5 fois plus de temps àM. sabuleti qu'àM. ruginodis pour qu'une grande larve ayant hiverné se transforme en nymphe blanche. 3. Nous n'avons pas observé de grandes différences dans la survie des larves et la production des reines, aux températures utilisées dans nos expériences. La plupart des espèces survivent le mieux à 22°C environ. 4. Les résultats sont brièvement discutés en fonction de la distribution écologique des 4 espèces dans le Sud de l'Angleterre. 5. Nous discutons les effets possibles d'un régime de température variable. Nous suggérons que l'amplitude des variations peut ne pas avoir un effet important alors que la périodicité des variations pourrait avoir un effet plus important.
    Notes: Summary The effect of temperature upon the development of large hibernated larvaæ of fourMyrmica species has been tested experimentally. Over the viable temperature range of 15–25°C, it was found that: 1. There are no differences between the species in the effect of temperature upon development times. All fit the model log Dev. time=a-b T°C with a common value for b. This gives an effective Q10 of about 3.1 which agrees with respirometrical estimates for worker ants. 2. The value for the intercept (a) differs significantly between most species confirming the intrinsic difference that has been demonstrated at a constant 22.5°C in previous work. The development times of larvæ can be ordered from fastest to slowest being:Myrmica ruginodis Nyl.,Myrmica rubra L.,Myrmica scabrinodis Nyl. andMyrmica sabuleti Meinert. At any temperature it takesM. sabuleti about 1.5 times as long asM. ruginodis to grow from a large hibernated larva to a white pupa. 3. No large differences in larval survival or gyne production could be detected between the temperature treatments. There was an indication that most species, survived best at about 22°C. 4. The results are discussed briefly in terms of the ecological distribution of the four species in the South of England. 5. The possible effects of a fluctuating temperature regime are discussed, it is suggested that the amplitude of fluctuations may not have any great effect whereas the periodicity could be more important.
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  • 2
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    Insectes sociaux 30 (1983), S. 149-164 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Chromosomenzahlen von 40 Ameisenarten werden mitgeteilt. Für 22 Arten wird zusätzlich der Karyotyp vorgelegt. Die haploiden Chromosomenzahlen bewegen sich zwischen n=8 und n=26. Bemerkenswert sind die Karyotypen der GattungLasius. Diese Karyotypen besitzen, abgesehen von einem oder zwei mediozentrischen Paaren, ausschliesslich acrozentrische Chromosomen. Alle übrigen Karyotypen bestehen überwiegend aus medio- bzw. submediozentrischen Chromosomen. In der GattungCamponotus entspricht die Gruppierung in Untergattungen auch einer Gruppierung von unterschiedlichen Chromosomenzahlen. Für die GattungenAphœnogaster undLeptothorax gilt diese Entsprechung nicht.
    Notes: Summary The chromosome numbers of 40 ant species are reported. For 22 species the karyotypes as well as the chromosome numbers are presented. The chromosome numbers range between n=8 and n=26. Remarkable karyotypes are those of the genusLasius in exhibiting mainly acrocentric chromosomes. In all other karyotypes the majority of chromosomes show medio- or submediocentric centromere position. Differences in chromosome numbers in the genusCamponotus reflect the grouping in subgenera with the exception ofTanœmyrmex. This pattern is not true for the generaAphœnogaster andLeptothorax, where a variety of chromosome numbers were found in the different subgenera.
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  • 3
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    Insectes sociaux 30 (1983), S. 210-220 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary Density effects inEublaberus distanti have been tested upon larvæ in groups of 20, 100 and 500 individuals. Increased density leads to higher larval mortality, particularly in young larvæ, a larger difference between slow development and rapid development, and a decrease in adult size. Density effects in cockroaches can be explained in terms of population dynamics comparable to phasic modifications of desert Locusts.
    Notes: Resume Les effets de la densité ont été testés sur des lots de larves de l'espèceEublaberus distanti, lots de 20, 100 et 500 individus par 615 cm2. Lorsque la densité augmente, la mortalité larvaire s'accroit, surtout chez les larves jeunes. L'augmentation de densité accentue les différences entre individus à développement rapide et développement plus lent, de même qu'elle implique une réduction de taille chez les adultes. Les effets de la densité s'expliquent par la dynamique de la régulation des populations de Blattes, comparable aux modifications phasaires des Acridiens migrateurs.
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  • 4
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    Insectes sociaux 30 (1983), S. 235-240 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Ein Volk vonHarpagoxenus sublœvis wurde in einem naturnahen Habitat künstlich angesiedelt. Am 7. und 8. Juli 1981, zwischen 2015 und 2130 MEZ, konnte erstmalig unter Freilandbedingungen das Locksterzelverhalten ergatomorpher Jungweibchen in Nestnähe beobachtet werden. Gleichzeitig fand am 7. Juli ein Sklavenraubzug desHarpagoxenus-Volkes auf ein benachbartesLeptothorax acervorum (Fabricius)-Nest statt. Das bisher nur aus Laborbeobachtungen bekannte Sexualverhalten wird somit unter Freilandbedingungen in gleicher Form gezeigt.
    Notes: Summary A colony ofHarpagoxenus sublœvis was artificially established in a near-natural habitat. The sexual calling behavior of young ergatomorphic queens was observed for the first time under field conditions on July 7 and 8 1981, between 2015 and 2130 Central European Time. Simultaneously, on July 7, theHarpagoxenus colony conducted a slave raid on a neighboring nest ofLeptothorax acervorum (Fabricius). Previously the sexual behavior was known only from laboratory studies, these observations now show that it is performed in an identical manner under natural conditions.
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  • 5
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    Insectes sociaux 30 (1983), S. 255-258 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary The author proposes a new method of marking (with wire rings) which renders possible the individual identification of all the members of the colony.
    Notes: Resume L'auteur propose une nouvelle méthode de marquage, au moyen de ceintures de métal, permettant d'identifier chaque membre de la société.
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  • 6
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary In the antCataglyphis cursor, four categories of workers can be defined: minim, small, medium, large and very large. In each category, the workers are able to lay reproductive eggs and to produce, by parthenogenesis, queens, males and new workers of all sizes. Medium sized workers show the higher productivity. Average egg size and fecundity are related to workers size. All eggs seem able to develop. Difference between workers appear more quantitative than qualitative; the monophasic polymorphism of this species corresponds to this biological resemblance.
    Notes: Resume Chez la fourmiCataglyphis cursor, on peut définir 4 catégories d'ouvrières: minimes, petites, moyennes, grandes et très grandes. Dans chaque catégorie, les ouvrières sont capables de pondre et de produire par parthénogenèse, des reines, des mâles et de nouvelles ouvrières de toutes tailles. Les ouvrières moyennes présentent la plus forte productivité. La grosseur moyenne des œufs et la fécondité varient avec la taille des ouvrières; tous les œufs semblent capables de se développer. Les différences entre ouvrières apparaissent donc davantage comme quantitatives que qualitatives; le polymorphisme monophasique de l'espèce correspond bien à cette similitude biologique.
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  • 7
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    Insectes sociaux 30 (1983), S. 57-69 
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Les reines du frelon oriental sont agressives l'une envers l'autre au début de la saison active, pendant les mois de mai, juin et juillet: elles défendent leur “Lebenraum” à l'intérieur du nid et ne permettent à aucune autre reine de pénétrer dans leur territoire. A cette période, toute rencontre de 2 reines, dans le nid de l'une ou dans tout autre endroit, déclenche un comportement agressif mutuel. Le combat qui s'ensuit peut durer des heures et dans son déroulement, si l'une des reines défait l'autre elle la pique au cou jusqu'à la mort. Cependant, dans de nombreux exemples, le combat n'apporte pas de solution: les combattants épuisés se retirent avant de reprendre le combat. D'autres fois, l'une des reines peut réussir à mutiler sa rivale en amputant l'extrémité de ses pattes. La reine estropiée abandonne le combat en adoptant une posture d' “infériorité” à l'égard du vainqueur et en offrant de la nourriture. Nous avons décrit en détail les différentes phases du combat entre les reines mises par deux.
    Notes: Summary Queens of the Oriental hornet are aggressive towards one another in the beginning of the active season, during the months of May, June and July: they defend their “Lebenraum” within the nest and do not enable any other queen to enter their territory. At that period any encounter between two queens, whether within the nest of the one or anawhere else, releases mutual aggressive behavior. The ensuing combat may last for hours and in its course, if the one queen beats the other, it stings it to death in the neck. In many instances, however, the combat remains unresolved and the exhausted combatants withdraw to recuperate before resuming their battle. At other times, one of the queens may succeed in maiming its rival by amputating the tips of its limbs at which point the disabled queen concedes the fight by assuming an “inferior” posture towards the victor and making a food offering. The various phases in the combat between queen pairs are described in detail.
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  • 8
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Les distributions de trois «formes», en réalité des espèces jumelles d'Iridomyrmex purpureus furent étudiées près de Morgan en Australie du Sud, où la précipitation annuelle est de 230 mm. La dispersion des colonies a été décrite en détail pour une «forme bleue» et pour la formepurpureus sens. strict. qui existait dans cette région bien au-delà de ses limites pour les basses précipitations. Une colonie exceptionnellement grande d'I. purpureus couvrait un territoire de 10 ha: comprenant plus de 85 nids, elle avait plus de 1 500 entrées individuelles. Nous avons décrit les interactions entre les ouvrières des différentes formes, et leurs interactions au sein et entre les colonies de la même forme. La totalité de la faune de fourmis de la région et les faunes qui accompagnaient les différentes espèces d'Iridomyrmex furent étudiées au moyen de récoltes faites à la main et de piègeages dans des fosses. La diversité (abondance d'espèces) et la présence d'espèces de fourmis sans adaptations particulières sont liées au type de végétation et auxIridomyrmex associées. Les prises dans les pièges suggérant que le nombre d'individus et le nombre d'espèces d'autres taxons actifs à la surface du sol, en particulier les collemboles, sont affectés par le nombre de fourmis, en particulier les espèces d'Iridomyrmex et d'autres fourmis sans adaptations particulières. Au niveau évolutif, lesIridomyrmex influencent aussi la faune associé. On a noté la présence d'araignées zodariides présentant un mimétisme de couleur par rapport aux espèces presque identiques d'I. purpureus, dont ils sont des prédateurs. Nous avons noté et discuté des cas possibles de mimétisme d'I. purpureus par des fourmis du genreCamponotus.
    Notes: Summary The distributions of three “forms”, actually sibling species, of meat ant were studied near Morgan, South Australia, an area with mean annual rainfall of 230 mm. Colony dispersion is described for a “blue form” and for formpurpureus sens. strict. which occurs in this locality far beyond its normal low rainfall limit. An unusually large colony ofpurpureus had a territory covering 10 ha with more than 85 nests and over 1,500 individual nest entrances. Worker interactions between forms, and within and between colonies within forms are described. The ant fauna of the locality as a whole and the faunas accompanying differentIridomyrmex species were investigated by means of hand collections and pitfall trapping. Diversity (species — richness) and the occurrence of widely adapted ant species are related to vegetation type and associatedIridomymex. Catches of pitfall traps suggested that the numbers of individuals and species of other taxa active on the soil surface, predominantly Collembola, were affected by numbers of ants, particularlyIridomyrmex species and other, widely adapted ants.Iridomyrmex also influence associated fauna at an evolutionary level. The presence of zodariid spiders which are sibling species-specific colour mimics and predators of meat ants is noted. Possible cases of mimicry of meat ants by ants of the genusCamponotus are recorded and discussed.
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  • 9
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    Development genes and evolution 106 (1925), S. 124-192 
    ISSN: 1432-041X
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  • 10
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    Development genes and evolution 106 (1925), S. XXVI 
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  • 11
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    Development genes and evolution 106 (1925), S. 11-26 
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  • 12
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    Development genes and evolution 106 (1925), S. 75-85 
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  • 13
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    Development genes and evolution 106 (1925), S. 193-248 
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  • 14
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    Development genes and evolution 106 (1925), S. 249-278 
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  • 15
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    Development genes and evolution 106 (1925), S. 290-302 
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  • 16
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    Development genes and evolution 106 (1925), S. 279-289 
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    Development genes and evolution 106 (1925), S. 320-352 
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    Development genes and evolution 106 (1925), S. 303-319 
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    Development genes and evolution 106 (1925), S. 353-356 
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    Development genes and evolution 106 (1925), S. 357-408 
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  • 21
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    Development genes and evolution 106 (1925), S. 456-462 
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    Development genes and evolution 106 (1925), S. 409-455 
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    Development genes and evolution 106 (1925), S. 463-468 
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    Development genes and evolution 106 (1925), S. 503-541 
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    Development genes and evolution 106 (1925), S. 542-610 
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    Development genes and evolution 106 (1925), S. 611-639 
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  • 27
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    Development genes and evolution 106 (1925), S. 469-502 
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    Development genes and evolution 104 (1925), S. 25-49 
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  • 29
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    Development genes and evolution 104 (1925), S. 72-87 
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    Development genes and evolution 104 (1925), S. 121-124 
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    Development genes and evolution 105 (1925), S. 114-119 
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    Development genes and evolution 105 (1925), S. 19-44 
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    Notes: Zusammenfassung Die geschilderten Transplantationsversuche, deren Sinn darin bestand, ein Stückchen präsumptive Medullarplatte in seiner Entwicklung au\erhalb der normalen Umgebung zu verfolgen, beantworten die erste in der Einleitung gestellte Frage. Sie zeigen, da\ die Medullarplatte determiniert ist, ehe am Keim äu\erlich sichtbare Prozesse in ihrem Bereich zu erkennen sind. VomDotterpfropfstadium ab ist dies der Fall.
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    Development genes and evolution 105 (1925), S. 120-148 
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  • 34
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    Development genes and evolution 192 (1983), S. 1-7 
    ISSN: 1432-041X
    Keywords: Fat body ; Basement membrane ; Ageing ; Transplantation ; Monoclonal antibody
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    Topics: Biology
    Notes: Summary The hemocytes oftu-Sz ts melanotic tumor larvae ofDrosophila melanogaster encapsulate heterospecific and surface-modified homospecific tissue implants, but do not encapsulate unmodified homospecific implants (R. Rizki and Rizki 1980). In the present study we usedtu-Sz ts hosts to assay changes in larval fat body surfaces during development. Donor fat bodies from various ages of larvae were accepted (remained unencapsulated) intu-Sz ts hosts whereas fat bodies from donors with everted spiracles and all subsequent stages of development that were tested were rejected (encapsulated). Since the demarcation between acceptance and rejection by thetu-Sz ts blood cells did not coincide with the gross morphological changes that appear in the fat body during metamorphosis (dissolution of the basement membrane and dispersal of the freed fat body cells at pupation), we compared acceptable and nonacceptable fat body surfaces by three other methods. Fat body surface ultrastructure was examined, fat bodies were treated with fluorescein isothiocyanate-conjugated lectins, and fat body surfaces were reacted with a monoclonal antibody specific for basement membrane. These approaches did not uncover fat body surface changes associated with eversion of the anterior spiracles, suggesting that recognition of tissue surface heterogeneities by the insect hemocytes exceeds the resolving power of the other three methods. However, the monoclonal antibody fails to bind to the basement membrane ofD. virilis larvae, whose fat body is always rejected intu-Sz ts hosts. This supports our suggestion that the molecular architecture of the basement membrane may be important in eliciting the encapsulation response.
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    Development genes and evolution 192 (1983), S. 13-20 
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    Keywords: Hydra carnea ; Fertilization ; Sperm-egg interactions ; Site-specificity
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    Topics: Biology
    Notes: Summary Fertilization in the freshwater hydrozoanHydra carnea has been examined by light, scanning and transmission electron microscopy. Sperm penetrate the jelly coat which covers the entire egg surface only at the site of the emission of the polar bodies. The egg surface exhibits a small depression, the so called fertilization pit at this site. Sperm-egg fusion takes place only at the bottom of the fertilization pit.Hydra sperm lack a structurally distinct acrosome and in most of the observed cases, fusion was initiated by contact between the membrane of the lateral part of the sperm head and the egg surfacce. Neither microvilli nor a fertilization cone are formed at the site of gamete fusion. The process of membrane fusion takes only a few seconds and within 1 to 2 min sperm head and midpiece are incorporated in the egg. Electron dense material is released by the egg upon insemination but cortical granule exocytosis does not occur and a fertilization envelope is not formed. The possible polyspermy-preventing mechanisms in hydrozoans are discussed. Hydra eggs can be cut into halves whereupon the egg membranes reseal at the cut edges and the fragments assume a spherical shape. Fragments containing the female pronucleus can be inseminated and exhibit normal cleavage and development. The observation that in such isolated parts the jelly coat will not fuse along the cut edges was used to determine its role in site-specific gamete fusion. These experiments indicate that site-specificity of gamete fusion can be attributed to special membrane properties at the fertilization pit.
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    Development genes and evolution 192 (1983), S. 28-36 
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    Keywords: Budding ; Polarity ; Positional information ; Ascidian
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    Topics: Biology
    Notes: Summary In the polysteelid ascidian,Polyandrocarpa misakiensis, buds can arise at any antero-posterior positional level around the basal margin of a functional zooid. In this study, each bud was cut into anterior and posterior halves along its proximo-distal axis. When an anterior half was combined with a posterior half from a higher (more posterior) level, the future zooid developed the same anteroposterior polarity as a normal bud. When the same operation was performed with a posterior half from a lower (more anterior) level, the antero-posterior polarity was inverted, resulting in a reversed body asymmetry (situs inversus viscerum). Bud polarity depended not on the size or the growth stage of the fragmented buds, but on the difference in parental positional levels from which respective buds to be fused had originated. Surgically constructed doublehalf buds developed a single polarity instead of a pattern reduplication. Insertion experiments with bud pieces showed that the gap between the positional levels was recognized at the proximal region of operated buds. The results of this study are inconsistent with the predictions of the polar coordinate model for pattern formation. It is concluded that a parent zooid possesses antero-posterior position-specific potential for determining bud polarity.
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  • 37
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    Development genes and evolution 192 (1983), S. 37-41 
    ISSN: 1432-041X
    Keywords: Tunicamycin ; Exogastrulation ; Neural induction ; Cell permeability
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    Topics: Biology
    Notes: Summary Bufo arenarum eggs at late blastula and gastrula were treated with tunicamycin, an inhibitor of glycoprotein glycosylation, to investigate its effects on morphogenesis and neural induction. Because of the low permeability of the amphibian egg to a number of drugs, the blastocoel was opened surgically prior to treatment. Almost all of the eggs treated with the antimetabolite, at a concentration of 10 μg/ml, from late blastula stage for 24h exhibited exogastrulation. The effect is dose- and stage-dependent as shown by the lower proportion of exogastrulae obtained when eggs are treated at a lower concentration (5 μg/ml) or after the onset of gastrulation. Treatment with the antimetabolite did not interfere with neural induction, as partial exogastrulae developed a small neural tube. The most striking biochemical effect was an enhanced uptake of glucose, mannose and leucine. The incorporation of mannose into acid-insoluble material was severely inhibited by tunicamycin, with a concomitant decrease of leucine incorporation into the acid-soluble pool.
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  • 38
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    Development genes and evolution 192 (1983), S. 51-51 
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  • 39
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    Development genes and evolution 192 (1983), S. 48-50 
    ISSN: 1432-041X
    Keywords: Drosophila ; Hybrid lethality ; Imaginal discs ; Interspecific transplantation
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    Topics: Biology
    Notes: Summary Females ofDrosophila melanogaster, crossed with males ofDrosophila mauritiana, produce only female offspring. The male hybrid larvae grow very slowly, fail to pupate and die after prolonged larval life. Imaginal discs from these male hybrids transplanted into Drosophila melanogaster larvae can give rise to adult structures with normal patterns. Differentiation of hybrid imaginal disc tissue is improved by short term culture in non-hybrid larvae prior to metamorphosis, suggesting that the hybrid larval haemolymph is inadequate to sustain normal imaginal disc growth. This may represent the physiological basis of the reproductive isolating mechanism separating the twoDrosophila species
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  • 40
    ISSN: 1432-041X
    Keywords: Immunofluorescence ; Telotrophic Meroistic Ovary ; Postribosomal Particles ; Insect Oogenesis ; Early Insect Development
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    Notes: Summary During previtellogenesis, the oocytes of the telotrophic meroistic ovary ofDysdercus are provided with ribosomes and ribonucleoprotein (RNP) particles by the nurse cells. At the end of vitellogenesis, the oocyte itself becomes active as shown by autoradiography. The proteins synthesized by the oocyte are stored in cytoplasmic postribosomal particles which are preformed by the tropharium. The proteins of these particles were separated by SDS polyacrylamide gels and their endogenous oocyte proteins revealed by fluorography. The synthesis, transport, and storage of the postribosomal particles are demonstrated by indirect immunofluorescence. The young oocytes of previtellogenic follicles show a diffuse distribution of these particles. In late vitellogenesis, fluorescence becomes more and more concentrated in spots throughout a distinct region in the middle part of the oocyte. Thus, in freshly laid eggs, the periplasm is free of fluorescence. During migration of the cleavage nuclei the postribosomal particles were shifted into the cortex. Fluorescence is then most intense in the periplasmic region. During blastoderm formation, however, fluorescence decreases.
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  • 41
    ISSN: 1432-041X
    Keywords: Early neurogenesis ; Neurogenic mutants ; Drosophila
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    Notes: Summary The central nervous system (CNS) ofDrosophila develops from precursor cells called neuroblasts. Neuroblasts segregate in early embryogenesis from an apparantly undifferentiated ectoderm and move into the embryo, whereas most of the remaining ectodermal cells continue development as epidermal cell precursors. Segregation of neuroblasts occurs within a region called the neurogenic field. We are interested in understanding how the genome ofDrosophila controls the parcelling of the ectoderm into epidermal and neural territories. We describe here mutations belonging to seven complementation groups which effect an abnormal neurogenesis. The phenotypes produced by these mutations are similar. Essential features of these phenotypes are a conspicuous hypertrophy of the CNS accompanied by epidermal defects; the remaining organs and tissues of the mutants are apparently unaffected. The study of mutant phenotype development strongly suggests this phenotype to be due to misrouting into the neural pathway of development of ectodermal cells which in the wildtype would have given rise to epidermal cells, i.e. to an initial enlargement of the neurogenic region at the expense of the epidermogenic region. These observations indicate that the seven genetic loci revealed by the mutations described in this study contribute to control the neurogenic field. The present results suggest that in wildtype development neurogenic genes are supressed within all derivatives of the mesoderm and endoderm and some derivatives of the ectoderm, and conditionally expressed in the remaining ectoderm. The organisation of the neurogenic field in the wildtype is discussed.
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  • 42
    ISSN: 1432-041X
    Keywords: Gastropoda ; Mesoderm induction ; Dorsoventral polarity ; Epigenetics ; Mosaic/regulative development
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    Notes: Summary In equally cleaving gastropods, the interactions between micromeres and macromeres involved in the determination of the mesentoblast mother cell (3D) were studied by changing the spatial arrangement of the micromeres by deleting one first quartet micromere or its progeny. A fixed relation was found between the deletion site and the place of origin of 3D; therefore, a fixed relation also exists in the configuration of the three remaining first quartet micromeres and the 3D. These results argue against the possibility that the animal-vegetal interactions do not choose between macromeres, but only permit the expression of a choice already made in another way and at another moment. The results are consistent with a stochastic model in which accidental differences between the macromeres in the number or extent of contacts with first quartet micromeres play a discriminating role during micromere — macromere interactions, that lead to 3D determination. Embryos which lack a given first quartet micromere show a total absence of regulation in the larval head pattern; only the cephalic plates show regulative abilities while forming the adult head structures. Therefore, in later stages new activating and restraining factors seem to play a part in the head development.
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    Development genes and evolution 192 (1983), S. 86-94 
    ISSN: 1432-041X
    Keywords: Dictyostelium discoideum ; Pattern formation ; Differentiation markers
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    Topics: Biology
    Notes: Summary The appearance and spatial distrubution of ultrastructural markers ofDictyostelium discoideum differentiation were quantitatively analysed. Our results combined with data from the literature on the functions of cells at various stages of development lead to the following conclusions. When food is no longer available all amoebae initially develop an autophagic apparatus in order to sustain metabolism. After slugs have been formed, autophagy is suppressed in the prespore cells. During aggregation a number of cells gradually form prespore characteristics. These cells arise at random but later they become located in the basal part of the tip-forming aggregate. From the early slug stage onwards, cells of the posterior two third region gradually enter into the prespore pathway. During prolonged slug migration the optimal acquirement of prespore characteristics is blocked. Cells of the anterior region show no active differentiation but they maintain the morphology and most of the functions of aggregating cells. At the rear-guard of the slug and later on in the basal region of the maturing fruiting body, a second anteriorlike region appears. Actual stalk cell differentiation takes place only at the apex and at the base of the developing fruiting body.
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  • 44
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    Development genes and evolution 192 (1983), S. 95-102 
    ISSN: 1432-041X
    Keywords: Polychaeta ; Typosyllis ; Reproduction ; Endocrine control
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    Notes: Summary When exposed to a “winter” light-temperature cycle, reproduction in the polychaeteTyposyllis prolifera is inhibited by a hormone from the proventriculus. When exposed to a “summer” cycle, worms show periodic reproduction following an endogenous lunar rhythmictiy. The endocrine system mediating the stimulation of reproduction by summer conditions, was studied by extirpation and transplantation of prostomium and/or proventriculus. A previously unknown prostomial hormone was found to play a major role in this process. Summer conditions induce a temporary endocrine activity in the prostomium. This homone probably does not act directly on peripheral targets, but stimulates reproduction by inactivating the proventricular endocrine system. The experimental evidence of a hierarchic neuroendocrine system governing reproductive activity in syllid polychaetes is discussed.
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  • 45
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    Development genes and evolution 192 (1983), S. 108-112 
    ISSN: 1432-041X
    Keywords: Gangliosides ; Fetal human brain ; Acetylcholinesterase
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    Topics: Biology
    Notes: Summary Correlative histological, histochemical and biochemical investigations on laminar compartments from four different areas of fetal human neopallium at 28 weeks of gestation revealed discrete distribution of gangliosides in the cerebral wall. Highest level of total ganglioside concentration was found in the layers of cortical anlage (cortical plate and “subplate layer”) which are concomittantly characterized by highest activity of acetylcholinesterase (AChE) and which are known to be involved in intensive synaptogenesis at this stage of cortical development. In three of four areas the proportion of GD1a — ganglioside from total ganglioside amount tended to increase and that of GT1b to decrease from inside (ventricle) to outside (cortical anlage) throughout the cerebral wall.
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  • 46
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    Development genes and evolution 192 (1983), S. 120-129 
    ISSN: 1432-041X
    Keywords: Intracellular inhibition ; Polar lobe-Polychaeta ; Embryogenesis
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    Topics: Biology
    Notes: Summary The embryo ofSabellaria cementarium (Polychaeta) forms a polar lobe at each of the first two cleavage divisions which becomes absorbed into one of the blastomeres at the end of the division. Lobe removal experiments show that the polar lobe preceding first cleavage is necessary for the development of the apical tuft and the posttrochal region of the trochophore larva. The polar lobe preceding second cleavage is smaller than the first polar lobe and is necessary only for post-trochal region development. In blastomere isolation experiments, isolates containing the C but not the D blastomere form apical tufts. Isolates containing the D but not the C blastomere do not form apical tufts. When the polar lobe preceding second cleavage is removed and the C and D blastomeres are separated and raised in isolation, each can form an apical tuft. When the second cleavage is equalized with sodium dodecyl sulfate (SDS) such that both the C and the D blastomeres receive second polar lobe material, no apical tuft is formed. These results suggest that apical tuft determinants are distributed to both the C and D blastomeres at second cleavage but that the second polar lobe contains an inhibitor for apical tuft formation which is shunted to the D blastomere after the completion of second cleavage.
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  • 47
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    Development genes and evolution 192 (1983), S. 130-137 
    ISSN: 1432-041X
    Keywords: Vegetalizing factor ; Inducer concentration ; Incubation time with inducer ; Pattern formation
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    Notes: Summary Early amphibian gastrula ectoderm (Xenopus laevis) has been treated with vegetalizing factor using the sandwich technique, varying the period of incubation and the inducer concentration. The pattern of induced tissues depends on three factors: the inducer concentration, the size of inducer pellet and the time of exposure of ectodermal target cells to inducer. Short treatment with inducer will result in the formation of blood cells and heart structures. An increase in incubation time or inducer concentration, or both, will cause the formation of increasing amounts of such dorsal mesodermal structures as pronephros, somites and notochord. Neural structures can only be observed in explants with considerable amounts of somites and notochord. Ectoderm treated with high concentrations of vegetalizing factor for the whole period of competence will differentiate into endoderm. Furthermore, the results show thatX. laevis ectoderm does not show any autoneuralizing tendency under our experimental conditions. It therefore seems to be a suitable tool for the study of primary embryonic induction.
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  • 48
    ISSN: 1432-041X
    Keywords: Mouse embryogenesis ; Cytochalasin B ; Polyploid ; Chromosome replication ; Protein synthesis
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    Notes: Summary The cleavage of fertilized mouse eggs was prevented during cytochalasin B incubation and consequently these eggs became tetraploid the following day during in vitro culture. When the eggs were cultured further in normal medium, they cleaved and gave rise to tetraploid blastocysts. Protein synthesis was analysed in these embryos at different developmental stages using two-dimensional polyacrylamide gel electrophoresis. The protein synthesis pattern of one-cell tetraploid eggs was intermediate between those of normal one- and two-cell embryos. Tetraploid two-cell embryos expressed protein sets equivalent to those of untreated four-cell embryos, and tetraploid four-cell embryos synthesized proteins similar to those of four- to eight-cell controls. At subsequent pre-implantation stages the asynchrony was no longer detectable. When fertilized eggs were cultured continuously in the presence of cytochalasin B, they became tetraploid, octoploid and more and more polyploid without cleavage occurring. The protein synthesis patterns expressed by these one-cell polyploid eggs did not resemble that of normal fertilized eggs, but were similar to those of cleaving control embryos and blastocysts of equivalent age and nuclear division. These results strongly suggest that in early mouse embryos stage-specific translation is temporally correlated with chromosome replication (karyokinesis) and independent of cell division (cytokinesis) or cell interaction.
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  • 49
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    Development genes and evolution 192 (1983), S. 152-158 
    ISSN: 1432-041X
    Keywords: Calliphora ; Fat body ; RNA polymerase ; Ecdysteroids
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    Notes: Summary In vivo labelling of RNA polymerases I and II with S35-methionine shows that ecdysterone causes a de novo synthesis of both enzymes in nuclei of fat body cells inCalliphora 3rd instar larvae. Binding experiments with H3-α-amanitin demonstrate that the concentration of RNA polymerase II molecules increases two- to threefold within 3 h after ecdysterone treatment. The enhanced polymerase concentration coincides with an enhanced enzymatic activity and an increase in RNA synthesis in response to ecdysteroids.
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  • 50
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    Keywords: Embryonic induction ; Epithelial cell differentiation ; Organ culture ; Immunoperoxidase
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    Notes: Summary Undifferentiated metanephric mesenchymes, when grown in transfilter contact with an inductor tissue, differentiate into epithelial kidney tubules. The segregation of these tubules into the different segments of the nephron was studied. In explants grown in continuous transfilter contact with the inductor, immunohistological and histochemical markers specific for the glomerular epithelial, proximal tubule, and distal tubule cells appeared by 4 1/2 to 5 days, 4 days, and 5 days of culture, respectively. Electron microscopy confirmed segmentation of the tubules: Avascular glomeruli with glomerular basement membrane material, proximal tubules with brush border formation, and distal tubules were revealed in the explants after 5 days of culture. A short (18 h) transfilter induction pulse, followed by a prolonged subculture in the absence of the inductor, resulted sulted in the formation of only a small number of tubules in about half of the explants while the rest remained undifferentiated. These scarce tubules showed the markers specific for the proximal tubules only. The segregation of all three aspects of the nephron seems to be programmed during the transfilter culture, but apparently the time needed for the induction of the different segments varies.
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    Development genes and evolution 192 (1983), S. 159-163 
    ISSN: 1432-041X
    Keywords: RNA synthesis ; Early insect embryogenesis ; Nucleotide pools
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    Notes: Summary The total amount of ATP and UTP was measured in embryos ofDrosophila melanogaster andBruchidius obtectus at different development stages. The pool-sizes were measured by their ability to enhance poly(AU) synthesis in an in vitro test, using RNA polymerase ofE. coli, poly-d(AT), ATP, and3H-UTP. In embryos ofD. melanogaster, the amount of UTP decreased from 4.5 pmoles/ embryo during cleavage and early blastoderm to 2 pmoles at later stages. The ATP pool decreased from 14 pmoles/ embryo to 6 pmoles at the same developmental stages. In embryos ofB. obtectus, the UTP pool expanded from about 1 pmole/embryo during cleavage and early blastoderm to about 3 pmoles during gastrulation and organogenesis. Much more ATP was found inB. obtectus embryos: during fertilization 23 pmoles/embryo were found. At late syncytial blastoderm stages the amount of ATP rose to about 50 pmoles/embryo. At cellular blastoderm stages and during gastrulation only 26 pmoles/embryo of ATP were found. During organogenesis the ATP pool decreased to about 14 pmoles/embryo.
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    Development genes and evolution 192 (1983), S. 179-188 
    ISSN: 1432-041X
    Keywords: Pattern formation ; Molecular asymmetries ; Mirror-image doublets ; Cortical pattern ; Ciliate
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    Notes: Summary Mirror-image doublets of the hypotrich ciliateParaurostyla weissei were induced by modifying culture conditions. Successive steps of doublet formation involve inhibiting the separation of daughter cells during cell division and the shifting of these to attain a parallel configuration. The posterior part of the adoral band of membranelles in the right component then turns to the left and fuses with the distal terminal of the membranellar band in the left component. In effect, part of the adoral band and some of the paroral membranelles become apposed upside down, and the paroral membranelles of the right component are located on the left side of the adoral membranelles. A new site of oral primordium formation is initiated at the junction of the two oral apparatuses, the ciliature of which is arranged in a mirror-image pattern. During further cortical reorganization, the whole body ciliature of the right component becomes organized as a mirror-image of the normal left component. Both components of the doublet show the same ultrastructure of body ciliature and lack the right marginal cirri; the symmetry-reversal half, however, possesses multiple rows of left marginal cirri. The individual adoral membranelles and paroral membranelles in the symmetry-reversal component are rotated anteroposteriorly. Some aspects of the patterning of cortical structures are discussed.
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    Development genes and evolution 192 (1983), S. 222-227 
    ISSN: 1432-041X
    Keywords: Silkmoth chorion ; Transcription ; Northern analysis
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    Topics: Biology
    Notes: Summary cDNA clones for two distinct families ofBombyx mori chorion protiens, Class A (m2774) and Class Hc (m5000), were used to study the developmental regulation of specific chorion mRNAs. Individual follicles from maturing ovarioles were assayed by Northern blotting techniques and amino acid pulse-labeling to determine concomitant RNA accumulation and protein synthesis patterns with a temporal resolution of 2.2–2.6 h of developmental age. RNAs hybridizing to the two cloned chorion sequences at high criterion showed distinctive, non-overlapping patterns of accumulation during the middle-late and very late stages of choriogenesis. Moreover, the periods of expression of these RNAs coincided exactly with the synthetic periods of two distinct subsets of chorion proteins, one containing Class A and B components, and the other containing Class Hc components alone. These results suggest that chorion gene transcription and translation are tightly coupled.
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  • 54
    ISSN: 1432-041X
    Keywords: Amphibia ; Cleavage cycle ; Gastrulation ; Asymmetry ; Time-lapse cinematography
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    Notes: Summary The animal and the vegetative side of 15 embryos ofXenopus laevis were studied from the 5th cleavage to gastrulation by means of time-lapse cinematography. The duration of cleavage cycles, defined for the embryo as a whole as the period between the earliest blastomere divisions of one cycle to those of the next, varies quite a lot between individual embryos, both with respect to synchronous and lengthened cycles. Cycle lengthening may start at either cycle 10, 11 or 12. Cycle 13 deviates from the individual rhythm, and moreover its duration is inversely correlated with the period elapsing from the beginning of this cycle to the onset of gastrulation which occurs in cycles 14 or 15. In each cleavage cycle, the regional sequence of first blastomere divisions is visible on films as a “cleavage wave” runming over the animal cap. The direction of the waves varies in different embryos during the synchronous period but begins to change from cycle 10 onwards, resulting in a similar direction in most embryos prior to gastrulation: from the ventral/left to the dorsal/right half. This change reflects an asymmetry in the lengthening of the cycles in the animal cap: more dorsally than ventrally, and more on the right than on the left. The possible significance of the results for the timing of gastrulation and for the pattern of the future embryo is discussed.
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    Development genes and evolution 192 (1983), S. 228-233 
    ISSN: 1432-041X
    Keywords: Cell fusion ; Oogenesis ; Somatic nurse cells ; Dipteran insect
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    Topics: Biology
    Notes: Summary Formation of the oocyte-nurse chamber complex in the cecidomyid insectMycophila speyeri was studied in situ and in vitro by electron microscopy and time-lapse cinemicrography. At the end of the oogonial divisions each oogonium passes through a mitotic division with incomplete cytokinesis. This division gives rise to two sister cells, a prospective nurse cell and the oocyte, which remain connected by an intercellular bridge. In two phases of nurse chamber formation, first four and then (usually) one or two ovarian cells of mesodermal origin fuse with the prospective nurse cell. This results in a syncytial nurse chamber containing one germ-cell-derived nucleus and a varying number of mesoderm-cell-derived nuclei. In two subsequent fusion steps, two mesodermal cells fuse with the oocyte, giving rise to an oocyte containing one large and two small nuclei. Thus, four fusion steps lead to the formation of the complete oocyte-nurse chamber complex. Characteristics of the cell fusions are: (1) in each case one or more somatic cell(s) fuse with a germ-line cell and (2) cell contact between the fusing cells is established by the somatic cell, which approaches the germ-line cells.
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    Development genes and evolution 192 (1983), S. 248-255 
    ISSN: 1432-041X
    Keywords: Morphogenesis ; Ooplasmic segregation ; Polar Lobe ; Cell surface ; cytochalasin B
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    Notes: Summary In the eggs ofSabellaria alveolata specific morphogenetic determinants are segregated into the vegetal part of the egg which is constricted off to form a polar lobe during the first cleavages. Segregation is supposed to take place during meiosis. In this paper we describe the appearance of a patch of small blebs at the vegetal pole of the eggs after both the first and the second meiotic division and after the first cleavage, as assessed by scanning electron microscopy. We investigated the possible functional relationship between the segregation process and the modulation of the surface architecture at the vegetal pole by treating the eggs with cytochalasin B during meiosis. As a result, both the appearance of the blebs and the development of lobe-dependent structures in the larva are suppressed. From this result it is argued that cortical processes at the vegetal pole are likely to be involved in the segregation of morphogenetic determinants.
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    Development genes and evolution 192 (1983), S. A3 
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    Development genes and evolution 192 (1983), S. 8-12 
    ISSN: 1432-041X
    Keywords: Determination ; Mesoderm ; Dorsal marginal zone ; Cynops
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    Topics: Biology
    Notes: Summary The stepwise process of the formation and determination of mesoderm inCynops pyrrhogaster was analyzed. The presumptive ectoderm (PE) of the early gastrula was transformed into mesoderm within 12 h when transplanted into the upper half of the dorsal marginal zone of the same stage. The self-differentiation capacity and the neural-inducing activity of this newly mesodermized PE (MPE) were examined by both isolation and sandwich cultures. The MPE showed self-differentiation for notochord and muscle in the isolation culture. In the sandwich culture, the MPE made contact with the PE of the successive gastrula stages. The MPE was capable of inducing neural tissues even in the PE of the mid-gastrula, which has high neural competence but loses it within a short period of 6 h. These results show that firstly the mesodermization of the PE is completed within 12 h and secondly both the self-differentiation capacity and the neural-inducing activity are established immediately after the mesodermization of the PE.
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    Development genes and evolution 192 (1983), S. 21-27 
    ISSN: 1432-041X
    Keywords: Vitamin A (Retinoic acid) ; Chick embryo ; Integument Morphogenesis ; Ptilopody
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Intra-amniotic injection of 125 μg of retinoic acid to 10-day old chick embryos causes the formation of feathers on the scales of the anterior face of the tarsometatarsus. The early effects of retinoic acid (RA) on the chick foot integument have been studied between 12 h and 72 h following RA injections by two methods. Firstly, sequential fixation in glutaraldehyde and then osmium tetroxide to follow the early changes at the macroscopical and ultrastructural levels. Secondly, sequential grafts of contralateral samples on to chorioallantoic membrane (CAM) of nontreated chick embryos to test their morphogenetic performance and to determine the minimum time for RA to take effect. Results show that during the first 24 h RA causes morphological changes of both epidermal and dermal cells in almost half of the injected embryos. In particular, the dermal-epidermal junction is transformed from scale-type into feather-type. However, the development of grafted samples shows that feather morphogenesis is irreversibly undertaken only 24 to 48 h after the treatment. At this stage, roundish feather-like placodes are formed instead of the normal rectangular, scale placodes. The scales, the formation of which has been temporarily inhibited, resume their development between 48 h and 72 h after the the injection, proximally to the feather buds, so that feathers are finally carried by the distal tips of the scales.
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    Development genes and evolution 104 (1925), S. 649-658 
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    Notes: Zusammenfassung Während bei wirbellosen Tieren Tyrosin als Chromogen bei der enzymatischen Melaninbildung durch Tyrosinase nachgewiesen erscheint (v. Fürth, mitgeteilt inPrzibram u. Mitw. v.Dembowski undBrecher: Einwirkung der Tyrosinase auf Dopa 1921), ist die Frage des Chromogens bei den Wirbeltieren noch offen, obwohl nachOnslow's (1915) Versuchen an dem Vorkommen einer Tyrosinase als melaninbildendes Ferment auch in den Häuten der Säuger wohl nicht mehr gezweifelt werden kann. Außer dem Tyrosin kommt bei den Wirbellosen auch Dopa als Melaninbildner vor, ist jedoch bisher bloß in den Kokonen mancher Insekten nachgewiesen worden (Przibram 1922,Sciacchitano 1923). DaBloch (1917) gerade das Dopa als Grundlage für die Pigmentbildung der Wirbeltiere für wahrscheinlich hält, so war es von Interesse, dem Vorkommen dieses Stoffes in den pigmentbildenden Geweben nachzuspüren. Die Untersuchung von Haut und Hautbekleidung bei Fischen, Vögeln und Säugetieren fiel völlig negativ aus; es konnte in den Extrakten weder die charakteristische Grünfärbung bei Eisenchloridzusatz noch der Umschlag in Purpurrot bei Hinzufügen von Natriumkarbonat beobachtet werden, wie sie Dopalösungen und Wasserextrakte der erwähnten Kokone stets zeigen. Dopa ist also gewiß nicht das gewöhnliche Chromogen der Wirbeltierhaut und ihrer Bedeckung. Mittels derMillonschen Reaktion läßt sich in allen genannten Extrakten Tyrosin nachweisen, aber es bleibt dabei unentschieden, ob wirklich freies Tyrosin angezeigt oder bloß durch die Reaktion in dem vorhandenen Eiweiß erkennbar wird. Wurde eine Befreiung gekochter Extrakte verschiedener Schmetterlingspuppen und Fischhäute vom Eiweiß nach dem Vorgangev. Fürth's (Phosphorwolframsäure, Barytwasser, Kohlensäure oder 10%ige Schwefelsäure) vorgenommen, so fiel dieMillonsche Reaktion bald negativ, bald positiv aus. Der Verdacht, daß dieses Verhalten einer wesentlichen Vernichtung des Tyrosins durch die eingreifenden Prozeduren zur Eiweißentfernung zuzuschreiben sei, bestätigte sich in Mischungen von Hühnereiweiß und Tyrosin, welche nach gleicher Behandlung eine sehr wesentliche Schwächung derMillonschen Reaktion bis zu ihrem Schwunde aufwiesen. Tyrosin, das in den Häuten und Hautbedeckungen, wie überhaupt in jedem Eiweiß vorhanden ist, könnte also auch dort das chromogen abgeben, wo sein Nachweis nach Entfernung des Eiweißes nicht mehr gelingt.
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    Development genes and evolution 105 (1925), S. 501-580 
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    Development genes and evolution 105 (1925), S. 732-777 
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    Development genes and evolution 104 (1925), S. 1-24 
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    Development genes and evolution 104 (1925), S. 50-71 
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    Development genes and evolution 104 (1925), S. 138-184 
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    Development genes and evolution 104 (1925), S. 125-137 
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    Development genes and evolution 104 (1925), S. 185-209 
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    Development genes and evolution 104 (1925), S. 317-358 
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    Development genes and evolution 104 (1925), S. 699-699 
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    Development genes and evolution 105 (1925), S. 63-113 
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    Development genes and evolution 105 (1925), S. 208-208 
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    Development genes and evolution 105 (1925), S. 149-201 
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    Development genes and evolution 105 (1925), S. 330-384 
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    Development genes and evolution 105 (1925), S. 430-469 
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    Development genes and evolution 105 (1925), S. 474-474 
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    Development genes and evolution 105 (1925), S. 581-586 
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    Development genes and evolution 105 (1925), S. 587-609 
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    Notes: Schlu\folgerungen 1. Karpfen, denen alle Nahrungszufuhr unterbunden wird, die also absolut hungern, wachsen in die LÄnge, und zwar so lange, als der Wachstumsantrieb über die ungünstigen Bedingungen des Stoffwechsels (Hungerstoffwechsel) überhand erhÄlt. 2. Das LÄngenwachstum geschieht durch Umbau; das Skelet nimmt hauptsÄchlich auf Kosten des Muskelsystems und des Reservestoffdepots (insofern dieses nicht zum Betriebsstoffwechsel aufgebraucht wird) zu. 3. Ältere Karpfen, nÄmlich in ihrer Entwicklung fortgeschrittenere, wachsen weniger intensiv, vertragen aber das Hungern viel lÄnger und besser. 4. Lebenswichtige Körperteile (Kopf) wachsen am lÄngsten und können sogar an Masse (nur Lebendgewicht, wÄhrend bei der Trockensubstanz Gleichgewicht oder Abbau eintreten kann) auf Kosten anderer Körperteile, welche funktionell weniger wichtig sind, zunehmen. 5. Der Wachstumsantrieb kann durch sekundÄre Einflüsse zeitlich beeinflu\t werden, wie z. B. Jahreszeit und Temperatur des Milieus.
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    Development genes and evolution 105 (1925), S. 633-654 
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    Development genes and evolution 105 (1925), S. 655-666 
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    Notes: Zusammenfassung Die oben angeführte Methodik, deren Ausarbeitung das Hauptziel unserer Arbeit war, hat bisher folgendes gelehrt: 1. Wir haben, zum Unterschiede von den bisherigen Experimentatoren, intrauterin und intraamnial operiert, ohne eine Unterbrechung der GraviditÄt hervorzurufen oder den Foetus zu töten. Uterus und EihÄute wurden eröffnet und wir sahen nach seromuskulÄrer Naht die Uteruswunde nach 6 Tagen verheilt. Die EihÄute wurden nicht genÄht. Ein jüngerer Foetus wurde schwer verletzt, er blieb trotzdem etwa 6 Tage am Leben und erreichte fast das Dreifache seiner LÄnge (Prot. Nr. V). Die Extremitäten von 21 Tage alten Foeten wurden wiederholt amputiert (Prot. Nr. I, VIII) oder abgebunden (IX) und die Foeten wurden reif. Und schlie\lich gelang es uns, zwei Foeten intrauterin zusammenzunÄhen (Prot. Nr. XI); in diesem Falle blieb der eine Partner am Leben, der andere ging zugrunde (nachdem er um ca. 10 mm weiter gewachsen war), blieb jedoch mit dem lebenden Bruder in Zusammenhang. Ein gleichzeitig am anderen Horn durchgeführter Eingriff (Amputation einer foetalen Extremität) störte den Ablauf der TrÄchtigkeit nicht. 2. Die Experimente beweisen — neben der technischen Durchführbarkeit —, da\ eine Regeneration vom 16. Tag [Skelet des Foetus vollkommenknorpelig ausgebildet (Normentafeln,Koebner)] beim Kaninchenfoetus nicht erfolgt, hingegen sieht man eine gute Heilungstendenz der Früchte.
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    Development genes and evolution 105 (1925), S. 711-717 
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    Development genes and evolution 105 (1925), S. 778-816 
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    Development genes and evolution 105 (1925), S. 817-820 
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  • 83
    ISSN: 1432-041X
    Keywords: Vitellin ; Yolk granule ; Yolk protein ; Silkworm ; Embryogenesis ; Immunocytochemistry
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    Notes: Summary Vitellin was purified from eggs of the silkworm,Bombyx mori, by a new method in which vitellin was extracted from isolated yolk granules. The purified vitellin had a molecular weight of 540,000. An antibody against purified vitellin was prepared in rabbits. It reacted with the hemolymph vitellogenin as well as with purified vitellin, but not with other proteins in the hemolymph or in the extract from yolk granules. The anti-vitellin IgG was used to immunocytochemically locate vitellin in theBombyx non-diapause egg during early developmental stages. In the egg, just after oviposition, vitellin was located in internal yolk granules and in small yolk granules of the periplasm. During the early developmental stages studied, vitellin was not metabolized uniformly throughout the egg. The vitellin of the internal yolk granules located at the posterior-dorsal part and of the small peripheral yolk granules was utilized in 16 h and 2 days, respectively, after oviposition. A thin, very vitellin-poor layer was located between the periplasm and the vitellin-rich interior in the newly laid egg. it was always in close contact with the periphery where blastoderm and germ-band cells developed.
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    Development genes and evolution 192 (1983), S. 164-170 
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    Keywords: Drosophila ; Imaginal disc ; Morphogenesis ; Tissue culture
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    Notes: Summary The early morphogenesis of the eye-antennal disc ofDrosophila in response to 20-hydroxy ecdysone involves the curling of the eye anlagen dorsally over the antenna. During this process, the area of the peripodial membrane is substantially reduced. The peripodial membrane is taut at this stage, and if it is cut the curling of the disc cannot continue, and the eye anlagen returns to its original position within one minute of the operation. In contrast, cutting the columnar epithelium between the eye and antennal anlagen does not disrupt curling, but actually facilitates it. During curling, the cells of the peripodial membrane appear healthy, and exhibit basal extensions. We suggest that the curling of the eye is mediated by the conversion of cuboidal peripodial membrane cells into pseudostratified columnar epithelium at the edges of the peripodial membrane. Subsequently, cells of the peripodial membrane secrete first a pupal cuticle, and then an imaginal cuticle.
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    Development genes and evolution 192 (1983), S. 171-178 
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    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
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    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
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    Development genes and evolution 192 (1983), S. 189-195 
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    Keywords: Drosophila melanogaster ; Embryo Metabolism ; Protein biosynthesis ; Ovary ; Growth and development egg yolk
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    Notes: Summary The accumulation of endogenously synthesized non-yolk proteins, and of exogenously derived yolk, was quantitated during oogenesis and embryogenesis ofDrosophila. Rates of non-yolk protein accumulation were calculated, and were correlated with polysome content at each developmental stage. Three distinct phases of non-yolk protein accumulation were observed: 1) relatively slow accumulation, lasting to stage 9 of oogenesis; 2) very rapid accumulation between stages 10 and 12 of oogenesis, when half of the protein of the mature egg is accumulated in less than 4 h; and 3) no further protein accumulation from stage 12 of oogenesis through at least the gastrula stage of embryogenesis. During phases 1 and 2, rates of non-yolk protein accumulation correlate well with the polysome content of egg chambers. Surprisingly, during the entire phase 3 the content of polysomes remains at high levels, even though no detectable protein accumulation occurs. This finding is in agreement with the low levels of protein synthesis that have been measured during early embryogenesis, and strongly suggests that late in oogenesis the efficiency of translation suddenly drops by about 20-fold. Moreover, our results imply that polysome content cannot always be directly correlated with protein synthetic activity.
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  • 87
    ISSN: 1432-041X
    Keywords: Balbiani ring ; Cell-free translation ; Chironomus messenger RNA ; Secretory proteins
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    Notes: Summary Cell-free translation of salivary gland RNA or of purified Balbiani ring RNA (75S) in a reticulocyte lysate system gives rise to high molecular weight translational products (HMTP). In addition to a common size (approx. 1×106 daltons) HMTP share imunogenic determinants with the giant secretory proteins of salivary glands. This suggests that HMTP correspond to in vivo secreted proteins and thus, corroborates the notion that 75S-RNA is the messenger for these proteins. The time course of HMTP synthesis and the lack of appearance of lower molecular weight components as translational products of 75S-RNA indicate that the synthesis of HMTP (and of secretory proteins) occurs in one piece by an uninterrupted process. HMTP are regarded the largest polypeptides so far synthesized in a cell-free system.
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  • 88
    ISSN: 1432-041X
    Keywords: Collagen ; Fibronectin ; Laminin ; Skin ; Scale morphogenesis
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    Notes: Summary Collagen types I and III were purified from the skin of 3-or 7-week-old chickens, collagen type IV from bovine skin or EHS mouse tumour, fibronectin from human serum, and laminin from EHS mouse tumour. Antibodies were produced in rabbits or sheep, and used in indirect immunofluorescence on frozen sections of 9-to 16-day-old normal or mutant (scaleless) chick-embryo foot skin. In normal scale-forming skin and inscaleless skin, the distribution of anti-laminin and anti-type IV collagen label was uniform along the dermal-epidermal junction and showed no stage-related variations, except for fluorescent granules located in the dermis of early scale rudiments. By contrast, in normal scale-forming skin, the density of anti-types I and III label decreased in the dermis within scale rudiments, whereas it gradually increased in interscale skin. Conversely, anti-fibronectin label accumulated at a higher density within scale rudiments than in interscale skin. In the dermis of thescaleless mutant, anti-types I and III label and antifibronectin label were distributed evenly: the density of anti-collagen label increased with age, while that of antifibronectin decreased and almost completely vanished in 16-day-old skin, except around blood vessels. The microheterogeneous distribution of some extracellular matrix components, namely interstitial collagen types I and III and fibronectin, is interpreted as part of the morphogenetic message that the dermis is known to transmit to the epidermis during the formation of scales. The even distribution of these components in mutantscaleless skin is in agreement with this view. Basement membrane constituents laminin and type-IV collagen do not appear to be part of the dermal morphogenetic message.
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    Development genes and evolution 192 (1983), S. 280-284 
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    Keywords: Evagination ; Morphogenesis ; Metamorphosis ; Intersexual genital disc ; Drosophila
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    Topics: Biology
    Notes: Summary Morphogenetic movements of the intersexual genital disc of thedoublesex-dominant mutant ofDrosophila melanogaster were followed during metamorphosis. Intersexual genital discs contain well developed genital primordia of both sexes as well as an anal primordium, and all of these primordia evaginate simultaneously. The female genital primordium is deflected to the ventral side by the male genital primordium which is located anterior to it. Subsequently the anterior parts of the two genital primordia project their internal appendages in parallel in the anterior direction. The morphogenetic movements closely resemble those of the corresponding parts of normal males and females. The disc opens at the stalk along the posterior edge and the two genital primordia completely evert their posterior parts. These areas undergo complex rearrangements whereby the anlage for the male genital arch as well as that for the 8th tergite evert and move around the lateral side of the disc. They both fuse dorsally after enclosing the anal tube. The formation of the characteristic abnormalities of the intersexual genitalia seems not to result simply from spatial problems of the simultaneous evagination of the genital anlagen but rather to be a direct result of the ambiguous genetic signalling in the intersexual cells of these primordia.
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  • 90
    ISSN: 1432-041X
    Keywords: Drosophila ; Cell degeneration ; Imaginal disc ; Basal lamina ; Blood cells
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    Notes: Summary The mutationsvestigial (vg; recessive) andUltravestigial (vg U; dominant) ofDrosophila melanogaster give rise to identical mutant adult phenotypes in which much of the cases this results from cell death in the presumptive wing margin of the wing disc in the third larval instar, but the process of cell degeneration is quite different in the two mutants. Invg cell death occurs continuously throughout the third larval instar, while invg U it occurs only in the early third instar. Cells fragment and some of the fragments condense, becoming electron dense (“apoptosis”). Both condensed and ultrastructurally normal cell fragments are extruded to the basal side of thevg disc epithelium. They accumulate under the basal lamina in the wing pouch area until they are phagocytosed by blood cells entering the wing pouch during the six hours following pupariation. Fragments are not extruded from thevg U epithelium but are apparently phagocytosed by neighboring epithelial cells. The basal lamina undergoes mophological changes following pupariation and is phagocytosed by blood cells in both wild-type andvestigial, but investigial the degenerated cell fragments are also engulfed by the same blood cells.
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    Development genes and evolution 192 (1983), S. 295-298 
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    Keywords: Leafhopper egg ; Combination of germ anlage parts ; Test for regeneration
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    Topics: Biology
    Notes: Summary Immerging U-shaped germ bands of the leafhopperEuscelis plebejus were cut twice by constriction in order to combine the anterior and posterior ends of the embryo. Although these terminal parts fused in a number of cases, no intercalary regeneration was observed. In addition, the experiments revealed that constriction during anatrepsis (germ anlage extension) causes gaps of varying size in the abdominal part of the segment pattern. The data suggest that “differential adhesion” between yolk cells and the surface of the germ anlage might play a part in the immersion of the germ anlage into the yolk.
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    Development genes and evolution 192 (1983), S. 299-302 
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    Keywords: Differentiation ; Teratogens ; Drosophila ; 5-Azacytidine ; Methylation
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    Topics: Biology
    Notes: Summary The effects of cytidine and cytidine analogs were studied inDrosophila embryonic cell cultures and two wild-type established cell lines, Oregon-R and Schneider line 2. Primary embryonic cultures have been shown to be an excellent system for the study of embryonic development; a number of cell types undergo normal differentiation in vitro. Treatment of these cultures with putative teratogens resulted in an inhibition of muscle and/or neuron differentiation in our study. Treatment of these cells with cytidine and seven other analogs had no effect on neuron and muscle differentiation. The compound 5-azacytidine, when added to primary cell cultures, inhibited normal differentiation at subtoxic doses while inducing the production of three proteins that comigrate with the heat-shock proteins, hsp 23, 22a and 22b. 5-Azacytidine did not stimulate differentiation in Oregon-R or SchneiderDrosophila cell lines. The in vitro blockage of differentiation by 5-azacytidine suggests that it may act as a teratogen.
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    Development genes and evolution 106 (1925), S. I 
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    Development genes and evolution 106 (1925), S. 6-10 
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    Development genes and evolution 106 (1925), S. 62-74 
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    Development genes and evolution 104 (1925), S. 262-272 
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    Development genes and evolution 104 (1925), S. 273-312 
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    Development genes and evolution 104 (1925), S. 395-408 
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    Development genes and evolution 104 (1925), S. 421-433 
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    Notes: Summary The head and foot ofPelmatohydra oligactis function in regeneration as unipotent systems. The exact extent of the unipotent tissue immediately posterior to the tentacles and anterior to the foot is not determined in these experiments. The intermediate tissue is pluripotent. The potentiality for head formation is stronger at the oral end and decreases towards the aboral end as the potentiality for foot formation increases. In these grafting experiments the stock has no influence over the graft which retains its individuality.
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    Development genes and evolution 104 (1925), S. 611-648 
    ISSN: 1432-041X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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