Zur phylogenetischen und funktionellen Bedeutung der sogenannten notalorgane der Mecoptera (insecta,Mecoptera)

An account is given of the morphology and function of the notal and postnotal organ in Mecoptera. The phylogenetic significance of these structures is discussed.     

DNA-Replikation und Chromosomenstruktur von Mesostoma (Turbellaria)

During meiosis in M. ehrenbergi (2n=10) and M. lingua (2n=8) male certain chromosomes never pair completely. In these bivalents only terminal pairing appears, crossing over could not be proved by ³H-thymidine autoradiography. DNA amounts of the M. ehrenbergi and M. lingua genomes are in a proportion of 10∶1. The mitotic S-phase of spermatogonia in M. ehrenbergi is twice as long as in M. lingua. In metaphase of spermatogonia a differentiated DNA replication pattern can be identified in M. ehrenbergi as late-pulse-replicating segments. After incorporation of ³H-thymidine X₂-metaphase chromosomes can be found, which show single chromatid labeling, terminal and intercalary isolabeling as well as kinds of chromosome labeling, which can only result from sister strand exchange. After treating the chromosomes with low temperature, colchicine or by hydrolysis (60° C) substructures of the chromatin become visible in both spezies which however are evaluated as artefacts. — Formation of the different isolabeling types is discussed on the basis of a two-strand model of the chromosome fibril. A hypothesis is formulated that the surplusage of DNA in M. ehrenbergi is distributed over all the length of the chromatids as small parts of heterochromatin. This hypothesis is supported by investigations of the DNA replication and the contractility of the chromosomes. Furthermore, a pattern of small DNA particles can be demonstrated after partial destruction of the DNA in metaphase chromosomes of M. ehrenbergi, which could represent this intercalary heterochromatin.     

An intranuclear paracrystalloid body in the gametocytes of Panorpa communis (Mecoptera)

During the meiotic prophase the nuclei of the spermatocytes and oocytes of Panorpa communis contain a paracrystalloid body (PB). This is built up of about 100 filaments of 80 Å thickness all running parallel to one another. The filaments are connected by a network of many thin fibers. At pachytene and diplotene the PB is connected with the nucleolus. In spermatocytes at late diplotene the PB is enveloped by RNP-material, which is produced by certain chromosomes at the diffuse diplotene stage. Thereafter the PB is gradually removed. During this process the RNP-material coils up to form three or four spherical RNP-bodies. It is suggested that the PB has a function in assembling and connecting the RNP-material to form long ribbons which build up the RNP-bodies.     

Die Spermatogenese der Zecke Ornithodorus moubata (Murr)

Zusammenfassung Die Genese der schwanzlosen Spermatozoen der Zecke Ornithodorus moubata wurde licht- und elektronenmikroskopisch untersucht.In der Keimzone des Hodens finden sich die kleinsten Zellen der Spermatogenese, die Spermatogonien A, die einzeln durch somatische Zellen voneinander isoliert sind. In einer Vermehrungsphase von 4 Teilungen entstehen Ballen von je 16 Spermatogonien B. Durch Wachstum gehen die Spermatogonien B in Spermatozyten I. Ordnung über. Dabei entsteht in ihnen eine Randstruktur, die sich nach den rasch ablaufenden Reifeteilungen in den Spermatiden zu einer Vakuole entwickelt, in die bandartige Zellfortsätze hineinhängen. Gleichzeitig mit einer Längsstreckung der Spermatide stülpt sich die spätere Spitze in die Vakuole ein und führt zu einer handschuhfingerartigen Umkrempung der Spermatide. Dieser letzte Schritt erfolgt erst nach der Kopulation im Weibchen. Dann liegen die ursprünglich in die Vakuole hängenden Fortsätze dem reifen Spermatozoon außen als Leisten an.Die Kernkondensation und die Akrosombildung werden im einzelnen beschrieben. Durch die komplizierte Umgestaltung der Spermatide erfahren auch Kern und Akrosom sowie die Zentriolen unfangreiche Ortsveränderungen, die erst im Weibchen abgeschlossen werden.

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The spermatogenesis of the tick Ornithodorus moubata

Summary The genesis of the tailless spermatozoa of the tick Ornithodorus moubata has been studied by light and electron microscopy.In the germ zone of the testis the smallest cells of the spermatogenesis are located, the spermatogonia A which are separated from each other by somatic cells. The result of a multiplication phase with 4 mitoses are clusters of 16 spermatogonia B. While growing up the spermatogonia B differentiate into spermatocytes I. They show a special structure of their border which, after the quickly passed maturation divisions, gets more developed in the spermatides and turns into a vacuole with ribbon-like cytoplasmic processes hanging into it. Simultaneously with an elongation of the spermatide the subsequent apex invaginates into the vacuole and induces an inversion of the spermatide like the finger of a glove. This last step takes place only after the copulation in the female. Then the processes previously hanging into the vacuole are lying as groins close to the outside of the mature spermatozoon. The condensation of the nucleus and the formation of the acrosome are described in particular. Because of the complicated transformation of the spermatide also the nucleus, the acrosome and the centrioles undergo extensive migrations being accomplished in the female.

     

家蚕联会复合体组型分析

作者以表面铺张——硝酸银染色技术制备标本,从亚显微水平对雌、雄家蚕联会复合体(Synptonemal Complex,SC)的行为及组型进行观察和分析。在减数分裂前期,雌、雄家蚕SC的形态和行为均无明显差异。SC的形成起始于偶线期,成熟于粗线期,消失开始于双线期。在粗线期可见28条清晰的SC,在各SC均未见有相当于着丝粒区域的分化结构。无论在精母细胞或卵母细胞中,均未发现异形双价体。从早粗线期到晚粗线期,SC的平均总长由205.5μm伸长至348.9μm。作者根据10个细胞的测量及分析结果,绘制了家蚕SC组型模式图,并就家蚕的性决定进行了讨论。     

Core-Strukturen in den meiotischen und post-meiotischen Kernen der Spermatogenese von Gryllus domesticus

Summary electron microscope study of spermatogenesis and spermiogenesis in Gryllus domesticus has revealed the existence of peculiar lamellate bodies which occur both in spermatocyte and spermatid nuclei. These bodies must be considered as multiple complexes of the axial core structures which are regularly found in paired pachytene chromosomes. Their shape is irregular, and their constituent structural elements, although having dimensions and a fine structure identical to those of regular axial complexes, may assemble in sheets rather than ribbons, often in a concentric rather than planparallel multiple layer system.Spcrmatocyte nuclei may either contain just one or two large bodies of this type, often but not always in close association with the nucleolus and/or the X chromosome, or they may show several such structures of smaller dimensions which have some connection to chromosome fibrils. None of the two types of nuclei simultaneously contains regular axial core complexes. In spermatid nuclei one or two such multiple structures are usually found, again often in association to the X and/or (in O-spermatids) to what appears to be a nucleolus.It is considered likely that the multiple core complexes are due to the self-assembly of those protein molecules which typically assemble only under the control of and in close association with the pachytene chromosomes to form ordered axial complexes. Their occurrence in spermatids shows that the constituent molecular material may not be decomposed during the meiotic divisions after it is dissociated from the chromosomes.

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Mit Unterstützung durch die Göttinger Akademie der Wissenschaften.

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Herrn Prof. Dr. H. Bauer zu seinem 60. Geburtstag gewidmet.     

Die funktionelle Polymorphie des Sertoli-Syncytiums und ihr Zusammenhang mit der Spermatogenese

Ohne Zusammenfassung     

Das exoskelet von Notiothauma reedi MacLachlan,ein beitrag zur morphologie und phylogenie der Mecoptera (Insecta)

The present contribution deals with the exoskeleton of Notiothauma reedi MacLachlan. A special attention has been paid to the external male genital apparatus with particular reference to the sperm-pump. Finally the structures, which have a bearing on the phylogeny of the order Mecoptera have been duly discussed.

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Abkürzungen a Analis - apx Höcker am Analkomplex - at vordere Tentorialgrube - Atf antennifer - au Auxilium - Ax Axillare - Ba Basalare - BaSp Basalarspalt - bbsch mediales Borstenbüschel an der Lacinien-Basis - bc Basicostalsklerit - bcb Basicostalborsten - bsk Basalsklerit der Maxille - bt Basituberculus des Gonostylus - c Costa - Cd Cardo - Cer Cercus - Clp Clypeus - cu Cubitus - Cx Coxa - DCv Dorsocervicale - Dej Ductus ejaculatorius - ec vorderes Mandibelgelenk - Epm Epimerum - Eps Episternum - es Epistomalsutur - fb Frenularborsten - fl laterobasaler Membranflügel des Labrum - Fl Flagellum - flg Flügel des Pumpenkörpersklerites - For Foramen occipitale - Fr Frons - fs Fortsatz der Subgena - fspmk Fortsätze des Pumpenkörpersklerites - Ga Galea - gb Gonobasis - Ge Gena - gel Gelenk zwischen Pumpenkörpersklerit und Pistillträger - gesp nicht verschlossener Teil der Genitalspalte - glfl Gleitfläche des Pumpenkörpersklerites - GP Gelenkfortsatz - gst Gonostylus - h Humeralader - ha Hypandrium - hc hinteres Mandibelgelenk - hdr mediale Hakendornen der Lacinia - hsk Halshautsklerit - HP Humeralplatte - jb Jugumborsten - Ju Jugum - l Leiste auf dem Clypeolabrum - la lappiger Fortsatz am Hinterende der Genitalfalten - lblc laterale Borstenreihe der Lacinia - lblr lateraler Borstensaum des labrum - Lc Lacinia - LCv Laterocervicale - lepi lateraler Fortsatz des Epiandrium - lm mediale Lamelle des Pumpenkörpersklerites - loc Lateralocellus - Lr Labrum - lsplc laterale Spange der Lacinia - lth laterales Tergalhorn des T_VI und T_VII - m Media - Md Mandibel - mepi medianer Fortsatz des Epiandrium - Mer Meron - mld Mulde des Pumpenkörpersklerites - mOc Medianocellus - MP Mittelplatte - mt Mediotuberculus des Gonostylus - mth medianes Tergalhorn des T_V - N Notum - Ng Nygma - no Notalorgan - ns Sulcus auf dem Pronotum - Occ Occiput - ocs Occipitalnaht - pcs Praecoxalsutur - Pd Pedicellus - pf pfannenartiger Anhang des Pumpenkörpersklerites - Pge Postgena - PgeL Postgenallobus - Plb Palpus labialis - plFlG pleurales Flügelgelenk - plHG pleurales Hüftgelenk - PlS Pleuralsutur - pmk Pumpenkörpersklerit - Pmt Postmentum - Pmx Palpus maxillaris - PN Postnotum - po Postnotalorgan - PrEps Praeepisternum - Prm Praementum - PrSct Praescutum - ps Pistill - PSge Processus subgenalis - Pst Pterostigma - pstr Pistillträger - pt hintere Tentorialgrube - qua terminale Borstenquaste - qua terminale Borstenquaste der Maxille - r Radius - rbga rückwärtige Borstenreihe der Galea - rs Sector radii - rsplc rückwärtige Spange der Lacinia - sa Furcalgrube - Sa Subalare - sc Subcosta - Sc Scapus - Scl Scutellum - Sct Scutum - Sge Subgena - sgs Subgenalnaht - sl terminaler Seitenlappen des Labrum - SL sternaler Gelenkfortsatz für die Coxa - spga laterale Spange der Galea - sprn Spermarinne des Pumpenkörpersklerites - St Sternum - Stg Stigma - STg Subtegula - Sti Stipes - sto Stylarorgan - T Tergum - TB Tentorialbrücke - TG Tegula - Thy Thyridium - Tn Trochantinus - Tr Trochanter - trs Transversalsutur des N₁ - ts Sulcus temporalis - u membranbekleidete Medialseite des Pumpenkörpersklerites - ub Unguitractorborsten - Un Unguis - Utr Unguitractor - Vx Vertex - w wulstartige Verdickung am Hinterende des Flügels des Pumpenkörpersklerites - wnkgr Winkelgruben - wnkz Winkelzähne - x Anhang am Hinterende der linken Genitalfalte - y caudales Ende der Genitalspalte - z l. Aufgabelung der Media - zi zipfelförmiger Anhang des Flügels des Pumpenkörpersklerites     

Wing-hearts in Mecoptera (insecta)

The accessory pulsatile organs for hemolymph circulation in the wings of 7 Mecoptera species were investigated by means of serial semi-thin sections, SEM and TEM. The wing-hearts are located in the dorsal meso- and metathorax, and have no connection to the aorta. Each wing-heart consists of a small hemolymph chamber formed above by the convex scutellum, and below by a horizontal muscular diaphragm. The chamber is connected to the posterior wing veins by a cuticular tube on each side of the body. The diaphragm (10–15 μm thick) is convex in cross-section and consists of transversely extended muscle fibers. Their ultrastructure reveals typical characters of myocardial and other visceral muscle fibers. The diaphragm muscle is innervated by a pair of thin nerves originating from the thoracic ganglion of each corresponding segment. The diaphragm is held in a convex position by numerous elastic strands (2 μm in diameter), which extend through the wing-heart lumen between the scutellum and the diaphragm. The diastolic phase of the wing-heart is caused by contraction of the diaphragm muscle fibers. Thus, the diaphragm flattens and hemolymph is drawn from the posterior wing veins. The systolic phase is caused by the elasticity of the suspending strands after relaxation of the muscle fibers. The elastic strands pull the diaphragm back into convex position and hemolymph is expelled out of the scutellum lumen into the thorax cavity through a valvular opening on the anterior side. The hemolymph flow from the posterior wing base to the scutellum lumen, was visualized by staining the hemolymph. In Panorpa communis the volume of the wing-heart lumen measures 1.6 × 10⁻² mm³ in the mesothorax, and 1.2 × 10⁻² mm³ in the metathorax. Each heartbeat transports a maximum of 65% of these volumes. The pumping frequency was 78 ± 20 beats per min, registered with a non-invasive photo-optical method in restrained animals. Corresponding pulsating movements occur as a passive phenomenon of wing-heart activity in a distinct area of the wing base. Only minor differences were found in the construction of wing-hearts among the investigated species, except for Boreus hyemalis, which lacks these accessory circulatory organs. The functional morphology of the wing-hearts in Mecoptera is compared with that of other Holometabola and aspects of the evolution of these organs are discussed.     

Die Geschlechtschromosomen in der Spermatogenese des Menschen

Ohne Zusammenfassung