Further studies on polyploid amphibians (Ceratophrydidawe)

Odontophrynus cultripes Reinhardt and Lutken, 1862 has 22 chromosomes in its diploid complement. Spermatocyte I contained 11 ring bivalents and metaphase II exhibited 11 chromosomes. Odontophrynus americanus (Duméril and Bibron) 1882 has 44 chromosomes in somatic as well as germ cells, these can be sorted into 11 groups of homologues. Metaphase I showed varying numbers of quadrivalents and metaphase II exhibited 22 dyads. Ceratophrys dorsata Wied., 1824 has 104 chromosomes in somatic and germ cells; these 104 chromosomes comprise 8 each of 13 kinds of homologues. The spermatocyte I contained ring octovalents and other multivalents, and metaphase II 52 chromosomes. The above findings indicate that evolution by polyploidization occurred in South American frogs belonging to the family Ceratophrydidae.This work was supported by a grant (GM-14577-01) from the National Institute of General Medical Sciences U. S. Public Health Service.     

The kinetochore fiber structure in the acentric spindles of the green algaOedogonium

Summary The microtubule (MT) arrangement in three kinetochore fibers in the acentric spindles of the green algaOedogonium cardiacum were reconstructed from serial sections of prometaphase and metaphase cells. The majority of the MTs attached to the kinetochore (kMTs) are relatively short, extending less than a third of the distance to the putative spindle pole region, and none extended the full distance. Fine filaments and a matrix described earlier (Schibler andPickett-Heaps 1980) were associated with the MTs all along the fibers. Live cells ofOedogonium were also studied by time lapse cinematography for correlation with the ultrastructural observations. Late prometaphase and metaphase kinetochore fibers appear to move independently as if unattached at their poleward ends. These observations suggest that kinetochore fibers inOedogonium are not attached to a specific pole structure from late prometaphase until the inception of anaphase. The results are discussed with reference to spindle structure and function in general.     

Ultrastructure of meiosis in the mossRhynchostegium serrulatum I. Prophasic microtubules and spindle dynamics

Summary An extensive system of microtubules develops during meiotic prophase in the mossRhynchostegium serrulatum (Hedw.)Jaeg. &Sauerb. Development of the cytoskeleton can be traced to early prophase when the nucleus is acentric and the single plastid divides into four plastids. The cytoskeletal microtubules are associated with equidistant positioning of the four plastids at the distal tetrad poles and with migration of the nucleus to a central position in the sporocyte. The cytoskeleton, which interconnects plastids and encloses the nucleus, contributes to the establishment of moss sporocyte polarity. Just prior to metaphase I evidence of the prophase cytoskeleton is lost as the bipolar metaphase I spindle develops in association with discrete polar organizers located in opposite cleavage furrows between plastids.     

Mitosis in the protostelidPlanoprotostelium aurantium

Summary Mitosis in the protostelidPlanoprotostelium aurantium Olive andStoianovich is characterized by an open, centric spindle. The nuclear envelope breaks down prior to metaphase, begins to reform during late anaphase, and is complete by telophase. Centrioles are present at the poles throughout mitosis and are devoid of rootlet microtubules from metaphase to late anaphase. Chromosomes are small and numerous and are attached to single kinetochore microtubules during metaphase and early anaphase. Chromosome separation takes place by a presumed shortening of the chromosome to pole spindle followed by a lengthening of the interzonal spindle. Mitosis inP. aurantium is similar to that of certain other protostelid amoebae and to myxomycete amoebae, but it is considerably different from that of dictyostelid amoebae. The phylogenetic significance of this is discussed.This research represents part of a Ph.D. dissertation presented to the University of North Carolina.     

The mitotic configuration of Chaetomium globosum

The somatic nuclear division ofChaetomium globosum was studied utilizing acetocarmin and aceto-orcein techniques. Nuclear division in hyphae of this species was found to be mitotic, but diversity in morphology and division configuration was noted. Identifiable chromosomes, the metaphase plate, and the chromosome bridge were commonly seen.A combination of extremely small nuclei, difficulties in staining, multinucleate conditions, and protoplasmic streaming in hyphae presented difficulties for these studies. Contradictory views are held on the structure of the nucleus, presence of the centriolar body, and other karyological features as described byFinley (1970)Rabinow &Bakerspigel (1965). Nuclear division structural details in a few other fungal species such as the centriolar body, spindle apparatus, and nuclear membrane disassociation have been examined by electron microscopy (Motta, 1969;Ichida &Fuller, 1968;Namboodiri &Lowry, 1967).The present study and the previous report onC. globosum (Hsu, Yu &Volz, 1972) presents comparative data for a NASA Appollo 16 MEED Mycology investigation now in progress.     

Vorkommen und Verteilung adrenerger Nervenfasern im Darm der Schleie (Tinca vulgaris cuv.)

Zusammenfassung Mit Hilfe der von Falck entwickelten histochemischen Methode zum Nachweis von Catecholaminen wird gezeigt, daß im Darm der Schleie (Tinca vulg.) die sympathischen Fasern vorwiegend in die glatte Muskulatur ziehen. Wie sich auf Grund weiterer histochemischer und pharmakologischer Versuche ergibt, ist die fluoreszierende Substanz, die innerhalb und außerhalb des Darmes in den Nervenfasern des Splanchicus und in Nervenzellen eines auf dem Oesophagus gelegenen Ganglion vorkommt, vermutlich Dopamin. In manchen Nervenfasern kommt außerdem eine fluoreszierende Substanz vor, deren histochemisches Verhalten darauf hindeutet, daß es sich um 5-Hydroxytryptamin handelt.

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Summary By means of Falck's method for the histochemical detection of catecholamines it is shown that in the gut of the tench (Tinca vulg.) the sympathetic nerve fibres are mainly distributed within the layer of smooth musculature. As shown by further histochemical and pharmacological tests, the fluorescent substance in the fibres of the splanchnic nerve inside and outside of the gut as well as in nerve cells of a ganglion situated on the oesophagus is most likely dopamine. In addition there is evidence for the presence of 5-hydroxytryptamine in some of the nerve fibres.

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Mit dankenswerter Unterstützung durch eine Sachbeihilfe der Joachim-Jungius-Gesellschaft zur Förderung der Wissenschaften, Hamburg.     

The sensory papilla X-organ in Boreomysis arctica (Krøyer) (Crustacea Malacostraca Mysidacea)

Summary The SPX-organ in Boreomysis arctica (Krøyer) (Crustacea Malacostraca Mysidacea) was investigated light and electron microscopically. The organ consists of a group of cells (the SPX-cells) and a vesicle surrounded by a connective tissue sheath. It is situated near the base of the sensory papilla of the eye-stalk. Neurosecretory material is produced in the SPX-cells and transported in axon-like projections from these cells into the vesicle. These processes contain no neurotubuli. Numerous fibres from an afferent nerve emanating from the medulla terminalis also enter the vesicle, where they form a dense irregular meshwork. This nerve transports no neurosecretory material. There are numerous synaptic contacts between the afferent nerve fibres and the neurosecretory processes from the SPX-cells. The neurosecretory material released from them accumulates in haemocoelic spaces in the vesicle. Release is most probably effected by the afferent nerve. Acknowledgements. We are indebted to Prof. H. Brattström and the staff of Biologisk Stasjon, Espegrend for working facilities and material. Mrs B. Morawetz and Mrs L. Eriksson gave us skilled technical assistance. The investigation was made possible by grants from the Swedish Natural Science Research Council.     

Meiosis in the male of Puto albicans (Coccoidea-Homoptera)

Cytologically, Puto has proved more primitive than its taxonomic position would indicate. In the single previously described example (Hughes-Schrader, 1944), an uncomplicated inverted meiotic sequence was described for the males. The present example, P. albicans, showed a significantly more primitive inverted sequence. Unlike the other examples reported for aphids and coccids, the chromatids of the dyads neither dissociated nor reassociated during interkinesis. Instead, they remained closely associated and interconnected by an unresolved terminal chiasmate attachment. At first metaphase, the spindle attachments were localized to a restricted region of the poleward surface of the chromatids. Localization of attachment during meiosis and close association of chromatids during interkinesis are both suggestive of similar but not identical conditions expected in ancestors with an uninverted meiotic sequence. A second species proved intermediate between P. albicans and that described by Hughes-Schrader in which a complete cycle of dissociation and reassociation occurred during interkinesis. In P. albicans the pachytene bivalents showed no structures suggestive of centric localizations. At their greatest condensation at first metaphase, the chromatids were clearly subdivided into half chromatids. Limited observations were made on chromosomes of other species of Puto and of Phenacoleachia zealandica, and also on spermiogenesis and mycetocyte formation in Puto. The discussion is devoted to considerations of chromatid subdivision, holokinetic chromosomes, and meiotic inversion and some evolutionary implications are mentioned.Supported by grant GB 4289 from the National Science Foundation.     

Studies of the effects of aminopterin on the crypts of Lieberkühn in rats

Summary Studies have been made on the effects of an intramuscular injection of aminopterin on the crypts of Lieberkühn in rats. A decrease in the mitotic counts was accompanied by a rapid increase in the number of abnormal cells present in the epithelium of the crypt. Three hours after administration of the aminopterin, an almost complete absence of true metaphase chromosoms was found. By 24 hours, a partial return towards normal mitotic activity was observed but the number of abnormal cells present was still very high. It is suggested that the mitotic changes are in keeping with the conclusion of Grampa and Dustin (1952) of an arrest at interphase but that a secondary arrest at metaphase cannot be excluded.A morphological feature of some of the abnormal cells was the presence of a Feulgen positive granule in the cytoplasm, which by electron microscopy was also shown to contain many cytoplasmic constituents. It is suggested that material is lost from the nucleus and incorporated into a granule in the cytoplasm. A possible explanation of the purpose and function of the granule, as a means of disposing of unwanted or aberrant material, is put forward. Acknowledgements. I am grateful to Professor R. J. Brocklehurst for his continued interest and support of this work, and to the Stage II, B. Sc. students (1964) who counted the cells in many of the specimens as a laboratory exercise. My thanks are also due to Mr. J. Clements for technical assistance.     

Measurement of the potential across the sieve plates in Vitis vinifera

Summary The electrical potential difference across the sieve plates in the primary phloem of Vitis vinifera was measured by inserting micro-electrodes into the sieve-tubes. The values obtained ranged from 4–48 mV. The potential across the transverse walls of the phloem fibres was also determined and found to range from I–II mV. These results are discussed in relation to the theory of translocation based on electro-osmosis put forward independently by Fensom and Spanner.     

Cytochemical localization and function of the 3-linked glucan callose in the developing cotton fibre cell wall

Summary Several recent biochemical studies concerning the hemicellulosic content of the developing cotton fibre wall have pointed to an important increase of 1,3-linked glucans at the onset of the secondary wall formation and their slow decrease until the end of fibre development (Meinert andDelmer 1977,Huwyler et al. 1978, 1979,Maltby et al. 1979). These almost insoluble glucans are extra-cellular and possibly associated with the S₁ or winding layer, but no other data on their exact localization were given.By means of a specific fluorescence method, using a 0.05% decolourized aniline blue solution, we show that one of these 3-linked glucans,callose, is always localized, independently of the fibre age, in the innermost wall layer bordering the cell lumen, from the onset of the secondary thickening up to the end of fibre development. Some possible roles assumed by these callose deposits are suggested and discussed. They may be involved in the normal mechanism of cellulose biosynthesis, as being effectively consumed by turnover or, more probably, as forming a permanently restored interface or matrix where cellulose microfibrils undergo a sort of maturation and are oriented before their definitive incorporation in the organized cell wall. They are not to be confused with the wound callose deposits which characterize damaged or immature fibres.     

Some observations on the mode of division of somatic nuclei of Mucor and Allomyces

Summary A series of successive photographs of the division of the living nucleus in a germinating sporangiospore of Mucor fragilis has been obtained. In this sequence the nucleus is seen to divide directly by elongation and constriction. The nucleolus divides at the same time and in the same way. These observations agree with the finding, first made by Léger (1896) and several times confirmed since then, that the nuclei of Mucorales apparently divide without first arranging their chromosomes in a metaphase plate and without the help of a spindle apparatus.In stained preparations of Mucor chromosomes are not normally visible as separate entities but they can be clearly seen in Feulgen preparations of dividing somatic nuclei of Allomyces arbuscula. In contrast to Mucor the nucleolus of Allomyces is dissolved during division. The chromosomes seem to sort themselves out on their own and form new nucleoli. Metaphase plates and spindles have not been encountered.To Professor Dr. E. G. Pringsheim, teacher and friend, on his 80th bithday.     

The fine structure of the olfactory tract in the teleost Carassius carassius L.

Summary Electronmicrographic montages of the olfactory tract at two levels in each of two fish (Carassius carassius L.) were constructed and fibre diameters measured using a Zeiss TGZ 3 particle size analyzer. Medial and lateral tract divisions, rhinocele and dorsal tela were identified. Ciliated ependymal cells line the rhinocele. Meninges form the outer covering of both tract divisions and the tela roofing the central canal.The lateral tract consists of 10–14 fasciculi in which myelinated nerve fibres are prominent. These fibres range in diameter between 0.2 and 1.8 (mean 0.7 ) consistent with conduction velocities averaging 0.6 m/sec recorded in the carp lateral olfactory tract.The medial division of the olfactory tract contains two larger fasciculi within which are numerous fine unmyelinated nerve fibres (mean diameter 0.17 ) arranged in bundles partly enveloped by glial cell processes. Myelinated nerve fibres are unevenly distributed within both fasciculi and have mean diameters of 0.6 .An interesting observation is the consistent presence of synapses within the largest bundle of the medial tract at all levels.Supported by Grant 5 Ro5 TW00154-03 from the National Institutes of Health, United States Public Health Service.The authors are indebted to the Fisheries and Wildlife Department who generously provided the fish from Snob's Creek Fish Hatchery, and gratefully acknowledge the technical assistance of Mr. T. Armitage, Mr. J. Simmons and Miss D. Harrison.     

Fluorescence studies on neural structures and endocrine cells in the pancreas of the cat

Summary With the use of the Falck-Hillarp histochemical technique for the detection of monoamines, nerve fibre fluorescence is observed throughout the tail of the pancreas of the cat and the arrangement and distribution of the nerve fibres can be studied in both the exocrine and endocrine tissue. In the exocrine pancreas, adrenergic nerve fibres innervate arterioles, larger veins and major pancreatic ducts. Adrenergic nerve fibres also appear to terminate on the non-adrenergic nerve cell bodies of the intrapancreatic ganglia. In the islets of Langerhans, adrenergic nerve fibres innervate both the endocrine cells and blood vessels. Some of the islet cells exhibit fluorescence with the Falck-Hillarp technique and these cells have been identified as alpha cells. In animals treated with reserpine, the fluorescence in nerve fibres and in alpha cells is absent.The author wishes to thank ProfessorG. C. Schofield and Dr.G. C. Smith for their encouragement and valuable criticism during the course of this study. The assistance of MissJ. Bennett and MissW. Kemp and the photographic help of Mr.J. S. Simmons, F.R.P.S., are gratefully acknowledged. The diagram was drawn by MissS. Flett.     

Holocentric chromosome behaviour inCuscuta (Cuscutaceae)

The present study demonstrates thatCuscuta babylonica Choisy has holocentric chromosomes. Evidence for this phenomenon comes from three different observations. (1) Mitosis: During metaphase and anaphase the sister-chromatids are situated parallel to the equatorial plane with no sign of localized kinetochore activity. (2) Inverted meiosis in microsporocytes. (3) X-rayed microsporocytes, in which the numerous chromosome fragments do not show any lagging or formation of micronuclei. We assume that only one out of the three subgenera inCuscuta, namely subg.Cuscuta, has holocentric chromosomes, while the two other subgenera have monocentric chromosomes.     

Light,fluorescence and electron microscopic studies on “neurosecretion” in tritonia diomedia bergh (Mollusca,Nudibranchia)

Summary Membrane-limited electron-dense inclusions designated as elementary neurosecretory granules have a characteristic distribution in cerebropleural ganglia of the nudibranch snail Tritonia diomedia. They occur in the neuropile and also in individual nerve fibres, connectives and commissures. These granules have been found neither in perikarya of nerve cells nor in proximal segments of their processes.Specific fluorescence obtained in Tritonia preparations with Sterba's pseudoisocyanin method for neurosecretory products has the same pattern of location.The distribution of stainable material in preparations prepared with ordinary neurosecretory procedures (chrome haematoxylin-phloxin after Gomori-Bargmann and paraldehydefuchsin after Gomori-Gabe) is similar to that described by different authors in other gastropods, but strongly differs from the locationof elementary neurosecretory granules and of pseudoisocyanin-positive material. The adequacy of different histological methods for studying neurosecretion in gastropods is discussed.     

Assignment of d-amino-acid oxidase gene to a human and a mouse chromosome

Summary. A part of d-amino-acid oxidase gene was amplified in the human and mouse by polymerase chain reaction. The amplified fragments were ligated to plasmids and then cloned. The plasmids containing the parts of d-amino-acid oxidase gene were biotinylated and hybridized to human and mouse metaphase chromosomes. The chromosomal slides were treated with fluorescein isothiocyanate (FITC)-conjugated avidin. The hybridized signals were amplified with biotinylated anti-avidin antibody and FITC-avidin. The chromosomes were counter-stained with diamidino-phenylindole for assignment of the signal to a specific band. Using this fluorescence in situ hybridization (FISH), d-amino-acid oxidase gene was assigned to human chromosome 12q23–24.1 and mouse chromosome 5E3-F. Since these regions are syntenic between human and mouse, the present results indicate that the locus for this enzyme has been conserved through evolution. Received July 11, 2000 Accepted November 10, 2000     

Catecholaminhaltige Nervenfasern im Hoden des Menschen

Zusammenfassung Mit Hilfe der von Falck und Hillarp entwickelten Methode zur fluoreszenzmikroskopischen Lokalisation von Catechol- und Tryptaminen konnten im Hoden und Nebenhoden des Menschen grünfluoreszierende Nervenfasern nachgewiesen werden. Sie bilden Geflechte um kleine Blutgefäße; einzelne Fasern ziehen durch das Interstitium und nehmen Kontakt mit Leydig-Zellen und der Lamina propria der Tubuli contorti des Hodens auf. An den Berührungsstellen kommen intensiv fluoreszierende Varicositäten vor.

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Summary The testis and epididymis of man was investigated by means of Falcks and Hillarps method for the fluorescence-microscopical detection of catechol- and tryptamines. It is shown that in the testis and epididymis there are nerve fibres containing catecholamines. These are located in small varicosities along the nerve fibres and particularly near their terminals. The nerve fibres form plexus around small blood-vessels. Some nerve fibres run through the interstitial tissue to approach Leydig-cells and others to approach the lamina propria of the tubuli contori of the testis.

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Mit dankenswerter Unterstützung durch eine Sachbeihilfe der Joachim-Jungius-Gesellschaft zur Förderung der Wissenschaften, Hamburg, an Prof. Fleischhauer.     

The fine structure of the light organ of the glowworm Lampyris noctiluca

Summary The four main parts of the glowworm light organ are the cuticle, the hypodermis, the photocyte layer and the reflector cell layer. The hypodermis is one cell thick and it contains hypodermic glands. These glandular cells have a lumen that opens to the outside of the cuticle. Projecting into the lumen are numerous microvilli. Between the hypodermis and photocytes are typical insect tunicated nerve fibres. They pass down between the photocyte and reflector layer cells. They do not appear to innervate the photocytes and they are thought to innervate adjacent muscle fibres or to be sensory. Tracheoles are commonly present between the photocytes but no tracheolar end organs are found. The photocytes contain amorphous granules, mitochondria, photocyte granules and a vesiculated reticulum. All, except the mitochondria, are absent from the reflector layer and so probably have some connection with light production. The reflector layer contains glycogen granules, clear spaces thought to be the sites of urate crystals, and membranous granules. The latter granules are sometimes found in photocytes adjacent to the reflector layer whilst amorphous granules are sometimes absent from these adjacent cells. So a cell layer with some features of the photocyte and reflector layer cells is present. These morphological findings are discussed with regard to the unknown function of the reflector layer and the control of light emission. Acknowledgments. We would like to thank Professor J. Z. Young and Dr. E. G. Gray for their advice and encouragement, Mrs. Jane, Astafiev for drawing fig. 1, Mr. S. Waterman for photographic assistance, Miss Cheryl Martin for secretarial assistance, and many colleagues for help in collecting specimens of glowworms.     

Actin Distribution in Mitotic Apparatus of Somatic Embryo Cells of Norway Spruce

F-actin distribution was studied in mitotic cells of embryogenic suspension culture of Norway spruce [Picea abies (L.) Karst.]. Actin was present in dividing cells of embryo head during whole mitosis. Transient co-localization of actin microfilaments with preprophase band of microtubules was observed. Weak actin staining occurred with non-kinetochor microtubular fibers in metaphase spindle. F-actin was not localized with kinetochore microtubular fibres in metaphase as well as with shortening kinetochore fibres in late anaphase. On the other hand, abundant actin microfilaments array was formed in the area of late anaphase spindle in equatorial level of the cell between separating chromatids. F-actin was also present in phragmoplast area in telophase. This revised version was published online in July 2006 with corrections to the Cover Date.