The karyotype ofDusicyon griseus (Carnivora canidae)

Resumen Se describe el cariotipo deDusicyon griseus el cual posee una fórmula cromosómica de2N=74 y un número fundamental (NF) de 76. Por otra parte, se entrega por primera vez información acerca de los cromosomas sexuales de una especie de este género. Desde este punto de vista llama la atención que el cromosomay es un microcromosoma.     

Cytogenic study of Lophocebus albigena (Primate Catarrhini Cercopithecidae). Description of a male karyotype

GTG chromosomic banding of a male and a female Lophocebus albigena is reported. The chromosome number of the karyotypes is 2 n = 42, characterized by a pair of marked chromosomes and a mediocentric Y chromosome, similar to that of the Lophocebus aterimus.     

Mitotic karyotype and nucleoli of the marbled newtTriturus marmoratus (Latreille)

Riassunto I cromosomi mitotici diTriturus marmoratus sono stati ordinati in cariotipo. Gli organizzatori nucleolari sono due per cellula, ma negli spermatogoni primitivi sono presenti numerosi nucleoli liberi.

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With financial support by Consiglio Nazionale delle Ricerche, Rome.     

The occurrence of an intermediate didelphid karyotype in the short-tailed opossum (GenusMonodelphis)

Resumen Se han estudiado los cromosomas de dos especies de didélfidos del géneroMonodelphis: M. brevicaudata palliolata del norte de Venezuela yM. dimidiata de la Prov. de Buenos Aires, Argentina. Ambas especies tienen un cariotipo muy similar, compuesto de 18 cromosomas. Este cariotipo es intermedio entre el que presentanCaluromys yMarmosa (2n=14) y el deDidelphis, Philander yLutreolina (2n=22). Se postula la fisión céntrica en dos pares de submetacentricos del primer tipo, para explicar el origen del cariotipo deMonodelphis.     

Distribution of constitutive heterochromatin (C-bands) in the somatic chromosomes of an Indian bird,Chrysomma sinense (Gmelin)

Summary The localization of constitutive heterochromatin has been studied in a passerine bird,Chrysomma sinense (2n=±70). In all the 7 pairs of macrochromosomes pericentric heterochromatin has been observed as usual except in pairs Nos 2 and 4, in which both pericentric and non-centromeric heterochromatin have been recorded.The authors are grateful to Prof. B. K. Behura, Department of Zoology, Utkal University, for necessary laboratory and library facilities. T.S. is grateful to the CSIR for providing financial assistance under the JRF scheme.     

Unusual distribution of constitutive heterochromatin (C-bands) in the somatic chromosomes of a passerine birdErithacus svecicus

Summary The distribution of constitutive heterochromatin (C-bands) has been studied in a passerine bird,Erithacus svecicus (Linnaeus) (Turdidae, Passeriformes, Aves) (2n=76±). In 7 out of 9 pairs of macrochromosomes pericentromeric heterochromatin has been observed. The smaller 2 pairs of macrochromosomes are entirely heterochromatic.The authors are grateful to Prof. B.K. Behura, P.G. Dept. of Zoology, Utkal University for extending laboratory and library facilities. T.S. is grateful to CSIR, India for providing financial assistance under SRF scheme.     

Characterization of the domestic horse (Equus caballus) karyotype using G-and C-banding techniques

Summary Giemsa banding techniques have been used to identify the chromosomes of the domestic horse.     

Chromosomes and the karyotype of the Pangolin,Manis pentadactyla L. (Pholidota-Mammalia)

Zusammenfassung In Knochenmarkzellen wurden die Chromosomen eines männlichen Pangolins (Manis pentadactyla L.) untersucht. Die Zahl der diploiden Chromosomen beträgt 36. Dieser zytologische Befund unterstützt die Ansicht, dass man die Pangoline in eine besondere Ordnung der Pholidota einreiht.     

Constitutive heterochromatin and nucleolus organizer region in the knifefish,Apteronotus albifrons (Pisces,Apteronotidae)

Summary The C-banding and silver staining of the chromosomes of the knifefishApteronotus albifrons (2n=24), demonstrated the presence of constitutive heterochromatin in the centromeric region of every chromosome, except pair 4, where the entire long arm was darkly stained, the silver stain positive nucleolus organizer region (NOR) being embedded in it.The authors are grateful to Dr Sen Pathak (University of Texas System Cancer Center at Houston, Texas, USA) and Dr Yatiyo Yassuda (Universidade de São Paulo, São Paulo, Brasil) for their suggestions. This study was supported in part by grants of the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq).     

The karyotype and genome structure of the pirate perchAphredoderus sayanus (Aphredoderidae: Teleostei)

Summary The standard karyotype, genome size (DNA content), and genomic DNA base composition and distribution of the relict paracanthopterygian fish,Aphredoderus sayanus, were investigated. Several features of theA. sayanus genome appear to be derived rather than primitive conditions. These include a large number (at least 10 pairs) of bi-armed chromosomes, a low genome size, and high DNA asymmetry. This may indicate thatA. sayanus is not a typical paracanthopterygian fish in terms of its genome structure.     

The karyotype ofOxymycterus sp (Cricetidae,Rodentia) from Central Brazil

Cytogenetical data, including G-, C-bands and NORs distribution ofOxymycterus sp (2n=54; FN=64) captured in Distrito Federal, state of Goiás, Central Brazil are presented. Our results are compared to the karyotype information already available on this genus.     

The golgi apparatus in the male germ-cells ofVaginula (Pulmonata)

Zusammenfassung Der Verfasser macht am Golgikörper der männlichen Geschlechtszellen vonVaginula eine Nachuntersuchung mit dem Phasenkontrastmikroskop und bestätigt, dass zwischen Golgikörperbildner und Akrosomgenese kein verwandtschaftlicher Zusammenhang besteht. Damit werden entgegenstehende Auffassungen vonNath widerlegt.     

Activation with (±)N-n-propyl-nor-apomorphine (NPA) of the male rat copulatory behavior

Summary I.p. (±)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.     

The karyotype ofTyphlonectes compressicauda (Amphibia: Gymnophiona) with comments on chromosome evolution in caecilians

Summary Typhlonectes compressicauda has a diploid number of 28. Its karyotype, when compared to that of other caecilians, suggests some discordance in the hypothesized model of chromosome reduction in the evolution of amphibian lineages.We thank Sharon B. Emerson and Diana Diehl, University of Illinois at Chicago Circle, for helping us to acquire specimens. The work was supported by National Science Foundation Grant DEB 77-22642 to MHW.     

Antigonadotrophic effect of melatonin in male lizards (Callisaurus draconoides)

Summary Results of a preliminary experiment indicate that injections of melatonin elicit testicular regression in male lizards having maximally recrudesced gonads at the outset of study.Supported by grants from the National Science Foundation (No. BMS74-04861), the American Philosophical Society (Penrose Fund), and the Biomedical Research program at Colorado State University.     

The potency of male accessory gland material in the mosquito (Aedes aegypti)

Summary Injections of male accessory gland material fromAedes aegypti into the hemocoeles of virgin female mosquitoes indicate that the potency of the secretion is equivalent to the amount of semen which a male normally places within the female. This estimation is far less than had been previously calculated. It is suggested that the termmatrone for male accessory gland material is inappropriate since it does not convert a maid into a matron but prevents reinsemination of an impregnated female.Scientific Article No. A2098, Contribution No. 5054 of the Maryland Agricultural Experiment Station.     

Activation with (+/-)N-n-propyl-nor-apomorphine (NPA) of the male rat copulatory behavior

I.p. (+/-)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.