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.     

Polymorphism in the somatic chromosomes ofNeotoma micropus Baird,the plains woodrat

Zusammenfassung Die somatischen Chromosomen von 100 Ratten (Wildfänge),Neotoma micropus Baird (Cricetidae), zeigen ein nicht-Robertsonsches polymorphes System mit 2 verschiedenen homologen Chromosomenpaaren. Sie stellen 4 verschiedene Rattenpopulationen mit Polymorphismus dar.

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Supported in part by an American Philosophical Society Grant from the Penrose Fund and a Texas Tech University Faculty Grant.     

Centromeric heterochromatin in the karyotype of the male Greater Kudu (Tragelaphus strepsiceros)

Summary The chromosomes of a male Kudu (Tragelaphus strepsiceros) have been studied by C-banding and H³ thymidine labelling. It is suggested that heterochromatin may have accumulated on the 14th pair of autosomes before its translocation to the Y-chromosome.     

Centromere nature of the chromosomes ofRanatra (Heteroptera)

Zusammenfassung Histologisch-cytologische Untersuchungen zeigen, dass die Chromosomen vonRanatra monozentrisch sind. Der Befund steht im Gegensatz zu Ergebnissen anderer Autoren an andern Heteroptera-Arten, die polyzentrische Chromosomen haben. Die Natur des Centromers ist also bei verschiedenen Arten der Heteropteren verschieden.     

The karyotype,C-bands and AgNO3-bands of a lungless salamander from Korea:Onychodactylus fischeri (Boulenger) (Amphibia,Urodela)

The karyotype of a lungless salamander,Onychodactylus fischeri, from Korea was analyzed and compared with that of the Japanese congeneric species,O. japonicus. In both species the diploid karyotype consists of78 chromosomes, including 6 pairs of large chromosomes, 6 pairs of medium-sized ones, and the remaining 27 pairs of microchromosomes. The chromosome number ofO. fischeri, 2n=78, is, like that ofO. japonicus, the largest so far reported in the order Urodela. C-banding showed that constitutive heterochromatin inO. fischeri was mainly in the centromeric regions and near the secondary constrictions of the large chromosomes. AgNO₃-bands were located in the secondary constrictions associated with C-band heterochromatin.     

Heterochromatin characterization and distribution in the chromosomes of two populations ofIdotea baltica basteri Audouin, 1826 (Isopoda,Valvifera)

Two mediterranean populations ofIdotea baltica basteri from Messina and Naples showed a set of chromosomes composed by 58 all-biarmed chromosomes. The heterochromatin was located in the pericentromeric region of the chromosomes, and its composition appeared heterogeneous. In fact, not all the homologs showed heterochromatin resistant to digestion with three restriction enzymes (Alu I, Hae III and Sau 3A). Moreover, the two populations showed polymorphism in a band of G+C-rich telomeric heterochromatin, which was present only in the population from Messina. It is hypothesized that chromosomal polymorphism might reflect the geographical isolation of the two populations. It is also suggested that a process of diversification is taking place.     

Somatic chromosomes of the flat-headed bats (Tylonycteris spp)

Zusammenfassung Zwei sympatrische, nahverwandte Fledermausarten,Tylonycteris pachypus (Temminck) undT. robustula Thomas, besitzen 46 beziehungsweise 32 Chromosomen, was offenbar den Robertson'schen Translokationen zuzuschreiben ist.     

The chromosomes of two species of the genusOryzomys (rodentia-cricetidae)

Resumen Oryzomys es un género altamente politípico y primitivo que ocupa un área geográfica que se extiende por todo el continente Sudamericano y el sur de Norteamérica. De este género se describen los cromosomas de dos especies pertenecientes al subgéneroOryzomys. O. albigularis (posiblementeO. a. camcolus) (2N=66) yO. delicatus (2N=60) cuyos cromosomas son fundamentalmente del tipo acrocéntrico o subtelocéntrico con algunos pares matacéntricos o submetacéntricos.     

Behavioral phenomenology of sleep (somatic and vegetative)

Conclusions The foregoing analysis of behavioral sleep phenomenology shows that the most significant factual and theoretical aspects of sleep can be logically organized only according to several criteria, it being impossible to choose a singli one as truly paradigmatic. For this reason an ordinal classification of sleep phases was preferred. This fact does not detract from the usefulness of classifications based consistently on 1 criterion at a time (e.g.: synchronized-desynchronized; quiet-active; orthodoxical-paradoxical; NREM-REM; homeostatic-poikilostatic; spindle wave-slow wave-fast wave; external appetitive-internal appetitive-internal consummatory; and so on). In this respect, the bioelectrical classification is surely the best as it allows an analytical subdivision of the evolution of sleep with high resolving power^137–139. In particular, the electroencephalographic activity of late phase II (stage 4 in man¹³⁹ and slow wave¹¹ or deep slow wave¹⁴⁰ sleep in the cat) appears to be related to the triggering mechanisms and to the quantitative regulation of the circadian amount of phase III^3,5,11,140. However, in extending the field of functional implications of sleep phenomenology other criteria may be more significant. In fact, the somatic and vegetative events of sleep also lend themselves to an analysis according to the behavioral model of ethology^6,141–144 and the theory of homeostasis^{3–5, 145}, respectively. As an example, a number of classifying criteria are indicated in the table, where others, particularly neurochemical ones^146,147, could be added. At any rate, the difficulty of organizing sleep events into a satisfactory operational scheme is due to the fact that sleep is still an open problem as far as its mechanisms and functional significance are concerned.     

Meiotic chromosomes of the small indian lark (Alauda gulgula gulgula)

Cellular and Molecular Life Sciences -     

The mitotic chromosomes of the lampreyMordacia mordax (agnatha: Petromyzonidae)

Résumé L'étude des chromosomes somatiques de la lamproie de l'hémisphère sud,Mordacia mordax (Richardson), montre que l'équipement chromosomique diploïde de cette espèce est composé de 76 chromosomes très petits. La plupart des chromosomes sont métacentrique ou bien submétacentrique. Ces chromosomes sont différents en nombre de ceux décrits pour les lamproies de l'hémisphère nord.     

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).