Karyotype and DNA content of Pharctolaemus ansorgei Blgr. (Teleostei: Gonorynchifomes).

The diploid DNA content of Pharctolaemus ansorgei spinosus (Phractolaemidae) is estimated by Feulgen cytophotometry at 3 pg. The karyotype has 28 chromosomes and 54 chromosome arms; it significantly resembles the karyotype of Chanos chanos (Chanidae).     

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 diploid deoxyribonucleic acid (DNA) content of basal cell carcinomas in man

Zusammenfassung Der Desoxyribonukleinsäuregehalt ist bei Basalzellkarzinomen diploid im Tumor selbst, weicht jedoch bei invadierenden Stellen nach Diploidie ab.     

Artbastarde in der GattungTilapia (Cichlidae,Teleostei) und ihr Verhalten

Summary The young ofTilapia mossambica (mouth-brooder) show a characteristic contact-behaviour, which is related to the behaviour of the mother fish, who takes them back into the mouth cavity in cases of disturbance. This contacting is lacking in the young ofTilapia tholloni (substrate spawner). Contacting, as studied in our experiments with models, is genetically determined and is dominant over thetholloni pattern in the crossT. mossambica ×T. tholloni .     

Karyotype of South American pampas ofPseudalopex gymnocercus (Carnivora,Canidae)

Summary The karyotype of the pampas fox has 2n=74 and a NF=76. Except forChrysocyon brachyurus, 2n=74 is a common diploid number for the South American Canidae. This number is higher than in theVulpes group and lower than in the group of the typicalCanis. No marker chromosomes are present in the South American Canidae.     

Karyotype of the ‘Carpincho’Hydrochaeris hydrochaeris uruguayensis (Rodentia Hydrochaeridae)

Resumen Se describe por primera vez el cariotipo del roedor mas grande existente, el que posee2n=66 chromosomas.     

Increase in muscle fibres in the lateralis muscle (white portion) of Mugilidae (Pisces,Teleostei)

Summary A cycle of postlarval growth is described in the white portion of the lateralis muscle of Mugilidae. The cycle was identified histochemically by the myosin-ATPase reaction.This work was supported by a CNR grant (Oceanografia e fondi marini project).     

The nuclear content of DNA in three different strains ofArtemia salina leach (Phyllopoda,Branchiopodidae)

Zusammenfassung DNS-Messungen an Interphasekernen vonArtemia salina parthenogenetica 2n undArtemia salina anfigonica zeigen ein Mengenverhältnis von 1.21, während zwischenArtemia salina parthenogenetica 4n undArtemia salina anfigonica DNS Werte im Verhältnis 21 gefunden wurden.     

Epigenetic control of pectoral fin web shape inLipophrys canevae (Blennidae,Teleostei)

Summary Between the lower pectoral fin rays ofL. canevae the fin web shows a saw-like regression. Hypermorphic fin web growth can be induced by fin ray amputation distal to the site of fin web attachment, but not by injuring the fin web alone.Acknowledgement. The financial support by the Austrian Fonds zur Förderung der wissenschaftlichen Forschung is gratefully acknowledged (Proj. Nr P7311B to GPW).     

Karyotype and chromosome banding in the Turkish desert woodlouseDesertellio elongatus (Crustacea,Isopoda, Oniscidea)

The karyotype ofD. elongatus was investigated by means of C-banding, silver staining, and mithramycin-and quinacrine fluorescent staining. The diploid chromosome number is 2n=50. C-banding shows pericentromerically localized constitutive heterochromatin in every chromosome. Two of the chromosome pairs carry two telomeric nucleolus organizer regions each. No heteromorphic sex chromosomes were found.     

Karyotype and chromosome banding in the reed frogHyperolius viridiflavus ommatostictus (Amphibia,Anura, Hyperoliidae)

Summary C-banding and mithramycin staining were used to characterize the karyotypes of 10 specimens of the African reed frogHyperolius viridiflavus ommatostictus from Tanzania. The diploid chromosome number is 2n=24. Although no heteromorphic sex chromosomes were present in the mitotic karyotypes, in many diakineses of male meiosis one or two bivalents exhibited an end-to-end arrangement. In the laboratory 7 out of 24 females changed sex spontaneously. This indicates that an XY/XX system of sex determination operates inH. viridiflavus ommatostictus.This study was supported by the Deutsche Forschungsgemeinschaft (Schm 484/2-4). We thank K. E. Linsenmair and C. M. Richards for helpful comments on an earlier draft.