Ring chromosomes and leukaemia

Summary The observation of 2 leukaemic patients with ring chromosomes, and their comparison with a few previously reported cases, suggests a close association between this rare chromosomal abnormality and erythroleukaemia and indicate a poor prognostic significance of this finding.     

Induction of uncoiled chromosomes by vibration.

Chromatin condensation during metaphase can be removed by simple vibration of metaphase cells prior to fixation. Uncoiled chromosome arms consist of long threads with dense regions at irregular distances each from the other.     

X.85、X.86和城域网多业务环X.msr

本文主要介绍武汉邮科院代表信息产业倍在电联SG17最近几年所提出的三个技术标准X．85（IP over SDH using LPAS)、X．86(Ethernet over LPAS)和城域网多业务环X.msr，以及芯片、设备开发和应用的情况。     

Giemsa centromere staining ofHumulus lupulus L. Metaphase chromosomes

Summary Giemsa staining of hop (Humulus lupulus L.) chromosomes at metaphase revealed kinetochore-like structures in the centromeric region.The authors are grateful to Dr C. K. Atal, for his keen interest and constant encouragement in the present study.     

Naturally occurring translocation dicentric chromosomes and somatic reduction inLathyrus sativus L.

Summary A naturally-occurring case of terminal translocation resulting into end-to-end association of somatic chromosomes, and mitotic anaphase movement without chromatid separation in a variety ofLathyrus sativus is reported.     

Bridges between chromosomes

Résumé Dans les cultures de cellules du triton, les ponts interchromosomaux peuvent se former dans les figures métaphasiques sous l'influence d'une solution hypotonique. Ce résultat, obtenu au microscope à la lumière ordinaire, pose la question de savoir si les ponts déjà décrits dans les micrographes électroniques sont également dus à l'emploi des solutions hypotoniques.     

Galactose induced Balbiani-ring-like structures in chromosomes I and II of Chironomus thummi.

In one strain of Chironomus thummi, galactose feeding of the larvae induced the appearance of 2 Balbiani-ring-like structures on salivary gland chromosomes I and II. This phenomenon may be related to the galactose induction of BR6 in C. pallidivittatus.     

The mitotic chromosomes of the lamprey,Petromyzon marinus L.

Résumé L'étude des chromosomes somatiques de la lamproie,Petromyzon marinus L. a montré que l'équipment chromosomique diploïde de cette espèce est composé de 168 chromosomes très petits, dont queleues-uns des plus grands sont métacentriques. Le chiffre semble représenter le plus grand nombre de chromosomes trouvé dans une espèce de Vertébré. On a comparé les chromosomes de P.marinus avec ceux des autres espèces de lamproies.

---

---

Holder of a Science Research Council Fellowship.     

Accessory chromosomes inPhysalis ixocarpa

Zusammenfassung Das Vorkommen eines Neben-Chromosoms ist zum ersten Mal in der GattungPhysalis festgestellt worden. Das kleine Chromosom besitzt ein in der Mitte liegendes Centromer und tritt sowohl bei der Mitose, wie auch bei der Meiose in Erscheinung. Pflanzen mit diesem Chromosom sind steril.     

Evolution and biology of supernumerary B chromosomes

B chromosomes (Bs) are dispensable components of the genome exhibiting non-Mendelian inheritance and have been widely reported on over several thousand eukaryotes, but still remain an evolutionary mystery ever since their first discovery over a century ago [1]. Recent advances in genome analysis have significantly improved our knowledge on the origin and composition of Bs in the last few years. In contrast to the prevalent view that Bs do not harbor genes, recent analysis revealed that Bs of sequenced species are rich in gene-derived sequences. We summarize the latest findings on supernumerary chromosomes with a special focus on the origin, DNA composition, and the non-Mendelian accumulation mechanism of Bs.     

Chromosome studies of oriental anophelines. I. The salivary gland chromosomes ofAnopheles barbirostris

Zusammenfassung Es werden verschiedene tropische Anophelesarten, besonders die orientalische, cytogenetisch untersucht. Es wird eine Standard-Chromosomenkarte vonAnopheles barbirostris van der Wulp (Typ der Barbirostris-Gruppe einer orientalischen Region und zur Serie Myzorhynchus, der Untergattung Anopheles gehörend) als erste der Serie orientalischer Anophelesarten vorgeschlagen.     

Structural correspondence between nucleolus- and sphere-organizing regions of the lampbrush chromosomes and secondary constrictions of the mitotic chromosomes

Riassunto Le regioni nucleolo-e sfera-organizzatrici dei «lampbrush chromosomes» diTriturus alpestris apuanus corrispondono a costrizioni secondarie presenti sui rispettivi cromosomi mitotici. Questo dato ripropone l'interesse per lo studio dell'origine e del significato delle sfere negli ovociti in accrescimento.

---

---

With financial support by C.N.R., Rome.     

Association of human satellited chromosomes

Résumé On présente ici les résultats de l'examen de trois cents cellules humaines métaphasées afin de démontrer que dans le karyotype humain, tous les acrocentriques ont une part active dans l'association des satellites. Les chromosomes acrocentriques homologues aussi bien que les chromosomes acrocentriques non-homologues laissent voir ce phénomène avec des fréquences relativement hautes.

---

---

Acknowledgments: I would like to thank Mr. B. McLaverty for helping with the chromosome preparations.     

Action of diphenylhydantoin on chromosomes

The effect of diphenyl hydantoin, (DPH) a nonbarbituate anticonvulsant drug, on chromosomes and fertility was tested in cultured human lymphocytes, mouse fertility, and rat maternal marrow chromosomes and fetal development. Whole human blood from 5 male and 5 female subjects was cultured for 68 hours with phytohemagglutinin, then incubated for 2 hours in isotonic salts with .05-.3 mg per ml DPH, .02 mcg per ml colchicine, or .4 mg per ml sodium diethylbarbiturate. The mean number of metaphases per 1000 stimulated cells was 10.0 in controls, 40.3 with colchicine, 27.9 with diethylbarbiturate, and 30.5 with .25 mg DPH per ml. Both diphenylbarbiturate and DPH produced linear dose effect curves. These results were demonstrated not to be due to urea, since there were no differences in urea content, with a 2 hour urease micromethod. Mouse fertility was totally inhibited in 6 virgin mice given .1mg DPH daily for 10 days compared to 41 pups both of 6 control mice. In 6 pregnant rats given 25 mg DPH per 100 gm/orally 4 times daily for 2 days on gestation Days 7 and 8, there were 5 rats with all fetuses resorbed and 1 rat with 3 living and several resorptions. 6 controls had 6-14 normal fetuses each. 50 metaphase plates from each rat's femoral marrow and each fetus were examined 2 hous after injecting .3 mg colchicine per 100 gm. 30% of the metaphase cells from treated females and fetuses showed strongly contracted chromosomes and reduced number os "pulverized" chromosomes. These phenomena may have been due to inhibition by DPH of folic acid metabolism which is involved in purine synthesis.