DNA synthetic rates among cells of populations in vitro

Zusammenfassung In vitro gezüchtete Hühnerembryozellen werden mit³H-Thymidin oder¹⁴C-Thymidin «pulse-labeled», wobei «grain counts» und DNS-Gehalt in individuellen Zellen gemessen werden. Für keine der beiden Isotopen wurde eine Beziehung zwischen DNS-Gehalt und «grain count» gefunden, woraus folgt, dass die Geschwindigkeit der DNS-Synthese von Zelle zu Zelle variiert.     

High genetic variability despite haplodiploidy in primitive sawflies of the genusCephalcia (Hymenoptera,Pamphiliidae)

Hymenoptera are haplodiploid and usually display very low genetic variation. Most data concern social or parasiticApocrita, while the little information available for the primitive phytophagous species of the suborder Symphyta is contradictory. The present study is related to seven species of the genusCephalcia, living in coniferous forests of Northern Eurasia and sharing spruce (Picea sp. pl.) as host plant. Individuals from 22 populations belonging toCephalcia abietis, C. alashanica, C. arvensis, C. erythrogaster, C. fallenii, C. fulva, C. klugii from Europe and China were surveyed for genetic variation at 28 loci using enzyme electrophoresis. Pairs of sibling species were recognized withinC. arvensis andC. fallenii, corresponding to different phenological and morphological forms. In the latter case, reproductive isolation in sympatry occurs despite low genetic distance (D=0.059). Large genetic distances and fixed alternate alleles were observed between Chinese and European populations ofC. abietis andC. arvensis. Expected heterozygosity ofCephalcia populations (0.197, SD 0.064) is significantly higher than that of other Symphyta (Tenthredinoidea) (averageH _exp 0.059, SD 0.032) (two-tailed Mann-Whitney test, Z=4.39, p<0.01). These data suggest that haplodiploidy per se does not reduce the genetic variation in mostCephalcia populations. Most of the factors that can lower the potential for genetic diversity in a haplodiploid genetic system are not so effective inCephalcia populations, which seem to be comparable to diplodiploid insect populations in diversity. In a few isolated populations the large number of fixed loci and the large genetic distances may support the predicted faster rate of fixation, as a consequence of haplodiploidy.     

Adrenal gland growth of the ovine fetus in the end of gestation: evolution of DNA and of membrane proteins]

The adrenal weight of the ovine fetus increases dramatically during late pregnancy. This increase is achieved in three periods: one of DNA duplication between two phases of cellular hypertrophy. During cellular hypertrophy an important biosynthesis of membrane proteins is observed. This development concerns essentially the adrenal cortex.     

Glutamine synthetase,an enzyme characteristic of vertebrate systems in invertebrate tissues

Zusammenfassung Nachweis eines Invertebraten-Enzyms, das bei Vertebraten insbesondere im Nervengewebe eine wichtige Rolle spielt. Diese Glutamin-Synthetase wurde vor allem im optischen Ganglion in der Retina und im Gehirn zweier Tintenfischarten gefunden und überdies in sehr geringer Menge bei Crustaceen und Echinodermen.

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We wish to acknowledge the support of NSF Grant No. GE-19211 to J.E.M. during this study.     

Localization of human A,B and H isoantigens in Cynomolgus monkey tissues

Summary The presence and distribution of human A, B and H isoantigens were demonstrated in Cynomolgus monkey (Macaca fascicularis) by means of red cell adherence test. Although no human antigens were found on primate erythrocytes, various epithelial tissues revealed the presence of A, B or H antigenic substance. The distribution and localization was similar to that found in human tissues. Majority of specimens from each individual animal possessed only 1 human type isoantigen with the exception of the salivary and sweat glands, where all animals showed the presence of H antigen in addition to other specificity, and of Brunner's gland, where all sections reacted positively also for A antigen.     

Changes in acid phosphatase activity in 6 tissues of the fifth instar milkweed bug,Oncopeltus fasciatus

Summary Acid phosphatase activity in the hemolymph and cuticle was higher during the early part of the fifth instar than at any other time. The enzyme activity in the fat body, testes, salivary glands, and midgut was statistically the same throughout the instar.Acknowledgment. This research was supported in part by NSF grant GB 26542-Al to D. F.     

Replication of intranucleolar DNA in smittia (diptera,chironomidae)

Riassunto Ghiandole salivari di larve diSmittia (Chironomidae) sono state incubate in vitro in presenza di timidina tritiata. Le modalità di marcatura dei cromosomi e dei nucleoli dimostrano che in questo materiale non esiste correlazione tra frequenza di marcatura del DNA intranucleolare e modalità o intensità di marcatura del DNA cromosomico. In particolare sono stati riscontrati casi in cui il DNA intranucleolare appare marcato mentre il DNA cromosomico non è in fase di replicazione. I risultati ottenuti sembrano indicare che il DNA intra-nucleolare inSmittia sia costituito da una o più unità di replicazione autonome.     

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.     

Paratopic interaction,a mechanism in the generation of structure bound enzymatic activity

Summary A general mechanism is recognized that can cause specific enzymatic activity at interphases. It consists of 2 proteins bound in close juxtaposition at a micelle or membrane surface. One, the enzymesensu strictu, bears the active site, the other, the paraenzyme, is essential for generation or specific modification of the enzymatic activity.     

DNA,a controlling factor in the conversion of plasminogen to plasmin

Résumé Les résultats de ces études démontrent la formation de «complexes» entre l'acide désoxyribonucléique et la plasminogène. L'acide désoxyribonucléique inhibe l'action catalytique de la plasminogène humaine sur la plasmine.