The increased population of the Wild Boar (Sus scrofa L.) in Europe

In this paper the recent population changes of the Wild Boar in different European countries is analysed through the study of hunting statistics. A simultaneous increase in numbers is observed throughout the whole area during the period 1965–1975. From 1975 onwards the population stabilizes itself apart from in peripheral areas like Finland. Potentially favourable factors which play a part in this process are discussed and certain reproductive and dispersive characteristics which favour its invasive behaviour are discussed.     

Uptake of glycine-N15 by components of cell nuclei

1. The uptake of glycine-N¹⁵ by components of cell nuclei was studied. The nuclear components were derived both from tissues with high metabolic rates-mammalian liver, kidney, and pancreas-and from cells with relatively low rates of metabolism-avian erythrocytes and echinoderm sperm. N¹⁵ uptake by nuclear components of liver, kidney, and pancreas was far more rapid than by those of erythrocytes and sperm. 2. The nuclear components of liver, kidney, and pancreas for which measurements were made were DNA, histone, and residual protein of chromatin. Uptake into DNA was low, into histone higher, and into residual protein much higher still, being comparable with that into mixed cytoplasmic protein. 3. A comparison of the uptake of N¹⁵ by the chromosomal components, histone and DNA of liver, pancreas, and kidney showed that chromosomal "activity" varies in different cells and also in the same cell depending upon its over-all activity.     

Purine and pyrimidine contents of some desoxypentose nucleic acids

The distribution of purines and pyrimidines in desoxypentose nucleic acids prepared from a variety of animal and plant sources has been studied. 1. The nucleic acids were prepared from calf thymus, calf kidney, sheep spleen, horse spleen, chicken erythrocyte, turtle erythrocyte, trout sperm, shad testes, sea urchin sperm, wheat germ, and Pneumococcus Type III. 2. Separate hydrolyses were carried out for the determination of purines and pyrimidines. These procedures permitted nearly quantitative recovery of nucleic acid phosphorus in many of the preparations examined. 3. In the case of those preparations where a quantitative recovery was obtained it can be concluded that no bases other than adenine, guanine, thymine, and cytosine were present in appreciable amounts. 4. The distribution of purines and pyrimidines in all the nucleic acids studied renders the tetranucleotide hypothesis untenable. 5. The results of the analyses have indicated no great differences in the composition of these nucleic acids with respect to purines and pyrimidines.     

Some aspects of the desoxyribonuclease activities of animal tissues

It has been found that many animal tissues contain "acid" desoxyribonucleases with pH optima near 5.2. A chemical method for the determination of this activity is described. The pancreatic desoxyribonuclease crystallized by Kunitz and shown to have a neutral pH optimum occurs in the pancreas together with the "acid" enzyme, but only the "neutral" enzyme occurs in the pancreatic juice. The ratio of "neutral" to "acid" DNAase activities in the pancreas is greater than 200, but in all other tissues examined there is no appreciable concentration of the neutral enzyme. It is concluded that neutral DNAase, like trypsin or lipase, has a digestive function. Some problems in the activation of the secretory enzyme in neutral pancreatic extracts are described. This activation can be interpreted in terms of a specific inhibitor or an inactive form of the enzyme. A comparison of the "acid" DNAase activities of different organs of the calf, horse, chicken, mouse, and rat indicates a possible connection between the DNAase concentration of a tissue and its capacity for proliferation or regeneration. However, the comparative DNAase activities of fetal and adult tissues do not support the view that DNAase function is limited to some simple role in the mechanics of cell division. Studies on the incorporation of glycine-N¹⁵ into the desoxypentose nucleic acids of avian red cells, and mouse liver, pancreas, and kidney show that the N¹⁵ uptake into the DNA of the chromosome is most rapid in tissues with high DNAase concentrations. No N¹⁵ incorporation is observed in the DNA of avian red cells, which have negligible concentrations of the enzyme. The analyses of tissues and nuclei isolated in non-aqueous media show that the bulk of the enzyme occurs in the cytoplasm of the cell, and that nuclear concentrations vary from tissue to tissue. A theory relating the DNAase activity of the cell to its over-all desoxypentose nucleotide metabolism is discussed. No evidence has been found for the presence of inhibitors of the "acid" DNAase in animal tissues.     

Chromosome numbers in Brazilian species of Crotalaria (Leguminosae, Papilionoideae) and their taxonomic significance

Chromosome numbers were counted for 23 species of Crotalaria native to Brazil. Among these data there were new counts for 15 taxa, and some confirmed previous reports or represented numbers that were different from those cited previously. The chromosome numbers most frequently found were 2 n  = 16 and 2 n  = 32. Only C. incana L. had 2 n  = 14 and C. tweediana Benth. had 2 n  = 54. The counts 2 n  = 32 and 54 were found in species of section Calycinae and 2 n  = 16 and 14 in species of section Chrysocalycinae . The data revealed the importance of chromosomal parameters in the characterization of sections Calycinae and Chrysocalycinae in Brazil. We discuss the systematic significance and evolutionary aspects for the genus, comparing the results with the two sections that are native in Brazil.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 271–277.