At least two penicillin-binding proteins, PBP 1D (74 K) and PBP 6B (34K), were found in the soluble fraction of Escherichia coli K-12. These PBPs were not observed in the cell envelope fraction and thus are thought to exist in the cytoplasm or in the periplasm of the cell. The PBPs in the soluble fraction did not release the bound [14C] penicillin G and appear not to possess penicillinase activity.
Chromosome studies were carried out in cultured cells from a mouse neuroblastoma. C1300 tissue and in three clones established from this tumor. They possessed characteristic karyotypes with remarkable markers. Double minutes (DMs) were demonstrated in all cell lines, in addition to some other chromosomes aberrations, such as microchromosomes and chromosome pulverization.
Segregation of 1/12 chromosome translocation occurring in Lewis-strain rats was studied with the data from mating between translocation heterozygous and normal rats. The translocation chromosomes segregated as expected in their offspring. In the offspring between the translocation heterozygotes, the number of the translocation heterozygotes was significantly larger, in contrast to the smaller number of the translocation homozygotes. Fertility of the translocation homozygotes, however, was rather superior in comparison with that of the normal rats.
Quercetin, a ubiquitous flavonoid, was found to induce chromosome aberrations and sister chromatid exchanges (SCEs) in cultured human and Chinese hamster cells without the application of metabolic activation systems. The increment in the frequency of SCEs was dose dependent, the maximum rates being 1.7-3.3 times the control values. The frequency of chromosome aberrations was elevated up to 1.5-7.8 times the highest control level, although clear dosage effects were obtained only in Chinese hamster cells.
Alb and Tf variations in Swamp, River and their crossbred buffaloes in Malaysia and the Philippines were analyzed by starch-gel electrophoresis. Three Alb phenotypes (AlbA, AX, X) were found in the Swamp, two phenotypes (AlbA, AB) in the River, and five phenotypes (AlbAB, B, AX, BX, X) in the crossbred buffalo populations. The AlbB gene existed only in the River buffaloes, whereas the AlbX gene existed only in the Swamp buffaloes with high gene frequencies. Their crossbreds had both genes. Also, the AlbA gene was observed in both types of the buffaloes. All of the Swamp buffaloes except one animal in Malaysia showed two Tf phenotypes (TfAD, D). The River buffaloes had three phenotypes: TfD, DE, E whereas the crossbred had five: TfAD, AE, D, DE, E. There was no TfA gene in the River buffaloes, and very few or no TfE gene in the Swamp buffaloes. The most common gene was TfD in the Swamp buffaloes (0.850-0.935), and TfE in the River buffaloes (0.750-0.906). Their crossbred had both TfA and TfE genes. Therefore, the distinct genetic differences were indicated between the Swamp and River buffaloes.