Comparison of the chromosomes of Triticum timopheevi with related wheats using the techniques of C-banding and in situ hybridization

Summary The chromosomes of the tetraploid wheats Triticum timopheevi (Genome AAGG) and T. araraticum (Genome AAGG) were C-banded at mitosis. The identity of the banded and unbanded chromosomes was then established by firstly making comparisons with the hexaploid species T. zhukovskyi which has the genome formula AAAAGG. Secondly, the meiotic pairing in F₁ hybrids between T. timopheevi and diploid wheats was examined by means of C-banding. The results showed that the banded chromosomes belonged to the G genome, while the unbanded chromosomes belonged to the A genome. Only one of the two pairs of satellited chromosomes had strong heterochromatic bands. The relationship between the genomes of T. timopheevi and T. dicoccum (Genome AABB) was then assessed at meiosis in hybrids between these species, using the techniques of C-banding and in situ hybridisation of a cloned ribosomal RNA gene probe. It was concluded that there were differences both in the amount and distribution of heterochromatin and also translocation differences between the species.     

Predominance of gonadotropin α-subunit resulting from preferential loss of hCGβ production in an established cell line

Summary The BeWo line of trophoblastic cells, maintained in continuous culture since 1966, was employed to investigate the phenomenon of gonadotropin α-subunit predominance that exists in several cell lines. The secretion of complete human chorionic gonadotropin (hCG) relative to α-subunit was compared in several different BeWo sublines, all of which were derived from BeWo stock roller tube colonies. In all of the BeWo sublines, secretion of hCG originally exceeded secretion of α-subunit. With time in culture, however, there was a marked decline in production of hCG/hCGβ, but not in α-subunit. Thus it appears that the production of hCGβ by BeWo choriocarcinoma cells is more labile than the production of the α-subunit.     

Pokeweed mitogen inhibition of protein synthesis in cultured lymphoblastoid lines

Summary Pokeweed mitogen (PWM) and ricin are both lectins derived from plant seeds. They are glycoproteins and share the ability to agglutinate a variety of animal cells including erythrocytes. The effect of these two lectins on protein synthesis was studied in four longterm lymphoblastoid lines (8866 and GM1531, which are B cell lines; and CCRF/CEM and MOLT 4, which are T-cell lines). Ricin (50 μg/ml) completely inhibited protein synthesis by 2 hr in both B-cell and T-cell lines as measured by the uptake to [³H]leucine. The PWM appeared more specific and at a concentration of 500 μg/ml inhibited protein synthesis only in B-cell lines (8866 and GM 1531). This effect was maximal at 5 hr. To investigate the reason for the differential effect of PWM on T and B cells,¹²⁵I-labeled PWM was incubated with 8866, MOLT 4, and CCRF/CEM to see if a significant difference in binding to B cells and T cells could be demonstrated. It does not appear that the differential effect on T and B cells is due to a difference in the amount of PWM bound. On the other hand it is possible that the B cells may bind some toxic subcomponent of the PWM preparation that the T cells do not bind because of a difference in composition or arrangement of cell surface glycoproteins.     

Two relative efficiencies of polymorphic enzymes for characterizing cell lines,detecting contaminations,and monitoring transplants

Summary A new calculation of the relative efficiency of polymorphic enzyme markers, called the REB, was determined and compared with one of Fisher's determinations of the relative efficiency called REA here. The REA estimates the chance of failing, and 1-REA of succeeding, to show a phenotypic difference between two randomly selected persons or cultured cell lines (Case 1). In this study it was shown that the REA also estimates the chance of detecting a cell line mislabeling or similar mixup (Case 2) and a cell line cross-contamination leading to the complete replacement of an original line by contaminating line (Case 3). The new REB determines the probability of failing, and 1-REB of succeeding, to detect a contamination of an original line by another line leading to their coexistence, or at least a sufficiently long period of transitional coexistence before one overgrows the other. The REA and REB also apply to determining the efficiency of polymorphic markers in detecting donor and recipient cells in tissue transplants. This work was developed from the author's involvement in the human tumor cell-line characterization project at Sloan-Kettering Institute and he acknowledges this opportunity and the benefits of his association with Dr. J?rgen Fogh and colleagues in the Human Tumor Cell Laboratory.     

Characterization of WiDr: A human colon carcinoma cell line

Summary We describe the establishment and characterization of WiDr, a cell line derived from a human colon carcinoma. It produces carcinoembryonic antigen in culture, and has a doubling time of 15 hr with plating efficiency of 51%. The HLA antigenic profile and the allozyme genetic signature (composed of eight gene-enzyme systems) of WiDr cells are different from those of HeLa cells. Furthermore, WiDr cells possess three marker chromosomes, again distinct from the HeLa marker chromosomes. Finally, it is highly tumorigenic in four different xenogeneic animal models. Based on these studies, WiDr represents a useful model cell line for tumor cell biology investigations.     

Antimetabolic activities of 2-fluoro-L-histidine.

2-Fluoro-L-Histidine inhibits protein synthesis in various cell cultures, as measured by ³H-leucine incorporation. This histidine analog also inhibits the cytopathogenicity of a number of RNA and DNA viruses in primary and continuous cell cultures; it blocks the transformation of normal mouse (MO) cells by murine sarcoma virus, and partially suppresses the release of murine leukemia virus by a continuously infected mouse cell line (JLSV5). In human skin fibroblasts, it reduces the interferon-inducing capacity of poly(I)·poly(C). Inhibition of cell protein synthesis may be the common cause of the various effects. 4-Fluoro-L-histidine is essentially inert in all of the test systems examined.     

Sex and side differences and correlations between quantitative palmar characteristics in a sample Sardinian population

Differences between the sexes and between the sides and the correlations between four quantitative characteristics of palmar dermatoglyphics in a sample population of 809 individuals (418 males and 391 females) from the city of Cagliari, Sardinia, are tested. Males have a greater number of ridges than females, shown by a greater a-b ridge count and A-d ridge count, and a more transverse slope of the main lines, shown by a greater main line index and papillary number. The left palm shows a greater number of ridges than the right palm between the A line and the triradius d and between the triradii a and b, with a lower main line index and papillary number. The a-b ridge count has a negative correlation with the main line index and with the papillary number and a positive one with the A-d ridge count; these correlations are greater in the left palms, especially in the males.     

Cryopreservation of cell line Paesun by a rapid cooling

The purpose of the present study was to clarify the possibility of a rapid cryopreservation for cell line Paesun by cooling in the range of 30–40 °C/min to vapor phase of −120 ∼-140 °C before immersion into liquid phase of liquid nitrogen using 10% Me₂SO. After thawing, these cells were examined with assaying viability by trypan blue exclusion staining and survival by cloning in monolayer; the percentages of cell and colony recovery obtained in rapid cooling had a tendency to be lower than that by slow cooling of 1 °C/min but there were no significant differences between them. In addition, post-thaw cells were examined by assaying proliferation and susceptibility to virus lines; there were no significant differences between before and after cryopreservation. In conclusion, these findings indicate that Paesun can be successfully cryopreserved by the rapid cooling rate of 30 °C–40 °C/min.