The effect of 12-O-tetradecanoylphorbol-13-acetate on hormone-induced differentiation of rat parotid gland in organ culture

Parotid glands of 5-day-old rats were maintained in DM-153 synthetic, serum-free medium in organ culture for 24 to 48 hr. Differentiation of acinar cells in vitro, as revealed by an increase in amylase activity in the gland and in the culture fluid, as well as by the immunocytochemical demonstration of amylase in the acinar cells, was accelerated by insulin, prednisolone, and l-thyroxine added to the culture medium. The potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate (10^?7M) inhibited both the unstimulated and hormone-stimulated differentiation of the gland without causing cellular degeneration or necrosis.     

Author index for Volume 121, Number 1

Transformation of primary rat kidney cells with specific genome fragments of oncogenic human adenovirus type 12 provides a suitable model for the study of separate phenotypic manifestations of (tumorigenic) transformation. In this model, oncogenic transformation by specific virus fragments was accompanied by the appearance of a new, high-molecular-weight class of glycoprotein-bound carbohydrates similar as observed in a variety of spontaneous and experimental tumors. These tumor-associated carbohydrate changes were absent on the surface of nontumorigenic cells, morphologically transformed by other Ad 12 genome fragments or on untransformed control cells. It is concluded that tumor-associated changes in membrane carbohydrates are expressed simultaneously with a 60kD T antigen required for oncogenicity. These changes in carbohydrate composition can be distinguished from those induced by morphological transformation and growth per se.     

The synthesis of coliphage T1 DNA: Degradation of the host chromosome

T1 derives most of the thymine for synthesis of its DNA from the host DNA. Nevertheless, degradation of host DNA to acid-soluble products cannot be observed even when synthesis of phage DNA is inhibited. The methods of inhibition were infection of a nonpermissive host with amber mutants with a DO (no DNA synthesis) phenotype, infection of a nonpermissive host with an amber mutant with a DA (DNA synthesis arrest) phenotype, shift to a nonpermissive temperature after infection with a ts mutant with a DO phenotype, and addition of nalidixic acid. We conclude that degradation of the host chromosome is linked to ongoing synthesis of phage DNA. During T1's development cycle, the bacterial nuclear region maintains a normal appearance by electron microscopy. Filling and filled phage heads are observed chiefly near the boundary of the nuclear region.     

RNA tumor virus phosphoproteins: subvirion location of the multiple phosphorylated species.

An analysis of core particles of 1.23 g/cm³ density of the endogenous feline type C virus (RD-114) showed the presence of all of the major low molecular weight structural proteins, namely p30, p12, p10, and the phosphoprotein pp15, in relative proportions similar to those detected in intact RD-114 virions. The protein kinase activity of the virus was also found to be associated with the core. A comparison of the content of multiple phosphorylated species of the pp15 derived from the core with that isolated from the whole virion demonstrated that all major phosphorylated species of RD-114 pp15 were located in the core structure.     

Inherited aplastic anemia with abnormal clones in bone marrow and increased endoreduplication in peripheral lymphocytes

Cytogenetic studies in peripheral blood and bone marrow cells from a female patient (aged 31 years) with inherited aplastic anemia and without other congenital anomalies are reported. Endoreduplication was increased in stimulated peripheral lymphocytes in several investigations. Chromosome breaks were shown to be near the control frequency, although chromatid exchange figures and dicentrics were present. Cytogenetic analysis was extended to the three children of our patient. Abnormal clones were detected in bone marrow preparations of our patient in all cytogenetic investigations. At the first examination, two of these clones were prevalent, with their karyotypes being 48,XX,+9,+16 and 46,XX,dup(1)(q24→q32),t(17;?)(p12–13;?). The prevailing karyotype after 2 years was 46,XX,t(17;?)(p12–13;?). Involvement of chromosomes #1 and #17 is discussed, taking into account data from the literature concerning several human neoplasias.     

Membrane-bound antiviral antibodies as receptors for Sendai virions in receptor-depleted erythrocytes

Anti-Sendai virus antibodies were covalently coupled to neuraminidase-treated human erythrocytes by the use of the bifunctional crosslinking reagents, N-succinimidyl-3-(2-pyridyldithio)propionate or succinimidyl-4-(p-maleimidophenyl)butyrate. Neuraminidase-treated erythrocytes bearing antibodies were able to bind Sendai virus particles, while treated erythrocytes lacking the antibodies failed to do so. Virus particles attached to erythrocyte membranes via the antibodies were able to cause hemolysis (virus-cell fusion) and promoted cell-cell fusion. Similar results were obtained when the antibodies were coupled to cat erythrocytes which lack receptors for Sendai virus particles. Reconstituted Sendai virus envelopes, similar to intact virus particles, were able to hemolyze and to induce fusion of neuraminidase-treated antibody-bearing erythrocytes. However, reconstituted envelopes containing inactive HN (hemagglutinin-neuraminidase) but active F (fusion) glycoproteins, despite attachment to antibody-bearing erythrocytes, failed to hemolyze or to induce cell-to-cell fusion. Fusion could be restored by insertion of an active HN glycoprotein into the membranes of the reconstituted envelopes. These results suggest that the HN glycoprotein, besides being the viral attachment protein, also participates in the membrane fusion process.     

Double minutes and other chromosomal aberrations in two malignant cell lines of the German cockroach Blattella germanica

Structural anomalies of mitotic chromosomes from two tumorigenic cell lines of the German cockroach (Blattella germanica) is described. Aberrations, such as unpairable marker chromosomes, double minutes, di- and tricentrics, ring chromosomes, tri- and quadriradials, and chromosome and chromatid gaps and breaks, were observed in varying proportions. This study reports that the double minute chromosomes (DMs) are associated with insect tumor cells, similar to the findings in both murine and human tumor cells.