Spatial and temporal expression of the period gene in Drosophila melanogaster

The temporal and spatial expression of the period gene of Drosophila melanogaster has been analyzed by examining the expression of a per beta-galactosidase fusion gene in transformants and by in situ hybridization experiments with wild-type flies. Several strains of Drosophila melanogaster, transformed with the fusion gene, have been generated. The gene is active in mid-late embryos in the midline of the nervous system. Thereafter, beta-galactosidase activity is undetectable until the pupal stage when the prothoracic gland-corpora allata and the optic lobes are beta-galactosidase positive. In adults a surprisingly large number of tissues stain positively, including antennae, proboscis, eyes, optic lobes, cells of the central brain, cells of the thoracic ganglia, gut, Malpighian tubules, and ovarian follicle cells. The temporal pattern of expression agrees well with previous estimates made from developmental Northern blots with RNA extracted from wild-type animals. We suggest that many of the tissues that express the per gene contain their own intrinsic oscillator activity.

[Isolation of a metastatic ascitic subpopulation from a human lung adenocarcinoma cell line in nude mice and studies on its biological properties]

An ascitic subpopulation (Anip) was isolated from human lung adenocarcinoma cell line AGZY-83-a through serial intraperitoneal passages in nude mice. Anip manifested a much higher metastatic potential than the parent line. Spontaneous lung metastases occurred in 95% of the mice xenografted intraperitoneally, and the diffuse pattern of the metastases in the lung was very impressive. Anip also differed more or less from the parent line in morphology, growth, rate, electrophoretic mobility, platelet aggregating activity and noticeably in the chromosome histogram. The present model may be used in the study of tumor invasion and metastasis, as large amounts of well dispersed metastatic human carcinoma cells could be reproduced by ascites and much information about the biology of invasion and metastasis of human tumor cells in nude mice could be obtained.

[Effect of sodium selenite on the chromosomal aberration of V 79 cells induced in vitro by MNNG and MNU]

Effect of sodium selenite on chromosomal aberration of V 79 cells induced by MNNG and MNU was studied. Na2SeO3 alone, at the concentration of 10(-7)-10(-4) M, increased the incidence of chromosomal aberration. However, Na2SeO3 at 10(-7)-10(-5) M, having been preincubated with the cells for 4 hours, could reduce the number of cells with chromosomal aberration induced by MNNG. Na2SeO3 at 10(-7)-10(-4) M inhibited mutagenic activity of chromosomal aberration induced by MNU. The same inhibition was observed even sodium selenite was added to the medium simultaneously with this carcinogen. The results indicate that sodium selenite alone, at the concentration range used in this experiment, is an aberration-inducing agent. But when combined with the carcinogen, anti-cancer effect is obtained.

[Sister chromatid exchanges (SCE), chromosomal aberrations and micronuclei of cultured peripheral lymphocytes in patients with lung cancer, miners and non-mining workers of the tin mine in Yunnan]

Determination of SCE frequency, chromosomal aberration and micronucleus rate of cultured peripheral lymphocytes in 32 patients with lung cancer, 33 miners and 40 non-mining workers in Yunnan Tin Mine was carried out. The results showed that the cancer patients had higher SCE incidence, chromosomal aberration and micronucleus rate, the non-mining workers had the least and miners on an intermediate level. There was a significant difference of SCE, chromosomal aberrations and micronucleus rate between patients and non-mining workers (P less than 0.05-0.01). We also found that miners had a significant higher SCE and chromosomal aberration rate but not micronucleus rate as compared with the non-mining workers. We proposed that some carcinogens present in the Yunnan Tin Mine be responsible for the genetic damages in the miners. Chemical drugs may be considered to contribute to the genetic damage in cancer patients who had a tendency toward an increased SCE, chromosomal aberration and micronucleus rate as compared to the miners, though without reaching a statistical significance. We suggested that combination assay of SCE with chromosomal aberration or micronucleus be an useful index for screening of the high risk population and monitoring the chemical drug prevention of lung cancers in Yunnan Tin Mine.

Bioavailability of selenium to residents in a low-selenium area of China

For 8 wk 5 groups of 10 men each were given 0.5 g/day DL-methionine, 150 micrograms Se/day as sodium selenite with or without methionine or 150 micrograms Se/day as selenomethionine with or without methionine. Twenty subjects received placebo as controls. Initially plasma Se rose more rapidly than RBC Se. Increases in Se levels were significantly greater with selenomethionine than with the selenite supplement. In the placebo and methionine supplemented groups neither plasma nor RBC Se varied significantly over the course of the study. Supplementation with selenium resulted in marked increases in plasma and RBC GSH-Px within 2 and 4 wk, respectively. Plasma and RBC GSH-Px activity did not differ significantly between Se-supplemented groups. These studies suggest that selenomethionine-Se was more effective in raising plasma and RBC Se than was selenite-Se. Methionine supplements may increase the bioavailability of selenium in severely deficient subjects.

Establishment of lymphoblastoid cell lines from Marek's disease primary tumors

Seven lymphoblastoid cell lines were developed from 15 Marek's disease primary lymphomas treated to remove adherent cells (46.7% success rate) and 1 cell line was developed from 15 untreated lymphomas (6.7% success rate). These cell lines are designated as MDCC-RP22 through MDCC-RP29. Tumor materials were from 151(5) x 7(1) chickens infected with either JM-111S clone or the GA-22 clone of Marek's disease virus. Factors contributing to the establishment of cell lines include, in addition to the removal of adherent cells at the initial stage of culture, the periodic adjustment and the concentration of viable cells, including the removal of dead cells. The cell lines bear T-cell surface markers and Marek's disease tumor associated surface antigen (MATSA). MDCC-RP22 and MDCC-RP23 are high virus producers.

Comb lesions and mortality patterns in white leghorn layers affected by Marek's disease

Marek's disease was diagnosed as the cause of prolonged high mortality in two commercial flocks of white leghorn layers by gross and microscopic examination of affected tissues and by immunofluorescent study of live tumor cells using anti-Marek's disease tumor-associated surface antigen, anti-immunoglobulin M, and monoclonal antibodies. The disease was characterized by swollen, necrotic, lymphomatous combs and mortality that rose above normal at 28 weeks of age, peaked at 35-36 weeks, and returned to normal by 45-46 weeks.

A monoclonal antibody reactive with Marek's disease tumor-associated surface antigen

An antibody-secreting hybridoma, RPH-6, to Marek's disease tumor-associated surface antigen (MATSA) was produced by somatic-cell hybridization between the mouse myeloma SP2/O-Ag/14 and spleen cells from MSB1 immunized mice. The antibody reacted with 95 to 100% of the cells from eight of 10 chicken MD cell lines and one of two turkey MD cell lines. It did not react with chicken MD cell lines RP1 and SK3, turkey MD cell line RP19, lymphoid leukosis (LL) cell lines, RP9 and RP12, and reticuloendotheliosis virus (REV) cell line RP14. A weak reaction was observed with REV cell line RP13 (10 to 20%), and a very slight reaction with normal chicken spleen cells (1 to 5%). RPH-6 produces immunoglobulin of the IgM class. Cell culture and mouse ascitic fluids have titers of 10(2) and 10(6), respectively, by fluorescent antibody (FA) test against MD tumor cell lines. The antibody did not react with Marek's disease virus (MDV) internal antigen or membrane antigen as detected by indirect FA test on chicken embryo fibroblast cultures grown on coverslips. The 51Cr release assay showed RPH-6 is highly cytotoxic (60% release) only against MD lymphoblastoid cell lines, with antibody prepared from mouse ascites having a cytotoxic titer approaching 10(6). Results from using RPH-6 for differential diagnosis of chicken lymphoid tumors of unknown origin were in complete agreement with those obtained with rabbit anti-MATSA reference serum and pathologic diagnosis.

Monoclonal antibodies with specificity for three different serotypes of Marek's disease viruses in chickens

A total of 50 antibody-secreting hybridoma cells against Marek's disease virus (MDV) and turkey herpesvirus (HVT) have been produced. Eleven hybridomas were used for serotyping a panel of 15 pathogenic and nonpathogenic strains of MDV and HVT, representing three serotypes. The antibodies from the culture medium have fluorescence antibody (FA) titers of up to 100 and those from mouse ascitic fluid have titers ranging from 10(4) to 10(6). Monoclonal antibody T81 is type-common, i.e., it reacts at equal titer with all MDV and HVT tested. Of the remaining 10 antibodies, eight react only with pathogenic and attenuated strains of MDV (presumably serotype 1), one reacts only with nonpathogenic MDV (presumably) serotype 2), and one reacts only with strains of HVT (presumably serotype 3). Two hybridomas belong to IgG2a and IgG2b subclasses, respectively, and the remaining nine belong to IgG1 subclass. None of the antibodies specific for MDV strains reacted with homologous viruses in serum neutralization (SN), agar gel precipitin (AGP), or membrane immunofluorescence tests. Antibody L78, which is specific for HVT, was reactive with its homologous virus in the SN test; antibody from the culture medium showed an SN titer of 10 and that from mouse ascites a titer of 10,000. None of the antibodies specific for MDV or HVT reacted with other avian or mammalian herpesviruses, avian leukosis viruses (ALV), reticuloendotheliosis viruses (REV), or Marek's disease tumor-associated surface antigen (MATSA) expressed in a lymphoblastoid cell line, MDCC-MSB-1.