Transcriptional induction of two genes in human cells by beta interferon

The binding of interferons to distinct cell surface receptors leads to the induction of synthesis of several unique polypeptides and their corresponding mRNAs (1-6). We have isolated two cDNAs that are complementary to nuclear RNA whose synthesis is induced from undetectable levels to maximal rates of transcription within 30-60 min after the addition of beta interferon to human fibroblasts or to HeLa cells. These results prove that a single polypeptide can, by binding to a specific plasma membrane receptor, promptly activate the transcription of a defined set of genes.

Characterization of diesel exhaust in a chronic inhalation study

We describe characterization of the exposure atmosphere in a life-span study of rats and mice exposed to chronic inhalation of diluted diesel exhaust. Diesel exhaust was generated by one of two General Motors 1980 Model, 5.7-liter V8 diesel engines connected to an eddy current dynamometer/flywheel system and operated on the Federal Test Procedure urban driving cycle. Animals were exposed 7 hours/day, 5 days/week to exhaust at particle concentrations of approximately 7000, 3500, and 350 micrograms/m3 or to clean air. Throughout the 24-month study, the mean particle mass concentration remained within 5% of the target values. Measured gas concentrations of CO, CO2, NO, NO2, and hydrocarbons were roughly proportional to the dilution ratio. A combination of a Lovelace Multijet cascade impactor followed by a parallel flow diffusion battery gave mass median diameters of 0.23 to 0.26 microns averaged over complete cycles and geometric standard deviations larger than 4. The aerosol concentration profile was associated with the operating cycle. The measured diesel particle size was similar to previously reported values of particles released to the atmosphere from the same model engine.

Different mRNAs induced by interferon in cells from inbred mouse strains A/J and A2G

Treatment of cells from inbred mouse strains A/J and A2G with interferon resulted in the development of different antiviral states for influenza viruses. A2G mice-derived cells that carry the resistance gene Mx were efficiently protected by interferon against influenza viruses, whereas the interferon protection against the same viruses in wild-type A/J mice-derived cells was only marginal. The two cell types, however, were equally protected by interferon against vesicular stomatitis virus and other non-orthomyxoviruses. The interferon-induced mRNAs of mouse embryonic fibroblast cells that carried either homozygous wild-type alleles or homozygous Mx alleles were compared. The isolated polysome-bound mRNAs from A/J (+/+) and A2G (Mx/Mx) cells were translated in a cell-free translation system, and the translation products were analyzed after two-dimensional gel electrophoresis. New mRNAs coding for at least eight proteins with molecular weights (MW) ranging from 30,000 to 80,000 were found in interferon-treated cells but not in control cells. Differences in the interferon-induced mRNAs from A/J and A2G cells were also found. An mRNA coding for a 72,000-MW protein was found in interferon-treated A2G cells but not in interferon-treated A/J cells. Interferon-treated A/J cells, on the other hand, contained an mRNA coding for a 65,000-MW protein that was not found in interferon-treated A2G cells. The in vitro-synthesized 65,000-MW protein efficiently bound to GMP. Cytoplasmic extracts prepared from interferon-treated A/J cells also contained a GMP-binding 65,000-MW protein that was undetectable in similarly treated A2G cells.

Interferon induction of fibroblast proteins with guanylate binding activity

Treatment of human diploid fibroblastic cells with interferon induces the synthesis of two guanylate binding proteins (GBP) with molecular weights of 67,000 and 56,000. The Mr = 67,000 protein (67K GBP) is synthesized upon treatment with either alpha-, beta-, or gamma-interferon. Among these interferons, gamma-interferon induces a higher level of 67K GBP synthesis. The 67K GBP synthesized in either beta- or gamma-interferon-treated cells has two charge forms with isoelectric points of 6.0 and 5.8, respectively. The synthesis of the Mr = 56,000 protein is induced by the treatment using either alpha- or beta-interferon, but its synthesis in gamma-interferon-treated cells is undetectable. The amounts of the radioactive GBPs synthesized in human fibroblasts are proportional to the amounts of the purified beta-interferon used for the inductions. Syntheses of GBPs require the transcription of cellular genes because their syntheses are completely blocked by actinomycin D treatments. The mRNA for the 67K GBP is found in fibroblasts that are treated by either alpha-, beta-, or gamma-interferon, but it is not detected in untreated cells. More 67K GBP mRNA is accumulated in the gamma-interferon-treated than in alpha- or beta-interferon-treated fibroblasts. This is consistent with more 67K GBP synthesis found in gamma-interferon-treated fibroblasts.

Characterization of a phosphotyrosyl protein phosphatase activity associated with a phosphoseryl protein phosphatase of Mr = 95,000 from bovine heart

A cytosolic phosphoprotein phosphatase of Mr = 95,000 purified from bovine cardiac muscle, which contains a catalytic subunit of Mr = 35,000, is known to be associated with a Mg2+-activated p-nitrophenyl phosphatase activity. We have found that the enzyme preparation is also active toward phosphotyrosyl-IgG and -casein phosphorylated by pp60v-src, the transforming gene product of Rous sarcoma virus. The properties of this phosphotyrosyl protein phosphatase activity closely resemble those of the p-nitrophenyl phosphatase activity but sharply differ from those of the phosphorylase phosphatase activity. Comparative studies of the activities of the Mr = 95,000 phosphatase, bovine kidney alkaline phosphatase, and ATP X Mg-dependent phosphatase toward phosphoseryl, phosphothreonyl, and phosphotyrosyl proteins and p-nitrophenyl phosphate under various conditions have been carried out. The results indicate that the Mr = 95,000 enzyme exhibits higher activity toward phosphoseryl and phosphothreonyl proteins than toward phosphotyrosyl proteins, while the kidney alkaline phosphatase preferentially dephosphorylates phosphotyrosyl proteins. ATP X Mg-dependent phosphatase is inactive toward phosphotyrosyl proteins.

Elemental analysis of freeze-dried thin sections of Samanea motor organs: barriers to ion diffusion through the apoplast

Leaflet movements in the legume Samanea saman are dependent upon massive redistribution of potassium (K), chloride (Cl), and other solutes between opposing (extensor and flexor) halves of the motor organ (pulvinus). Solutes are known to diffuse through the apoplast during redistribution. To test the possibility that solute diffusion might be restricted by apoplastic barriers, we analyzed elements in the apoplast in freeze-dried cryosections of pulvini using scanning electron microscopy/x-ray microanalysis. Large discontinuities in apoplastic K and Cl at the extensor-flexor interface provide evidence for a barrier to solute diffusion. The barrier extends from the epidermis on upper and lower sides of the pulvinus to cambial cells in the central vascular core. It is completed by hydrophobic regions between phloem and cambium, and between xylem rays and surrounding vascular tissue, as deduced by discontinuities in apoplastic solutes and by staining of fresh sections with lipid-soluble Sudan dyes. Thus, symplastic pathways are necessary for ion redistribution in the Samanea pulvinus during leaflet movement. In pulvini from leaflets in the closed state, all cells on the flexor side of the barrier have high internal as well as external K and Cl, whereas cells on the extensor side have barely detectable internal or external K or Cl. Approximately 60% of these ions are known to migrate to the extensor during opening; all return to the flexor during subsequent closure. We propose that solutes lost from shrinking cells in the outer cortex diffuse through the apoplast to plasmodesmata-rich cells of the inner cortex, collenchyma, and phloem; and that solutes cross the barrier by moving through plasmodesmata.

A model for aerosol deposition in the human tracheobronchial region

An aerosol deposition model in the human tracheobronchial tree based on impaction and sedimentation is proposed. Using this model, a mean deposition radius of conducting airways can be obtained from in vivo T-B deposition data or from physical dimensions of human lung casts. Agreement was found between the model and deposition data for three normal healthy subjects in the literature. Contributions of sedimentation to T-B deposition is estimated to be 42 - 78% at 250 cm3/sec average inspiration flow rate, and decreased to 8-29% at 750 cm3/sec average inspiration flow rate. Mean deposition radii are estimated to be 0.33 to 0.43 cm and correlate with pulmonary functional residual capacities.

Association of phenotypic reversion of transformed cells induced by interferon with morphological and biochemical changes in the cytoskeleton

The distribution of microfilament bundles, intermediate filaments, microtubules, vinculin plaques, and extracellular fibronectin matrices was examined by indirect immunofluorescence in X-ray-transformed C3H/10T1/2 cells. The transformed phenotype correlated with a lack of actin cables and vinculin-containing plaques. Prolonged treatment of these transformed cells with interferon resulted in a reversion of the transformed phenotype which was associated with the reappearance of extensive microfilament bundles together with vinculin-containing plaques. Both interferon-treated and untreated transformed cells displayed a similar distribution of mitochondria, intermediate filaments, microtubules, and fibronectin. Significant qualitative and quantitative differences between the two types of cells were found in the proteins associated with the cytoskeletal framework by two-dimensional gel analysis.

Expression of keratin and vimentin intermediate filaments in rabbit bladder epithelial cells at different stages of benzo[a]pyrene-induced neoplastic progression

Rabbit bladder epithelium, grown on collagen gels and exposed to the chemical carcinogen benzo[a]pyrene, produced nontumorigenic altered foci as well as tumorigenic epithelial cell lines during 120-180 d in culture. Immunofluorescence studies revealed extensive keratin filaments in both primary epithelial cells and benzo[a]pyrene-induced altered epithelial foci but showed no detectable vimentin filaments. The absence of vimentin expression in these cells was confirmed by two-dimensional gel electrophoresis. In contrast, immunofluorescence staining of the cloned benzo[a]pyrene-transformed rabbit bladder epithelial cell line, RBC-1, revealed a reduction in filamentous keratin concomitant with the expression of vimentin filaments. The epithelial nature of this cell line was established by the observation that cells injected into nude mice formed well-differentiated adenocarcinomas. Frozen sections of such tumors showed strong staining with antikeratins antibodies, but no detectable staining with antivimentin antibodies. These results demonstrated a differential expression of intermediate filament type in cells at different stages of neoplastic progression and in cells maintained in different growth environments. It is apparent that the expression of intermediate filaments throughout neoplastic progression is best studied by use of an in vivo model system in parallel with culture studies.

Stabilization of a degradable protein by its overexpression in Escherichia coli

Synthesis of proteins in Escherichia coli using recombinant DNA methodology has become an important tool for isolating and studying proteins. However, the E. coli protein degradation systems can interfere with the expression of cloned genes. To examine the effect of protein degradation, we have cloned the X90 allele of the E. coli lacZ gene. The X90 allele, an ochre mutant, codes for beta-galactosidase lacking approx. 12 amino acids from the carboxyl terminus. The X90 protein is rapidly degraded in wild-type E. coli. Randomly sheared DNA fragments from lambda placZ-X90 were inserted into the EcoRI site of the plasmid pOP203-UV5-3, a derivative of pMB9 containing the lactose operator-promoter region. Recombinant plasmids that carry the lacZ-X90 gene were identified by the Lac+ phenotype of their transformants in an ochre-suppressor-containing host and the Lac- phenotype in Su degrees or supE hosts. One recombinant plasmid, p41, with an insert of 7.6 kb codes for the synthesis of the X90 promoter at a quantity equal to or greater than 50% of the total cellular protein of several strains. In contrast to the normal situation, the X90 molecules synthesized in great excess from the plasmid are stable in Su degrees hosts and can be recovered primarily from the 10 000 X g pellets of sonication lysates. The surprising stability of the overproduced X90 protein may be due to the formation of proteinaceous aggregates.

Detection of phosphotyrosine-containing 34,000-dalton protein in the framework of cells transformed with Rous sarcoma virus

Phosphotyrosine-containing 34,000-dalton protein is detected by treatment of a two-dimensional gel of cellular framework with 1 M NaOH at 40 degrees C for 1 hr. The alkali-resistant 32PO4-labeled 34,000-dalton protein is detected in various cell lines transformed by Rous sarcoma virus but not in lines transformed by simian virus 40, polyoma virus, herpes simplex II virus, adenovirus type 2, or chemical carcinogens. In addition, interferons or fibronectin matrices have no detectable effect on the phosphorylation of the 34,000-dalton protein in Rous sarcoma virus-transformed cells.

Diffraction-limited imaging through a phase-distorting medium

An achromatic method of seeing through a phase-distorting medium, such as a turbulent atmosphere, utilizes a grating interferometer. Measurements are made at sample points throughout the region of fringe formation. A set of nonlinear simultaneous equations is generated and then solved by computer.

Isolation and characterization of mutations in the structural gene for protease III (ptr)

Escherichia coli mutants defective in protease III were isolated by enzyme assays of heavily mutagenized colones. One mutant produced thermolabile enzyme, and it is presumed to have a mutation in the structural gene of protease III. Two other mutants mapping at the same site had less than 5% of the wild-type protease III level. The genetic locus of these mutations, designated ptr, was located at approximately 60 min on the E. coli linkage map based on its high frequency (70%) of contransduction by P1 with argA. Strains with less than 5% of the wild-type protease III activity grew normally and degraded nonsense fragments of beta-galactosidase at wild-type rates.

Purification and characterization of protease III from Escherichia coli

An endoproteolytic enzyme of Escherichia coli, designated protease III, has been purified about 9,600-fold to homogeneity with a 6% yield. The purified enzyme consists of a single polypeptide chain of Mr 110,000 and is most active at pH 7.4. Protease III is very sensitive to metal-chelating agents and reducing agents. The EDTA-inactivated enzyme can be reactivated by Zn2+, Co2+ or Mn2+. Protease III is devoid of activity toward aminopeptidase, carboxypeptidase, or esterase substrates but rapidly degrades small proteins. When fragments of beta-galactosidase are used as substrates for protease III, the enzyme preferentially degrades proteins with molecular weights of less than 7,000. Protease III cleaves the oxidized insulin B chain at two sites with an initial rapid cleavage at Tyr-Leu (16-17) and a second slower cut at Phe-Tyr (25-26).

Characterization of a Bacillus cereus protease mutant defective in an early stage of spore germination

Temperature-sensitive sporulation mutants of Bacillus cereus were screened for intracellular protease activity that was more heat labile than that of the parental strain. One mutant grew as well as the wild type at 30 and 37 degrees C but sporulated poorly at 37 degrees C in an enriched or minimal medium. These spores germinated very slowly in response to alanine plus adenosine or calcium dipicolinate. During germination, spores produced by the mutant rapidly became heat sensitive, but released dipicolonic acid and mucopeptide fragments more slowly than the wild type and decreased only partially in density while remaining phase white (semirefractile). In freeze-etch electron micrographs, the mature spores were deficient in the outer cross-patched coat layer. During germination, the spore coat changes associated with wild-type germination occurred very slowly in this mutant. Although the original mutant was also a pyrimidine auxotroph, reversion to prototrophy did not alter any of the phenotypic properties discussed. Selection of revertants that germinated rapidly or sporulated well at 37 degrees C, however, resulted in restoratin of all wild-type properties (exclusive of the pyrimidine requirement) including heat-stable protease activity. The reversion frequency was consistent with an initial point mutation, indicating that a protease alteration resulted in production of spores defective in a very early stage of germination.

Characterization and function of intracellular proteases in sporulating Bacillus cereus

Intracellular proteases from sporulating Bacillus cereus have been purified by ammonium sulfate fractionation, heat treatment and DEAE cellulose column chromatography. After the last purification step, two protease activities, with an activity ratio of about thirty to one are resolved. Both proteases are resistant to o-phenanthroline but sensitive to phenyl methyl sulfonyl fluoride. Their separation by polyacrylamide gel electrophoresis and DEAE cellulose column chromatography, their difference in heat sensitivity and a mutation affecting only the major intracellular protease (IP1) suggest that the two are products of distinct genes. An IP1 mutant previously shown to produce coat defective spores (4) also turnsover protein with a reduced rate during late sporulation stages. Correlated with the slower turnover rate in this mutant is the more rapid disappearance of IP1. A partial revertant of this mutant has a protein turnover rate intermediate between that of the original mutant and wild type. These correlations imply that IP1 has an important role in protein turnover during sporulation.

Pregnancy in liver cirrhosis and/or portal hypertension

Clinical features of pregnancy in women with liver cirrhosis and/or portal hypertension have been reviewed. Termination of pregnancy is seldom indicated in a woman with compensated cirrhosis or a young woman with extrahepatic venous obstruction. However, the risk of spontaneous abortion is increased in cirrhotic women without shunt even if there is no deterioration of liver function. The risk of bleeding from esophageal varices or deterioration of liver function is usually unpredictable. Shunt surgery can be done with relatively little effect on both the mother and the fetus if conservative measurements fail to control the hematemesis. Vaginal delivery can be anticipated in most women, and cesarean section should be preserved for obstetric indications. The risk of postpartum hemorrhage is greatly increased, particularly in patients with previous shunt surgery. Perinatal loss is high because of the increased rate of premature delivery and stillbirth. Maternal prognosis is grave in women with cirrhosis.