601
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Multiple response patterns to oestrogenic stimulation in the avian liver. JOURNAL OF STEROID BIOCHEMISTRY 1979; 11:231-6. [PMID: 226789 DOI: 10.1016/0022-4731(79)90302-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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602
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Ethylene production by callus and suspension cells from cortex tissue of postclimacteric apples. PLANT PHYSIOLOGY 1979; 63:811-5. [PMID: 16660818 PMCID: PMC542925 DOI: 10.1104/pp.63.5.811] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Cortex tissue from postclimacteric ;Golden Delicious' apples (Malus domestica, Borkh.) stored at 0 C for 9 months after harvest were induced to form callus in vitro. Cell suspension cultures were subsequently formed from calli. Of five media tested, only the medium of Schenk and Hildebrandt (Can J Bot 1972, 50: 192) and that of Uchimiya and Murashige (Plant Physiol 1974, 54: 936) allowed callus formation. During growth both the callus and cell cultures produced ethylene in a pattern which showed a rapid rise and then a fall as the culture grew. (14)C-Labeled methionine was converted to labeled ethylene by the cell suspension cultures, which also could be inhibited from producing ethylene by a rhizobitoxine analog or free radical scavengers. Ethylene production in these cultures, like that in intact fruit tissue slices, could be stimulated by IAA or suppressed by N(6)-(gamma,gamma-dimethylallyl) adenosine and GA(3).
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603
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Abstract
A 64-year-old woman presented with retroperitoneal lymphoma metastatic to the left ureter. Lymphoma was not diagnosed and her clinical course was not fully explained until after surgery. The lack of superficial lymphoma delayed diagnosis and therefore prevented effective treatment. Her situation became unmanageable when it was complicated by bacteremia (E coli) and fungemia (Candida albicans).
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604
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Decrease in functional albumin mRNA during estrogen-induced vitellogenin biosynthesis in avian liver. Proc Natl Acad Sci U S A 1978; 75:5974-8. [PMID: 282619 PMCID: PMC393099 DOI: 10.1073/pnas.75.12.5974] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Translation of rooster liver RNA in a wheat germ extract is shown to yield albumin as one of the cell-free products. Quantitation of albumin mRNA by the translation assay indicates that functional albumin mRNA represents 10% of total liver mRNA activity in control roosters. After estrogen administration, this level decreases in a continuous fashion until functional albumin mRNA represents 5% of total mRNA activity at 12 days. This decrease in functional albumin mRNA was correlated with several parameters of vitellogenin induction. Functional vitellogenin mRNA increases to a maximum at 4 days after hormone treatment and returns to control levels by 12 days. A similar pattern is seen for the hormone-stimulated increase in total mRNA activity. The decrease in functional albumin mRNA, therefore, persists after the vitellogenic response of the liver has been completed. These results suggest that the decrease in hepatic albumin synthesis after hormone treatment is due to an estrogen-mediated decrease in the content of albumin mRNA.
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605
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Abstract
To understand the effects of ultrasound in biological systems at the molecular level, sonolysis of nucleic acid bases at sonic intensities less than or equal to 5 W/cm2 was studied. These sonoreactions were followed by UV-spectral decrease and by sonoproduct analysis. The order of reactivity was found to be thymine greater than uracil greater than cytosine greater than guanine greater than adenine. The extent of sonoreactions depends on the exposure time and the rate of the intensity. Aeration was necessary for maintenance of a reasonable reaction rate. "Threshold" intensities for uracil and thymine were observed at approximately 0.5 W/cm2. The effectiveness of the dissolved gases in producing sonoreactions was Ar greater than 02 greater than air greater than N2 greater than He greater than N2O, suggestive of free radicals mediating these reactions since N2O is an effective radical scavenger. Studies of the effects of substituents have shown that electronic rather than steric effects may have a greater influence. Preliminary identification indicates that cis- and trans-uracil glycols are the major products of uracil. Thus, a stepwise mechanism of pyrimidine sonolysis is proposed. Sonolysis of a dilute aqueous solution of uracil yielded pseudo-first-order kinetics in terms of [Ura] with a rate constant of 3.9 X 10(-2) min-1, implying that the rate-limiting step is the reaction of HO- with the base.
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606
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Abstract
Uninfected cells from two different phenotypes of chicken embryos express significant amounts of endogenous viral information, though they do not produce virus particles. Cells of the phenotype gs(+)chf(+) are positive for both group-specific (gs) antigens and chicken helper factor (chf) activity, whereas cells of a second phenotype, gs(L)chf(+)(h(E)), demonstrate noncoordinate expression of these two viral activities (very low amounts of gs antigens, but extremely high helper activity). RNA from these cells was analyzed to determine the size, genetic content, and relative abundance of virus-specific RNAs in cells of each phenotype. Two major size classes of polyadenylic acid-containing RNA, homologous to the avian leukosis virus genome, were detectable in cells of both types. The larger RNA, which contained most of the sequences of the leukosis virus genome, was of different sizes in the two phenotypes, 31S in gs(+)chf(+) cells but 35S in the noncoordinate cell type. Analysis of the viral RNA with gene-specific complementary DNA probes revealed the following characteristics. (i) The 31S RNA appeared to lack portions of the gag and pol genes. (ii) A smaller RNA species, which sedimented at 21S in both cell types, was a transcript of the 3'-proximal portion of the viral genome, consisting of the env gene and the "common" sequences. (iii) The amount of env-specific RNA in the 21S region was more than six times higher in the noncoordinate cell type than in the gs(+)chf(+) cells; this difference was concordant with the 5- to 10-fold higher chf activity in the noncoordinate cells. (iv) The endogenous viral RNA in uninfected cells and the RNA from Rous-associated virus-0 virions hybridized only partially with DNA complementary to the common region of the Rous-associated virus-2 genome, whereas the RNA of all exogenous viruses tested hybridized almost completely to this complementary DNA. Small amounts of src-specific polyadenylated RNA were also present in uninfected chicken cells. This RNA sedimented as a single peak at 26S and was not covalently linked to any other identifiable virus-specific RNA sequences. The amount of src RNA was the same in the above two types of expression-positive cells and also in cells that were gs(-)chf(-), indicating that the transcription of the cellular sequences homologous to the src gene is independent of the transcription of the other endogenous viral genes.
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607
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608
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609
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610
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611
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612
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5,5'-diuridinyl, a major photoproduct from UV-irradiation of polynucleotides containing bromouracil. Photochem Photobiol 1977; 25:11-3. [PMID: 847020 DOI: 10.1111/j.1751-1097.1977.tb07417.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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613
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614
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615
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616
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617
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618
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Radiation chemistry of nucleic acids: identification of the major hydroperoxy thymine. Biochem Biophys Res Commun 1973; 54:1124-31. [PMID: 4753187 DOI: 10.1016/0006-291x(73)90823-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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619
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Radiation chemistry of nucleic acids. Isolation and characterization of glycols of 1-carbamylimidazolidone as products of cytosine. J Am Chem Soc 1973; 95:2711-2. [PMID: 4694532 DOI: 10.1021/ja00789a064] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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620
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621
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622
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623
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624
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625
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Radiation chemistry of nucleic acides. Isolation and characterization of thymine glycols. J Am Chem Soc 1972; 94:4764-5. [PMID: 5036173 DOI: 10.1021/ja00768a073] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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626
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627
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628
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629
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630
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631
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632
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Uracil-thymine adduct from a mixture of uracil and thymine irradiated with ultraviolet light. Biochemistry 1970; 9:4416-20. [PMID: 5472712 DOI: 10.1021/bi00824a024] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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633
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Abstract
Thymine trimer was isolated from a frozen aqueous solution of thymine which was irradiated with ultraviolet light and was presumably formed through the rearrangement of an initial oxetane photoproduct. X-ray diffraction analysis of a single crystal has confirmed the trimeric diol structure and has established the stereoconfiguration of the molecule. The possible importance of the diol structure in photobiology is pointed out.
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634
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635
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636
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637
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Abstract
Thymine-thymine adduct is a product isolated from thymine irradiated with ultraviolet light in frozen aqueous solution. This compound is presumably formed through the rearrangement of an initial photoproduct. Single crystal x-ray diffraction analysis has confirmed the molecular formula of the adduct, 5-hydroxy-6-4'-(5'-methylpyrimid-2'-one)-dihydrothymine, except for the possibility of a hydrogen atom on the 3' nitrogren rather than the 1' nitrogen, and has established the stereoconfiguration of the molecule.
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638
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Abstract
Two new products were isolated from uracil irradiated with ultraviolet light in frozen aqueous solution. As judged by mass, nuclear magnetic resonance, and ultraviolet and infrared spectra, one is a photopolymer, U(3) and the structure of the other is probably 6-4'-[ pyrimidin-2'-one]-uracil. Formations of these products between pyrimidine bases are apparently common photoreactions, and may be important to the study of the photochemistry and photobiology of nucleic acids.
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639
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640
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641
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Abstract
A product isolated from thymine irradiated with ultraviolet light in frozen aqueous solution undergoes dehydration on heating with acids. As judged by elemental analysis, mass, ultraviolet, infrared, and nuclear magnetic resonance spectra, the most probable structures for this compound and its dehydration product, respectively, are 5-hydroxy-6-4'-[5''-methylpyrimidin-2'-one]-dihydrothymine and 6-4'-[5'-methylpyrimidin-2'-one]-thymine. Apparently, this compound is a thymine-thymine adduct and presumably is formed through the rearrangement of an initial photoproduct. Both compounds are closely related to 6-4'-[pyrimidin-2'-one]-thymine which has been isolated from acid hydrolyzates of ultraviolet-irradiated DNA and supposedly is derived from cytosine-thymine adduct. Formation of such adducts between pyrimidine bases is apparently a common photoreaction and may be important to the study of the photochemistry and photobiology of nucleic acids.
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642
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Addendum: concerning the mechanism of formation of UV-induced thymine photoproducts in DNA. Proc Natl Acad Sci U S A 1967; 58:2483. [PMID: 5242221 PMCID: PMC223861 DOI: 10.1073/pnas.58.6.2483] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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643
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644
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Abstract
A new thymine-derived product was separated from DNA irradiated with utlraviolet light in vitro and in vivo. This compound was mistaken to be thymine homodiner (T=T) by other workers because it is chromatographically indistinguishable from T=T in most eluents. It has absorbancy maximums at 312, 312, and 300 millimicrons in neutral, pH 2, and pH 11 aqueous solutions, respectively. When it is irradiated in aqueous solution with wavelengths of 360 and 313 millimicrons its spectrum reverts to one similar to that of thymine. Therefore, at least three thymine-derived products can be detected in ultraviolet irradiated DNA, namely the homodimer, a material with absorbancy maximum at 312 millimicrons, and a "minor" product suggested by others to be a dimer of cytosine and thymine. In cells, the latter two are formed in aboult equal amounts. While these three products were shown to exist in the acid hydrolyzates of ultraviolet irradiated DNA, a material with absorbancy maximum at about 310 millimicrons was demonstrated to form in ultraviolet irradiated DNA without further treatment. The magnitude of this spectral increase varied directly with the incrcase in the adenine-thymine contents in the DNA as shlown by differential transmittance spectra of the irradiated Micrococcus lysodeikticus, calf thymus, Bacillus cereus, and Hemophilus influenzae DNA.
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645
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Structure of homodimers of thymine and dimethylthymine. A nuclear magnetic resonance study. J Org Chem 1967; 32:1620-2. [PMID: 6041433 DOI: 10.1021/jo01280a075] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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646
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647
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648
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649
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