Metabolic model and dosimetric data for copper

A metabolic model for copper is derived and presented in the context of the International Commission on Radiological Protection (ICRP) dosimetry models for the lungs and gastrointestinal tract. Research sponsored by the Energy Research and Development Administration under contract with Union Carbide Corporation.     

On the action of ribonuclease in salivary gland cells of drosophila

Summary It was shown that ribonuclease degrades the nucleolus in actively metabolizing cells. It does this without inhibiting RNA synthesis in the puffs and the nucleolus organizer. DNA synthesis still continues before or after puff formation, while amino acid incorporation is inhibited before the puffs are formed, indicating pre-existence of proteins involved in the process of puff formation.Dedicated to Professor H. Bauer on the occasion of his 60th birthday. — Research sponsored jointly by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation, the International Laboratory of Genetics and Biophysics, Naples, Italy (Partially supported by Euratom), and the Whitman Laboratory, University of Chicago, Chicago, Illinois.Supported by NTH Postdoctoral Fellowship 2-F 2–6 M-17, 187-02.     

Estimates of microcurie-days residence,bone dose equivalent,and (MPC)W for thorium-232 in man using a mammillary model

A four-compartment mammillary model for the distribution and excretion of thorium and its daughter radium is studied and applied to the problem of estimating the radiation dose to organs and tissues of man for the case of a single intake of²³²Th. The long-lived daughter²²⁸Ra (∼6 y) grows in with time and gives birth to the other short-lived daughters (<0.4 day) which irradiate those tissues in the vicinity of their point of production. Some data on²²⁸Th and its daughter²²⁴Ra are available on dogs from which a model is derived and tested. Then, from some single-intake data (Th and Ra) on man, parameters for the model are estimated and estimates of residence times of the²³²Th daughters in man are made. Also, the 50-year radiation dose (dose equivalent) to bone from a single intake of²³²Th is estimated. Research sponsored by the U.S. Atomic Energy Commission under contract with Union Carbide Corporation.     

Sequence of puff formation inRhynchosciara polytene chromosomes

The chief characteristics of the life cycle ofRhynchosciara sp. are: egg stage (12 days); three larval instars of approximately 6 days each, followed by a 4th instar of approximately 40 days duration; pupation (6 days); and adult form (5–6 days). Maps of the 4 polytene chromosomes ofRhynchosciara sp. have been prepared, and the temporal sequence of puff formation on the chromosomes described. The cocoon is synthesized during the prepupal period, and at this time major puffs are seen on all chromosomes. The largest and most numerous puffs occur on the salivary gland chromosomes during the 24 hours prior to the last or prepupal molt. Three of the puffs that occur at this time are DNA-puffs (Summary see p. 249). Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation.     

Determinationsmosaike aus kombiniert implantierten Imaginalscheiben vonEphestia kühniella Zeller

Ohne ZusammenfassungOperated by Union Carbide Corporation for the United States Atomic Energy Commission.Appointment supported by the International Cooperation Administration under a program administered by the National Academy of Sciences of the United States.     

Continuous ethanol production by a flocculent strain of Zymomonas mobilis

Summary Cell retention and ethanol production using the flocculent bacterium Zymomonas mobilis NRRL B-12526 were studied in three bioreactor configurations. The flocculent growth characteristic of this strain and a special reactor design were combined to achieve relatively high cell concentrations in a continuous bioreactor for the conversion of glucose to ethanol.Research sponsored by the Office of Energy Research, U.S. Department of Energy, under contract W-7405-eng-26 with the Union Carbide Corporation.     

Chromosome pairing in the oögonial cells of Drosophila melanogaster

Pairing between two nonhomologous chromosomes, one a free X-duplication and the other a free fourth chromosome, has been observed cytologically with high frequencies in the oögonial cells of Drosophila melanogaster. The frequencies of nonhomologous pairing ranged from 27 to 47% and showed a positive correlation with the similarity in size between the two participating nonhomologues. Partial homology increased pairing frequency between nonhomologues in the oögonial cell, in contrast to the behavior of the same nonhomologues at distributive pairing in the oöcyte, where pairing is strictly size-dependent. Pairing between homologues in the same oögonial cells occurred at a frequency of only 71% and was higher for the autosomes (73%) than for the sex chromosomes (66%). An increased frequency of homologous pairing was found for older gonial cysts (4-cell, 72.0% ; 8-cell, 76.1%) as compared with younger cysts (1-cell, 59.1% ; 2-cell, 53.1%).Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation.     

Phenol oxidase activity and the Lozenge locus of Drosophila melanogaster

We have found that the phenol oxidase activity in 50-hr Drosophila melanogaster pupae is much greater than that of adult flies. The mutants lz and lz ^g have all of the phenol oxidase components present in wild type, whereas the mutant tyr-1 has all of the wild-type components but the activity of each component is greatly reduced in comparison with wild-type activity. The newly discovered lozenge allele, lz ^rfg, lacks all phenol oxidase activity.Predoctoral fellow supported by Grant GM 1974 from the National Institute of General Medical Sciences, National Institutes of Health.The Oak Ridge National Laboratory is operated for the U.S. Atomic Energy Commission by Union Carbide Corporation.     

Approximate bandwidths for π and σ energy states in poly (dA.dT)

Using energy levels of the π and σ orbitals for adenine and thymine obtained by the CNDO method, the widths of those levels for poly (dA · dT) are calculated approximately. The results indicate that the bands are very narrow and that the exciton theory provides the best approximation for these biopolymers. This investigation was supported in part by NIH Fellowship (1F03 CA 5296-01) from the National Cancer Institute. Operated by the Union Carbide Corporation for the U.S. Atomic Energy Commission.     

Nuclear track registration in solids by etching

Summary A review is given on recent developments in the field of charged particle track registration in insulating solids by preferential etching. The basic mechanism of latent track formation in minerals and inorganic glasses seems to be a spike formation process. In the more sensitive organic polymers, radiation induced chemical changes along the track probably predominate. The sensitivity, etching kinetics, and stability of tracks in plastics and some of the factors which affect them are discussed on the basis of experimental data.Several microscopic and macroscopic methods for simplified or automatic track counting are described briefly. Among the many applications of the etching method, neutron dosimetry via (n, f), (n, ), and recoil reactions are discussed in some detail. Other applications in nuclear physics, chemistry, biology, space research, and for age determinations in geological and archeological samples are listed.Research sponsored by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation.Based on a lecture at the University of Tennessee, February 13, 1968.     

Early spermatogenesis inRhynchosciara

Summary The development of differentiation of spermatogonia in the testes ofRhynchosciara is a relatively synchronous process. The testes are composed of three cell types. The first are small cells, possibly aberrant spermatogonia which have failed to differentiate, which actively synthesize RNA and DNA from the beginning of the first instar to the beginning of meiosis. The second cell type consists of large polytene cells whose cytoplasm anastomoses extensively and which may have a Sertoli cell-like function. The third cell type, the spermatogonia, synthesizes RNA from the first instar until the beginning of meiosis. However, DNA synthesis as well as mitotic division stops at mid-fourth instar. Groups of these cells are connected via cytoplasmic bridges, probably formed as a result of incomplete cytokinesis. These groups of cells develop synchronously. Shortly after the cessation of mitotic activity the mitochondria acquire unique inclusions. These consist of a mass of electron-lucid material which continues to accumulate throughout the last half of the fourth instar. Following the completion of meiosis, the mitochondria begin to fuse so that in the mature sperm there is a single mass of material in the matrix of what appears to be a single elongated mitochondrion. This research was sponsored by the United States Atomic Energy Commission under contract with the Union Carbide Corporation.     

Cycling of organic and inorganic sulphur in a chestnut oak forest

Summary Sulfur (S) cycling in a chestnut oak forest on Walker Branch Watershed, Tennessee, was dominated by geochemical processes involving sulfate. Even though available SO ₄ ^2- was present far in excess of forest nutritional requirements, the ecosystem as a whole accumulated 60% of incoming SO₄–S. Most (90%) of this accumulation occurred by SO ₄ ^2- adsorption in sesquioxide-rich subsurface soils, with a relatively minor amount accumulating and cycling as SO ₄ ^2- within vegetative components. Organic sulfates are thought to constitute a large proportion of total S in surface soils, also, and to provide a pool of readily mineralized available S within the ecosystem.Research sponsored by Division of Biomedical and Environmental Research, U.S. Department of Energy, under contract W-7405-eng-26 with Union Carbide Corporation. Soil ester sulfate work sponsored by contract RP-1813-1 with the Electric Power Research Institute. Publication No. 1990, Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830     

Melanogenesis in amphibians

Summary The pigmented epithelium of Rana pipiens tadpole eyes normally develops at least two types of melanosomes: (1) an elongated melanin granule of relatively homogeneous electron density, and (2) a complex melanosome which has an outer electrondense area and one or more less dense cores. Evidence indicates that complex melanosomes are formed by new melanin enclosing preexisting melanosomes. An organized fibrillar premelanosome is demonstrated with the aid of the antimelanogenic compound phenylthiourea (PTU). These premelanosomes are the developing forms of the elongated melanosomes. There is evidence that the premelanosomes originate in the smooth endoplasmic reticulum. Phenylthiourea blocks melanin synthesis in the premelanosomes; however, removal of the PTU allows pigment deposition. This finding of an organized, fibrillar premelanosome in an amphibian marks the lowest phylogenetic group in which these organelles have been described.An Oak Ridge Graduate Fellow from Catholic University of America, Washington, D.C., under appointment from Oak Ridge Associated Universities.The MAN Program is supported by the National Cancer Institute, the National Institute of General Medical Sciences, the National Institute of Allergy and Infectious Diseases, and the U.S. Atomic Energy Commission.Oak Ridge National Laboratory is operated by Union Carbide Corporation Nuclear Division for the U.S. Atomic Energy Commission.     

The dose effect ofma-l+ andry+ on xanthine dehydrogenase activity inDrosophila melanogaster

Summary Two loci,ma-l ⁺ andry ⁺, necessary for xanthine dehydrogenase activity inDrosophila melanogaster have been studied for dosage effects utilizing deficiencies and duplications induced for this purpose. Comparisons of one, two and three doses ofma-l ⁺ in the female or one and two doses in the male indicate that there is no increase in specific enzyme activity with dose. On the other hand, comparisons of one, two and three doses ofry ⁺ in the male and female reveal an increase in enzyme activity that is roughly proportional to dose. Since dosage ofry ⁺ is limiting, whereas that ofma-l ⁺ is not, the final concentration of xanthine dehydrogenase is shown to depend on the number of doses ofry ⁺.The implications of these findings with respect to the hypothesis of dosage compensation and to the mechanism of control of enzyme and protein concentration are discussed.Operated by Union Carbide Corporation for the U.S. Atomic Energy Commission.     

Genetics and physiological expression of β-hydroxy acid dehydrogenase in Drosophila

A mutant Had ^nl was induced in Drosophila melanogaster and found to be deficient in -hydroxy acid dehydrogenase. This mutation was utilized to study the genetics and physiological expression of Had ⁺. Had⁺ was mapped to the X chromosome at 54.4 and seems to be the structural gene for the enzyme. Enzyme activity in male and female flies indicates that the gene shows both dosage compensation independent from dose effect and differential activity during ontogeny. Electrophoretic mobility data indicate that the enzyme is a dimer which forms by random association of subunits. The fact that the mutant shows no detrimental effect implies that the enzyme is dispensable, at least under laboratory conditions. The biological and technical implications of this gene-enzyme system are discussed.This research was sponsored by the Energy Research and Development Administration under contract with the Union Carbide Corporation. J. E. T. was a postdoctoral investigator supported by USPHS Fellowship No. 1-F02-GM53673-01 during a portion of this work.     

Epidemic models with spatial spread due to population migration

A spatial diffusion operator that governs the migration of polymorphic populations is derived and some specific epidemic models are analyzed in the presence of this type of diffusion. Threshold criteria and asymptotic behavior of solutions are derived, and it is shown that spatially heterogeneous steady states can occur in these models.The work of this author was partially supported by the National Science Foundation's Ecosystem Studies Program under Interagency Agreement No. DED80-21024 with the U.S. Department of Energy under contract W-7405-eng-26 with Union Carbide Corporation     

A cyclic pattern of hydrogen evolution by Anabaena flos-aquae

Summary Photoproduction of H₂ from water by Anabaena flos-aquae in a batch reactor (flowing argon gas phase) followed a reproducible cyclic pattern. Chloramphenicol inhibited events in the cylce, indicating a requirement for protein synthesis.This work was done while the author was employed at the Northern Regional Research Center, U.S.D.A., A.R.S., Peoria, I11Operated by the Union Carbide Corporation under contract W-7405-eng-26 for the U.S. Department of Energy     

Non-symbiotic nitrogen fixation in soil

Summary 1. The fixation of N¹⁵-labeled nitrogen in small vessels of California soil under various conditions of pH, substrate level, oxygen tension, and other soil conditions was observed.2. Nitrate concentrations greater than 1.0–1.5 microequivalents per gram soil were found to suppress nitrogen fixation but not the growth ofAzotobacter.3. Large amounts of nitrogen were fixed when soluble organic substrates (e.g. glucose or sucrose) were added to the soil.4. Moderate fixation also resulted from the inversion of a disc of sod.5. Fixed nitrogen appeared largely in the nitrate and ammonia-amide fractions with that in the nitrate fraction probably representing nitrification of more reduced initial products of fixation.6. Under conditions of these experiments growing grass did not enhance fixation. At higher light intensities, however, such an enhancement might be observed.7. The incorporation of grass cuttings, straw or alfalfa meal into the soil caused only a slight increase in fixation.8. The inoculation of soils with large populations ofAzotobacter did not result in increased fixation.This investigation was supported in part by a contract with the United States Atomic Energy Commission.     

The muc+ gene of plasmid pKM101 prevents respiration shutoff in far ultraviolet-irradiated Salmonella typhimurium

Summary The plasmid pKM101 is known to protect Escherichia coli and Salmonella typhimurium against killing by far UV irradiation and to enhance UV-induced mutagenesis. The muc ⁺ gene of the plasmid is responsible for both of these effects. This paper shows that respiration of S. typhimurium shuts off about an hour after UV irradiation and that pKM101 prevents the shutoff. Plasmids which contained Tn5 translocatable elements, either in (and having produced a muc mutation) or flanking the muc ⁺ gene, have been introduced into S. typhimurium. The muc mutant plasmid, which does not protect its host against UV killing and does not enhance UV induced mutagenesis, also does not protect against UV induced respiration shutoff. Like-wise, plasmids in which the Tn5 translocatable elements flank the nuc ⁺ gene protect against shutoff of respiration. Thus the muc ⁺ gene of pKM101 is responsible for protection against UV induced shutoff of respiration in S. typhimurium.Research sponsored by the Office of Health and Environmental Research, U.S. Department of Energy, under contract W-7405-eng-26 with the Union Carbide Corporation and by the National Science Foundation under grant No. PCM 7908647 with the University of Tennessee, Knoxville     

Nonhomologous pairing in oogonia and ganglia of Drosophila melanogaster

A high frequency of chromosome pairing between an X-duplication (Dp) and a compound 4 (–44), each of which lacks its homologue in the genome, has been observed in somatic ganglia cells in female and male larvae as well as in oogonia of adult Drosophila melanogaster. Three Dp's of different sizes were used. Pairing was determined both by inspection and by precise measurement of the distances between chromosomes; the two methods agreed in virtually every case. Nonhomologous pairing frequencies ranged from 23.0 to 62.6%, showing a strong dependency on size. The Dp that was closest in size to –44 produced the greatest frequency of pairing in each of the three tissues. Homologues in the same cells paired with a frequency of 89% or greater. The X and Y in the male ganglia showed a pairing frequency of only 45.7%, thus resembling nonhomologues in their pairing behavior. Genetic studies were also carried out on the three genotypes. Segregation data for the Dp's and –44 established that the same pattern of pairing observed in the mitotic cells was present in the oocytes — the Dp which was closest in size to the –44 again producing the greatest frequency of pairing. In the oocytes the pairing frequencies were much higher than those observed in the mitotic cells.From a dissertation submitted to the University of Tennessee in partial fulfillment of the requirements for the degree of Doctor of Philosophy. This work was jointly sponsored by National Science Foundation Grant No. GZ-1323, and by the U.S. Atomic Energy Commission under contract with the Union Carbide Corporation.