TY - CHAP TI - Oxygen toxicity AU - Hassan, H.M. AU - Krinsky, N.I. AU - Morris, J.G. AU - Pfenning, N. AU - Schlegel, H. AU - Shilo, M. AU - Vogels, G.D. AU - Weser, U. AU - Wolfe, R. AU - Kuenen, J.G. T2 - Strategy of Microbial Life in Extreme Environments A2 - Shilo, M. PY - 1979/// SP - 223-241 PB - Dahlem Konferenzen, Verlag Chemie ER - TY - CHAP TI - Superoxide dismutase and its role for survival in the presence of oxygen AU - Hassan, H.M. AU - Fridovich, I. T2 - Strategy of Microbial Life in Extreme Environments A2 - Shilo, M. PY - 1979/// SP - 179 193 PB - DahlemKonferenzen, Verlag Chemie [Wiley-VCH] ER - TY - SOUND TI - Clinical Application of Superoxide Dismutase AU - Hassan, H. DA - 1979/10/19/ PY - 1979/10/19/ ER - TY - JOUR TI - Superoxide, Hydrogen Peroxide, and Oxygen Tolerance of Oxygen-Sensitive Mutants of Escherichia coli AU - Hassan, H. M. AU - Fridovich, I. T2 - Clinical Infectious Diseases AB - Oxygen-intolerant mutants of Escherichia coli K12 were selected by a replica plating technique after treatment with the mutagen, N-methyl-N′-nitro-N-nitrosoguanidine, to a lethality of 99.5%. One group of mutants had lost the ability to induce both peroxidase and catalase when exposed to oxygen but retained the ability to induce the manganese-superoxide dismutase. The second group of mutants had lost the ability to induce the activity of all these enzymes. Failure to induce peroxidase and catalase was associated with enhanced susceptibility of the bacteria to the lethal effect of oxygen. When a member of the first group of mutants was prevented from producing the manganese-superoxide dismutase by the presence of puromycin, its susceptibility to the lethal effects of oxygen was greatly increased. Two types of revertants were seen. In one group the ability to induce enzyme activity was recovered and was accompanied by the return of oxygen tolerance. Members of the other group lost the ability to respire and, therefore, no longer produced O2- and H2O2. These results indicated that enzymic scavenging of both H2O2 and O2- provides an important defense against oxygen toxicity. The parallel loss of peroxidase and catalase, which was seen in all mutants, suggests that these enzymes constitute a precursor-product pair in E. coli. The parallel loss in two of these mutants of peroxidase, catalase, and the manganese-superoxide dismutase suggests a control linkage for these enzymes, the basis of which remains to be explored. DA - 1979/3/1/ PY - 1979/3/1/ DO - 10.1093/clinids/1.2.357 VL - 1 IS - 2 SP - 357-369 J2 - Clinical Infectious Diseases LA - en OP - SN - 1058-4838 1537-6591 UR - http://dx.doi.org/10.1093/clinids/1.2.357 DB - Crossref ER - TY - JOUR TI - Intracellular production of superoxide radical and of hydrogen peroxide by redox active compounds AU - Hassan, H.Moustafa AU - Fridovich, Irwin T2 - Archives of Biochemistry and Biophysics AB - Several compounds have been found capable of diverting the electron flow in Escherichia coli and thus causing increased intracellular production of O2− and H2O2. One indication of this electron-shunting action was increased cyanide-resistant respiration and one cellular response was increased biosynthesis of the manganese-containing superoxide dismutase and of catalase. Blocking cytochrome oxidase with cyanide or azide increased the electron flow available for reduction of paraquat and presumably of the other exogenous compounds tested and thus increased their biological effects. Paraquat, pyocyanine, phenazine methosulfate, streptonigrin, juglone, menadione, plumbagin, methylene blue, and azure C were all effective in elevating intracellular production of O2− and H2O2. The effect of alloxan appeared paradoxical in that it increased cyanide-resistant respiration without significantly increasing the cell content of the manganese-superoxide dismutase and with only a small effect on the level of catalase. The alloxan effect on cyanide-resistant respiration was artifactual and was due to an oxygen-consuming reaction between alloxan and cyanide, rather than to a diversion of the intracellular electron flow. With paraquat as a representative electron-shunting compound, the increase in biosynthesis of the manganese-superoxide dismutase was prevented by inhibitors of transcription or of translation, but not by an inhibitor of replication. The increase in this enzyme activity, caused by paraquat and presumably by the other compounds, was thus due to de novo enzyme synthesis activated or derepressed at the level of transcription. DA - 1979/9// PY - 1979/9// DO - 10.1016/0003-9861(79)90289-3 VL - 196 IS - 2 SP - 385-395 J2 - Archives of Biochemistry and Biophysics LA - en OP - SN - 0003-9861 UR - http://dx.doi.org/10.1016/0003-9861(79)90289-3 DB - Crossref ER - TY - JOUR TI - Paraquat and Escherichia coli. Mechanism of production of extracellular superoxide radical. AU - Hassan, H.M. AU - Fridovich, I. T2 - Journal of Biological Chemistry AB - Paraquat mediates a superoxide dismutase-inhibitable reduction of cytochrome c by suspensions of Escherichia coli B. Glucose was most effective in providing electrons for this cytochrome c reduction, but other nutrients could serve in this capacity, provided the cells were preconditioned by growth on these nutrients. Paraquat reduction depended upon a NADPH:paraquat diaphorase, present in the cytosol. Reduced paraquat could diffuse across the cell envelope and react with dioxygen, in the suspending medium, thus generating O2- in that compartment. Most of the paraquat reduced in the cell, under the conditions used, reoxidized in situ and most of the O2- production was thus intracellular. The partitioning of reduced paraquat between intracellular and extracellular compartments, prior to reaction with dioxygen, depended upon intracellular pO2 and any strategy which raised intracellular pO2 decreased the efflux of reduced paraquat and thus decreased extracellular O2- production. Extracellular O2- and H2O2 did contribute to cell damage in proportion to the amount produced. O2- appeared to be unable to cross the cell envelope in either direction and the only O2- which was effective in raising the rate of biosynthesis of the manganese-superoxide dismutase, was that generated within the cell. DA - 1979/11// PY - 1979/11// DO - 10.1016/s0021-9258(19)86598-5 VL - 254 IS - 21 SP - 10846-10852 J2 - Journal of Biological Chemistry LA - en OP - SN - 0021-9258 UR - http://dx.doi.org/10.1016/s0021-9258(19)86598-5 DB - Crossref ER - TY - JOUR TI - Paraquat and the exacerbation of oxygen toxicity AU - Fridovich, Irwin AU - Hassan, H.Moustafa T2 - Trends in Biochemical Sciences AB - Paraquat subverts electron flow from the normal cytochrome pathway and increases intracellular production of superoxide radical. This radical, which is the cause of paraquat toxicity, elicits increased synthesis of the defensive enzyme, superoxide dismutase. DA - 1979/5// PY - 1979/5// DO - 10.1016/0968-0004(79)90395-5 VL - 4 IS - 5 SP - 113-115 J2 - Trends in Biochemical Sciences LA - en OP - SN - 0968-0004 UR - http://dx.doi.org/10.1016/0968-0004(79)90395-5 DB - Crossref ER - TY - JOUR TI - Physiological changes in caged layers during a forced molt. 3. Plasma thyroxine, plasma triiodothyronine, adrenal cholesterol, and total adrenal steroids AU - Brake, J. AU - Thaxton, P. AU - Benton, E.H. T2 - Poultry Science AB - The effects of forced molting on plasma levels of thyroxine (T4), triiodothyronine (T3), and adrenal cholesterol and total adrenal steroid content were studied. Commercially available strains of Single Comb White Leghorn (SCWL) hens, reared and maintained under commercial conditions, were used in the three trials. The hens were moved to environmentally modified facilities prior to the forced molt which was accomplished by reducing daylength and by withdrawing feed and water. Egg production ceased within one week of initiation of this procedure. The hens were sampled either daily or an alternate days for up to 22 days beginning at the time of feed removal. Plasma T4 initially decreased upon removal of feed, but increased above control levels by the sixth day of feed withdrawal. Plasma T3 levels remained relatively constant throughout the feed withdrawal period. Resumption of feeding with a fortified ground corn ration resulted in a decrease in T4 and concomitant increase in T3. Changes in adrenal cholesterol and total adrenal steroids were not consistent. However, there was a trend toward increased total adrenal steroids during feed withdrawal, and an increase in adrenal cholesterol upon the resumption of feeding. DA - 1979/// PY - 1979/// DO - 10.3382/ps.0581345 VL - 58 SP - 1345–1350 ER - TY - JOUR TI - Physiological changes in caged layers during a forced molt. 1. Body temperature and selected blood constituents AU - Brake, J. AU - Thaxton, P. T2 - Poultry Science AB - The effects of forced molting on body temperature and selected blood constituents were studied. Caged layers, reared under commercial conditions, were force molted successively at 72 and 104 weeks of age. This was accomplished by removing feed for up to 12 days and water for up to 3 days while simultaneously reducing the daylength to 10 hr or less. This procedure resulted in a cessation of egg production within one week of the initiation of feed removal. There was a significant increase in body temperature during feather loss and renewal. Packed cell volume and hemoglobin increased significantly immediately upon removal of feed and water and remained elevated above control levels for the duration of the pause in egg production, while plasma total calcium, and inorganic phosphate decreased significantly during the corresponding period. Plasma total protein and plasma glucose did not exhibit consistent trends. Body temperature and the levels of the measured plasma constituents returned to normal levels upon the resumption of egg production. DA - 1979/// PY - 1979/// DO - 10.3382/ps.0580699 VL - 58 SP - 699–706 ER - TY - JOUR TI - Force molting caged broiler breeder hens AU - Brake, J. AU - McDaniel, G.R. T2 - Highlights of Agricultural Research DA - 1979/// PY - 1979/// VL - 26 IS - 4 ER - TY - JOUR TI - Force molt caged layers in six weeks AU - Brake, John T. T2 - Highlight of Agricultural Research DA - 1979/// PY - 1979/// VL - 26 IS - 2 ER - TY - JOUR TI - Facility expands poultry research capabilities AU - Brake, John AU - Koon, J.L. AU - Jr., C.A. Flood T2 - Highlights of Agricultural Research DA - 1979/// PY - 1979/// VL - 26 IS - 3 ER - TY - JOUR TI - Comparison of fortified ground corn and pullet grower feeding regimes during a forced molt on subsequent layer performance AU - Brake, J. AU - Thaxton, P. AU - Garlich, J.D. AU - Sherwood, D.H. T2 - Poultry Science AB - A flock of 160 Hyline W-36 (Trial 1) and a flock of 3,000 Shaver 288 SCWL hens (Trial 2) were force molted by a combination of photoperiod manipulation and feed and water withdrawal. Feed was withdrawn for ten days and water was withdrawn for two days beginning on the third day of feed withdrawal. Following the period of feed and water withdrawal, half of each flock was fed a fortified ground corn ration and the other half was fed a pullet grower ration for 18 days. Feed consumption, feed conversion, egg production, and mortality were determined during the molt and for five (Trial 1) or six (Trial 2) 28-day periods thereafter. Quantitative assessments of egg size and shell quality were conducted. The hens which received the pullet grower ration returned to production earlier than those fed the fortified ground corn ration and reached peak production four weeks earlier than the group fed the fortified ground corn ration. Overall, the hens which received the pullet grower ration exhibited improved egg production and maintained egg size and shell quality comparable to that of the hens which received the fortified ground corn ration. Additionally, no significant difference in overall feed utilization or mortality was observed. DA - 1979/// PY - 1979/// DO - 10.3382/ps.0580785 VL - 58 SP - 785–790 ER - TY - MGZN TI - Auburn program reduces molt period to six weeks AU - Brake, John T. T2 - Feedstuffs DA - 1979/8/20/ PY - 1979/8/20/ VL - 51 M1 - 34 ER - TY - JOUR TI - WOOD CHIPS FOR POULTRY LITTER AU - CARTER, TA AU - ALLISON, RC AU - MILLS, WC AU - WEST, , JR T2 - POULTRY SCIENCE AB - Green wood chip litter from standing pine, hardwood trees, and a 50/50 pine-hardwood mix was compared to shavings from air-dried lumber. Eight-week old weight, feed conversion, and mortality of broilers reared on the four litter types were not significantly different (P<.05). There was a slightly greater breast blister involvement with broilers reared on all types of wood chip treatments. Although the initial moisture of the wood chip litters was high (42.2% for hardwood chips and 50.8% for pine chips), the moisture content of all litter was similar after the eight week growing period. DA - 1979/// PY - 1979/// DO - 10.3382/ps.0580994 VL - 58 IS - 4 SP - 994-997 SN - 0032-5791 ER -