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Interaction Between The Component Enzymes Of The Glycine Decarboxylase Multienzyme Complex, David J. Oliver, Michel Neuburger, Jacques Bourguignon, Roland Douce Oct 1990

Interaction Between The Component Enzymes Of The Glycine Decarboxylase Multienzyme Complex, David J. Oliver, Michel Neuburger, Jacques Bourguignon, Roland Douce

David J. Oliver

The glycine decarboxylase multienzyme complex comprises about one-third of the soluble protein of the matrix of pea (Pisum sativum) leaf mitochondria where it exists at a concentration of approximately 130 milligrams protein/milliliter. Under these conditions the complex is stable with an approximate subunit ratio of 2 P-protein dimers:27 H-protein monomers:9 T-protein monomers:1 L-protein dimer. When the complex is diluted it tends to dissociate into its component enzymes. This prevents the purification of the intact complex by gel filtration or ultracentrifugation. In the dissociated state the H-protein acts as a mobile cosubstrate that commutes between the other three enzymes and shows …


Preparing For Africanized Honey Bees: Evaluating Control In Mating Apiaries, Richard L. Hellmich Ii, Gordon D. Waller Aug 1990

Preparing For Africanized Honey Bees: Evaluating Control In Mating Apiaries, Richard L. Hellmich Ii, Gordon D. Waller

Richard L Hellmich

A measure of queen mating control at an apiary is the number of matings with managed drones expressed as a percentage of total matings (managed and feral drones). In Texas, USA, using cordovan queens and drones for tests in July, it was found that at a commercial apiary near other apiaries 93% of all matings were with managed drones. At an isolated (outlying) apiary, the figure was 83%. It is estimated that in April-May, when most queens are produced in this area, mating control would be 96-98% and 93-96% respectively. It is concluded that 90-95% is a realistic level for …


Surface Moisture And Osmotic Stress As Factors That Affect The Sanitizing Of Beef Tissue Surfaces, James S. Dickson Aug 1990

Surface Moisture And Osmotic Stress As Factors That Affect The Sanitizing Of Beef Tissue Surfaces, James S. Dickson

James S. Dickson

The use of osmotic stress or desiccation in combination with 2% acetic acid reduced the numbers of Salmonella typhimurium or Listeria monocytogenes on beef tissue to a greater degree than the acid alone. Bacteria were osmotically stressed by NaCl, CaCl2, or sucrose solutions. Pre-washing with 20% NaCl followed by sanitizing with acetic acid reduced the numbers of S. typhimurium an additional 1.5-to 2-log cycles compared with acetic acid alone. Similar reductions were seen by allowing the tissue surfaces to dry before the application of the acid. Desiccation in combination with acetic acid was also effective in reducing the numbers of …


Use Of A Bacteriocin Produced By Pediococcus Acidilactici To Inhibit Listeria Monocytogenes Associated With Fresh Meat, J. W. Nielsen, James S. Dickson, J. D. Crouse Jul 1990

Use Of A Bacteriocin Produced By Pediococcus Acidilactici To Inhibit Listeria Monocytogenes Associated With Fresh Meat, J. W. Nielsen, James S. Dickson, J. D. Crouse

James S. Dickson

A bacteriocin produced by Pediococcus acidilactici had an inhibitory and bactericidal effect on Listeria monocytogenes associated with fresh meat. MICs were significantly lower than minimum killing concentrations. When meat was inoculated with L. monocytogenes, the bacteriocin reduced the number of attached bacteria in 2 min by 0.5 to 2.2 log cycles depending upon bacteriocin concentration. Meat treated initially with the bacteriocin resulted in attachment of 1.0 to 2.5 log cycles fewer bacteria than that attained with the control. The bacteriocin, after 28 days of refrigerated storage on meat surfaces, was stable and exhibited an inhibitory effect on L. monocytogenes.


Stratification Not Required For Tree-Of-Heaven Seed Germination, William R. Graves Jan 1990

Stratification Not Required For Tree-Of-Heaven Seed Germination, William R. Graves

William R Graves

Tree-of-heaven (Ailanthus altissima (Mill.) Swingle) seed germination and shoot dry weight were determined after stratifying samaras at 5 and 25 °C for up to 28 days. Seeds of samaras stratified at 5 °C for 0, 4, and 12 days showed 70, 77, and 96% germination, respectively, 7 days after sowing. Fourteen days after sowing, 90% of nonstratified seeds had germinated, but shoot weight of nonstratified seedlings was 16% less than that of seedlings from fruit stratified at 5 °C for 12 days. Germination 7 days after sowing was greater after stratification at 5 °C than at 25 °C, but the …


Flight Characteristics Of Foraging Africanized And European Honey Bees (Hymenoptera: Apidae), Robert G. Danka, Richard L. Hellmich Ii, Anita M. Collins, Thomas E. Rinderer, Vernon L. Wright Jan 1990

Flight Characteristics Of Foraging Africanized And European Honey Bees (Hymenoptera: Apidae), Robert G. Danka, Richard L. Hellmich Ii, Anita M. Collins, Thomas E. Rinderer, Vernon L. Wright

Richard L Hellmich

Interfloral movement and visitation parameters were quantified for individual Africanized and European honey bees (Apis mellifera) foraging in a field of sesame in Venezuela. The 2 bee types showed nearly identical movement and visitation characteristics for most of the parameters measured. Africanized bees spent slightly less time per flower visit (mean ± SD; 10±4 s vs. 12±6 s) and tended to travel at a slightly faster rate (210±150 cm/min vs. 180±120 cm/min.) The frequencies of visits for various resources differed; Africanized bees collected only pollen on 51% of visits and only nectar on 22% of visits, whereas for European bees, …


Introduction: Structural Properties For Determining Mechanisms Of Toxic Action, Steven P. Bradbury, Robert L. Lipnick Jan 1990

Introduction: Structural Properties For Determining Mechanisms Of Toxic Action, Steven P. Bradbury, Robert L. Lipnick

Steven P. Bradbury

The U.S. Environmental Protection Agency (EPA), under a variety of Federal legislation, is charged with the responsibility of assessing the hazards of chemicals to human health and the environment. In some cases EPA incorporates predictive techniques in its decisionmaking processes. In the context of some statutes, predictive toxicological methods can be cost-effective components in an overall approach for prioritizing chemicals for in-depth toxicological investigation. Predictive approaches are also used where empirical toxicological data are either unavailable or not required under a specific statute. For example, under Section 5 of the Toxic Substances Control Act (TSCA), EPA's Office of Toxic Substances …


Influence Of Cytochrome P450 Mixed-Function Oxidase Induction On The Acute Toxicity To Rainbow Trout (Salmo Gairdneri) Of Primary Aromatic Amines, Steven P. Bradbury, Joop L. M. Hermens, Steven J. Broderius Jan 1990

Influence Of Cytochrome P450 Mixed-Function Oxidase Induction On The Acute Toxicity To Rainbow Trout (Salmo Gairdneri) Of Primary Aromatic Amines, Steven P. Bradbury, Joop L. M. Hermens, Steven J. Broderius

Steven P. Bradbury

The influence of enzyme induction on the acute toxicity of aniline and 4-chloroaniline to rainbow trout (Salmo gairdneri) was investigated. For these two xenobiotics, bioactivation reactions are known to occur in mammals. Induction of cytochrome P450 mixed-function oxidase was obtained by intraperitoneal (ip) injection of trout with a mixture of polychlorinated biphenyls (Aroclor 1254). Five days after ip injection with three different doses of Aroclor 1254 (50. 100. and 200 mg/kg). benzo[a)pyrene hydroxylase activity in trout liver microsomes increased five- to sixfold. Cytochrome P450 concentrations in the microsomes were slightly. but significantly. enhanced in two of the three dose levels. …


Evaluation Of Chicken Heterophil Adherence, Claire B. Andreasen, Kenneth S. Latimer, W. L. Steffens Jan 1990

Evaluation Of Chicken Heterophil Adherence, Claire B. Andreasen, Kenneth S. Latimer, W. L. Steffens

Claire B. Andreasen

Adherence of chicken heterophils was evaluated at 37 C using preconstructed columns containing various weights of nylon fiber (75 mg, 100 mg, or 125 mg) and whole blood anticoagulated with sodium heparin or 10% disodium ethylenediamine tetraacetic acid (EDTA). Additionally, 50-mg and 75-mg nylon fiber columns incubated at 41 C were used to evaluate heterophil adherence at an increased temperature. The mean percent adherence for heparin-anticoagulated blood applied to 75-mg, 100-mg, and 125-mg nylon fiber columns at 37 C was 76%, 92% and 97.4%, respectively. Samples applied to 50-mg and 75-mg columns at 41 C had adherence values of 27% …


Forage Quality Of Genetically Diverse Alfalfa Germplasms At Four Phenological Growth Stages, Andrew W. Lenssen, E. L. Sorensen, G. L. Posler Jan 1990

Forage Quality Of Genetically Diverse Alfalfa Germplasms At Four Phenological Growth Stages, Andrew W. Lenssen, E. L. Sorensen, G. L. Posler

Andrew W. Lenssen

Forage quality of various alfalfa (Medicago sativa L.) cultivars has been determined under different environmental conditions, and numerous trials with alfalfa have documented an inverse relationship between forage quality and maturity. Little information is available, however, regarding the comparative forage quality of the germplasm sources from which most USA cultivars were developed. We compared forage quality of these germplasm sources at four phenological stages under disease- and insect-free conditions in a greenhouse. Germplasm sources (cultivars) tested were: Indian (Sirsa # 9), African (African), Peruvian (Hairy Peruvian), Flemish (DuPuits), Turkistan (Lahontan), Chilean (Kansas Common), M. varia (Grimm), and Ladak (Ladak). Four …


Organ Hypertrophy And Responses Of Colon Microbial Populations Of Growing Swine To High Dietary Protein, James S. Dickson, Wilson G. Pond, Vincent H. Varel, Friday O. I. Anugwa, Gary S. Ross Jan 1990

Organ Hypertrophy And Responses Of Colon Microbial Populations Of Growing Swine To High Dietary Protein, James S. Dickson, Wilson G. Pond, Vincent H. Varel, Friday O. I. Anugwa, Gary S. Ross

James S. Dickson

Thirty-two castrated male crossbred growing pigs (average initial wt 26.9 kg) were used to determine the effect of a high level of dietary protein (37%) compared with a normal level of protein (15%) on enterobacteria and Campylobactersp. inhabitation in the large intestine and on visceral organ hypertrophy and the interrelationships between these two factors. Pigs were kept in pairs (eight pens of two pigs/diet) and fed their respective diets ad libitum. Eight pigs (two pens of two pigs fed each diet) were killed at wk 4, 8. 12 and 16 without fasting. Fecal samples were obtained every 2 wk from …


Transfer Of Listeria Monocytogenes And Salmonella Typhimurium Between Beef Tissue Surfaces, James S. Dickson Jan 1990

Transfer Of Listeria Monocytogenes And Salmonella Typhimurium Between Beef Tissue Surfaces, James S. Dickson

James S. Dickson

Beef tissue surfaces were inoculated with either Listeria monocytogenes or Salmonella typhimurium and placed in contact with uninoculated tissue surfaces. The transfer of bacteria from one surface to another was determined under conditions designed to simulate contamination during meat processing. Bacterial transfer decreased when the initial inoculum was allowed to adsorb to the base tissue prior to contact with the second tissue. The type of base tissue was a factor (P<0.05), with a greater transfer from fat with contact times of less than 1 min and a greater transfer from lean with longer contact times.


Comparison Of Homogenization By Blending Or Stomaching On The Recovery Of Listeria Monocytogenes From Beef Tissues, James S. Dickson Jan 1990

Comparison Of Homogenization By Blending Or Stomaching On The Recovery Of Listeria Monocytogenes From Beef Tissues, James S. Dickson

James S. Dickson

Homogenization by blending or stomaching was compared for the recovery of Listeria monocytogenes from inoculated intact beef tissue. There were no differences in numbers of recovered bacteria (P > 0.10) attributable to either homogenization time or method. Fewer viable bacteria (PcO.05) were recovered in phosphate buffer than either buffered peptone water or 2% trisodium citrate buffer. Tween 80 increased the numbers of bacteria recovered from fat tissue (PcO.05). Stomaching is an acceptable method for homogenizing samples for Listeria analysis.


Multi-Isfet Sensors For Soil Nitrate Analysis, Stuart J. Birrell, John W. Hummel Jan 1990

Multi-Isfet Sensors For Soil Nitrate Analysis, Stuart J. Birrell, John W. Hummel

Stuart J. Birrell

The management of a field as a heterogeneous area is now being investigated by many researchers in universities, companies, and research institutions. However, for site-specific application of inputs, it is necessary to develop systems to sense the variation of important properties in real time. Several studies have shown that ion selective electrodes can be used to measure soil nitrates. This work involves an investigation in the use of Ion Selective Field Effect Transistors (ISFETs), to measure soil nitrate levels.


Biochemical And Immunochemical Comparison Of Africanized And European Honeybee Venoms, D. R. Nelson, Anita M. Collins, Richard L. Hellmich, R. T. Jones, R. M. Helm, D. L. Squillace, J. W. Yunginger Jan 1990

Biochemical And Immunochemical Comparison Of Africanized And European Honeybee Venoms, D. R. Nelson, Anita M. Collins, Richard L. Hellmich, R. T. Jones, R. M. Helm, D. L. Squillace, J. W. Yunginger

Richard L Hellmich

Africanized honeybees (HBs) pose a hazard to both normal and sting-sensitive subjects in certain areas of Central and South America, and it is predicted that they will soon be present in the southern United States as well. Using an electrical stimulation device, we collected Africanized HB venom (AHV) in Venezuela and European HB venom (EHV) in Louisiana. These venoms, along with commercial European HB venom (CHV), were compared by thin-layer isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The Coomassie brilliant blue and silver-stained banding patterns of AHV and EHV were essentially identical to CHV. Western blots were prepared …


Modeling Environmental Response To Power Interruptions In Swine Nurseries, Jay D. Harmon, E. R. Collins Jr., E. T. Kornegay Jan 1990

Modeling Environmental Response To Power Interruptions In Swine Nurseries, Jay D. Harmon, E. R. Collins Jr., E. T. Kornegay

Jay D. Harmon

A deterministic simulation model was developed to help assess emergency environmental needs of swine nurseries by modeling short term power interruptions. The model accounts for heat exchange by conduction, convection, radiation and air infiltration. A sub-model, developed by the North Central Region Committee 179, was used to predict swine heat and moisture loss. The model was validated using a nursery constructed of concrete block. The model performed well for cases with a constant solar load but tended to overpredict temperature changes during periods of no solar load. Validation indicated that wind velocity had the most effect upon model error. Sensitivity …