Permeation of organic molecules of widely differing solubilities and of water through isolated cuticles of orange leaves     

David G. Davis  Jeanette S. Mullins  Gary E. Stolzenberg  Gordon D. Booth 《Pest management science》1979,10(1):19-31

Water penetrated through isolated leaf cuticles of dwarf orange (Citrus mitis Blanco, ?Calamondin’?) as undissociated molecules because both [¹⁸O] water (¹H₂¹⁸O) and HTO (¹H³H¹⁶O) permeated at the same rate. HTO penetrated to 3 to 21% of the theoretical equilibrium value (TEV) in an unstirred system within 10 days for astomatous cuticles and 50 to 60% of TEV for stomatous cuticles. The permeability coefficient (k) of HTO through astomatous cuticles at 25°C was 6.8 × 10^?7 cm s^?1. Two highly water-soluble ¹⁴C-labelled compounds, trichloroacetic acid (TCA) and 1,2,4-triazol-3-ylamine [aminotriazole (BSI) or amitrole (ISO)], and two nearly water-insoluble ¹⁴C-labelled compounds, 1-naphthyl methylcarbamate (carbaryl) and 2,6-dichloro-4-nitroaniline (dicloran), were compared to HTO as a reference standard in permeation studies. All four organic molecules permeated without decomposing. The relative k values for TCA, aminotriazole, carbaryl, HTO and dicloran were 0.32, 0.47, 0.71, 1.0, and 1.5 respectively. Although this suggested that the permeation of organic molecules may be inversely related to water solubility, this could not be established with certainty due to large variations in the data. The k values were obtained for 12 other organic compounds through a variety of biological and model membranes or were calculated from the literature. Any relationships between k and various molecular characteristics were unclear because a wide variety of cuticle sources and experimental design was used by different investigators working in this area. The calculation of k is considered essential in all permeability studies so that comparisons can be made between laboratories.  相似文献   

Diagnostic criteria for degenerative suspensory ligament desmitis in Peruvian Paso horses     

Jeanette L. Mero DVM  Janet M. Scarlett DVM  PhD 《Journal of Equine Veterinary Science》2005,25(5):224-228

  相似文献   

Growth,Consumption and Respiration by Larvae of the Kelp-Fly Fucellia Capensis (Diptera:Anthomyiidae)     

Jeanette Stenton-Dozey  C.L. Griffiths 《African Zoology》2013,48(4):280-283

At 18 °C the eggs of the kelp-fly, Fucellia capensis, hatch in 24 – 32 h and the larval and pupal stages last 10 – 12 and 9 – 14 days respectively. The growth curve is discontinuous, with declining relative growth rates in successive larval instars. Food consumption is relatively independent of size, at 0,25 mg dry kelp mg^-1 wet larva day^-1. Respiration rate is related to larval mass by the equation: Respiration rate (μl O₂ h^-1) = 2,75 (wet mass larva)^0,66. In terms of energy an individual larva consumes 245,5 J over its lifespan, grows to the equivalent of 43,9 J and respires 51,6 J, indicating an assimilation efficiency of 30% and a gross growth efficiency of 17%. Kelp-fly larvae are probably less significant consumers of drift kelp than amphipods or isopods, but they promote the decay of wrack beds and are favoured as food by sea-shore birds.  相似文献   

Effects of Temperature and Salinity on Weight Gain, Oxygen Consumption Rate, and Growth Efficiency in Juvenile Red-Claw Crayfish Cherax quadricarinatus   总被引：1，自引：0，他引：1  

Mark E.  Meade Jeanette E.  Doeller  DavidW.  Kraus Stephen A.  Watts 《Journal of the World Aquaculture Society》2002,33(2):188-198

Abstract.— Weight gain and metabolic rates, as determined by oxygen consumption rates, were examined in juvenile Australian red-claw crayfish Cherax quadricarinatus exposed to different temperatures (16–32 C in 2 C increments) or salinities (0–30 ppt in 5 ppt increments). Mean weight gain, molting frequency, and survival (%) were dependent on temperature and salinity. In freshwater (0 ppt), maximal weight gain and molting frequency were observed at 28 C with maximal survival observed over the temperature range of 24–30 C. Metabolic rates in freshwater were temperature dependent (mean Q₁₀= 2.44). Maximal weight gain and molting frequency were observed at salinities of 0 and 5 ppt (28 C); however, survival was reduced at salinities ≥ 5 ppt. Metabolic rates were not salinity dependent and did not differ significantly over the salinity range from 0–20 ppt. Growth efficiencies, calculated by dividing weight gain by total metabolic energy expenditure (i.e., weight gain + metabolic rate), were highest at a temperature of 20 C (0 ppt) and at salinities of 0 and 5 ppt (28 C). These data suggest that, at higher culture temperatures, maximal weight gain of red-claw juveniles may be reduced when food resources are limited. Maximal weight gain, at optimal temperatures (28 C) with unlimited food supply, does not appear to be effected by low salinity conditions. Because of the potential commercial value of red-claw, culturists, should be aware of the relationship between environmental condition and metabolic energy requirements to ensure maximal weight gain and survival of juveniles.  相似文献   

Activation of transcription factor NF-kappaB requires ELKS, an IkappaB kinase regulatory subunit     

Ducut Sigala JL  Bottero V  Young DB  Shevchenko A  Mercurio F  Verma IM 《Science (New York, N.Y.)》2004,304(5679):1963-1967

  相似文献   

Confirmation that PCR can be used to identify NAD-dependent and NAD-independent Haemophilus paragallinarum isolates.     

J K Miflin  X Chen  R R Bragg  J M Welgemoed  J M Greyling  R F Horner  P J Blackall 《The Onderstepoort journal of veterinary research》1999,66(1):55-57

Seventy five bacteria tentatively identified as Haemophilus paragallinarum (the causative agent of infectious coryza), eight identified as Ornithobacterium rhinotracheale and 13 identified as NAD-independent Pasteurella species were isolated from chickens with respiratory infection in various provinces in South Africa. The isolates were characterized by conventional biochemical and serological methods. A polymerase chain reaction (PCR) assay specific for H. paragallinarum was used to identify the cultures directly from colonies. The PCR assay gave positive results for all isolates that were identified by conventional methods as H. paragallinarum, irrespective of whether they were nicotinamide adenine dinucleotide (NAD)-dependent (43 isolates) or NAD-independent (32 isolates). The eight isolates that were identified by conventional methods as O. rhinotracheale and the 13 isolates identified as various Pasteurella species gave negative results in the PCR assay. This study has demonstrated that colony PCR is a rapid method for uniquely identifying both NAD-dependent and NAD-independent strains of H. paragallinarum and distinguishing them from other bacteria, such as O. rhinotracheale and Pasteurella species.  相似文献   

Comparing the minimum inhibitory and mutant prevention concentrations of selected antibiotics against animal isolates of Pasteurella multocida and Salmonella typhimurium     

Jeanette M. Wentzel  Louise J. Biggs  Moritz van Vuuren 《The Onderstepoort journal of veterinary research》2022,89(1)

Historically, the use of antibiotics was not well regulated in veterinary medicine. The emergence of antibiotic resistance (ABR) in pathogenic bacteria in human and veterinary medicine has driven the need for greater antibiotic stewardship. The preservation of certain antibiotic classes for use exclusively in humans, especially in cases of multidrug resistance, has highlighted the need for veterinarians to reduce its use and redefine dosage regimens of antibiotics to ensure efficacy and guard against the development of ABR pathogens. The minimum inhibitory concentration (MIC), the lowest concentration of an antibiotic drug that will prevent the growth of a bacterium, is recognised as a method to assist in antibiotic dosage determination. Minimum inhibitory concentrations sometimes fail to deal with first-step mutants in bacterial populations; therefore dosing regimens based solely on MIC can lead to the development of ABR. The mutant prevention concentration (MPC) is the minimum inhibitory antibiotic concentration of the most resistant first-step mutant. Mutant prevention concentration determination as a complementary and sometimes preferable alternative to MIC determination for veterinarians when managing bacterial pathogens. The results of this study focused on livestock pathogens and antibiotics used to treat them, which had a MIC value of 0.25 µg/mL for enrofloxacin against all 27 isolates of Salmonella typhimurium. The MPC values were 0.50 µg/mL, with the exception of five isolates that had MPC values of 4.00 µg/mL. The MPC test yielded 65.52% (18 isolates) Salmonella isolates with florfenicol MICs in the sensitive range, while 11 isolates were in the resistant range. Seventeen isolates (58.62%) of Pasteurella multocida had MIC values in the susceptible range and 41.38% (12 isolates) had an intermediate MIC value. Mutant prevention concentration determinations as done in this study is effective for the antibiotic treatment of bacterial infections and minimising the development of resistance. The MPC method can be used to better control to prevent the development of antibiotic drug resistance used in animals.  相似文献