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Start Over Coverage 23-29

2. Cryptosporidium parvum infection in experimentally infected mice: infection dynamics and effect of immunosuppression

Creator:
Tarazona, Raquel, Blewett, David A., and Carmona, Manuel Dominguez
Format:
print
Type:
model:internalpart and TEXT
Subject:
Cryptosporidiosis, infectivity, oocyst shedding, cyclophosphamide, and immunosuppression
Language:
English
Description:
The elicci of mouse strain, age, sex, and the size of infective dose on the susceptibility to infection with the coccidium Cryptosporidium, parvum Tyzzer, 1912 was determined using several murine models. Mice were infected with C. parvum oocysts originally of cervine origin, maintained by repeat passage in calves. All mice in the experimental groups proved susceptible to infection, though this resulted asymptomatic in all cases. C. parvum infection in BALB/c and Porton mice exhibited some variation. BALB/c mice demonstrated a longer prepatent period than Porton mice. They also produced a greater oocyst output over the patent period, though the differences were not statistically significant. Differences were observed between mice infected at either 3 or 4 weeks of age. Prepatent period was shorter in those mice infected at 3 weeks of age, reaching 100% infection rate by day 7 post-inoculation. The patent period was longer in younger mice showing that age at time of infection can modify the oocyst shedding profile. However, no sex related differences in the course of infection were observed. The effect of different infective doses of oocysts was analysed. The three doses used (l-O4, IO5, 106) proved infective for all mice, there were no statistical differences in either prépaient or patent periods, or in the oocyst shedding profiles. Experimental cryptosporidiosis was also induced in cyclophosphamide-immunosuppressed mice. Cyclophosphamide was orally administered by stomach lube at a dose of 50 mg/kg/day starting 10 days before the intragastric inoculation of 10fi oocysts of C. parvum per mouse and continuing until the end of the experiment, Immunosupprcsscd mice had a shorter prepatent period, remained infected longer and shed more oocysts than immunocompetent mice. Immunosuppression produced high mortality rates; during the course of the experiment 44% of immunosuppressed-infcctcd and 30% of immunosuppressed-uninfccted mice died. There were no deaths in the untreated groups. Differences in the clinical course of the infection were also observed between immunosuppressed and immunocompetent mice; however, some mice recovered without immunosuppression withdrawal.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Physiological and biochemical responses of two tree species in urban areas to different air pollution levels

Creator:
Baek, S. G. and Woo, S. Y.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
botanika, botany, antioxidant enzyme, chlorophyll content, chloroplasts, photosynthetic rate, and plastoglobuli
Language:
Multiple languages
Description:
We investigated the physiological and biochemical differences in Pterocarpus indicus and Erythrina orientalis grown in four sites at different pollution levels in the Philippines: Makati, Pasig and Quezon (high pollution levels; HP) located in Metro Manila, and La Mesa Watershed (a non-polluted area; NP). Among these four areas, HP sites had higher net photosynthetic rates (PN) than NP sites, except for Makati. Among HP sites, Makati and Quezon had the lowest PN for P. indicus and E. orientalis, respectively. Chlorophyll (Chl) contents were significantly lower in HP than in NP sites. Trees in Makati had the lowest Chl contents among HP sites, and P. indicus had higher Chl contents than did E. orientalis. In addition, the chloroplasts in HP trees had small starch grains with numerous dark, large plastoglobuli. Furthermore, antioxidant enzymes, indicative of the defense mechanism, showed a significantly higher activity in HP than in NP trees. and S. G. Baek, S. Y. Woo.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5. Response of spinach leaves (Spinacia oleracea L.) to ozone measured by gas exchange, chlorophyll a fluorescence, antioxidant systems, and lipid peroxidation

Creator:
Calatayud, A., Iglesias, D. J., Talón, M., and Barreno, E.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
antioxidant enzymes, ascorbate, chlorophyll fluorescence, intracelullar CO2 concentration, malondialdehyde, photosynthetic rate, quantum efficiency of photosystem 2, quenching, and stomatal conductance
Language:
Multiple languages
Description:
Spinach (Spinacia oleracea L. cv. Clermont) leaves grown in open-top chambers and exposed to three different concentrations of ozone were measured for gas exchange, chlorophyll a fluorescence, antioxidant systems, and lipid peroxidation at the end of growing season. High O3 concentration reduced Fv/Fm, indicating that the efficiency in the energy conversion of photosystem 2 (PS2) was altered. The rate of non-cyclic electron transport rate and the capacity to reduce the quinone pool were also affected. The development of non-photochemical quenching was not high enough to decrease the photon excess in the PS2. The limitation of photosynthetic activity was probably correlated with stomata closure and with an increase in intercellular CO2 concentration. Under oxidative stress, superoxide dismutase (SOD) activity was stimulated in parallel with lipid peroxidation. We did not find any differences in the ascorbate (AsA) pool and ascorbate peroxidase (APX) or glutathione reductase (GR) activities between air qualities. Small, but similar responses were observed in spinach leaves exposed to ambient ozone concentration. and A. Calatayud ...[et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

6. Short-term responses of photosynthetic membrane lipids and photochemical efficiency in plants of Phaseolus vulgaris and Vigna unguiculata submitted to high irradiance

Creator:
Ferreira, L. C. S., Bressan-Smith, R., Elias, T. F., Silva, F. F., Viana, L. H., and Oliveira, J. G.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
chlorophyll a fluorescence, cultivar differences, French bean, lipid peroxidation, photoinhibition, photosynthesis, and species differences
Language:
Multiple languages
Description:
Primary leaves of young plants of common bean (Phaseolus vulgaris cv. Carioca and Negro Huasteco) and cowpea (Vigna unguiculata Walp cv. Epace 10) were exposed to high irradiance (HI) of 2 000 µmol m-2 s-1 for 10, 20, and 30 min. The initial fluorescence (F0) was nearly constant in response to HI in each genotype except for Carioca. A distinct reduction of maximum fluorescence (Fm) was clearly observed in stressed genotypes of beans after 20 min followed by a slight recovery for the longer stress times. In common bean, the maximum quantum yield (Fv/Fm) was reduced slowly from 10 to 30 min of HI. In cowpea, only a slight reduction of Fv/Fm was observed at 20 min followed by recovery to normal values at 30 min. HI resulted in changes in the photochemical (qP) and non-photochemical (qN) quenching in both species, but to a different extent. In cowpea plants, more efficiency in the use of the absorbed energy under photoinhibitory conditions was related to increase in qP and decrease in qN. In addition, lipid peroxidation changed significantly in common bean genotypes with an evident increase after 20 min of HI. Hence the photosynthetic apparatus of cowpea was more tolerant to HI than that of common bean and the integrity of cowpea cell membranes was apparently maintained under HI. and L. C. S. Ferreira ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

7. Uncertainty of Deardorff’s soil moisture model based on continuous TDR measurements for sandy loam soil

Creator:
Brandyk, Andrzej, Kiczko, Adam, Majewski, Grzegorz, Kleniewska, Małgorzata, and Krukowski, Marcin
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
soil moisture, modelling, parameters uncertainty, and GSA-GLUE analysis
Language:
Slovak
Description:
Knowledge on soil moisture is indispensable for a range of hydrological models, since it exerts a considerable influence on runoff conditions. Proper tools are nowadays applied in order to gain in-sight into soil moisture status, especially of uppermost soil layers, which are prone to weather changes and land use practices. In order to establish relationships between meteorological conditions and topsoil moisture, a simple model would be required, characterized by low computational effort, simple structure and low number of identified and calibrated parameters. We demonstrated, that existing model for shallow soils, considering mass exchange between two layers ( the upper and the lower), as well as with the atmosphere and subsoil, worked well for sandy loam with deep ground water table in Warsaw conurbation. GLUE (Generalized Likelihood Uncertainty Estimation) linked with GSA (Global Sensitivity Analysis) provided for final determination of parameter values and model confidence ranges. Including the uncertainty in a model structure, caused that the median soil moisture solution of the GLUE was shifted from the one optimal in deterministic sense. From the point of view of practical model application, the main shortcoming were the underestimated water exchange rates between the lower soil layer (ranging from the depth of 0.1 to 0.2 m below ground level) and subsoil. General model quality was found to be satisfactory and promising for its utilization for establishing measures to regain retention in urbanized conditions.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public