Citrus juice characterization. Identification and estimation of the major phospholipids     

C E Vandercook  H C Guerrero  R L Price 《Journal of agricultural and food chemistry》1970,18(5):905-907

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Chlorogenic acids as a potential criterion in coffee genotype selections     

Guerrero G  Suárez M  Moreno G 《Journal of agricultural and food chemistry》2001,49(5):2454-2458

A systematic study by HPLC was conducted to determine the content of chlorogenic acids in green coffee beans of the Variedad Colombia (Coffea arabica Caturra var. x Híbrido de Timor) and in other genotypes of interest of C. arabica, Coffea canephora, Híbrido de Timor, and the F1 offspring derived from the crossing Caturra x Híbrido de Timor. Comparisons were made of the total content of these acids, their quantitative differences, and the presence or absence of some of them, using parametric statistical techniques and multivariate analysis. Total content differences were found between C. canephora accessions, between Típica and Caturra varieties of C. arabica, and between Híbrido de Timor accessions. The chromatographic profile comparisons with principal component analysis separated in the first component C. canephora accessions from the rest of the genotypes, whereas the second component separated C. canephora accessions.  相似文献   

Assessing air-drying and rewetting pre-treatment effect on some soil enzyme activities under Mediterranean conditions     

R. Zornoza  C. Guerrero  J. Mataix-Solera  V. Arcenegui  F. García-Orenes  J. Mataix-Beneyto 《Soil biology & biochemistry》2006,38(8):2125-2134

Soil enzyme activities are useful indicators of soil quality as they are very sensitive to disturbance. Sample storage or pre-treatments could affect the results in these assays, which are normally determined in fresh samples, kept cold or frozen. The objectives of this study were to (i) evaluate the effect of air-drying or air-drying and rewetting on β-glucosidase, acid phosphatase and urease activities in soils from different locations, degradation status and sampling seasons, and (ii) assess if air-drying or air-drying and rewetting is an accurate sample storage and pre-treatment procedure for enzyme activities in soil quality evaluations under semiarid Mediterranean conditions. Our results showed that urease, phosphatase and β-glucosidase activities were hardly affected by air-drying of degraded and non-degraded soils from the two locations studied in all seasons. Short incubations (4, 8 and 12 d at 23 °C) of rewetted air-dried soil at 55% of water-holding capacity showed different patterns depending on the enzyme studied. Urease and β-glucosidase activities were relatively stable during incubation, with several significant (P<0.05) shifts up and down in some soils and samplings. However, acid phosphatase showed an increase in activity with incubation, of between 5% and 50% relative to air-dried samples. These increases followed no pattern and were unrelated to soil characteristics or sampling date. Hence, urease, phosphatase and β-glucosidase activities determined in air-dried soil samples seem to be representative of those obtained under field-moist conditions. In contrast, short incubations of rewetted soil samples can produce fluctuations in these enzyme activities, mainly of acid phosphatase, and estimations in these conditions are not so representative of field-moist soil values.  相似文献   

Micro/nano encapsulation via electrified coaxial liquid jets     

Loscertales IG  Barrero A  Guerrero I  Cortijo R  Marquez M  Gañán-Calvo AM 《Science (New York, N.Y.)》2002,295(5560):1695-1698

We report a method to generate steady coaxial jets of immiscible liquids with diameters in the range of micrometer/nanometer size. This compound jet is generated by the action of electro-hydrodynamic (EHD) forces with a diameter that ranges from tens of nanometers to tens of micrometers. The eventual jet breakup results in an aerosol of monodisperse compound droplets with the outer liquid surrounding or encapsulating the inner one. Following this approach, we have produced monodisperse capsules with diameters varying between 10 and 0.15 micrometers, depending on the running parameters.  相似文献   

Activity of octylthiotrifluoropropan-2-one,a potent esterase inhibitor,on growth,development, and intraspecific communication in Spodoptera littoralis and Sesamia nonagrioides     

Reddy GV  Quero C  Guerrero A 《Journal of agricultural and food chemistry》2002,50(24):7062-7068

A series of experiments were conducted to examine the effect of 3-octylthio-1,1,1-trifluoro-2-propanone (OTFP) on growth, development, and behavior of the cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae), and the corn stalk borer, Sesamia nonagrioides (Lepidoptera: Noctuidae). The chemical behaved as an oviposition deterrent and, when added to the diet of the second-instar larvae of both insects, reduced diet consumption and growth, pupation, and adult emergence. Treatment of 100-5000 ng of the compound on fourth-instar larvae for 3-24 h, however, did not produce significant differences in the amount of diet ingested. Our results suggest that the effect of OTFP is long-lasting and that the inhibitor is not fully detoxified by the detoxification enzymes of the digestive tract of the insects. In behavioral assays, adult males which had been treated with the chemical at the larval stage were less attracted to the pheromone source than regular untreated males. When Sp. littoralis untreated females were used as the attractant source, treated males also displayed significantly fewer contacts with the cage-containing females than untreated or solvent-treated males. In the presence of treated females, only 27% of treated males successfully completed the flight in comparison to animals responding to solvent-treated females (54.5%). By contrast, when Se. nonagrioides females, whether they had been subjected or not to the treatment, were used as the attractant source, males were similarly attracted to them regardless of whether they had been treated or not at the larval stage. Analyses of gland extracts of Sp. littoralis treated females showed no difference from control insects in the qualitative or quantitative composition of the pheromone blend. The results obtained, in combination with other results previously reported by us (Riba, M.; Sans, A.; Bau, P.; Grolleau, G.; Renou, M.; Guerrero, A. J. Chem. Ecol. 2001, 27, 1879-1897), provide new and relevant information about the possible utility of these chemicals in future studies directed to the development of new approaches for pest control.  相似文献   

The activity of closantel as an equine antiparasitic agent     

J Guerrero  B F Michael  M W Rohovsky  B P Campbell 《Veterinary parasitology》1983,12(1):71-77

Eighteen pony foals were experimentally infected with 500 third stage larvae of Strongylus vulgaris at 2 weeks, and at 2, 4, 6 and 8 months after birth. For the duration of the study, all foals were kept in the same pasture with their mothers to allow natural infection with other parasites by exposure to a contaminated environment. Twelve of the foals were utilized in groups of 3 and treated orally five times at two month intervals starting at one month of age with closantel at doses of 5, 10, 20 or 40 mg kg-1. Ten months after birth the foals were necropsied to determine the parasitic burdens in the gastrointestinal tracts and the cranial mesenteric arteries. The results indicate a high antiparasitic activity of closantel against larval stages of Gasterophilus intestinalis and S. vulgaris, as well as against adult S. vulgaris, S. edentatus, Anoplocephala perfoliata and Triodontophorus spp., when used at doses of 20 or 40 mg kg-1.  相似文献   

2005 Guidelines for the diagnosis, prevention and management of heartworm (Dirofilaria immitis) infection in dogs   总被引：2，自引：0，他引：2  

Nelson CT  McCall JW  Rubin SB  Buzhardt LF  Dorion DW  Graham W  Longhofer SL  Guerrero J  Robertson-Plouch C  Paul A;Executive Board of the American Heartworm Society 《Veterinary parasitology》2005,133(2-3):255-266

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A survey of gastrointestinal helminths in cats of the metropolitan region of Rio de Janeiro, Brazil   总被引：4，自引：0，他引：4  

Labarthe N  Serrão ML  Ferreira AM  Almeida NK  Guerrero J 《Veterinary parasitology》2004,123(1-2):133-139

The prevalence of gastrointestinal helminth parasites in 135 cats over 1 year of age and inhabiting the metropolitan region of the city of Rio de Janeiro, Brazil was investigated by necropsy. These animals had two distinct origins: 99 cats (29 males and 70 females) were derived by capture in public areas (feral/stray) and 36 (12 males and 24 females) from shelters. The overall prevalence of gastrointestinal helminth parasites was 89.6%. The following parasites, with their respective prevalence in parenthesis, were found: Dipylidium caninum (52.6%), Ancylostoma braziliense (65.9%), Ancylostoma tubaeforme (8.9%), Toxocara cati (25.2%), Toxascaris leonina (11.9%), Physaloptera praeputialis (9.6%). Concurrent infections with two or more parasites were recorded in 59.5% of the individuals. Of the 121 parasitized cats, 94 were feral/strays and 27 were from shelters. Among feral/stray cats, 80 were infected with A. braziliense (85%) and 17 of the shelter felids were infected with D. caninum (63%). Feral/stray cats had higher worm intensities (6411/94-68.2) than shelter cats (992/27-36.7). The helminth parasites most frequently found in feral/stray cats were Ancylostoma braziliense (47.5%) and D. caninum (47%) while in shelter cats, D. caninum was the predominant species (85.2%). Twenty seven cats (22.3%) had only A. braziliense and 19 (15.7%) were parasitized only with D. caninum. Among those cats harboring mixed infections A. braziliense and D. caninum were the species more frequently found (P < 0.001).  相似文献   

Effects of mid-season avermectin treatments on pyrethroid resistance in horn fly (Diptera: Muscidae) populations at three locations in Louisiana     

Oremus G  Guerrero FD  Alison MW  Kimball MM  Kim JH  Foil LD 《Veterinary parasitology》2006,141(1-2):156-164

Between 1999 and 2002, the effect of mid-season doramectin treatments on the level of resistance in pyrethroid-resistant horn fly populations was examined at three separate Louisiana State University Agricultural Center research stations. The cattle were treated with pyrethroid ear tags in all years at all farms, and each farm received a mid-season doramectin treatment in 1 year. The number of weeks of control at Red River was 11 weeks higher in the year following the mid-season treatment of doramectin. At Macon Ridge, the number of weeks of control was 2 weeks higher in the year following the doramectin treatment. No change was observed at St. Joseph. The LC50s for fly populations tested at Macon Ridge and St. Joseph were found to increase for pyrethroids from the spring populations to the fall populations between 2000 and 2002. The LC50s for fly populations at Red River followed the same trends except in 2000, the year when the doramectin treatment was administered. Flies collected pre and post-treatment each year from St. Joseph and Red River were assayed for two alleles (kdr and skdr) associated with target site resistance to pyrethroids. Flies collected pretreatment at Macon Ridge in 1999 also were assayed for the kdr and skdr, and this population of flies had a frequency of 85.6% R-kdr alleles. At St. Joseph and Red River there was a general decline in the frequency of homozygous susceptible skdr (SS-skdr) and homozygous susceptible kdr (SS-kdr) individuals, as well as a general increase in homozygous resistant skdr (RR-skdr) and homozygous resistant kdr (RR-kdr) individuals, during the 4-year study. At both sites, the frequency of R-kdr alleles increased significantly in flies collected in the fall compared to flies collected in the spring with the exception of Red River in 2000, when dormacetin was applied. The frequency of the R-kdr alleles was significantly higher in flies collected in the fall compared to flies collected in the spring in the following year at both sites in two out of three comparisons. The frequency of R-skdr alleles was significantly lower in fly populations tested in the spring compared to fly populations tested in the fall at both farms in years when doramectin was not applied but there were no differences in the years when doramectin was applied. The frequency of R-skdr alleles was significantly higher in fly populations tested in the fall compared to in the spring the following year during all three comparisons at Red River and in one of three comparisons at St. Joseph.  相似文献   

Near infrared spectroscopy for determination of various physical,chemical and biochemical properties in Mediterranean soils     

R. Zornoza  C. Guerrero  J. Mataix-Solera  K.M. Scow  V. Arcenegui  J. Mataix-Beneyto 《Soil biology & biochemistry》2008,40(7):1923-1930

The potential of near infrared (NIR) reflectance spectroscopy to predict various physical, chemical and biochemical properties in Mediterranean soils from SE Spain was evaluated. Soil samples (n = 393) were obtained by sampling 13 locations during three years (2003–2005 period). These samples had a wide range of soil characteristics due to variations in land use, vegetation cover and specific climatic conditions. Biochemical properties also included microbial biomarkers based on phospholipid fatty acids (PLFA). Partial least squares (PLS) regression with cross validation was used to establish relationships between the NIR spectra and the reference data from physical, chemical and biochemical analyses. Based on the values of coefficient of determination (r²) and the ratio of standard deviation of validation set to root mean square error of cross validation (RPD), predicted results were evaluated as excellent (r² > 0.90 and RPD > 3) for soil organic carbon, Kjeldahl nitrogen, soil moisture, cation exchange capacity, microbial biomass carbon, basal soil respiration, acid phosphatase activity, β-glucosidase activity and PLFA biomarkers for total bacteria, Gram-positive bacteria, actinomycetes, vesicular-arbuscular mycorrhizal fungi and total PLFA biomass. Good predictions (0.81 < r² < 0.90 and 2.5 < RPD < 3) were obtained for exchangeable calcium and magnesium, water soluble carbon, water holding capacity and urease activity. Resultant models for protozoa and fungi were not accurate enough to satisfactorily estimate these variables, only permitting approximate predictions (0.66 < r² < 0.80 and 2.0 < RPD < 2.5). Electrical conductivity, pH, exchangeable phosphorus and sodium, metabolic quotient and Gram-negative bacteria were poorly predicted (r² < 0.66 and RPD < 2). Thus, the results obtained in this study reflect that NIR reflectance spectroscopy could be used as a rapid, inexpensive and non-destructive technique to predict some physical, chemical and biochemical soil properties for Mediterranean soils, including variables related to the composition of the soil microbial community composition.  相似文献