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Maribel Abadias Isabel Alegre Josep Usall Rosario Torres Inmaculada Viñas 《Postharvest Biology and Technology》2011,59(3):289-297
The risk of undesirable by-products from chlorine disinfection in fresh-cut industries, together with its limited efficacy, has led to a search for alternative agents. The aim of this study was to test several alternative putative antimicrobial substances to reduce Escherichia coli O157:H7, Salmonella spp. and Listeria spp. populations on fresh-cut apple. Carvacrol, vanillin, peroxyacetic acid, hydrogen peroxide, N-acetyl-l-cysteine and Citrox were selected for their results in in vitro assays against E. coli O157:H7 and Listeria spp., to be tested on fresh-cut apple plugs. Apple flesh was inoculated by dipping in a suspension of a mix of the studied pathogens at 106 cfu mL?1, and then treated with the antimicrobial substances. All treatments were compared to deionized water and a standard sodium hypochlorite treatment (SH, 100 mg L?1, pH 6.5). Pathogen population on apple plugs was monitored for up to 6 days at 10 °C. Bacterial reductions obtained by peroxyacetic acid (80 and 120 mg L?1), vanillin (12 g L?1), hydrogen peroxide (5, 10, 20 mL L?1) and N-acetyl-l-cysteine (5 and 10 g L?1) were similar or higher than reduction obtained by SH. In addition, bacterial populations were maintained at low levels throughout storage. No cells of any of the pathogens were detected in the peroxyacetic acid, hydrogen peroxide, Citrox and SH washing solutions after apple treatment. Peroxyacetic acid, hydrogen peroxide and N-acetyl-l-cysteine could be potential disinfectants for the fresh-cut industry as an alternative to chlorine disinfection. However, their effect on sensory quality and effectiveness under commercial processing conditions should be evaluated. 相似文献
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Radiographic features of the limbs of juvenile and subadult loggerhead sea turtles (Caretta caretta) 
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下载免费PDF全文 Ana Luisa Valente Ignasi Marco Maria Angeles Zamora Maria Luz Parga Santiago Lavín Ferran Alegre Rafaela Cuenca 《Canadian journal of veterinary research》2007,71(4):305-313
This study aimed to provide the normal radiographic anatomic appearance of the limbs of the loggerhead sea turtle, Caretta caretta. Dorsopalmar and dorsoplantar radiographs were taken of the forelimbs and hindlimbs of 15 juvenile and 15 subadult loggerhead sea turtles, 17 alive and 13 dead. For comparison, computed tomographic, gross anatomic, osteologic, and histologic studies were performed on the limbs of 5 of the sea turtles. Bones from the distal part of the fore and hind flippers were seen in detail with a mammographic film-screen combination. The pectoral and pelvic girdles, superimposed by the carapace, were better seen on standard radiographs with the use of rare-earth intensifying screens. Mammographic radiographs of the manus of 5 small juvenile turtles showed active growth zones. Visualization of bone contours in the distal part of the limbs was clearer than in mammals owing to the very few superimpositions. The presence of a substantial amount of cartilage in the epiphyses produced better visibility of limb ends. We conclude that use of a mammography film-screen combination is the best way to evaluate the bony and joint structures of the limbs of sea turtles. Radiography provides reliable images for clinical purposes. Considering the low cost and logistics of this technique, it is a practical ancillary test for marine animal rehabilitation centers to use. 相似文献
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Effects of drought on water relations, whole-shoot gas-exchange characteristics, and pigment and zeatin concentrations were investigated in the Mediterranean shrubs rosemary (Rosmarinus officinalis L.) and lavender (Lavandula stoechas L.). Two-year-old, greenhouse-grown plants were placed in a whole-shoot gas-exchange measurement system and subjected to 10 days of drought, resulting in severe water stress, and then re-watered for 5 days in order to study their recovery. Water stress resulted in a significant decline in maximum whole-shoot net CO2 assimilation rates (An) for both species that was associated with reductions in leaf area and stomatal conductance. Because shoot dark respiration rate (Rd) was less sensitive to water stress than An, shoot Rd/An ratio increased from about 15 to 95% during water stress. No major changes in chlorophyll and carotenoid concentrations of rosemary leaves were observed during the experiments, but chlorophyll and carotenoid concentrations fell significantly in water-stressed lavender leaves. Zeatin concentrations were higher in rosemary leaves than in lavender leaves during water stress. After re-watering, whole-shoot An and Rd rapidly recovered to their pre-drought rates. 相似文献
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Parejo I Jauregui O Sánchez-Rabaneda F Viladomat F Bastida J Codina C 《Journal of agricultural and food chemistry》2004,52(12):3679-3687
Liquid chromatography (LC) diode array detection (DAD) coupled to negative electrospray ionization (ESI) tandem mass spectrometry (MS/MS) was used for the rapid and sensitive identification of water-soluble phenolic compounds in fennel waste. The plant material was first extracted and then chromatographed on Sephadex LH-20 to afford seven fractions, each of them being subjected to LC-MS analysis. Identification of the compounds was carried out by interpretation of UV, MS, and MS/MS spectra. Forty-two phenolic substances were identified, 27 of which had not previously been reported in fennel, including hydroxycinnamic acid derivatives, flavonoid glycosides, and flavonoid aglycons. 相似文献
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Bovine herpesvirus‐1 (BHV‐1) and bovine herpesvirus‐5 (BHV‐5) are closely related viruses which exhibit some important differences at the genetic and immunogenic levels which may explain the differences in their pathogenicity and epidemiological characteristics. A multiplex polymerase chain reaction (M‐PCR) was developed to detect and differentiate between BHV‐1 and BHV‐5. In this M‐PCR two pairs of primers (TK1, TK2 and GD1, GD2) were used in the same reaction mix to amplify a thymidine kinase genomic region (183 bp) of BHV‐1 and one genomic region of the glycoprotein D (564 bp) of BHV‐5. The specificity of the M‐PCR was demonstrated when using both primers pairs simultaneously with BHV‐1 and BHV‐5 templates. The two expected bands were amplified without the apparition of non‐specific products. However, when other herpesvirus strains were used, there was no amplification. To evaluate the sensitivity of the assay, dilutions of purified viral DNA were made for M‐PCR amplification. The detection limit was 7 pg for BHV‐1 and 22 pg for BHV‐5. It was also determined by comparing the M‐PCR with viral isolation. M‐PCR was able to detect one log10 more than viral isolation for BHV‐1 and for BHV‐5 was two logarithms lower. The applicability of M‐PCR was demonstrated on different specimens. Twenty isolates from field samples (11 BHV‐1 and nine BHV‐5) were positive by M‐PCR, and the results were completely coincident with previous characterization using the immunoperoxidase assay. M‐PCR could detect viral DNA in organ samples from natural infections, such as semen and brain. In addition, M‐PCR detected more positive samples than observation of the citophatic effect in cell culture of nasal swabs from experimentally infected animals in two different assays. Owing to the difference in size of the M‐PCR products which allows easy identification in an electrophoretic run, it is not necessary to use extra blotting and hybridization steps or a second round of amplification to differentiate clearly between BHV‐1 and BHV‐5. 相似文献
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The effect of cattle grazing on soil physical and chemical properties in a silvopastoral system in the Peruvian Amazon 总被引：2，自引：0，他引：2
In a six-year-old peach palm (Bactris gasipaes) plantation, centrosema (Centrosema macrocarpum), a leguminous forage plant,
was established as a cover crop which was eventually grazed. This experiment was designed to monitor probable changes in soil
physical and chemical properties and measure peach palm fruit production and live-weight gain of cattle grazing this silvopastoral
system. The experiment was installed on land that was previously cleared by a D7 bulldozer having a straight blade that mixed
the thin layer of topsoil with the acid subsoil (20–40 cm) and severely compacted the soil. The results demonstrated that
the centrosema cover crop reduced soil bulk density, increased water infiltration rates and reduced mechanical resistance.
In general soil physical properties were improved with the use of Centrosema as forage and cover crop. Soil acidity and aluminum
saturation decreased considerably, while potassium concentrations increased. Calcium and magnesium concentrations decreased
over time as these minerals were stored in the pasture biomass, translocated to fresh peach palm fruits and/or exported to
animals. A strong competition for nutrients was observed between the peach palm plants and Centrosema. The low production
of peach palm fruits was in response to mechanized land clearing during initial establishment of the plantation, and also
probably due to deficits of N, P, K, Ca and Mg in the soil instead of being a consequence to the presence of cattle. The average
increase in live-weight gains of the cattle was at a rate of 445 g/animal/day during the four-years of the study. Such an
increase is substantially greater than those registered in the area under traditional grazing systems used in the region.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Ferran Jori Hugo Galvez Patricia Mendoza Manuel Cespedes Pedro Mayor 《Research in veterinary science》2009,86(3):383-387
Leptospirosis, an endemic zoonoses, is maintained in the environment by several wildlife species in the Peruvian Amazon. In order to evaluate the possible role of collared peccaries (CP) in the maintenance this disease, two serological surveys of leptospirosis were performed and zootechnical parameters were monitored in a captive CP colony in an interval of 27 months. Total seroprevalence changed from 100% (n = 27) to 86.4% (n = 22), with reactions to a diversity of serogroups of zoonotic importance. Serological reactions to Leptospira licerasiae serogroup Iquitos, a new species recently identified locally and Leptospira interrogans serogroup Icterohaemorrhagiae were highly prevalent. The observation of leptospiral antibodies in both surveys, changes on serological reactions to different serogroups in large part of the herd and poor reproductive performances, provided an indication of the role of CP farms as a favourable environment for maintaining leptospirosis. Further research regarding the role of CP in the epidemiology of leptospirosis in the Peruvian Amazon is encouraged. 相似文献
10.
Federico Rossi Ruth M. Potrafka Ferran Garcia Pichel Roberto De Philippis 《Soil biology & biochemistry》2012
Biological soil crusts (BSCs) are highly specialized topsoil microbial communities commonly found in arid and semiarid environments, permeated by a polymeric matrix of polysaccharides. BSCs can in principle influence edaphic properties such as texture, pore formation and water retention, which in turn determine water distribution and biological activity in dry lands. This paper investigates the influence of biotic and abiotic factors on BSC hydraulic conductivity, a parameter gauging the ease with which water can move through the pore spaces. Texture, phototroph abundance, microbial composition, and extracellular carbohydrate content were considered as potentially relevant parameters in a correlational study of BSC samples that spanned 1.5 orders of magnitude in hydraulic conductivity. A newly developed, non-destructive extraction method enabled us to directly quantify the specific role of extracellular polysaccharides on soil permeability on a variety of samples. Hydraulic conductivity showed a strongest correlation with texture (positive with sand content, negative with silt and clay). A weaker negative correlation with carbohydrate content, especially with polysaccharides having a molecular weight < 100 kDa, was also detected. In multiple regression analyses texture (silt content) was sufficient to explain most of the variation in hydraulic conductivity However, experimental removal of polymeric carbohydrates, resulted invariably in a substantial decrease in hydraulic conductivity for any given sample (between 1.7 and 3.3 fold). Our results suggest that while soil texture determines overall hydraulic conductivity in BSCs, the presence of exopolysaccharides can significantly enhance it, likely by conferring a spongy structure to a BSC thus increasing the number of waterways within it. 相似文献