Chitosan physico–chemical properties modulate defense responses and resistance in tobacco plants against the oomycete Phytophthora nicotianae     

Alejandro Bernardo Falcón-Rodríguez  Daimy Costales  Juan Carlos Cabrera  Miguel Ángel Martínez-Téllez 《Pesticide biochemistry and physiology》2011,100(3):221-228

Enzymatic defense responses and protection against Phytophthora nicotianae were studied in tobacco plants treated with chitosan of different molecular weights (MW) and degrees of acetylation (DA). The concentration and mode of chitosan application affected enzymatic induction in tobacco leaves. β-1,3-Glucanase (EC 3.2.1.6) activity required 10 times the polymer concentration relative to the oligochitosan mixture to induce the highest activity above control when treated by foliar spray, indicating the influence of molecular weight in this response. PAL (EC 4.3.1.5) and POD (EC 1.11.1.6) activities increased above control as a result of the influence of polymer degree of acetylation when treatments were applied by foliar spray. A higher DA favored PAL activity, whereas a lower DA induced higher POD activity. Using an in vitro bioassay, it was found that the three chitosan compounds caused a reduction of the infection index of P. nicotianae in tobacco plants that was dependent on elicitor concentrations. There was a significant relationship between the reduction of the infection index and an increase in PAL activity when chitosan was applied by foliar spray and by substrate drench to the plant rhizosphere. These results demonstrate the influence of chitosan physico–chemical properties in plant-induced resistance and the relevance of particular responses in plant protection against pathogens.  相似文献   

Resveratrol treatment controls microbial flora, prolongs shelf life, and preserves nutritional quality of fruit     

Jiménez JB  Orea JM  Montero C  Ureña AG  Navas E  Slowing K  Gómez-Serranillos MP  Carretero E  De Martinis D 《Journal of agricultural and food chemistry》2005,53(5):1526-1530

Resveratrol is known as a grapevine secondary metabolite with fungicide activity. Its exogenous application on harvested grapes resulted in the reduction of microbial flora growth, and consequently, prolonged shelf life, without affecting the nutritional quality of the fruit. Resveratrol treatment also resulted in being effective on fruit that normally does not accumulate such metabolites as, for example, tomatoes, apples, avocado pears, and peppers. As a result, all treated fruits maintained their post-harvest quality and health longer than the untreated ones. This study demonstrates the potential use of resveratrol as a natural pesticide to reduce post-harvest fungi development on a broad spectrum of fruit types.  相似文献   

A critical assessment of abattoir surveillance as a screening test for swine ascariasis.   总被引：1，自引：1，他引：0       下载免费PDF全文

T M Bernardo  I R Dohoo    T Ogilvie 《Canadian journal of veterinary research》1990,54(2):274-277

The following data on ascarid burden were collected on an individual basis for 380 hogs marketed in the fall of 1987: a series of fecal ascarid-egg counts during the growing period; the level of milk spot lesions on the liver at slaughter; and the number of ascarids in the small intestines at slaughter. The presence of milk spots had a high sensitivity, very low specificity, and a high negative predictive value as a screening test for ascariasis in individual hogs. Results were consistent whether ascariasis was measured as the presence of intestinal ascarids at slaughter (sensitivity 91%, specificity 22%, negative predictive value 82%), or by a positive fecal egg count during the hog's lifetime (sensitivity 96%, specificity 24%, negative predictive value 93%). The presence of milk spots does not necessarily indicate that an ascarid infection has been established in the small intestine. The absence of milk spots, however, is a reliable indicator of the absence of an established ascarid infection, provided that the prevalence of ascariasis is equal to or less than that observed in this study. The severity of the ascarid infection in an individual hog could not be ascertained by the number of milk spot lesions on the liver.  相似文献   

Influence of Puerperal Uterine Infection on Uterine Involution and Postpartum Ovarian Activity in Dairy Cows   总被引：1，自引：0，他引：1  

L Mateus  L Lopes da Costa  F Bernardo  & J Robalo Silva 《Reproduction in domestic animals》2002,37(1):31-35

This article presents the results of a clinical trial designed to study the effect of puerperal uterine infection on uterine involution and on ovarian activity in dairy cows, monitored twice weekly from parturition until the sixth week postpartum (wpp). Infection significantly retarded uterine involution assessed by the uterine body diameter and a score of intrauterine fluid volume (IUFV). By the sixth wpp, cows with normal puerperium (controls) and cows that showed mild puerperal endometritis had similar uterine body diameter and IUFV, indicating spontaneous recovery within the postpartum voluntary waiting period. However, in cows with severe puerperal endometritis, although uterine body diameter had regressed to pregravid size, IUFV remained significantly higher than in control and mild endometritis cows, indicating that chronic endometritis was established. The IUFV score was positively and significantly correlated with uterine swab bacterial growth density and allowed diagnosis of endometritis after the third wpp. Cows with mild or severe endometritis had a significantly higher prevalence and persistence of pathogenic bacteria ( Escherichia coli , Actinomyces pyogenes , Gram-negative anaerobes – GNA) than controls. Actinomyces pyogenes was associated to GNA in 74% of isolations. Ovarian activity measured by ultrasound scanning of the ovaries and plasma progesterone (P4) concentrations was more abnormal (prolonged anoestrus, prolonged luteal phases and ovarian cysts) in cows with severe endometritis than in controls.  相似文献   

What is the value of eucalyptus monocultures for the biodiversity of the Atlantic forest? A multitaxa study in southern Bahia,Brazil     

Pedro Luís Bernardo da Rocha  Blandina Felipe Viana  Márcio Zikán Cardoso  Amada Mariana Costa de Melo  Misonete Gueidneli Cavalcanti Costa  Rodrigo Nogueira de Vasconcelos  Tatiana Bichara Dantas 《林业研究》2013,24(2):263-272

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Bioactivity and Applications of Sulphated Polysaccharides from Marine Microalgae     

Maria Filomena de Jesus Raposo  Rui Manuel Santos Costa de Morais  Alcina Maria Miranda Bernardo de Morais 《Marine drugs》2013,11(1):233-252

Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina), and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS). It goes through the most studied activities of sulphated polysaccharides (sPS) or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review.  相似文献   

Maintenance of fresh boysenberry fruit quality with UV-C light and heat treatments combined with low storage temperature     

Ariel Vicente  Bernardo Repice  Gustavo Martínez  Alicia Chaves  Pedro Civello 《The Journal of Horticultural Science and Biotechnology》2013,88(2):246-251

Summary

Mature boysenberries (Rubus hybrid) were harvested, heat-treated (45°C for 1 or 3 h or 47°C for 1 h) or exposed to UV-C light (2.3, 4.6 or 9.2 kJ m^–2), and stored at 20°C for 2 d. Fruit treated with 9.2 kJ m^–2 or 45°C for 1 h showed less damaged drupelets per fruit and/or remained firmer than untreated fruit after 2 d. Those treatments were selected for further analyses. In another experiment, boysenberries were either UV-C (9.2 kJ m^–2) or heat-treated (45°C for 1 h) and stored either at 20°C for 1 d or at 0°C for 4 d before transfer to 20°C for 1 d. Both UV-C and heat treatments reduced softening and/or fruit damage. Treated fruit had lower respiration rates and anthocyanin leakage than control fruit suggesting greater tissue integrity. Titratable acidity, pH, total sugar content and antioxidant activity in treated fruit showed fewer changes than in control fruit when stored at 20°C for 1 d. Results suggest that heat or UV-C treatment, alone or in combination with refrigerated storage, may be a useful non-chemical mean of maintaining boysenberry fruit quality and extending postharvest life.  相似文献   

Occurrence and distribution study of residues from pesticides applied under controlled conditions in the field during rice processing   总被引：2，自引：0，他引：2  

Pareja L  Colazzo M  Pérez-Parada A  Besil N  Heinzen H  Böcking B  Cesio V  Fernández-Alba AR 《Journal of agricultural and food chemistry》2012,60(18):4440-4448

The results of an experiment to study the occurrence and distribution of pesticide residues during rice cropping and processing are reported. Four herbicides, nine fungicides, and two insecticides (azoxystrobin, byspiribac-sodium, carbendazim, clomazone, difenoconazole, epoxiconazole, isoprothiolane, kresoxim-methyl, propanil, quinclorac, tebuconazole, thiamethoxam, tricyclazole, trifloxystrobin, λ-cyhalotrin) were applied to an isolated rice-crop plot under controlled conditions, during the 2009-2010 cropping season in Uruguay. Paddy rice was harvested and industrially processed to brown rice, white rice, and rice bran, which were analyzed for pesticide residues using the original QuEChERS methodology and its citrate variation by LC-MS/MS and GC-MS. The distribution of pesticide residues was uneven among the different matrices. Ten different pesticide residues were found in paddy rice, seven in brown rice, and eight in rice bran. The highest concentrations were detected in paddy rice. These results provide information regarding the fate of pesticides in the rice food chain and its safety for consumers.  相似文献   

Ion levels in the gastrointestinal tract content of freshwater and marine–estuarine teleosts     

Becker AG  Gonçalves JF  Burns MD  Vieira JP  Radünz Neto J  Baldisserotto B 《Fish physiology and biochemistry》2012,38(4):1001-1017

This study investigated the relationship between ion levels (Na?, Cl?, K?, Ca2?, and Mg2?) in the fluid phase and total chyme of the contents of the gastrointestinal tract segments of freshwater and marine-estuarine teleosts collected in different salinities (0-34 ppt) in estuarine and freshwater portions of the S?o Gon?alo channel, southern Brazil. In addition, the relative contribution of feeding and osmoregulation to the ionic content of each portion of the gastrointestinal tract of fishes collected in different ambient salinities was analyzed. There was no relationship between salinity and ion levels in the fluid phase and total chyme of the segments of the gastrointestinal tract when considering all species together. However, there was a significant positive relationship between salinity and ion levels in the fluid phase and total chyme of two fish species (Micropogonias furnieri and Genidens barbus) collected in three or more different salinities. In most species, ion levels in the fluid phase and total chyme changed throughout the gastrointestinal tract, suggesting absorption, but the ionoregulatory mechanisms of the gastrointestinal tract seem to vary according to species.  相似文献   

Priority areas for the conservation of Atlantic forest large mammals     

Mauro Galetti  Henrique C. Giacomini  Christine S.S. Bernardo  Ricardo S. Bovendorp  Paulo Rubim  Camila I. Donatti  Rodrigo A. Begotti  Rodrigo de A. Nobre  Carlos A. Peres 《Biological conservation》2009,142(6):1229-1241

Large mammal faunas in tropical forest landscapes are widely affected by habitat fragmentation and hunting, yet the environmental determinants of their patterns of abundance remain poorly understood at large spatial scales. We analysed population abundance and biomass of 31 species of medium to large-bodied mammal species at 38 Atlantic forest sites (including three islands, 26 forest fragments and six continuous forest sites) as related to forest type, level of hunting pressure and forest fragment size using ANCOVAs. We also derived a novel measure of mammal conservation importance for each site based on a “Mammalian Conservation Priority index” (MP_i) which incorporates information on species richness, population abundance, body size distribution, conservation status, and forest patch area. Mammal abundance was affected by hunting pressure, whereas mammalian biomass of which was largely driven by ungulates, was significantly influenced by both forest type and hunting pressure. The MP_i index, when separated into its two main components (i.e. site forest area and species-based conservation index C_i), ordered sites along a gradient of management priorities that balances species-focused and habitat-focused conservation actions. Areas with the highest conservation priority were located in semi-deciduous forest fragments, followed by lowland forests. Many of these fragments, which are often embedded within large private landholdings including biofuel and citrus or coffee crops, cattle ranches and pulpwood plantations, could be used not only to comply with environmental legislation, but also enhance the prospects for biodiversity conservation, and reduce edge effects and hunting.  相似文献