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121.
Belinha I Amorim MA Rodrigues P de Freitas V Moradas-Ferreira P Mateus N Costa V 《Journal of agricultural and food chemistry》2007,55(6):2446-2451
Quercetin, the major flavonol found in several fruits and vegetables, is a natural antioxidant with potential anticancer and antiaging activities. In this paper, the effect of quercetin in Sacharomyces cerevisiae cells submitted to oxidative stress was studied. Hydrogen peroxide resistance increased in cells pretreated with quercetin. Cellular protection was correlated with a decrease in oxidative stress markers, namely, levels of reactive oxygen species, glutathione oxidation, protein carbonylation, and lipid peroxidation. The acquisition of H2O2 resistance was not associated with the induction of antioxidant defenses or with iron chelation. Oxidative stress is a limiting factor for longevity. In agreement, quercetin also increased 60% chronological life span. These results support the utilization of yeast as a useful model to screen in vivo for natural antioxidants with putative health beneficial effects. 相似文献
122.
Bacterial lipopolysaccharide induces porcine circovirus type 2 replication in swine alveolar macrophages 总被引:5,自引:0,他引:5
Monocyte/macrophage lineage cells are major target cells of porcine circovirus type 2 (PCV2). From tissues of field pigs suffering from postweaning multisystemic wasting syndrome (PMWS), both intracytoplasmic and intranuclear PCV2 signals, including antigens and nucleic acid, were easily detected in the monocyte/macrophage lineage cells. However, there was a high incidence of intracytoplasmic PCV2-positive signals, but lack of intranuclear signals and PCV2 replication in these cells in vitro. Concurrent infection with bacteria and activation of immune system are suggested to promote viral replication. In this study, lipopolysaccharide (LPS) and phorbol-12-myristate-13-acetate (PMA) were used to stimulate PCV2-inoculated alveolar macrophages (AMs). A decrease in intracytoplasmic but increase in intranuclear PCV2-positive signals, including antigens and nucleic acid, were detected in LPS-treated PCV2-inoculated AMs, but not in PMA-treated cells. Additionally, the replication product corresponding to PCV2 spliced major capsid protein (Cap) mRNA and a significant elevation in PCV2 titer were demonstrated in the LPS-treated PCV2-inoculated AMs. The results imply that Gram-negative bacterial co-infection in PCV2-infected pigs may be an important factor in promoting PCV2 replication and contributing, at least partially, to the full development of PMWS. 相似文献
123.
Crivineanu V Cozma V Carp-Carare M Darabus G Adam S 《Journal of veterinary medical education》2006,33(2):228-232
Romania has a long tradition in the field of veterinary medicine, interest in which can be traced back to the early nineteenth century. There are four main veterinary educational centers in Romania, one for each province: the Faculty of Veterinary Medicine in Bucharest in the south; the Faculty of Veterinary Medicine in Cluj-Napoca in the northwest; the Faculty of Veterinary Medicine in Ia?i in the northeast; and the Faculty of Veterinary Medicine Timi?oara in the south west. The authors of this article are faculty members representing each of these schools. 相似文献
124.
We investigated whether root grafts between lodgepole pine (Pinus contorta var. latifolia Dougl. ex. Loud.) trees can transfer sufficient carbohydrate reserves from a source tree to a grafted sink tree to affect the vigor of trees growing in a light-limited environment. Eleven plots were established in early spring and two grafted tree pairs and two independent non-grafted trees were selected at each plot. One tree in a grafted pair and one non-grafted tree were shaded at each plot, whereas the remaining trees were non-shaded during the experimental period. Shaded trees had significantly lower carbohydrate reserves and smaller crowns than non-shaded trees following one growing season. Grafted shaded trees had significantly higher root total nonstructural carbohydrate concentrations than non-grafted shaded trees, indicating that root grafts partially offset the effects of shading. Also, large root grafts transferred proportionately more carbohydrates to the shaded trees than small root grafts. Carbohydrates transferred through root grafts could allow grafted trees to persist under conditions where non-grafted trees would be removed by competition. 相似文献
125.
Yuri Gerasimov Victor Senkin Kari Väätäinen 《European Journal of Forest Research》2012,131(3):647-654
A field-based study was carried out to broaden our knowledge of fully mechanized cut-to-length harvesting productivity in
naturally grown forests in the northern European part of Russia (NEPR). The recorded data comprised 38 midsized single-grip
harvesters (JD 1270D) in clear-cutting operations in the Karelia, Komi, Vologda, Leningrad, Tver, and Kirov regions in NEPR,
4.3 million felled trees, and 1.4 million m3 u.b. (under bark) of processed timber. Harvesting operations were conducted in forest stands composed of spruce (48% on average),
pine (19%), birch (22%), and aspen (11%), with an average stem volume 0.31 m3 u.b. The cut-to-length harvesters produced from 4.3 to 14.9 m3 u.b./productive machine hour (PMH) and 16.0–49.5 m3 u.b./stem processing machine hour (S
proc
MH). A machine evaluation analysis and a regression analysis were used to formulate models for predicting cutting productivity
of modern single-grip harvester. The regression models were developed to estimate the productivity of the harvesters in the
regions taking into account two significant factors influencing the productivity: the stem volume and tree species of the
felled trees. Productivity/cubic meter u.b. of processed timber/PMH was calculated according to stem volume and tree species distributions in most forest-covered NEPR regions. Further research
is suggested to improve the developed productivity models and to allow prediction of system performance over a broad range
of stand and site conditions. 相似文献
126.
Segura-Correa José C. Segura-Correa Victor M. 《Tropical animal health and production》2009,41(8):1773-1778
Prenatal mortality is an important cause of production losses in the livestock industry. This study estimates the prevalences
of abortion and stillbirth in a beef cattle system and determines the significance of some risk factors, in the tropics of
Mexico. Data were obtained from a Zebu cattle herd and their crosses with Bos taurus breeds, in Yucatan, Mexico. The logit of the probability of an abortion or stillbirth was modeled using binary logistic regression.
The risk factors tested were: year of abortion (or calving), season of abortion (or calving), parity number and dam breed
group. The effect of twins on stillbirth was tested using Fisher exact test. Of the 4175 calvings studied 49 were abortions
(1.17%). Significant factors in the logistic regression analysis for abortions were season of abortion and parity number.
The risk of abortion was lower in the dry seasons compared to the rainy and windy seasons (P = 0.009). The risk of abortion
was higher in second parity cows followed by the third and first parity cows, as compared to older cows (P = 0.015). Of the
4126 births, 87 were stillbirths (2.11%). Significant factors in the logistic regression analysis for stillbirth were year
of calving (P = 0.0001) and parity number (P < 0.001). The risk of stillbirth in first parity cows was 2.6 times that of old
cows. Of the total births, 15 were twins (0.36%) of which 7 were born dead calves. Herd owners must focus on the significant
risk factors under their control to reduce the prevalence of prenatal mortality. 相似文献
127.
Fabio Ribeiro Braga Jackson Victor Araújo Andr Ricardo Silva Juliana Milani Araujo Rogrio Oliva Carvalho Alexandre Oliveira Tavela Artur Kanadani Campos Giovanni Ribeiro Carvalho 《Veterinary parasitology》2009,163(4):335-340
The viability of a fungal formulation using the nematode-trapping fungus Duddingtonia flagrans was assessed for the biological control of horse cyathostomin. Two groups (fungus-treated and control without fungus treatment), consisting of eight crossbred mares (3–18 years of age) were fed on Cynodon sp. pasture naturally infected with equine cyathostome larvae. Each animal of the treated group received oral doses of sodium alginate mycelial pellets (1 g/(10 kg live weight week)), during 6 months. Significant reduction (p < 0.01) in the number of eggs per gram of feces and coprocultures was found for animals of the fungus-treated group compared with the control group. There was difference (p < 0.01) of 78.5% reduction in herbage samples collected up to (0–20 cm) between the fungus-treated group and the control group, during the experimental period (May–October). Difference of 82.5% (p < 0.01) was found between the fungus-treated group and the control group in the sampling distance (20–40 cm) from fecal pats. During the last 3 months of the experimental period (August, September and October), fungus-treated mares had significant weight gain (p < 0.01) compared with the control group, an increment of 38 kg. The treatment with sodium alginate pellets containing the nematode-trapping fungus D. flagrans reduced cyathostomin in tropical southeastern Brazil and could be an effective tool for biological control of this parasitic nematode in horses. 相似文献
128.
Wiebren Santema Marije Overdijk Judith Barends Jeroen Krijgsveld Victor Rutten Ad Koets 《Veterinary microbiology》2009,138(1-2):191-196
Accurate immunodiagnosis of bovine paratuberculosis is among others hampered by the lack of specific antigens. One of the most frequently used antigen preparations is purified protein derivative (PPD), also known as tuberculin. This crude extract has limitations when used in diagnostic assays due to the presence of cross-reactive antigens. The aim of the current study was to systematically analyze the qualitative protein composition of PPD of the major mycobacterial pathogens.One-dimensional gel electrophoresis followed by tandem mass spectrometry analysis of PPD from Mycobacterium avium subspecies paratuberculosis (MAP), Mycobacterium avium subspecies avium (MAA) and Mycobacterium bovis (MB) identified 156, 95 and 132 proteins, respectively. Comparative sequence analysis led to the selection of a MAP-specific protein (MAP1718c), and finally heterologous expression in Escherichia coli of this and other diagnostic candidate proteins (MAP3515c and MAP1138c (LprG)) enabled evaluation of their immunogenicity. Lymphocyte proliferation responses did not indicate substantial diagnostic potential of the antigens tested. In contrast serum antibody levels for MAP1138c in paratuberculosis infected cows (N = 20) were significantly higher (p < 0.01) than in control animals (N = 20), despite the conserved nature of this protein.In conclusion, this study showed that a combination of proteomics and genomics, starting from complex protein mixtures, present in tuberculins, can reveal novel proteins aiding the development of immunodiagnostics for mycobacterial diseases. 相似文献
129.
Paula Pessina Andrea Fernández-Foren Enrique Cueto Luis Delucchi Victor Castillo Ana Meikle 《Acta veterinaria Scandinavica》2009,51(1):33