Fungi infection in fruits is an important factor in postharvest losses. The effect of a treatment with a fungal elicitor on the response of tomato fruit to Fusarium oxysporum infection and changes in the phenylpropanoid metabolic pathway was studied. Fungal elicitor retarded for 3 days the development of the Fusarium rot development in tomato, at concentration of 2 g?l?1 (B2-F treatment). This treatment also induced a 3.11- and 6.03-fold increase of caffeic and chlorogenic acids, respectively, as compared with the control. Furthermore, the flavonoids naringenin-7-O-glucoside, rutin and kaempferol-3-O-glucoside, showed a greater abundance in tomato under the B2-F treatment after 6 days at 20°C. It is concluded that the fungal elicitor reduced the development of Fusarium rot by inducing the biosynthesis of metabolites from the phenylpropanoid metabolic pathway which forms part of the defense response in tomato fruit. 相似文献
Our ability to have an experience of another's pain is characteristic of empathy. Using functional imaging, we assessed brain activity while volunteers experienced a painful stimulus and compared it to that elicited when they observed a signal indicating that their loved one--present in the same room--was receiving a similar pain stimulus. Bilateral anterior insula (AI), rostral anterior cingulate cortex (ACC), brainstem, and cerebellum were activated when subjects received pain and also by a signal that a loved one experienced pain. AI and ACC activation correlated with individual empathy scores. Activity in the posterior insula/secondary somatosensory cortex, the sensorimotor cortex (SI/MI), and the caudal ACC was specific to receiving pain. Thus, a neural response in AI and rostral ACC, activated in common for "self" and "other" conditions, suggests that the neural substrate for empathic experience does not involve the entire "pain matrix." We conclude that only that part of the pain network associated with its affective qualities, but not its sensory qualities, mediates empathy. 相似文献
ABSTRACT There is no evidence that Pyrenophora semeniperda, the causal agent of leaf spotting in many annual and perennial grasses, currently occurs in Europe or Asia. However, there is potential phytosanitary concern that the importation of infected commodities could result in the introduction of this fungus into Eurasia, putting crops at risk and possibly resulting in economic losses. To assist in assessing the risk of geographic range extension of P. semeniperda, an analysis was undertaken to estimate the potential global distribution of this species, based on climatic suitability. Geographic distribution data for P. semeniperda in part of its current range were used to fit parameter values in a CLIMEX pest risk assessment model, and the remaining distribution data were used to validate the model. The CLIMEX model correctly predicts that virtually all locations where P. semeniperda has been found are climatically suitable. Only five locations worldwide where the fungus was recorded present are predicted as being unsuitable. These "outliers" may have been transient populations occurring during a favorable season and then dying out. Exploratory adjustments of the model to accommodate these records created unsatisfactory distortions in the projected climatic suitability surfaces, extending the suitable climatic zone beyond well-established traditional range boundaries. We are therefore confident that the model is credibly predicting the potential distribution of P. semeniperda worldwide. The CLIMEX model suggests that P. semeniperda could potentially extend its range throughout Europe and temperate regions of Asia, Africa, and South America. Our heavy reliance upon geographic data to build this CLIMEX model departs from most previous published examples in plant pathology, which have depended primarily upon experimentally derived physiological data to estimate model parameters. The use of geographic data to infer climate parameters is popular in CLIMEX models of weeds and arthropod pests and can provide decision-makers with early risk assessments of potential pathogen invasions, particularly where the pathogens have long, or difficult-to-study, lifecycles. 相似文献
Fifty-eight blue-fronted Amazon parrot (Amazona aestiva) nestlings, recovered from the illegal trade, became ill at a wildlife rehabilitation center in S?o Paulo State, Brazil. Clinical signs observed were nonspecific, and the mortality rate was 96.5% despite initial treatment with norfloxacin. Postmortem examinations were performed on 10 birds. Liver and spleen smears showed structures suggestive of Chlamydophila psittaci in four cases. Diagnosis was confirmed by seminested polymerase chain reaction on tissue samples. Other birds from the same location showed no clinical signs of the disease, although high complement fixation titers to C. psittaci were found in 10 adult psittacines. All birds in the facility were treated with doxycycline. The two surviving nestlings did not recover after two doxycycline treatments and were euthanatized. The high mortality rate observed in this outbreak was attributed to poor conditions of husbandry and delays in the diagnosis and treatment of the disease. After diagnosis, improved control measures for chlamydiosis were instituted. 相似文献
Reliable niche models are a cornerstone of pest risk analyses, informing biosecurity policies and the management of biological invasions. Because species can invade and establish in areas with climates that are different from those that are found in their native range, it is important to accurately capture the range-limiting mechanisms in models that project climate suitability. We examined a published niche model for the beet armyworm, Spodoptera exigua, to assess its suitability for bioeconomic analyses of its pest threat, and identified issues with the model that rendered it unreliable for this purpose. Consequently, we refitted the CLIMEX model, paying close attention to the biology underpinning the stress mechanisms. This highlighted the necessity of carefully considering how the different stress mechanisms operate, and to select mechanisms which align with knowledge on the species’ biology. We also identified the important role of irrigation in modifying habitat suitability. The refitted model accords with both distribution data and our understanding of the biology of this species, including its seasonal range dynamics. The new model identifies establishment risks to South America, Africa, the Middle East and Asia, and highlights that under current climate, Europe is only climatically suitable during warm seasons when crops are available. The modelling exercise reinforced the importance of understanding the meaning of a location record (e.g. persistent versus ephemeral populations) and of carefully exploring the role of habitat-modifying factors, such as irrigation, in allowing species to persist in otherwise inclement localities. 相似文献
Although dilution of lake water has been used for improvement of water quality and algal blooms control, it has not necessarily succeeded to suppress the blooms. We hypothesized that the disappearance of algal blooms by dilution could be explained by flow regime, nutrient concentrations, and their interaction. This study investigated the effects of daily renewal rate (d), nitrogen (N) and phosphorus (P) concentration, and their interaction on the domination between Microcystis aeruginosa and Cyclotella sp. through a monoxenic culture experiment. The simulation model as functions of the N:P mass ratio and dilution rate (D) (calculated from d) was constructed, and the dominant characteristics of both species were predicted based on the model using parameters obtained in a monoculture experiment and our previous study. Results of monoxenic culture experiment revealed that M. aeruginosa dominated in all conditions (d = 5 or 15%; N = 1.0 or 2.5 or 5.0 mg-N L?1; P = 0.1 or 0.5 mg-P L?1) and the predicted cell densities were substantially correspondent to experimental data. Under various N:P ratios and D values, characteristics of domination for each species were predicted, indicating that Cyclotella sp. tended to be dominant under high P concentrations (P ≥ 0.36 mg-P L?1) when the N:P ratio was less than 7.0, and M. aeruginosa could not form algal blooms at the N:P ratio ≤ 7.0 (N ≤ 0.7 mg-N L?1). It was also suggested that the dilution rate leading to the Cyclotella sp. domination required 0.20 day?1 or higher regardless of the N:P ratios.
Graphical Abstract? M. aeruginosa and Cyclotella sp. could be a superior competitor in nutrient-limited and nutrient-rich conditions, respectively. ? The simulation model in this study indicated that the predicted cell density and nutrient concentration were substantially correspondent to experimental data. ? The model predicted that Cyclotella sp. tended to be dominant at the P ≥ 0.36 mg-P L?1 when the N:P ratio was less than 7.0, and M. aeruginosa could not form algal blooms at the N:P ratio ≤ 7.0 (N ≤ 0.7 mg-N L?1).
