Location and stability of a recombinant prion protein (recPrP) and its interaction with humic-like complexes were investigated
by low-temperature ashing (LTA), thermal gravimetric (TG), and scanning electron microscopy (SEM) analyses. Humic-like complexes
were obtained by abiotic polymerization of catechol, one of the possible precursors of soil humic matter, through the catalysis
of birnessite, a manganese oxide common in soil environment. The recPrP was immobilized in organomineral complexes via sorption
or entrapment. Complexes were treated by LTA, allowing the controlled removal of organic matter layer by layer, from the external
to the internal side, with minimal disturbance of mineral constituents. Thermal gravimetric and SEM analyses were performed
on specimens before and after LTA treatment. Entrapped recPrP, compared with sorbed, resulted less easily accessible to LTA
treatment and showed a higher thermal stability by TGA analyses. On the basis of these findings, we hypothesize that the processes
leading to newly formed organic complexes can enhance prion stability in soil and thus influence the environmental diffusion
of infectivity. 相似文献
The qualitative and quantitative anthocyanin composition of four wild tropical fruits from Colombia was studied. Compounds of "mora peque?a" ( Rubus megalococcus Focke.), "uva de árbol" ( Myrciaria aff. cauliflora O. Berg), coral, and motilón ( Hyeronima macrocarpa Mull. Arg.) fruits were separately extracted with methanol-acetic acid (95:5, v/v). The anthocyanin-rich extracts (AREs) were obtained by selective adsorption on Amberlite XAD-7. Each extract was analyzed by HPLC-PDA and HPLC-HRESI-MS(n) with LCMS-IT-TOF equipment in order to characterize the anthocyanin pigments and the coinjection in HPLC using standards allowed identifying the major constituents in each extract. The antioxidant activity was measured by electron paramagnetic resonance (EPR) and UV-vis spectroscopy, using ABTS and DPPH free radicals. The ARE of motilón ( H. macrocarpa Müll. Arg) exhibited the highest radical scavenging activity in comparison to the other extracts. A second-order kinetic model was followed in all of the cases. These results suggested that the studied fruits are promising not only as source of natural pigments but also as antioxidant materials for food industry. 相似文献
The objective of the study was to monitor for a period of 2 years (at 1, 3, 6, 9, 12, and 24 months) a group of former trichinellosis patients (n = 699) registered in Bra?ov county before the initiation of the National Supervision and Control Programme for trichinellosis in humans. During the study, immediate complications up to 6 months from hospital release, and related complications occurring up to 24 months from hospital release were identified. Immediate complications were cardiovascular (31%), muscular (19%), neurological (18%), ophthalmic (17%), allergic (9%), respiratory (1%), and other (5%). Complications were more frequent in children from the studied group, even if the trichinellosis disease manifestation was mild or moderate. Complications were also more frequent in female as compared to male patients, and in urban areas as compared to rural environments. Paraclinical data showed eosinophilia in 8–22% of patients, GPT and GOT within normal limits, and hypoproteinemia in the case of 178 former patients (31%). Hypocalcaemia and hypomagnesaemia persisted in the case of 401 former patients (71%). Two months following illness, 53 (9.4%) of the former patients remained ill, and 26 of them had retired on medical grounds. Nine months following illness, 212 (37.8%) of the former patients reported fatigue, myalgia (especially in the inferior limbs), cardiovascular disorders, neurological, psychiatric, and allergic illnesses. After one year, 102 (18%) of the former patients reported improvements in asthenia, muscular pains, allergic reactions, hypertension, cardiac arrhythmia, and angina pectoris crises. Trichinosis in humans cannot be considered only an acute disease that, once properly treated, etiologically, pathogenically, and symptomatically improves, but it can also become a chronic illness. 相似文献
The fungistatic activity of a lactic acid bacterium, which had been isolated from yellow pitahaya cultures, against fungi associated with basal rot(Fusarium oxysporum and Fusarium fujikuroi) was measured in the present study. Its activity was assessed in three fractions: fermented(S1), metabolic products(S2), and biomass(S3), using two fermentation substrates: Man Rogosa Sharpe agar(MRS) and potato dextrose agar(PDA). The bacterium was molecularly identified as Lactobacillus plantarum. S3 reduced F. fujikuroi growth by 100% over 48 h of fermentation, which occurred during the stationary phase of bacterial growth. The three fractions' fungistatic activity against F. fujikuroi depended on the substrate employed. The fermentation kinetic parameters for L. plantarum indicated that its specific growth rate was 0.46 h~(–1), with 93.63% substrate consumption, 0.045 kg kg~(–1) cell yield, and 0.54 kg kg~(–1) product yield. The kinetic parameters calculated will allow for bacteria production scaling. These in-vitro trials reveal L. plantarum's possible application as a biocontrol agent for diseases associated with Fusarium. However, further ex-vivo and in-vivo researches are required to demonstrate its behavior in crops. 相似文献
Gensburg Markham Prairie (GMP), a high-quality tallgrass prairie and wetland in the Chicago area, is surrounded by high-traffic highways and residential communities. Anthropogenic inputs are a concern given observed ecosystem degradation around the periphery of the prairie. To understand soil quality and the potential for habitat degradation in GMP, we evaluated concentrations of metals and phosphorus in soil profiles, identified possible sources of contamination, and assessed the likelihood that contamination would impact the prairie ecosystem.
Materials and methods
We collected 15 intact soil cores (to a depth of 120 cm) and 22 surface soil samples (0–10-cm depth), determined the soil type, and measured pH, organic matter, and concentrations of Pb, Cu, Zn, Mg, Fe, K, Ca, and P using ICP-OES. To quantify soil pollution, we calculated the element enrichment factor (EF) and single element pollution index (SEPI) for each sample. We also used principal component analysis (PCA) to interpret relationships between site variables, elemental concentrations, and sources of metals.
Results and discussion
Heavy metals (Pb, Cu, and Zn) and P were found to accumulate in surface samples. The mean EF values for Pb, Cu, Zn, and P revealed significant enrichment of these elements in the soil profiles. However, SEPI analyses indicate that GMP soils have a low level of contamination. PCA revealed that concentrations are highest for samples with high organic matter content near the ground surface and that Pb, Cu, and Zn have common sources of pollution.
Conclusions
We observed enrichment of Pb, Cu, Zn, and P because of deposition from the urban built environment, but the enrichment levels are low enough that they are not expected to negatively impact the ecosystem of GMP. The detailed soil chemistry data constitute a spatial contamination map that can be used to assess potential long-term impacts on the ecosystem, such as reduction of plant growth and species diversity, and inform site management and biodiversity conservation efforts.
Sweet cherry (Prunus avium L.) is a fruit of increasing economic importance though it is less significant than other stone fruit species such as peach. Cherry has received little attention concerning nitrogen (N) uptake and dynamics in mature trees. The aim of this work was to determine N uptake and partitioning as influenced by the timing of fertilizer application in 7-year-old sweet cherry trees cultivated in a cold region (Los Antiguos, Santa Cruz, Argentina; 71°38′ W, 46°32′ S). Nitrogen (95 kg ha−1) was applied as ammonium nitrate to a soil with ‘Bing’ sweet cherry trees grafted onto Prunusmahaleb rootstocks. Fertilization was split into two equal applications per treatment, involving either the commercial fertilizer ammonium nitrate or the same fertilizer labelled with 15N isotope (10% atom.). Treatments consisted of one early spring (full bloom, October 2005) or one summer (late January 2006, 15 days after harvest) application of 15N ammonium nitrate to three replicate trees. Fruit were harvested in early January and leaves were collected at both full canopy and leaf fall. All trees were excavated in winter (August, 2006). Trees were partitioned into their components: trunk, branches (current-season shoots, 1-year-old and over-1-year-old branches), buds of the same age, small roots (less than 1 mm thick), large roots, leaves (sampled in February and April), and fruit (collected at harvest). Those components were dried and analysed for total N and 15N content. Total N per tree and N content derived from the fertilizer did not differ between treatments. Summer postharvest 15N application partitioned not only to structural components (trunk and roots) but also to buds and leaves. Uptake efficiency was significantly (p = 0.0113) higher in the spring than in the summer application (65.7% vs. 37.44%). Nevertheless, 52.5% of N applied in spring was lost due to harvest and summer pruning. This emphasizes the importance of the postharvest N fertilization which increases N accumulation in both reserve organs and buds though, according to our data, it is less efficiently used. The extent of nitrogen uptake, efficiency of use and partitioning in the following growing seasons are still open questions that deserve further research. 相似文献