RESUMEN
Limiting the negative effects of an invasive species, such as Reynoutria japonica, has become a challenge for scientists and a necessity for managers. Ecologically relevant, technically feasible, and sustainable control methods must be created to reduce the development or spread of R. japonica in ecosystems. The objective of our study was to investigate how monthly mowing in association with plant competition affects the development of R. japonica over a three-year field experiment. Among the plant traits measured, the height growth of R. japonica was the most affected; it was strongly reduced in the presence of competing plants. Combined mowing and competition with restoration plants negatively affected the growth diameter of R. japonica. Most competitive sown species were well established and complementary in limiting the development of R. japonica. The plant communities showed interannual dynamics in which R. japonica declined progressively. The restoration methodology adopted in this study allows managers to make appropriate decisions to reduce the impact of R. japonica on ecosystems.
Asunto(s)
Ecosistema , Especies Introducidas , Ecología , Conservación de los Recursos NaturalesRESUMEN
Nephelometric immunoassays were developed for human IgG, IgA, and IgM quantitation in B-lymphocytes culture media. They allowed measurement of immunoglobulin (Ig) levels over a broad range of concentrations with good accuracy and precision. The kinetics of Ig production in B-lymphocyte cultures was followed and the mean amount of each Ig was determined in six different samples after three days of culture. The nephelometric immunoassays reported here could be used to study, in vitro, the influence of various molecules (inhibitory or amplifying effect) on B-lymphocytes' functional capacities.
Asunto(s)
Linfocitos B/química , Inmunoglobulina A/análisis , Inmunoglobulina G/análisis , Inmunoglobulina M/análisis , Células Cultivadas , Niño , Preescolar , Medios de Cultivo/análisis , Humanos , Inmunoensayo/métodos , Lactante , Nefelometría y Turbidimetría/métodos , Tonsila Palatina/citología , Reproducibilidad de los ResultadosRESUMEN
A nephelometric immunoassay was developed to quantify immunoglobulin A (IgA) in children's stools. This method enables IgA in faecal protein extracts to be measured over a large range of concentrations (1.61-51.50 mg/L) with good accuracy (linear recovery in dilution-overloading assay) and precision (within- and between-run coefficients of variation (CVs) of 1-6%). An excellent recovery (105%) was obtained in stool samples overloaded by purified colostral IgA, demonstrating that the method used for faecal IgA extraction is adapted, not to induce significant IgA degradation, and probably allow a complete extraction of IgA. The amount of faecal IgA, as determined in stool samples from 125 children (6-24 months old), was an average of 14 mg per 100 g of stools (about 10% of the total protein stool content), with large individual variation (3-30 mg per 100 g of stools). No correlation was observed between faecal IgA amounts and the children's age or sex. Such an immunoassay could enable exhaustive noninvasive investigations of the maturation of the intestinal immune system, as well as accurate studies of the effect of oral dietary supplementation on IgA regulation.
Asunto(s)
Heces/química , Inmunoensayo , Inmunoglobulina A/análisis , Nefelometría y Turbidimetría/métodos , Preescolar , Femenino , Humanos , Lactante , Masculino , Sensibilidad y EspecificidadRESUMEN
The mannan binding lectin (MBL) activates the complement system by the lectin pathway after the recognition of some structural motifs (saccharides) present on the surface of microorganisms. MBL has been mostly identified and quantified in human serum by ELISA or microparticle immunonephelometry assays. This article reports the MBL levels as assessed by a microparticle immunonephelometric assay in 76 human milk samples. Immunonephelometry was performed using skim-milk samples diluted 20 times over a calibration range of 0.07-4.82 mg/L. MBL is indeed present in human milk and its concentration decreases significantly during development from colostrum (0.55+/-0.09 mg/L) to transitional (0.18+/-0.02 mg/L) and mature milk (0.17+/-0.02 mg/L). This innate molecule may be involved in the primary defenses of the mammary gland and the neonate, whose immune system is immature. The high levels observed during the first days of lactation support the hypothesis that this molecule plays a key role in limiting the colonization of the newborn gut by pathogens.
Asunto(s)
Lactancia/metabolismo , Lectina de Unión a Manosa/metabolismo , Leche Humana/química , Femenino , Humanos , Nefelometría y Turbidimetría/métodosRESUMEN
OBJECTIVES/HYPOTHESIS: In rhinologic disorders such as polyposis or rhinitis, nasal cytology allows differentiation between patients according to the degree of eosinophilia in nasal secretions. The egress of eosinophil and/or neutrophil polymorphonuclears from the underlying mucosa might correlate with the release of soluble mediators of cell activation such as the chemokine IL-8, and such molecules of the innate immunity as the LPS-receptor CD14 or lysozyme. We assayed the levels of these three molecules in nasal secretions in correlation with cytologic findings and especially the degree of eosinophilia. STUDY DESIGN: Fifty-four patients from a prospective study of nasal secretions were enrolled in this work. They constituted two groups of 27 patients each, respectively, with or without more than 20% eosinophils in nasal secretions. Nasal secretions were collected by aspiration, weighed and diluted in a fixed amount of buffer. Classic cytologic analyses were performed on the pelleted cells and IL-8, sCD14, and lysozyme levels were assayed in the cell-free supernatants. METHODS: Cytologic analyses included cell-enumeration in Neubauer's chambers, and differentials performed on May-Grünwald Giemsa-stained cytospins. ELISA tests were used to assay the levels of IL-8 and sCD14. Lysozyme concentrations were assayed in immuno-nephelometry. RESULTS: Significantly lower levels of IL-8 and sCD14 were observed in patients with eosinophilia than in patients with a predominance of neutrophils, whereas no difference was observed in lysozyme concentrations. CONCLUSION: These data show that the egress of neutrophils in nasal secretions is associated with high levels of IL-8 and sCD14.