Immunomodulatory and Anti-Inflammatory Activity Induced by Oral Administration of a Probiotic Strain of

The aim of this work was to study the effect of the long-term cyclic administration of the probiotic strain of Lactobacillus ( L .) casei CRL 431 as a mucosal immunomodulator of the immune cells associated with the lamina propria of the small intestine, bronchus and other immune cells not associated with mucosal tissues, such as peritoneal macrophages. BALB/c mice were orally administered with a suspension of Lc 10 9 cfu/day/animal in non-fat milk (NFM) 10% for two consecutive days, the optimal dose selected in previous studies to reach protective immunity. This administration was repeated cyclically every 5 days for 98 days. Mice in the control group received only NFM 10%. Samples were taken after two days of L. casei administration and every 14 days until day 98. The small intestine and lungs were removed for histological slices preparation. Haematoxilin-eosin stains were made for histological studies of the small intestine. The number of IgA producing cells in the lamina propria of the small intestine and in bronchus was determined by immunofluorescence assays. Regulatory (IL-4, IL-10) and proinflammatory (TNF-α, INF-γ) cytokines were measured in the gut. Peritoneal macrophages were collected during the same periods for phagocytosis assays. We determined an increase in the number of IgA + cells in the lamina propria of the small intestine in all the periods assayed and in BALT only until day 28. The cytokines studied (IL-10, IL-4, TNF-α and INF-γ) increased in most of the periods assayed, the effect being more remarkable for the anti-inflammatory cytokines such as IL-4 and IL-10. INF-γ was also increased but no modifications in the histological studies of the small intestine were observed, suggesting other roles for this cytokine The phagocytic activity of PM increased for most of the periods assayed. We demonstrated that long-term cyclic oral L. casei administration favors mucosal immunity and modulates the immune response to maintain the homeostasis at the mucosal level

Facilitation of tree saplings by nurse plants: microhabitat amelioration or protection against herbivores?

12 pages, 4 figures, 4 tables, 73 references. We thank the Consejería de Medio Ambiente, Junta de Andalucía, and the direction of the National Park, for permission to work in Sierra Nevada. We are especially grateful to Empresa de Transformación Agraria S.A. (TRAGSA) for carrying out the experimental plantations. Jose M. Gómez, Sergio de Haro, Elena Baraza and Daniel García kindly helped with the field work. David Nesbitt looked over the English version of the manuscript.Question: Positive interactions are predicted to be common in communities developing under high physical stress or high herbivory pressure due to neighbour amelioration of limiting physical and consumer stresses, respectively. However, when both stress sources meet in the same community, the relative importance of the two facilitation mechanisms is poorly understood. We ask: What is the relative importance of abiotic vs. biotic mechanisms of facilitation of tree saplings by shrubs in Mediterranean mountain forests? Location: Sierra Nevada, SE Spain (1800-1850 m a.s.l.) Methods: Saplings of four tree taxa (Acer opalus ssp. granatense, Quercus ilex, Pinus nigra ssp. salzmanii and P. sylvestris var. nevadensis) were planted following a 2 × 2 factorial design: two levels of herbivory (control and ungulate exclusion) and two microhabitats (under shrubs and in open areas). Sapling survival and growth were monitored for five years. Results: Shrubs had positive effects on sapling survival both in control and ungulate excluded plots. This effect was species-specific, with shrubs increasing the survival of Acer opalus and Quercus ilex three and twofold, respectively, but having a minor effect on the Pinus species. Herbivory damage was also species-specific, being much higher for Acer opalus than for any other species. Shrubs did not protect saplings of any species against ungulates. Thus, all Acer saplings (the most damaged species) suffered herbivory outside the exclosures, which largely reduced sapling height. Conclusions: Protection from abiotic stress (summer drought and winter frost) was much more relevant than protection from biotic stress (herbivory). However, we propose that the final balance between the two mechanisms can be expected to vary strongly between sites, depending on the relative magnitude of the different sources of stress and the intrinsic traits (e.g. palatability) of the species interacting.This study was supported by a PFPU-MECD grant to L.G.A., the Andalusian government grant (PAI) rnm-220, and projects FEDER 1FD97-0743-CO3-02 and HETEROMED REN2002-04041-CO2-01/GLO from the Spanish Ministry of Science and Technology (MCYT).Peer reviewe