Clec9a-mediated ablation of conventional dendritic cells suggests a lymphoid path to generating dendritic cells In Vivo

Conventional dendritic cells (cDCs) are versatile activators of immune responses that develop as part of the myeloid lineage downstream of hematopoietic stem cells. We have recently shown that in mice precursors of cDCs, but not of other leukocytes, are marked by expression of DNGR-1/CLEC9A. To genetically deplete DNGR-1-expressing cDC precursors and their progeny, we crossed Clec9a-Cre mice to Rosa-lox-STOP-lox-diphtheria toxin (DTA) mice. These mice develop signs of age-dependent myeloproliferative disease, as has been observed in other DC-deficient mouse models. However, despite efficient depletion of cDC progenitors in these mice, cells with phenotypic characteristics of cDCs populate the spleen. These cells are functionally and transcriptionally similar to cDCs in wild type control mice but show somatic rearrangements of Ig-heavy chain genes, characteristic of lymphoid origin cells. Our studies reveal a previously unappreciated developmental heterogeneity of cDCs and suggest that the lymphoid lineage can generate cells with features of cDCs when myeloid cDC progenitors are impaired

Academic Development of First-Year Living-Learning Program Students before and after Hurricanes Katrina and Rita of 2005

Previous research suggests that the far-reaching impacts of hurricanes include the academic performance of students. In an examination of such impacts, we found a trend toward self-perceived decline in some performance indicators relative to students at peer universities. However, few longitudinal impacts were found, perhaps because of the sense of community offered by the living-learning program. These results may inform administrators and faculty of areas for emphasis in mitigating future impacts. Robert V. Rohli is a Professor of Geography and Faculty Director of the Residential Colleges Program at Louisiana State University in Baton Rouge, LA. Kurt J. Keppler is Vice Chancellor for Student Life & Enrollment at Louisiana State University. Daniel L. Winkler is a Graduate Assistant at Louisiana State University

Legehennen in einem mobilen Stallsystem - Auslaufnutzung und Flächenzustand -

The use of the free-range area by laying hens housed in a mobile system and the resulting condition of the range were investigated. The free-range was used very intensively. On an average of nine complete observation days 35 % of the birds (23 – 44 % means per day) were outside the house. The maximum of animals in the free range was 77 %. 75 % (60 – 95 %) of the hens outside the house stayed in an area of 20 m around the house. This led to deteriorated conditions of the range in these areas. By moving the mobile house regularly (after 2 weeks in summer and 6 weeks in winter) a destruction of the vegetation could be avoided, while after not moving the house for three months in winter a complementary seeding became necessary. We conclude that the use of mobile systems for poultry in conjunction with a regular change of position and sufficient area per animal can avoid destruction of the vegetation despite an intensive use of the free-range all year round

Legehennen in einem mobilen Stallsystem - Flächenmanagement und resultierende Stickstoffgehalte im Auslauf -

In the last years free range poultry was often criticised for its negative impacts on environment. As the animals do not use the run equally, a big part of the excreted nutrients are accumulated in the area close to the poultry house. This can lead to an increased rate of nutrient loss especially nitrogen by leaching. Within this study the use of a mobile housing system for 1.000 layers on an organic farm in North Hessia with a mean of 700 mm precipitation per year and an average of 8,9°C (soil texture: loam in the first, silt loam in the second year) was observed for two years. A documentation and optimization of the management and regular investigations into the contents of mineral nitrogen in all parts of the outdoor run were carried out. The aim of the study was to survey, if a well-balanced distribution of nutrients can be reached by moving the house within the free-range and which management is necessary for that. The results showed a better distribution of mineral nitrogen in the second year, when the house was moved in winter time every six weeks, while the contents were slightly less well-balanced, when it stayed at one position for three months in the first winter . In both years the highest amounts of mineral nitrogen in any part of the hen run with 37 and 24 mg / kg DM were much lower than the contents of up to 160 mg / kg DM close to stationary houses examined in other studies. The results of this study show that a well-balanced distribution of nutrients in free-ranges for poultry can be reached by using mobile housing systems combined with the right management

New insight into the atmospheric chloromethane budget gained using gained using

International audienceAtmospheric chloromethane (CH3Cl) plays an important role in stratospheric ozone destruction, but many uncertainties still exist regarding strengths of both sources and sinks and the processes leading to formation of this naturally occurring gas. Recent work has identified a novel chemical origin for CH3Cl, which can explain its production in a variety of terrestrial environments: The widespread structural component of plants, pectin, reacts readily with chloride ion to form CH3Cl at both ambient and elevated temperatures (Hamilton et al., 2003). It has been proposed that this abiotic chloride methylation process in terrestrial environments could be responsible for formation of a large proportion of atmospheric CH3Cl. However, more information is required to determine the global importance of this new source and its contribution to the atmospheric CH3Cl budget. A potentially powerful tool in studying the atmospheric CH3Cl budget is the use of stable carbon isotope ratios. In an accompanying paper it is reported that the reaction of CH3Cl with OH radical, the dominant sink for atmospheric CH3Cl, is accompanied by an unexpectedly large fractionation factor (Gola et al., 2005). Another recently published study shows that CH3Cl formed by the abiotic methylation process at ambient temperatures has a unique stable carbon isotope signature, extremely depleted in 13C, unequivocally distinguishing it from all other known sources (Keppler et al., 2004). Using these findings together with data existing in the literature, we here present three scenarios for an isotopic mass balance for atmospheric CH3Cl. Our calculations provide strong support for the proposal that the bulk fraction of atmospheric CH3Cl (1.8 to 2.5Tg yr?1) is produced by an abiotic chloride methylation process in terrestrial ecosystems, primarily located in tropical and subtropical areas, where turnover of biomass is highest. Furthermore our calculations also indicate that the microbial soil sink for CH3Cl is likely to be much larger (>1Tg yr?1) than that previously assumed

New insight into the atmospheric chloromethane budget gained using stable carbon isotope ratios

International audienceAtmospheric chloromethane (CH3Cl) plays an important role in stratospheric ozone destruction, but many uncertainties still exist regarding strengths of both sources and sinks and the processes leading to formation of this naturally occurring gas. Recent work has identified a novel chemical origin for CH3Cl, which can explain its production in a variety of terrestrial environments: the widespread structural component of plants, pectin, reacts readily with chloride ion to form CH3Cl at both ambient and elevated temperatures (Hamilton et al., 2003). It has been proposed that this abiotic chloride methylation process in terrestrial environments could be responsible for formation of a large proportion of atmospheric CH3Cl. However, more information is required to determine the global importance of this new source and its contribution to the atmospheric CH3Cl budget. A potentially powerful tool in studying the atmospheric CH3Cl budget is the use of stable carbon isotope ratios. In an accompanying paper it is reported that the reaction of CH3Cl with OH radical, the dominant sink for atmospheric CH3Cl, is accompanied by an unexpectedly large fractionation factor (Gola et al., 2005). Another recently published study shows that CH3Cl formed by the abiotic methylation process at ambient temperatures has a unique stable carbon isotope signature, extremely depleted in 13C, unequivocally distinguishing it from all other known sources (Keppler et al., 2004). Using these findings together with data existing in the literature, we here present three scenarios for an isotopic mass balance for atmospheric CH3Cl. Our calculations provide strong support for the proposal that the largest source of atmospheric CH3Cl (1800 to 2500 Gg yr-1) is the abiotic methylation of chloride in terrestrial ecosytems, primarily located in tropical and subtropical areas where turnover of biomass is highest. Furthermore our calculations also indicate that the microbial soil sink for CH3Cl is likely to be much larger (>1000 Gg yr-1) than that previously assumed