Bacteria-triggered CD4+ T regulatory cells suppress Helicobacter hepaticus-induced colitis

We have previously demonstrated that interleukin (IL)-10–deficient (IL-10 knockout [KO]) but not wild-type (WT) mice develop colitis after infection with Helicobacter hepaticus. Here, we show that infected recombination activating gene (RAG) KO mice develop intestinal inflammation after reconstitution with CD4+ T cells from IL-10 KO animals and that the cotransfer of CD4+ T cells from H. hepaticus–infected but not uninfected WT mice prevents this colitis. The disease-protective WT CD4+ cells are contained within the CD45RBlow fraction and unexpectedly were found in both the CD25+ and the CD25- subpopulations of these cells, their frequency being higher in the latter. The mechanism by which CD25+ and CD25- CD45RBlow CD4+ cells block colitis involves IL-10 and not transforming growth factor (TGF)-ß, as treatment with anti–IL-10R but not anti–TGF-ß monoclonal antibody abrogated their protective effect. In vitro, CD45RBlow CD4+ cells from infected WT mice were shown to produce IL-10 and suppress interferon-{gamma} production by IL-10 KO CD4+ cells in an H. hepaticus antigen–specific manner. Together, our data support the concept that H. hepaticus infection results in the induction in WT mice of regulatory T cells that prevent bacteria-induced colitis. The induction of such cells in response to gut flora may be a mechanism protecting normal individuals against inflammatory bowel disease

Phylogenetic reconstruction of the genus Tephrocactus (Cactaceae) based on molecular, morphological, and cytogenetical data

Tephrocactus comprises species mainly endemic to Argentina. Molecular phylogenetic analyses of all proposed species of the genus as well as classical (chromosome number, karyotype) and molecular cytogenetical techniques (DNA content, heterochromatin amount, rDNA genes) were conducted. Sequence data of two plastid DNA markers of Tephrocactus taxa were analyzed. Evolution of character states of cytogenetical and morphological (growth form, presence of leaves, glochids and tepal spiny mucrons, flower color) traits were reconstructed. Species show x = 11 with different ploidy levels (2n = 22, 44, 66, 77, 242, 319), small chromosomes, and symmetrical karyotypes. Tephrocactus was recovered as monophyletic with three main clades including 12 species, using molecular and morphological data. Tephrocactus geometricus, T. halophilus, and T. paediophilus are recognized as distinct species. Banding patterns showed CMA+/DAPI− constitutive heterochromatin associated with nuclear organized regions. Heterochromatin amount ranged from 2.99% to 6.50%. The 18S-5.8S-26S ribosomal DNA (rDNA) sites coincided with the CMA+/DAPI− signals. The 5S sites varied with ploidy levels of the taxa. DNA content (2C = 1.99–24.50 pg) had a significant and positive correlation with ploidy level and the number of rDNA genes. The ancestor is reconstructed to have been a dwarf shrub with strong articulation, glochids, and deciduous leaves, white, pink or pearly tepals without spiny mucrons, 2n = 22, low DNA content, and one pair of each rDNA gene followed by three polyploidization events. Tephrocactus diversification has been associated with polyploidy and few cumulative small cryptic chromosomal changes.Fil: Las Peñas, Maria Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Kiesling, Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Bernardello, Gabriel Luis Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Nacional de Córdoba; Argentin

Author Correction: Priority list of biodiversity metrics to observe from space (Nature Ecology & Evolution, (2021), 5, 7, (896-906), 10.1038/s41559-021-01451-x)

In the version of this Perspective initially published, there was an error in units reported in the main text. Specifically, in the first sentence of the sixth paragraph under the heading “A critical review of EBVs retrieved by remote sensing,” in the text now reading “Finally, when harmonizing the terminology used by ecological and remote sensing communities, it is important to emphasize that utilizing broadband optical wavelengths (for example, for PlanetScope, approximately 400-700 nm) at very high spatial resolution,” 400-700 nm originally appeared as “60-90 nm.” The error has been corrected in the online version of the article