Specialized functions of resident macrophages in brain and heart

The functions of macrophages in healthy tissues extend beyond their well-established roles as immune sentinels and effectors. Among tissues, cells of the brain and heart possess unique excitatory properties that likely demand special support. Accordingly, existing evidence demonstrates that microglia in the brain has an active role in synaptic organization, control of neuronal excitability, phagocytic removal of debris, and trophic support during brain development. In the heart, recent studies suggest that cardiac macrophages are involved in the regulation of heart homeostasis by phagocytosis, production of trophic, and immune-related factors, and by forming direct contacts with cardiomyocytes to regulate electrical conduction. In this review, we discuss mechanisms associated with the high degree of specialization of resident macrophages in both tissues, their origin and heterogeneity, and their contributions in regulating homeostasis under steady-state and pathological conditions.This work was supported by grants Fundació La Marató de TV3 (120/C/2015-20153032), intramural grant IGP-SO and SAF2015- 65607-RfromtheMinisteriodeCiencia,InnovaciónyUniversidades (MCIU)toA.H.J.A.N-AissupportedbyfellowshipSVP-2014-068595. I.B. is supported by fellowship MSCA-IF-EF-748381. The CNIC is supported by the MCIU and the Pro-CNIC Foundation, and Severo Ochoa Center of Excellence (MCIU award SEV-2015-0505). Illus- trations were created by adapting templates from Servier Medical Arts(http://www.servier.com/Powerpoint-image-bank,licensedunder aCreativeCommonsAttribution3.0License)S

Haematopoietic ESL-1 enables stem cell proliferation in the bone marrow by limiting TGF beta availability

The life-long maintenance of haematopoietic stem and progenitor cells (HSPCs) critically relies on environmental signals produced by cells that constitute the haematopoietic niche. Here we report a cell-intrinsic mechanism whereby haematopoietic cells limit proliferation within the bone marrow, and show that this pathway is repressed by E-selectin ligand 1 (ESL-1). Mice deficient in ESL-1 display aberrant HSPC quiescence, expansion of the immature pool and reduction in niche size. Remarkably, the traits were transplantable and dominant when mutant and wild-type precursors coexisted in the same environment, but were independent of E-selectin, the vascular receptor for ESL-1. Instead, quiescence is generated by unrestrained production of the cytokine TGF beta by mutant HSPC, and in vivo or in vitro blockade of the cytokine completely restores the homeostatic properties of the haematopoietic niche. These findings reveal that haematopoietic cells, including the more primitive compartment, can actively shape their own environment

Haematopoietic ESL-1 enables stem cell proliferation in the bone marrow by limiting TGF beta availability

The life-long maintenance of haematopoietic stem and progenitor cells (HSPCs) critically relies on environmental signals produced by cells that constitute the haematopoietic niche. Here we report a cell-intrinsic mechanism whereby haematopoietic cells limit proliferation within the bone marrow, and show that this pathway is repressed by E-selectin ligand 1 (ESL-1). Mice deficient in ESL-1 display aberrant HSPC quiescence, expansion of the immature pool and reduction in niche size. Remarkably, the traits were transplantable and dominant when mutant and wild-type precursors coexisted in the same environment, but were independent of E-selectin, the vascular receptor for ESL-1. Instead, quiescence is generated by unrestrained production of the cytokine TGF beta by mutant HSPC, and in vivo or in vitro blockade of the cytokine completely restores the homeostatic properties of the haematopoietic niche. These findings reveal that haematopoietic cells, including the more primitive compartment, can actively shape their own environment

Wild solitary bees and their use of bee hotels in southwest Spain

There is an increasing interest in preserving and, if possible, increasing wild bee populations as evidenced by increasinginvestigations into providing supplemental nesting resources, commonly called bee hotels. The study presented herewas carried out in 2017 and 2018 with two objectives: a) to understand the role that insect refuges could have onbeneficial arthropod fauna, especially bees, and b) to evaluate different materials and which species used them. We pre-sent the preliminary results of three constructed refuges in Seville, Spain: Hymenoptera visited the refuges most fre-quently (88.7% of the visitors), of which the social wasps (Polistes dominula(Christ)) were most common, followed bybees. Bees were observed visiting bamboo canes, Arundo canes, drilled logs, and grooved boards. Drilled logs were themost used material (31.5 and 37.6% occupied in 2017 and 2018, respectively), followed by bamboo canes (14.1 and17.4% of occupied in 2017 and 2018, respectively). For drilled logs, holes of 4.9–6.5mm (2017) and 7.0–9.2 mm (2018)were preferred, whilst diameters of 2.6/2.7–4.9/5.0 mm (both 2017 and 2018) were preferred for bamboo canes. Forgrooved boards, holes of 5.0 mm (only 2018) were preferred. The bee species most frequently nesting in bamboo caneswereCeratina cucurbitina(Rossi) andCeratina dentiventrisGerstacker, whereas in drilled logsHoplitis lepeletieri(P erez)was most common, butHoplitis adunca(Panzer) was also recorded. Their abundance throughout the study period variedbetween species, and their role in biodiversity and sustaining wild flora is discussed

Modest Declines in Proteome Quality Impair Hematopoietic Stem Cell Self-Renewal.

Low protein synthesis is a feature of somatic stem cells that promotes regeneration in multiple tissues. Modest increases in protein synthesis impair stem cell function, but the mechanisms by which this occurs are largely unknown. We determine that low protein synthesis within hematopoietic stem cells (HSCs) is associated with elevated proteome quality in vivo. HSCs contain less misfolded and unfolded proteins than myeloid progenitors. Increases in protein synthesis cause HSCs to accumulate misfolded and unfolded proteins. To test how proteome quality affects HSCs, we examine Aarssti/sti mice that harbor a tRNA editing defect that increases amino acid misincorporation. Aarssti/sti mice exhibit reduced HSC numbers, increased proliferation, and diminished serial reconstituting activity. Misfolded proteins overwhelm the proteasome within Aarssti/sti HSCs, which is associated with increased c-Myc abundance. Deletion of one Myc allele partially rescues serial reconstitution defects in Aarssti/sti HSCs. Thus, HSCs are dependent on low protein synthesis to maintain proteostasis, which promotes their self-renewal

Development of low-pH cementitious materials for HLRW repositories. Resistance against ground waters aggression

One of the most accepted engineering construction concepts of underground repositories for high radioactive waste considers the use of low-pH cementitious materials. This paper deals with the design of those based on Ordinary Portland Cements with high contents of silica fume and/or fly ashes that modify most of the concrete “standard” properties, the pore fluid composition and the microstructure of the hydrated products. Their resistance to long-term groundwater aggression is also evaluated. The results show that the use of OPC cement binders with high silica content produces low-pH pore waters and the microstructure of these cement pastes is different from the conventional OPC ones, generating C–S–H gels with lower CaO/SiO2 ratios that possibly bind alkali ions. Leaching tests show a good resistance of low-pH concretes against groundwater aggression although an altered front can be observe

Compuestos Laminados De Matriz Polimérica Reforzados Con Fibras Naturales: Comportamiento Mecánico

El grado de comprensión de la mecánica de materiales compuestos laminados subyace al nivel de sus aplicaciones y la consistencia de su desempeño. La especialización alcanzada por el tema se refleja en la amplitud de la documentación disponible, tanto en cantidad como en intereses específicos. Esta situación obliga a una sistematización periódica del conocimiento generado, cuyo propósito es sostener este proceso mediante la vinculación de nuevas personas e ideas a lo ya construido. En este artículo de sistematización el estado actual del conocimiento aplicado se presenta como una serie de ideas, a las que subyace el concepto de naturaleza multi-escalar del comportamiento mecánico de los materiales compuestos. En el transcurso se deja ver el rol de las técnicas de caracterización mecánica y microscópica en la construcción de conocimiento sobre el tema