Morphological Bases of Human Leydig Cell Dysfunction

In this chapter, we describe the histophysiology of human Leydig cells, their cytological characteristics, their differentiation processes, and the physiopathological processes occurring at various times throughout life. We first focus on the normal development of fetal Leydig cells as well as the pathologies of fetal Leydig cells that can affect numbers or hyperplasic processes (e.g., hypogonadotropic hypogonadism, cryptorchidism, congenital Leydig cell hyperplasia secondary to diabetes, and isoimmunization). Next, we explain the changes occurring at puberty with the onset and differentiation of adult Leydig cells and the pathophysiology of delayed puberty. We then describe the histophysiology of adult Leydig cells and the most frequent pathologies (e.g., hypogonadotropic hypogonadism, testicular dysgenesia, mild androgen insensitivity syndrome, 5-α-reductase defect, and Klinefelter syndrome). Finally, we discuss the morphological changes of these cells in the elderly

Primordial Germ Cell Reprogramming

Primordial germ cells (PGCs) are the embryonic precursors of the gametes. Thus, they are unipotent cells. However, PGCs share some common features with pluripotent stem cells. Among them, PGCs show alkaline phosphatase activity and express stage-specific embryonic antigens and pluripotency factors Lin28, Oct4, Sox2, and Nanog. Under specific conditions, they undergo spontaneous reprogramming in vivo. Moreover, they can be easily reprogrammed in vitro into pluripotent embryonic germ cells (EGCs) by culturing them in the presence of basic fibroblast growth factor or the epigenetic modulator trichostatin A. Previous work in our laboratory has also proven that hypoxia alone can reprogram PGCs into hypoxia-induced embryonic germ-like cells, which have a pluripotent phenotype but which do not show self-renewal capacity. Therefore, PGCs are an interesting model to further comprehensively understand the process of cell reprogramming. This chapter reviews various methods to achieve PGC reprogramming, as well as the molecular pathways involved. We focus on soluble factors and genetic strategies to obtain pluripotent cells from PGCs. Special emphasis will be given to factors implied in energetic metabolism, epigenetics, and cell signaling transduction, both in vitro and in vivo

Degradation assessment of recycled aggregates from Construction and Demolition Waste through wet-dry cycles

In recent years, several studies and applications of recycled aggregates coming from Construction and Demolition Waste (CDW) have been carried out, but the knowledge related to the long-term behaviour of these alternative materials is still fairly limited. The breakage of CDW particles is commonly pointed out as an issue for the use of these recycled materials. This paper studies the change of the particle size distribution of a recycled aggregate coming from CDW due to degradation agents simulated trough 10 wet-dry cycles under controlled conditions. The effects on particle density, water absorption, shape index, flakiness index, sand equivalent value, Los Angeles abrasion, aggregate crushing value, water-soluble sulphate content are assessed. Wet-Dry cycles have degraded the mixed recycled aggregate, increasing the amount of particles with small dimensions, however the changes in its mechanical and physical behaviour are not very significant. LA abrasion loss of this recycled aggregate is high making its use on unbound pavement layers difficult

Swimming abilities of temperate pelagic fish larvae prove that they may control their dispersion in coastal areas

The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sensorial acuity of temperate fish larvae allows them to find and swim towards coastal nursery areas, which are crucial for their recruitment. To gather further evidence to support this theory, it is necessary to understand how horizontal swimming capability varies along fish larvae ontogeny. Therefore, we studied the swimming capability of white seabream Diplodus sargus (Linnaeus, 1758) larvae along ontogeny, and their relationship with physiological condition. Thus, critical swimming speed (U-crit) and the distance swam (km) during endurance tests were determined for fish larvae from 15 to 55 days post-hatching (DPH), and their physiological condition (RNA, DNA and protein contents) was assessed. The critical swimming speed of white seabream larvae increased along ontogeny from 1.1 cm s(-1) (15 DPH) to 23 cm s(-1) (50 and 55 DPH), and the distance swam by larvae in the endurance experiments increased from 0.01 km (15 DPH) to 86.5 km (45 DPH). This finding supports one of the premises of the SAAB hypothesis, which proposes that fish larvae can influence their transport and distribution in coastal areas due to their swimming capabilities. The relationship between larvae's physiological condition and swimming capabilities were not evident in this study. Overall, this study provides critical information for understanding the link between population dynamics and connectivity with the management and conservation of fish stocks.Funding Agency Portuguese Foundation for Science and Technology SFRH/BD/104209/2014 Portuguese Foundation for Science and Technology UID/Multi/04326/2019 FCT, under the Transitional Norm DL57/2016/CP[1361]/CT[CT0008 CLIMFISH project-A framework for assess vulnerability of coastal fisheries to climate change in Portuguese coast n2/SAICT/2017-SAICTinfo:eu-repo/semantics/publishedVersio

Foliar treatments as a strategy to control iron chlorosis in orange trees

Different foliar treatments were applied to evaluate the recovery of iron chlorosis of orange trees (Citrus sinensis (L.) Osb. cv. 'Valencia late') grown on a calcareous soil. The treatments were: Fe (II) sulphate (500 mg Fe L-1), sulphuric acid (0.5 mM H2SO4), Fe (III)-chelate (Hampiron 654 GS, 120 mg Fe L-1) and distilled water as a control. The recovery from iron chlorosis was evaluated with the SPAD-502 apparatus and the values converted to total chlorophyll concentration. The effects of treatments on the mineral composition of leaves and flowers, and the size and quality of fruits were evaluated. The residual effect of treatments was also evaluated one year later. In orange trees, the use of frequent foliar sprays with Fe was able to alleviate Fe chlorosis and prevented yield and quality losses caused by Fe chlorosis. Compared with the control, sprays of Fe (II) sulphate led to higher concentrations of chlorophyll, Fe and Zn in leaves and flowers at the end of the experimental period, and significantly improved fruit size and quality. Leaf Fe concentration increased after the sulphuric acid spray, but this treatment did not affect fruit quality parameters. The mineral composition of flowers and leaves was correlated with some fruit quality parameters obtained one year later. These results suggest that foliar sprays with Fe could help to avoid fruit quality losses caused by Fe chlorosis in citrus orchards

Portland cement pastes analysed by synchrotron and laboratory X-ray imaging

Portland Cement (PC) is the most used construction material and the derived building materials have very complex hierarchical microstructures. Quantitative characterization of their microstructures is of paramount importance for assessing the performance and durability of the final products. As cement performance is controlled by its phase composition and microstructure, in particular, the pore network plays a critical role in the mechanical properties and durability. The chemical and hydration changes in PC binders affect their performances mainly because of the binding properties of the main component, the so-called C-S-H gel. Here, we analyse porosity in PC pastes using laboratory and synchrotron X-ray micro-tomography with different water to cement mass ratios (w/c) after 28 days of hydration. Monochromatic synchrotron X-ray microtomography is used for reference and the main aim is determining volume percentage of different components with focus on porosity. It will be shown, as expected, that higher amount of water (that increases fluidity of pastes) results in higher porosities at 28 days of hydration. Therefore, in the histogram and tomograms more pores, hydrated materials, and less anhydrous materials would appear with increasing w/c (see Figure 1). The excellent spatial resolution (and slightly better contrast) of synchrotron experiments serve as reference for data analysis. Despite 0.2-0.3 m voxel-sizes in all the used experimental setups (see Figure 2), the laboratory tomograms show some limitations that will be discussed. In this work, a two-steps approach is followed. Firstly, we will report the analysis of the histograms by classifying in the three types of components based on grey-levels: i) pores, ii) hydrated components; and iii) unreacted cement phases. Secondly, segmented pore contribution will be further analyzed and the results from laboratory tomograms will be compared with the reference values derived from synchrotron data.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Inhibition of PKCε induces primordial germ cell reprogramming into pluripotency by HIF1&2 upregulation and histone acetylation

Historically, primordial germ cells (PGCs) have been a good model to study pluripotency. Despite their low numbers and limited accessibility in the mouse embryo, they can be easily and rapidly reprogrammed at high efficiency with external physicochemical factors and do not require transcription factor transfection. Employing this model to deepen our understanding of cell reprogramming, we specifically aimed to determine the relevance of Ca2+ signal transduction pathway components in the reprogramming process. Our results showed that PGC reprogramming requires a normal extracellular [Ca2+] range, in contrast to neoplastic or transformed cells, which can continue to proliferate in Ca2+-deficient media, differentiating normal reprogramming from neoplastic transformation. Our results also showed that a spike in extracellular [Ca2+] of 1-3 mM can directly reprogram PGC. Intracellular manipulation of Ca2+ signal transduction pathway components revealed that inhibition of classical Ca2+ and diacylglycerol (DAG)-dependent PKCs, or intriguingly, of only the novel DAG-dependent PKC, PKCε, were able to induce reprogramming. PKCε inhibition changed the metabolism of PGCs toward glycolysis, increasing the proportion of inactive mitochondria. This metabolic switch from oxidative phosphorylation to glycolysis is mediated by hypoxia-inducible factors (HIFs), given we found upregulation of both HIF1α and HIF2α in the first 48 hours of culturing. PKCε inhibition did not change the classical pluripotency gene expression of PGCs, Oct4, or Nanog. PKCε inhibition changed the histone acetylation of PGCs, with histones H2B, H3, and H4 becoming acetylated in PKCε-inhibited cultures (markers were H2BacK20, H3acK9, and H4acK5K8, K12, K16), suggesting that reprogramming by PKCε inhibition is mediated by histone acetylation

Insights into the role of fungi in Pine Wilt Disease

Pine wilt disease (PWD) is a complex disease that severely affects the biodiversity and economy of Eurasian coniferous forests. Three factors are described as the main elements of the disease: the pinewood nematode (PWN) Bursaphelenchus xylophilus, the insect‐vector Monochamus spp., and the host tree, mainly Pinus spp. Nonetheless, other microbial interactors have also been considered. The study of mycoflora in PWD dates back the late seventies. Culturomic studies have revealed diverse fungal communities associated with all PWD key players, composed frequently of saprophytic fungi (i.e., Aspergillus, Fusarium, Trichoderma) but also of necrotrophic pathogens associated with bark beetles, such as ophiostomatoid or blue‐stain fungi. In particular, the ophiostomatoid fungi often recovered from wilted pine trees or insect pupal chambers/tunnels, are considered crucial for nematode multiplication and distribution in the host tree. Naturally occurring mycoflora, reported as possible biocontrol agents of the nematode, are also discussed in this review. This review discloses the contrasting effects of fungal communities in PWD and highlights promising fungal species as sources of PWD biocontrol in the framework of sustainable pest management actions

Antioxidant mechanisms to counteract TiO2-nanoparticles toxicity in wheat leaves and roots are organ dependent

Nanoparticles (NP) bioactivity is under deep scrutiny. In this work, the antioxidant response to TiO2-NP in wheat (Triticum aestivum) was determined. For that, enzymatic and the non-enzymatic antioxidants were evaluated in plants exposed to the P25 anatase:rutile material composed of TiO2-NP and under environmentally realistic doses (0; 5; 50; 150 mg/L for 20 days). Shoot but not root growth was reduced. In leaves, thiol metabolism and ascorbate accumulation were the preferred route whereas in roots the pre-existing antioxidant capacity was preferentially utilized. Both leaves and roots showed increased glutathione reductase and dehydroascorbate reductase activities and decreased ascorbate peroxidase activity. Roots, nevertheless, presented higher enzymatic basal levels than leaves. On the other hand, when examining non-enzymatic antioxidants, the ratio of reduced-to-oxidized glutathione (GSH/GSSG) increased in leaves and decreased in roots. Exposed leaves also presented higher total ascorbate accumulation compared to roots. TiO2-NP exposure down regulated, with more prominence in roots, antioxidant enzyme genes encoding catalase, ascorbate peroxidase, monodehydroascorbate reductase and dehydroascorbate reductase. In leaves, superoxide dismutase gene expression was increased. All data pinpoint to TiO2-NP toxicity above 5 mg/L, with aerial parts being more susceptible, which draws concerns on the safety doses for the use of these NPs in agricultural practices.publishe