1-O-acylceramides are natural components of human and mouse epidermis

The lipid-rich stratum corneum functions as a barrier against pathogens and desiccation inter alia by an unbroken meshwork of extracellular lipid lamellae. These lamellae are composed of cholesterol, fatty acids, and ceramides (Cers) in an equimolar ratio. The huge class of skin Cers consists of three groups: group I, “classical” long and very long chain Cers; group II, ultra-long chain Cers; and group III, ω-esterified ultra-long chain Cers, which are esterified either with linoleic acid or with cornified envelope proteins and are required for the water permeability barrier. Here, we describe 1-O-acylceramides as a new class of epidermal Cers in humans and mice. These Cers contain, in both the N- and 1-O-position, long to very long acyl chains. They derive from the group I of classical Cers and make up 5% of all esterified Cers. Considering their chemical structure and hydrophobicity, we presume 1-O-acylceramides to contribute to the water barrier homeostasis. Biosynthesis of 1-O-acylceramides is not dependent on lysosomal phospholipase A₂. However, glucosylceramide synthase deficiency was followed by a 7-fold increase of 1-O-acylceramides, which then contributed 30% to all esterified Cers. Furthermore, loss of neutral glucosylceramidase resulted in decreased levels of a 1-O-acylceramide subgroup. Therefore, we propose 1-O-acylceramides to be synthesized at endoplasmic reticulum-related sites.     

ORF9p Phosphorylation by ORF47p Is Crucial for the Formation and Egress of Varicella-Zoster Virus Viral Particles

The role of the tegument during the herpesvirus lytic cycle is still not clearly established, particularly at the late phase of infection, when the newly produced viral particles need to be fully assembled before being released from the infected cell. The varicella-zoster virus (VZV) protein coded by open reading frame (ORF) 9 (ORF9p) is an essential tegument protein, and, even though its mRNA is the most expressed during the productive infection, little is known about its functions. Using a GalK positive/negative selection technique, we modified a bacterial artificial chromosome (BAC) containing the complete VZV genome to create viruses expressing mutant versions of ORF9p. We showed that ORF9p is hyperphosphorylated during the infection, especially through its interaction with the viral Ser/Thr kinase ORF47p; we identified a consensus site within ORF9p recognized by ORF47p and demonstrated its importance for ORF9p phosphorylation. Strikingly, an ultrastructural analysis revealed that the mutation of this consensus site (glutamate 85 to arginine) strongly affects viral assembly and release, reproducing the ORF47 kinase-dead VZV phenotype. It also slightly diminishes the infectivity toward immature dendritic cells. Taken together, our results identify ORF9p as a new viral substrate of ORF47p and suggest a determinant role of this phosphorylation for viral infectivity, especially during the process of viral particle formation and egress.     

Continuous production of enzymes under carbon-limited conditions by Trichoderma harzianum P49P11

Carbon-limited chemostat cultures were performed using different carbon sources (glucose, 10 and 20 g/L; sucrose, 10 g/L; fructose/glucose, 5.26/5.26 g/L; carboxymethyl cellulose, 10 g/L; and carboxymethyl cellulose/glucose, 5/5 g/L) to verify the capability of the wild type strain Trichoderma harzianum to produce extracellular enzymes. All chemostat cultures were carried out at a fixed dilution rate of 0.05 h^?1. Experiments using glucose, fructose/glucose and sucrose were performed in duplicate. Glucose condition was found to induce the production of enzymes that can catalyse the hydrolysis of p-nitrophenyl-β-d-glucopyranoside (PNPGase). A concentration of 20 g/L of glucose in the feed provided the highest productivity (1048 ± 16 U/mol h). Extracellular polysaccharides were considered the source of inducers. Based on the obtained results, a new PNPGase production process was developed using mainly glucose. This process raises interesting possibilities of synthesizing the inducer substrate and the induced enzymes in a single step using an easily assimilated carbon source under carbon-limited conditions.     

Anatomopathological lesions of infection caused by Platynosomum illiciens (Braun, 1901) in Neotropical primates kept in captivity

This study described the hepatobiliary anatomopathological lesions associated with trematode Platynosomum illiciens parasitism in Neotropical primates kept in captivity. In the evaluated organs, we observed portal fibrosis, biliary epithelial hyperplasia, and inflammatory reaction with a predominance of lymphocytes and plasmocytes, and in some cases infiltration of eosinophils and neutrophils.     

Puddingwife wrasse: an important trophic link of an isolated oceanic island in Brazil

Environmental Biology of Fishes - Invertivorous fish species such as Halichoeres radiatus feed on benthic active prey and need to spend most of their time foraging. Even though the Labridae family...     

Soil protist function varies with elevation in the Swiss Alps

Protists are abundant and play key trophic functions in soil. Documenting how their trophic contributions vary across large environmental gradients is essential to understand and predict how biogeochemical cycles will be impacted by global changes. Here, using amplicon sequencing of environmental DNA in open habitat soil from 161 locations spanning 2600 m of elevation in the Swiss Alps (from 400 to 3000 m), we found that, over the whole study area, soils are dominated by consumers, followed by parasites and phototrophs. In contrast, the proportion of these groups in local communities shows large variations in relation to elevation. While there is, on average, three times more consumers than parasites at low elevation (400–1000 m), this ratio increases to 12 at high elevation (2000–3000 m). This suggests that the decrease in protist host biomass and diversity toward mountains tops impact protist functional composition. Furthermore, the taxonomic composition of protists that infect animals was related to elevation while that of protists that infect plants or of protist consumers was related to soil pH. This study provides a first step to document and understand how soil protist functions vary along the elevational gradient.     

Disentangle genus microdiversity within a complex microbial community by using a multi-distance long-read binning method: example of Candidatus Accumulibacter

Complete genomes can be recovered from metagenomes by assembling and binning DNA sequences into metagenome assembled genomes (MAGs). Yet, the presence of microdiversity can hamper the assembly and binning processes, possibly yielding chimeric, highly fragmented and incomplete genomes. Here, the metagenomes of four samples of aerobic granular sludge bioreactors containing Candidatus (Ca.) Accumulibacter, a phosphate-accumulating organism of interest for wastewater treatment, were sequenced with both PacBio and Illumina. Different strategies of genome assembly and binning were investigated, including published protocols and a binning procedure adapted to the binning of long contigs (MuLoBiSC). Multiple criteria were considered to select the best strategy for Ca. Accumulibacter, whose multiple strains in every sample represent a challenging microdiversity. In this case, the best strategy relies on long-read only assembly and a custom binning procedure including MuLoBiSC in metaWRAP. Several high-quality Ca. Accumulibacter MAGs, including a novel species, were obtained independently from different samples. Comparative genomic analysis showed that MAGs retrieved in different samples harbour genomic rearrangements in addition to accumulation of point mutations. The microdiversity of Ca. Accumulibacter, likely driven by mobile genetic elements, causes major difficulties in recovering MAGs, but it is also a hallmark of the panmictic lifestyle of these bacteria.     

Generation of specific Th1 and CD8+ T-cell responses by immunization with mouse CD8+ dendritic cells loaded with HIV-1 viral lysate or envelope glycoproteins

Immunization with antigen-pulsed dendritic cells (DCs) can be used to elicit optimal immune responses. We developed the SRDC cell line, with a morphology, phenotype and activity similar to mouse splenic CD4(-)CD8alpha(+)CD205(+)CD11b(-) dendritic cells, which induce a polarized Th1 immune response. We evaluated the ability of SRDCs pulsed with HIV-1 viral lysate, oligomeric soluble gp140 or capsid p24 to induce specific antibody and T-cell responses in CBA/J mice. Immunization with all loaded SRDCs elicited antibody responses against the antigens tested. However, only HIV-1 viral lysate and gp140-pulsed SRDCs elicited specific CD4(+) and CD8(+) T-cell responses. These findings demonstrate the value of well characterized DC lines for optimizing the antigen-loading mixture, according to the DC population targeted. Our data suggest that splenic DCs pulsed with complex antigens, such as HIV-1 viral lysate or oligomeric soluble gp140, could be used as vaccines, eliciting strong primary Th1-polarized and humoral immune responses against HIV proteins in vivo.