Epigenetic Maternal Effects on Endogenous Rhythms in Precocial Birds

Development involves interactions between genetic and environmental influences. Vertebrate mothers are generally the first individuals to encounter and interact with young animals. Thus, their role is primordial during ontogeny. The present study evaluated non‐genomic effects of mothers on the development of rhythms of precocial Japanese quail (Coturnix c. japonica). First, we investigated the influence of mothering on the ontogeny of endogenous rhythms of young. We compared circadian and ultradian rhythms of feeding activity of quail reared with or without adoptive mothers. More brooded than non‐brooded quail presented a circadian and/or an ultradian rhythm. Thus, the presence of the mother during the normal brooding period favors, in the long term, expression of rhythms in the young. Second, we investigated the influence of rhythmic phenotype of the mother on the development of endogenous rhythms of young by comparing quail brooded by circadian‐rhythmic adoptive mothers (R) to quail brooded by circadian‐arrhythmic adoptive mothers (A). More R‐brooded than A‐brooded quail expressed circadian rhythmicity, and circadian rhythm clarities were greater in R‐brooded than A‐brooded quail. Ultradian rhythmicity did not differ between R‐ and A‐brooded quail, nor between R and A adoptive mothers. Thus, the rhythmic phenotypes of quail mothers influence the rhythmic phenotypes of their young. Our results demonstrate that mothers of precocial birds influence epigenetically the ontogeny of endogenous rhythms of the young they raise.     

Broadly Neutralizing Immune Responses against Hepatitis C Virus Induced by Vectored Measles Viruses and a Recombinant Envelope Protein Booster

Hepatitis C virus (HCV) infection remains a serious public health problem worldwide. Treatments are limited, and no preventive vaccine is available. Toward developing an HCV vaccine, we engineered two recombinant measles viruses (MVs) expressing structural proteins from the prototypic HCV subtype 1a strain H77. One virus directs the synthesis of the HCV capsid (C) protein and envelope glycoproteins (E1 and E2), which fold properly and form a heterodimer. The other virus expresses the E1 and E2 glycoproteins separately, with each one fused to the cytoplasmic tail of the MV fusion protein. Although these hybrid glycoproteins were transported to the plasma membrane, they were not incorporated into MV particles. Immunization of MV-susceptible, genetically modified mice with either vector induced neutralizing antibodies to MV and HCV. A boost with soluble E2 protein enhanced titers of neutralizing antibody against the homologous HCV envelope. In animals primed with MV expressing properly folded HCV C-E1-E2, boosting also induced cross-neutralizating antibodies against two heterologous HCV strains. These results show that recombinant MVs retain the ability to induce MV-specific humoral immunity while also eliciting HCV neutralizing antibodies, and that anti-HCV immunity can be boosted with a single dose of purified E2 protein. The use of MV vectors could have advantages for pediatric HCV vaccination.     

Invasion of insect cells by Spiroplasma citri involves spiralin relocalization and lectin/glycoconjugate‐type interactions

Spiroplamas are helical, cell wall‐less bacteria belonging to the Class Mollicutes, a group of microorganisms phylogenetically related to low G+C, Gram‐positive bacteria. Spiroplasma species are all found associated with arthropods and a few, including Spiroplasma citri are pathogenic to plant. Thus S. citri has the ability to colonize cells of two very distinct hosts, the plant and the insect vector. While spiroplasmal factors involved in transmission by the leafhopper Circulifer haematoceps have been identified, their specific contribution to invasion of insect cells is poorly understood. In this study we provide evidence that the lipoprotein spiralin plays a major role in the very early step of cell invasion. Confocal laser scanning immunomicroscopy revealed a relocalization of spiralin at the contact zone of adhering spiroplasmas. The implication of a role for spiralin in adhesion to insect cells was further supported by adhesion assays showing that a spiralin‐less mutant was impaired in adhesion and that recombinant spiralin triggered adhesion of latex beads. We also showed that cytochalasin D induced changes in the surface‐exposed glycoconjugates, as inferred from the lectin binding patterns, and specifically improved adhesion of S. citri wild‐type but not of the spiralin‐less mutant. These results indicate that cytochalasin D exposes insect cell receptors of spiralin that are masked in untreated cells. In addition, competitive adhesion assays with lectins strongly suggest spiralin to exhibit glycoconjugate binding properties similar to that of the Vicia villosa agglutinin (VVA) lectin.     

Plasma FA composition in familial LCAT deficiency indicates SOAT2-derived cholesteryl ester formation in humans

Mutations in the LCAT gene cause familial LCAT deficiency (Online Mendelian Inheritance in Man ID: #245900), a very rare metabolic disorder. LCAT is the only enzyme able to esterify cholesterol in plasma, whereas sterol O-acyltransferases 1 and 2 are the enzymes esterifying cellular cholesterol in cells. Despite the complete lack of LCAT activity, patients with familial LCAT deficiency exhibit circulating cholesteryl esters (CEs) in apoB-containing lipoproteins. To analyze the origin of these CEs, we investigated 24 carriers of LCAT deficiency in this observational study. We found that CE plasma levels were significantly reduced and highly variable among carriers of two mutant LCAT alleles (22.5 [4.0–37.8] mg/dl) and slightly reduced in heterozygotes (218 [153–234] mg/dl). FA distribution in CE (CEFA) was evaluated in whole plasma and VLDL in a subgroup of the enrolled subjects. We found enrichment of C16:0, C18:0, and C18:1 species and a depletion in C18:2 and C20:4 species in the plasma of carriers of two mutant LCAT alleles. No changes were observed in heterozygotes. Furthermore, plasma triglyceride-FA distribution was remarkably similar between carriers of LCAT deficiency and controls. CEFA distribution in VLDL essentially recapitulated that of plasma, being mainly enriched in C16:0 and C18:1, while depleted in C18:2 and C20:4. Finally, after fat loading, chylomicrons of carriers of two mutant LCAT alleles showed CEs containing mainly saturated FAs. This study of CEFA composition in a large cohort of carriers of LCAT deficiency shows that in the absence of LCAT-derived CEs, CEs present in apoB-containing lipoproteins are derived from hepatic and intestinal sterol O-acyltransferase 2.     

Expression of SR-BI receptor and StAR protein in rat ocular tissues

The class-B type-I scavenger receptor (SR-BI) plays a key role in cholesterol homeostasis; it mediates the selective uptake of lipoprotein cholesterol to steroidogenic tissues. We show by RT-PCR, western blot, in situ hybridization and immunohistochemistry analysis that SR-BI is highly expressed in different neuro-retinal and non-neuronal cells types on rat eye. Immunohistochemistry of the steroidogenic acute regulatory protein (StAR) involved in neurosteroid production showed the same expression pattern than SR-BI in rat eye. Our results may suggest a key role of these genes in the ocular cholesterol metabolism for membranes biosynthesis and neurosteroidogenesis.     

Tropical soils degraded by slash‐and‐burn cultivation can be recultivated when amended with ashes and compost

In many tropical regions, slash‐and‐burn agriculture is considered as a driver of deforestation; the forest is converted into agricultural land by cutting and burning the trees. However, the fields are abandoned after few years because of yield decrease and weed invasion. Consequently, new surfaces are regularly cleared from the primary forest. We propose a reclamation strategy for abandoned fields allowing and sustaining re‐cultivation. In the dry region of south‐western Madagascar, we tested, according to a split‐plot design, an alternative selective slash‐and‐burn cultivation technique coupled with compost amendment on 30–year‐old abandoned fields. Corn plants (Zea mays L.) were grown on four different types of soil amendments: no amendment (control), compost, ashes (as in traditional slash‐and‐burn cultivation), and compost + ashes additions. Furthermore, two tree cover treatments were applied: 0% tree cover (as in traditional slash‐and‐burn cultivation) and 50% tree cover (selective slash‐and‐burn). Both corn growth and soil fertility parameters were monitored during the growing season 2015 up to final harvest. The amendment compost + ashes strongly increased corn yield, which was multiplied by 4–5 in comparison with ashes or compost alone, reaching 1.5 t/ha compared to 0.25 and 0.35 t/ha for ashes and compost, respectively. On control plots, yield was negligible as expected on these degraded soils. Structural equation modeling evidenced that compost and ashes were complementary fertilizing pathways promoting soil fertility through positive effects on soil moisture, pH, organic matter, and microbial activity. Concerning the tree cover treatment, yield was reduced on shaded plots (50% tree cover) compared to sunny plots (0% tree cover) for all soil amendments, except ashes. To conclude, our results provide empirical evidence on the potential of recultivating tropical degraded soils with compost and ashes. This would help mitigating deforestation of the primary forest by increasing lifespan of agricultural lands.     

Identification of quantitative trait loci affecting cattle temperament

In addition to its potential contribution to improving animal welfare, the study of the genetics of cattle behavior may provide more general insights into the genetic control of such complex traits. We carried out a genome scan in a Holstein x Charolais cross cattle population to identify quantitative trait loci (QTL) influencing temperament-related traits. Individuals belonging to the second-generation of this population (F(2) and backcross individuals) were subjected to 2 behavioral tests. The flight from feeder (FF) test measured the distance at which the animal moved away from an approaching human observer, whereas the social separation (SS) test categorized different activities which the animal engaged in when removed from its penmates. The entire population was genotyped with 165 microsatellite markers. A regression interval mapping analysis identified 29 regions exceeding the 5% chromosome-wide significance level, which individually explained a relatively small fraction of the phenotypic variance of the traits (from 3.8% to 8.4%). One of the significant associations influencing an FF test trait on chromosome 29 reached the 5% genome-wide significance level. Eight other QTL, all associated with an SS test trait, reached the 1% chromosome-wide significance level. The location of some QTL coincided with other previously reported temperament QTL in cattle, whereas those that are reported for the first time here may represent general loci controlling temperament differences between cattle breeds. No overlapping QTL were identified for the traits measured by the 2 different tests, supporting the hypothesis that different genetic factors influence behavioral responses to different situations.     

Archamamelis,hamamelidalean flowers from the Upper Cretaceous of Sweden

Lignite fossil flowers (including pollen) and isolated stamens of probable hamamelidalean (possible hamamelidaceous) affinities from the upper Cretaceous (Late Santonian or Early Campanian) of Sweden are described. The flowers are 6–7-merous with probably a double perianth, one whorl of stamens and (2-?)3 carpels. The stamens are disporangiate; each theca opens by a valve towards the centre of the flower. Pollen is tricolpate, tectate-columellate and reticulate; the endexine is lamellated in the apertural region. The gynoecium has free styles and a syncarpous ovary. In the one flower that was serially sectioned the ovary is either non-functional or development of the few (2?) ovules is retarded.     

Flexibility and mutagenic resiliency of glycosyltransferases

The human blood group A and B antigens are synthesized by two highly homologous enzymes, glycosyltransferase A (GTA) and glycosyltransferase B (GTB), respectively. These enzymes catalyze the transfer of either GalNAc or Gal from their corresponding UDP-donors to αFuc1–2βGal-R terminating acceptors. GTA and GTB differ at only four of 354 amino acids (R176G, G235S, L266M, G268A), which alter the donor specificity from UDP-GalNAc to UDP-Gal. Blood type O individuals synthesize truncated or non-functional enzymes. The cloning, crystallization and X-ray structure elucidations for GTA and GTB have revealed key residues responsible for donor discrimination and acceptor binding. Structural studies suggest that numerous conformational changes occur during the catalytic cycle. Over 300 ABO alleles are tabulated in the blood group antigen mutation database (BGMUT) that provides a framework for structure-function studies. Natural mutations are found in all regions of GTA and GTB from the active site, flexible loops, stem region and surfaces remote from the active site. Our characterizations of natural mutants near a flexible loop (V175M), on a remote surface site (P156L), in the metal binding motif (M212V) and near the acceptor binding site (L232P) demonstrate the resiliency of GTA and GTB to mutagenesis.