Moderate Heat Challenge Increased Yolk Steroid Hormones and Shaped Offspring Growth and Behavior in Chickens

Background

Environmental challenges might affect the maternal organism and indirectly affect the later ontogeny of the progeny. We investigated the cross-generation impact of a moderate heat challenge in chickens. We hypothesized that a warm temperature–within the thermotolerance range- would affect the hormonal environment provided to embryos by mothers, and in turn, affect the morphology and behavioral phenotype of offspring.

Methodology/Principal Findings

Laying hens were raised under a standard thermal condition at 21°C (controls) or 30°C (experimental) for 5 consecutive weeks. A significant increase was observed in the internal temperature of hens exposed to the warm treatment; however plasma corticosterone levels remained unaffected. The laying rate was not affected, but experimental hens laid lighter eggs than the controls during the treatment. As expected, the maternal thermal environment affected yolk hormone contents. Eggs laid by the experimental hens showed significantly higher concentrations of yolk progesterone, testosterone, and estradiol. All chicks were raised under standard thermal conditions. The quality of hatchlings, growth, feeding behavior and emotional reactivity of chicks were analyzed. Offspring of experimental hens (C30 chicks) were lighter but obtained better morphological quality scores at hatching than the controls (C21 chicks). C30 chicks expressed lesser distress calls when exposed to a novel food. Unlike C21 chicks, C30 chicks expressed no preference for energetic food.

Conclusion/Significance

Our findings suggest that moderate heat challenge triggers maternal effects and modulate the developmental trajectory of offspring in a way that may be adaptive. This suggests that the impact of heat challenges on captive or wild populations might have a cross-generation effect.     

metaBIT,an integrative and automated metagenomic pipeline for analysing microbial profiles from high‐throughput sequencing shotgun data

Micro‐organisms account for most of the Earth's biodiversity and yet remain largely unknown. The complexity and diversity of microbial communities present in clinical and environmental samples can now be robustly investigated in record times and prices thanks to recent advances in high‐throughput DNA sequencing (HTS). Here, we develop metaBIT, an open‐source computational pipeline automatizing routine microbial profiling of shotgun HTS data. Customizable by the user at different stringency levels, it performs robust taxonomy‐based assignment and relative abundance calculation of microbial taxa, as well as cross‐sample statistical analyses of microbial diversity distributions. We demonstrate the versatility of metaBIT within a range of published HTS data sets sampled from the environment (soil and seawater) and the human body (skin and gut), but also from archaeological specimens. We present the diversity of outputs provided by the pipeline for the visualization of microbial profiles (barplots, heatmaps) and for their characterization and comparison (diversity indices, hierarchical clustering and principal coordinates analyses). We show that metaBIT allows an automatic, fast and user‐friendly profiling of the microbial DNA present in HTS shotgun data sets. The applications of metaBIT are vast, from monitoring of laboratory errors and contaminations, to the reconstruction of past and present microbiota, and the detection of candidate species, including pathogens.     

Carbon emission along a eutrophication gradient in temperate riverine wetlands: effect of primary productivity and plant community composition

相似文献   

Oligodendrocyte ablation affects the coordinated interaction between granule and Purkinje neurons during cerebellum development

Oligodendrocytes (OLs) are the glial cells of the central nervous system (CNS) classically known to be devoted to the formation of myelin sheaths around most axons of the vertebrate brain. We have addressed the role of these cells during cerebellar development, by ablating OLs in vivo. Previous analyses had indicated that OL ablation during the first six postnatal days results into a striking cerebellar phenotype, whose major features are a strong reduction of granule neurons and aberrant Purkinje cells development. These two cell types are highly interconnected during cerebellar development through the production of molecules that help their proliferation, differentiation and maintenance. In this article, we present data showing that OL ablation has major effects on the physiology of Purkinje (PC) and granule cells (GC). In particular, OL ablation results into a reduction of sonic hedgehog (Shh), Brain Derived Neurotrophic Factor (BDNF), and Reelin (Rln) expression. These results indicate that absence of OLs profoundly alters the normal cerebellar developmental program.     

Rodrigues fruit bats (<Emphasis Type="Italic">Pteropus rodricensis</Emphasis>, Megachiroptera: Pteropodidae) retain genetic diversity despite population declines and founder events

Fruit bats of the genus Pteropus are important contributors to ecosystem maintenance on islands through their roles as pollinators and seed dispersers. However, island faunas are the most prone to extinction and there is a real need to assess the possible genetic implications of population reductions in terms of extinction risk. An effective method of ameliorating extinction risk in endangered species is the establishment of captive populations ex situ. The effectiveness of captive breeding programmes may be assessed by comparing the genetic variability of captive colonies to that of wild counterparts. Here, we use polymorphic microsatellite loci to assess genetic variability in wild, critically endangered Rodrigues fruit bats (Pteropus rodricensis, Dobson 1878) and we compare this variability to that in a captive colony. We document remarkable conservation of genetic variability in both the wild and captive populations, despite population declines and founder events. Our results demonstrate that the wild population has withstood the negative effects of population reductions and that captive breeding programmes can fulfil the goals of retaining genetic diversity and limiting inbreeding.     

Metabolic Changes in <Emphasis Type="Italic">Clostridium absonum</Emphasis> ATCC 27555 Accompanying Induction of Epimerization of a Primary Bile Acid

Some parameters of fermentation have been determined for Clostridium absonum in a chemostat by using a chemically defined medium with glucose as the sole source of carbon and energy. Steady-state continuous cultures were achieved at two dilution rates (D). Trends of the carbon flow were determined by comparison of ratios between the specific rates of formation of the three products of metabolism (lactate, acetate, butyrate). Chenodeoxycholate induced the 7- and 7-hydroxysteroid dehydrogenases of C. absonum. In the presence of this inducer, the growth yield and the carbon recovery decreased, the carbon flow distribution was altered favoring acetate production, and a deficit in the reoxydation of nucleotidic cofactors was observed. In the presence of chenodeoxycholate, C. absonum would favor the production of energy at the expense of the reoxidation of nucleotidic cofactors so as to ensure its growth, and the epimerization of chenodeoxycholate to ursodeoxycholate.     

Microspatial genetic heterogeneity and gene flow in stray cats (Felis catus L.): a comparison of coat colour and microsatellite loci

We analysed levels of genetic differentiation between nine local urban colonies of stray cats using eight coat colour and nine microsatellite loci. Both types of markers revealed a strong differentiation between colonies (FST = 0.15 and 0.09 for coat colour and microsatellite loci, respectively). Three coat colour loci showed extreme levels of genetic differentiation comparatively to other loci and are strongly suspected to be under divergent selective pressures. Microsatellite loci showed significant heterozygote deficiency within colonies (FIS = 0.14), suggesting that coat colour loci are not appropriate to investigate genetic structure at a fine scale because coat colour allele frequencies are based on Hardy-Weinberg equilibrium. The reported pattern conformed to that predicted from the social structuring of cat colonies: aggressive exclusion of immigrants, inbreeding and very low dispersal rate.     

New nitrogen mustards structurally related to (L)-carnitine

Enantiopure nitrogen mustards which mimic (L)-carnitine framework are prepared by a multi-step synthesis from the (R)-di-tert-butyl malate and their antitumor properties evaluated.     

Insecticide resistance enhances male reproductive success in a beetle

Abstract.— Malathion-specific resistance in the red flour beetle, Tribolium castaneum , is widespread and stable in natural populations even in the absence of pesticide exposure. To understand this stability, both resistant and susceptible males were placed in competition for susceptible female fertilization. Females were then isolated and their progeny was tested for malathion susceptibility. Male reproductive success was estimated for populations originating from different geographic areas and for isogenic strains. In most cases, resistant males had a greater reproductive success rate than susceptibles. The results suggest that male reproductive success is not traded against the selection for malathion resistance, even resistant individuals are at an advantage for this fitness trait. This absence of fitness cost may be the result of postselection of (1) modifier gene which ameliorate the fitness of resistant individuals or (2) nondeleterious resistance gene. Resistant phenotype superiority could be due to increased male mating success, improved ability of resistant males in sperm competition, female mate choice, and/or cryptic female choice of resistance gene(s). The effect of male phenotypic frequency on male reproductive success was also examined. We observed that male fertilization success is frequency dependent and inversely related to their frequency. However, this "rare male" advantage did not counteract the superiority of the resistant males.     

Reactivity, secondary structure, and molecular topology of the Escherichia coli sulfite reductase flavodoxin-like domain

The flavodoxin-like domain, missing in the three-dimensional structure of the monomeric, simplified model of the Escherichia coli sulfite reductase flavoprotein component (SiR-FP), has now been expressed independently. This 168 amino acid protein was named SiR-FP18 with respect to its native molecular weight and represents the FMN-binding domain of SiR-FP. This simplified biological object has kept the main characteristics of its counterpart in the native protein. It could incorporate FMN exclusively and stabilize a neutral air-stable semiquinone radical. Both the radical and the fully reduced forms of SiR-FP18 were able to transfer their electrons to DCPIP or cytochrome c quantitatively. SiR-FP18 was able to form a highly stable complex with SiR-HP, the hemoprotein component of the sulfite reductase containing an iron-sulfur cluster coupled to a siroheme. In agreement with the postulated catalytic cycle of SiR-FP, only the fully reduced form of SiR-FP18 could transfer one electron to SiR-HP, the transferred electron being localized exclusively on the heme. As isolated SiR-FP18 has kept the main characteristics of the FMN-binding domain of the native protein, a structural analysis by NMR was performed in order to complete the partial structure obtained previously. Structural modeling was performed using sequence homologues, cytochrome P450 reductase (CPR; 29% identity) and bacterial cytochrome P450 (P450-BM3; 26% identity), as conformational templates. These sequences were anchored using common secondary structural elements identified from heteronuclear NMR data measured on the protein backbone. The resulting structural model was validated, and subsequently refined using residual (C(alpha)-C', N-H(N), and C'-H(N)) dipolar couplings measured in an anisotropic medium. The overall fold of SiR-FP18 is very similar to that of bacterial flavodoxins and of the flavodoxin-like domain in CPR or P450-BM3.