The Intensity of IUGR-Induced Transcriptome Deregulations Is Inversely Correlated with the Onset of Organ Function in a Rat Model

A low-protein diet applied during pregnancy in the rat results in intrauterine growth restricted (IUGR) fetuses. In humans, IUGR is associated with increased perinatal morbidity, higher incidence of neuro-developmental defects and increased risk of adult metabolic anomalies, such as diabetes and cardiovascular disease. Development and function of many organs are affected by environmental conditions such as those inducing fetal and early postnatal growth restriction. This phenomenon, termed “fetal programming” has been studied unconnectedly in some organs, but very few studies (if any) have investigated at the same time several organs, on a more comparative basis. However, it is quite probable that IUGR affects differentially most organ systems, with possible persistent changes in gene expression. In this study we address transcriptional alterations induced by IUGR in a multi-organ perspective, by systematic analysis of 20-days rat fetuses. We show that (1) expressional alterations are apparently stronger in organs functioning late in foetal or postnatal life than in organs that are functioning early (2) hierarchical classification of the deregulations put together kidney and placenta in one cluster, liver, lungs and heart in another; (3) the epigenetic machinery is set up especially in the placenta, while its alterations are rather mild in other organs; (4) the genes appear deregulated in chromosome clusters; (5) the altered expression cascades varies from organ to organ, with noticeably a very significant modification of the complement and coagulation cascades in the kidney; (6) we found a significant increase in TF binding site for HNF4 proteins specifically for liver genes that are down-regulated in IUGR, suggesting that this decrease is achieved through the action of HNF transcription factors, that are themselves transcriptionnally induced in the liver by IUGR (x 1.84 fold). Altogether, our study suggests that a combination of tissue-specific mechanisms contributes to bring about tissue-driven modifications of gene cascades. The question of these cascades being activated to adapt the organ to harsh environmental condition, or as an endpoint consequence is still raised

Cockroaches Probably Cleaned Up after Dinosaurs

Dinosaurs undoubtedly produced huge quantities of excrements. But who cleaned up after them? Dung beetles and flies with rapid development were rare during most of the Mesozoic. Candidates for these duties are extinct cockroaches (Blattulidae), whose temporal range is associated with herbivorous dinosaurs. An opportunity to test this hypothesis arises from coprolites to some extent extruded from an immature cockroach preserved in the amber of Lebanon, studied using synchrotron X-ray microtomography. 1.06% of their volume is filled by particles of wood with smooth edges, in which size distribution directly supports their external pre-digestion. Because fungal pre-processing can be excluded based on the presence of large particles (combined with small total amount of wood) and absence of damages on wood, the likely source of wood are herbivore feces. Smaller particles were broken down biochemically in the cockroach hind gut, which indicates that the recent lignin-decomposing termite and cockroach endosymbionts might have been transferred to the cockroach gut upon feeding on dinosaur feces

Phylogenetic relationships in the genus Lethrus (Coleoptera: Geotrupidae) reveal contrasting evolutionary history in Europe

In this study we analysed for the first time the phylogenetic relationships among the European Lethrus species based on mitochondrial (COI, 16S) and nuclear (H3, wingless) markers. The phylogenetic inference based on these genes indicated that the European Lethrus species form a monophyletic group with two main lineages. One of them is distributed in the central part of the Balkan Peninsula (North Macedonia, northwestern Greece and southwestern Bulgaria) and includes five species (L. perun, L. raymondi, L. strymonensis, L. halkidikiensis and L. elephas). Three species of the other clade (L. schaumii, L. ares and L. schneideri) occur in the eastern part of the Balkan Peninsula (southeastern Bulgaria and northeastern Greece) while its fourth member, L. apterus, could colonize much larger areas in central and eastern Europe. Despite its large geographic distribution, L. apterus proved to be a single species. By contrast, we found strong intraspecific differentiation in both L. schaumii and L. halkidikiensis in spite of their restricted distribution. Surprisingly, two highly divergent mitogroups were also detected within a single L. schneideri population. As the microsatellite markers did not show any differentiation between them, this finding is likely to be accounted for by a unidirectional hybridization event. These findings highlight that phylogenetic studies or species descriptions should not be based on mitochondrial markers alone. Our study clearly demonstrates that allopatric speciation is the most important speciation mechanism in the European species of the genus Lethrus, although we also hypothesize that other well‐known factors, such as hybridization or the glacial‐interglacial dynamics, could significantly affect the speciation patterns of certain lineages