The genus Acropora comprises the most diverse and abundant scleractinian corals (Anthozoa, Cnidaria) in coral reefs, the most diverse marine ecosystems on Earth. However, the genetic basis for the success and wide distribution of Acropora are unknown. Here we sequenced complete genomes of fifteen Acropora species and three other acroporid taxa belonging to the genera Montipora and Astreopora, to examine genomic novelties that explain their evolutionary success. We successfully obtained reasonable draft genomes of all eighteen species. Molecular dating indicates that the Acropora ancestor survived warm periods without sea ice from the mid or late Cretaceous to the Early Eocene, and that diversification of Acropora may have been enhanced by subsequent cooling periods. In general, the scleractinian gene repertoire is highly conserved; however, coral- or cnidarian-specific possible stress response genes are tandemly duplicated in Acropora. Enzymes that cleave dimethlysulfonioproprionate into dimethyl sulfide, which promotes cloud formation and combats greenhouse gasses, are the most duplicated genes in the Acropora ancestor. These may have been acquired by horizontal gene transfer from algal symbionts belonging to the family Symbiodiniaceae, or from coccolithophores, suggesting that although functions of this enzyme in Acropora are unclear, Acropora may have survived warmer marine environments in the past by enhancing cloud formation. In addition, possible anti-microbial peptides and symbiosis-related genes are under positive selection in Acropora, perhaps enabling adaptation to diverse environments. Our results suggest unique Acropora adaptations to ancient, warm marine environments, and provide insights into its capacity to adjust to rising seawater temperatures.

Brain inflammation generally accompanies and accelerates neurodegeneration. Here we report a microglial mechanism in which polyglutamine binding protein 1 (PQBP1) senses extrinsic tau 3R/4R proteins by direct interaction and triggers an innate immune response by activating a cyclic GMP-AMP synthase (cGAS)-Stimulator of interferon genes (STING) pathway. Tamoxifen-inducible and microglia-specific depletion of PQBP1 in primary culture in vitro and mouse brain in vivo shows that PQBP1 is essential for sensing-tau to induce nuclear translocation of nuclear factor κB (NFκB), NFκB-dependent transcription of inflammation genes, brain inflammation in vivo, and eventually mouse cognitive impairment. Collectively, PQBP1 is an intracellular receptor in the cGAS-STING pathway not only for cDNA of human immunodeficiency virus (HIV) but also for the transmissible neurodegenerative disease protein tau. This study characterises a mechanism of brain inflammation that is common to virus infection and neurodegenerative disorders.

These results indicate that the PI3K/Akt signaling pathway is activated intrinsically and has a neuroprotective effect on injured RGCs.

Reef-building corals and photosynthetic, endosymbiotic algae of the family Symbiodiniaceae establish mutualistic relationships that are fundamental to coral biology, enabling coral reefs to support a vast diversity of marine species. Although numerous types of Symbiodiniaceae occur in coral reef environments, Acropora corals select specific types in early life stages. In order to study molecular mechanisms of coral-algal symbioses occurring in nature, we performed whole-genome transcriptomic analyses of Acropora tenuis larvae inoculated with Symbiodinium microadriaticum strains isolated from Acropora. In order to identify genes specifically involved in symbioses with native symbionts in early life stages, we also investigated transcriptomic responses of Acropora larvae exposed to closely related, non-symbiotic, and occasionally symbiotic Symbiodinium strains. We found that the number of differentially expressed genes was largest when larvae acquired native symbionts. Repertoires of differentially expressed genes indicated that corals reduced amino acid, sugar, and lipid metabolism, such that metabolic enzymes performing these functions were derived primarily from S. microadriaticum rather than from A. tenuis. Up-regulated gene expression of transporters for those metabolites occurred only when coral larvae acquired their natural symbionts, suggesting active utilization of native symbionts by host corals. We also discovered that in Acropora, genes for sugar and amino acid transporters, prosaposin-like, and Notch ligand-like, were up-regulated only in response to native symbionts, and included tandemly duplicated genes. Gene duplications in coral genomes may have been essential to establish genomic novelties for coral-algae symbiosis.

Intra- and interspecific variation in the early internal shell features of ammonoids has been examined in 14 Late Cretaceous species representing four suborders on the basis of large samples from Hokkaido (Japan) and the U.S. Western Interior Province. Our observations indicate that quantitative characters such as the size of the initial chamber and ammonitella, the length of the prosiphon, and the ammonitella angle exhibit moderate variation within species. The ranges of variation partly overlap among species, indicating that these characters are not suitable for studies of the higher-level systematics of ammonoids, but may sometimes help diagnose species. In contrast, there is much less variation within species with respect to qualitative characters such as the shape of the prosiphon, the presence or absence of accessory threads of the prosiphon, the shape of the caecum, and the initial position of the siphuncle. Examination of these characters shows that they appear to be stable at the superfamily level for the Ammonitina, but variable among species in the Lytoceratina. Thus, these characters are potentially more useful for higher-level phylogenetic analysis.