Nautilus is the sole surviving externally shelled cephalopod from the Palaeozoic. It is unique within cephalopod genealogy and critical to understanding the evolutionary novelties of cephalopods. Here, we present a complete Nautilus pompilius genome as a fundamental genomic reference on cephalopod innovations, such as the pinhole eye and biomineralization. Nautilus shows a compact, minimalist genome with few encoding genes and slow evolutionary rates in both non-coding and coding regions among known cephalopods. Importantly, multiple genomic innovations including gene losses, independent contraction and expansion of specific gene families and their associated regulatory networks likely moulded the evolution of the nautilus pinhole eye. The conserved molluscan biomineralization toolkit and lineage-specific repetitive low-complexity domains are essential to the construction of the nautilus shell. The nautilus genome constitutes a valuable resource for reconstructing the evolutionary scenarios and genomic innovations that shape the extant cephalopods.

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Tetracycline may have potential physiological, biochemical, and genetic toxicity to plant cells, and chromosome aberration and MDA might be sensitive bioindicators for tetracycline contamination than the other plant characteristics.

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The environmental risks and benefits associated with the introduction of CeO 2 nanoparticle (NP) in agricultural soil must be carefully assessed. The ferrous ion is rich in rhizosphere soil of rice due to the reduction states underground. The aim of this study was to investigate the effects of environmentally relevant-level CeO 2 NP (25 mg•kg −1 ) in the absence or presence of ferrous (30 mg•kg −1 ) amendment on soil bacterial communities and soil metabolomics in rice-planted soil over 150 days. Results showed that CeO 2 NP exposure changed soil bacterial community compositions and soil metabolomics, and the above changes were further shifted with the ferrous amendment. Several functionally significant bacterial phyla containing Proteobacteria and Bacteroidetes abundances, which were associated with carbon and nitrogen cycling, were promoted after CeO 2 NP exposure with ferrous amendment. However, CeO 2 NP inhibited plant-growth-promoting rhizobacteria containing genera Bacillus and Arthrobacter irrespective of the presence or absence of ferrous. Among rhizosphere soil enzyme activities, cellulose activity was the most sensitive for CeO 2 NP exposure. NP decreased Firmicutes and increased Chloroflexi, Rokubacteria, and Thaumarchaeota abundances at the phylum level, which contributed to reduce soil cellulose activity. Additionally, CeO 2 NP positively or negatively affected soil pH, Ce accumulation in root, and rice physiological properties (root-POD, stem-POD). As a result, the above factors were related to the changes of Chloroflexi, Gemmatimonadetes, Rokubacteria, Thaumarchaeota, and Nitrospirae at the phylum level. After adding CeO 2 NP with ferrous or not, the main metabolic changes were concentrated on fluctuations in starch and sucrose metabolism, nitrogen metabolism, sulfur metabolism, propanoate metabolism, fatty acid metabolism, and urea cycle. The eight changed metabolites containing glycerol monstearate, boric acid, monopalmitin, palmitic acid, alkane, ethanol, dicarboximide, and stearic acid accounted for the separation of different treatments with CeO 2 NP exposure. Activities of soil enzymes (urease, invertase, and cellulose), pH, and soil organic matter affected dominant metabolites containing fatty acids, inorganic acid, and sugar. Network analysis showed that the influence of soil bacterial community on metabolites varied with metabolites and bacteria species. The presence of CeO 2 NP mainly promoted fatty acids (hexanoic acid, nonanoic acid) and amino acid (oxoproline) and amine (diethanolamine) concentrations, which could be from the increased Proteobacteria abundance after CeO 2 NP exposure. Phylum Proteobacteria had the most genus species containing 13 genera affecting soil metabolite profiles. These results provide valuable information for understanding the impact of environmentally relevant-level CeO 2 NP exposure on soil microbial communities and metabolites with or without ferrous, which is needed to understand the ecological risk posed by long-term CeO 2 NP exposure in rice-planted soil ...