Investigations of gut microbial diversity among fish to provide baseline data for wild marine fish, especially the carnivorous coral reef fishes of the South China Sea, are lacking. The present study investigated the gut microbiota of four carnivorous coral reef fishes, including Oxycheilinus unifasciatus, Cephalopholis urodeta, Lutjanus kasmira, and Gnathodentex aurolineatus, from the South China Sea for the first time using high-throughput Illumina sequencing. Proteobacteria, Firmicutes, and Bacteroidetes constituted 98% of the gut microbiota of the four fishes, and 20 of the gut microbial genera recovered in this study represent new reports from marine fishes. Comparative analysis indicated that the four fishes shared a similar microbial community, suggesting that diet type (carnivorous) might play a more important role in shaping the gut microbiota of coral reef fishes than the species of fish. Furthermore, the genera Psychrobacter, Escherichia-Shigella, and Vibrio constituted the core microbial community of the four fishes, accounting for 61-91% of the total sequences in each fish. The lack of the genus Epulopiscium in the four fishes was in sharp contrast to what has been found in coral reef fishes from the Red Sea, in which Epulopiscium was shown to be the most dominant gut microbial genus in seven herbivorous coral reef fishes. In addition, while unique gut microbial genera accounted for a small proportion (8-13%) of the total sequences, many such genera were distributed in each coral reef fish species, including several genera (Endozoicomonas, Clostridium, and Staphylococcus) that are frequently found in marine fishes and 11 new reports of gut microbes in marine fishes. The present study expands our knowledge of the diversity and specificity of gut microbes associated with coral reef fishes.
Ammonium hexachlororuthenate ((NH 4 ) 2 RuCl 6 ) complex was used as a catalyst precursor and coconut activated carbon (AC) was used as the support in the preparation process of the Ru-based catalyst. (NH 4 ) 2 RuCl 6 /AC catalyst was prepared via an incipient wetness impregnation method and assessed in an acetylene hydrochlorination reaction. Meanwhile, the (NH 4 ) 2 RuCl 6 /AC catalyst was analyzed with low-temperature N 2 adsorption/desorption, thermogravimetry (TG), transmission electron microscopy (TEM), temperature programmed reduction (TPR), X-ray photoelectron spectra (XPS), and temperature programmed desorption (TPD) techniques. Catalytic performance test results show that the (NH 4 ) 2 RuCl 6 /AC catalyst exhibits a superior catalytic activity with the highest acetylene conversion of 90.5% under the conditions of 170 • C and an acetylene gas hourly space velocity of 180 h −1 . The characterization results illustrate that the presence of the NH 4 + cation can inhibit coke deposition as well as the agglomeration of ruthenium particles, and it can also enhance the adsorption ability for reactant HCl, hence improving the catalytic activity and stability.
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