Pangolins are unique placental mammals with eight species existing in the world, which have adapted to a highly specialized diet of ants and termites, and are of significance in the control of forest termite disaster. Besides their ecological value, pangolins are extremely important economic animals with the value as medicine and food. At present, illegal hunting and habitat destruction have drastically decreased the wild population of pangolins, pushing them to the edge of extinction. Captive breeding is an important way to protect these species, but because of pangolin’s specialized behaviors and high dependence on natural ecosystem, there still exist many technical barriers to successful captive breeding programs. In this paper, based on the literatures and our practical experience, we reviewed the status and existing problems in captive breeding of pangolins, including four aspects, the naturalistic habitat, dietary husbandry, reproduction and disease control. Some recommendations are presented for effective captive breeding and protection of pangolins.

Oxaliplatin, as a first-line drug, frequently causes chemoresistance in colorectal cancer (CRC). The role of N6-methyladenosine (m6A) modification in multiple biological functions has been well studied. However, the molecular mechanisms underlying m6A methylation in modulating anti-cancer drug resistance in CRC remain obscure. In the present study, we found that YTH m6A RNA-binding protein 3 (YTHDF3) was highly expressed in oxaliplatin-resistant (OXAR) CRC tissues and cells. Moreover, we observed that YTHDF3 could recognize the 5′ untranslated region of significantly m6A-methylated RNAs, which were associated with tumor resistance and recruit eukaryotic translation initiation factor 3 subunit A (eIF3A) to facilitate the translation of these target genes. Furthermore, we determined that eukaryotic translation initiation factor 2 alpha kinase 2 (eIF2AK2) bridged YTHDF3 and eIF3A, enhancing the stability of the YTHDF3/eIF3A complex in OXAR CRC cells. Taken together, our data identified YTHDF3 as a novel hallmark and revealed the molecular mechanism of YTHDF3 on gene translation via coordination with eIF2AK2 in OXAR CRC cells.

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Copper chaperone for superoxide dismutase-1 (CCS-1), facilitating copper insertion into superoxide dismutase 1 (SOD-1), is present in the nucleus. However, it is unknown how CCS-1 is translocated to the nucleus. The present study was undertaken to determine the effect of copper on nuclear translocation of CCS-1. Human umbilical vein endothelial cells (HUVECs) were subjected to hypoxia, causing an increase in both copper and CCS-1 in the nucleus. Treatment with tetraethylenepentamine (TEPA) not only decreased the total cellular concentration and the nuclear translocation of copper, but also completely suppressed the entry of CCS-1 to the nucleus. On the other hand, siRNA targeting CCS-1 neither inhibited the increase in total concentrations nor blocked the nuclear translocation of copper. This study thus demonstrates that under hypoxia condition, both copper and CCS-1 are transported to the nucleus. The nuclear translocation of CCS-1 is copper dependent, but the nuclear translocation of copper could take place alternatively in a CCS-1-independent pathway.

BACKGROUND: Phenylalanine dehydrogenase (PheDH; L-phenylalanine: NAD + oxidoreductase, deaminating (EC 1.4.1.20)) is widely used in the pharmaceutical industry. It is the main biocatalyst in the enantioselective synthesis of L-phenylalanine, related L-amino acids as well as some non-natural amino acids which are important pharmaceutical intermediates. However, growing demands for PheDH and its limited production result in the shortage of the enzyme's supply so that it is necessary to explore and establish an industrial production process for PheDH. RESULTS: In this study, the high-cell-density fermentation of recombinant Escherichia coli for expression of an engineered mutant R272M/E331Q/E196N of PheDH was investigated, which is a key catalyst with improved catalytic capability during the important intermediate production of saxagliptin. Cultivation media and induction conditions of recombinant E. coli were tested in shake flask experiments. A fed-batch fermentation strategy using MR2 as cultivation medium and lactose as inducer was developed in a 30 L fermenter. After 24 h of cultivation, the dry cell weight reached 52.32 g L-1 (based on OD 600), and the specific activity of crude extracts was 0.49 U mg-1. By applying the aqueous two-phase system strategy, a purified PheDH productivity of 191.96 mg•L −1 •h −1 was obtained. The specific activity, recovery, yield and purification fold of PheDH were 3.21 U mg-1 , 104.19%, 84.53% and 6.55, respectively. CONCLUSIONS: This study shows that the application of high-cell-density fermentation in conjunction with aqueous two-phase system strategy provides vital support for large-scale production of recombinant PheDH.