DNA‐binding protein A (dbpA) is reported to be upregulated in many cancers and associated with tumor progress. The present study aimed to investigate the role of dbpA in 5‐fluorouracil (5‐FU)‐resistant and oxaliplatin (L‐OHP)‐resistant colorectal cancer (CRC) cells. We found that 5‐FU and L‐OPH treatment promoted the expression of dbpA. Enhanced dbpA promoted the drug resistance of SW620 cells to 5‐FU and L‐OHP. DbpA knockdown inhibited cell proliferation, induced cell apoptosis, and cell cycle arrested in SW620/5‐FU and SW620/L‐OHP cells. Besides, dbpA short hairpin RNA (shRNA) enhanced the cytotoxicity of 5‐FU and L‐OHP to SW620/5‐FU and SW620/L‐OHP cells. Meanwhile, dbpA shRNA inhibited the activation of the Wnt/β‐catenin pathway that induced by 5‐FU stimulation in SW620/5‐FU cells. Activation of the Wnt/β‐catenin pathway or overexpression of checkpoint kinase 1 (Chk1) abrogated the promoting effect of dbpA downregulation on 5‐FU sensitivity of CRC cells. Importantly, downregulation of dbpA suppressed tumor growth and promoted CRC cells sensitivity to 5‐FU in vivo. Our study indicated that the knockdown of dbpA enhanced the sensitivity of CRC cells to 5‐FU via Wnt/β‐catenin/Chk1 pathway, and DbpA may be a potential therapeutic target to sensitize drug resistance CRC to 5‐FU and L‐OHP. 相似文献
Atg3‐catalyzed transferring of Atg8 to phosphatidylethanolamine (PE) in the phagophore membrane is essential for autophagy. Previous studies have demonstrated that this process requires Atg3 to interact with the phagophore membrane via its N‐terminal amphipathic helix. In this study, by using combined biochemical and biophysical approaches, our data showed that in addition to binding to the membranes, Atg3 attenuates lipid diffusion and enriches lipid molecules with smaller headgroup. Our data suggest that Atg3 promotes Atg8 lipidation via altering lipid diffusion and rearrangement. 相似文献
Functional divergence after gene duplication plays a central role in plant evolution. Among cereals, only Hordeum vulgare (barley), Triticum aestivum (wheat) and Secale cereale (rye) accumulate delphinidin‐derived (blue) anthocyanins in the aleurone layer of grains, whereas Oryza sativa (rice), Zea mays (maize) and Sorghum bicolor (sorghum) do not. The underlying genetic basis for this natural occurrence remains elusive. Here, we mapped the barley Blx1 locus involved in blue aleurone to an approximately 1.13 Mb genetic interval on chromosome 4HL, thus identifying a trigenic cluster named MbHF35 (containing HvMYB4H, HvMYC4H and HvF35H). Sequence and expression data supported the role of these genes in conferring blue‐coloured (blue aleurone) grains. Synteny analyses across monocot species showed that MbHF35 has only evolved within distinct Triticeae lineages, as a result of dispersed gene duplication. Phylogeny analyses revealed a shared evolution pattern for MbHF35 in Triticeae, suggesting that these genes have co‐evolved together. We also identified a Pooideae‐specific flavonoid 3′,5′‐hydroxylase (F3′5′H) lineage, termed here Mo_F35H2, which has a higher amino acid similarity with eudicot F3′5′Hs, demonstrating a scenario of convergent evolution. Indeed, selection tests identified 13 amino acid residues in Mo_F35H2 that underwent positive selection, possibly driven by protein thermostablility selection. Furthermore, through the interrogation of barley germplasm there is evidence that HvMYB4H and HvMYC4H have undergone human selection. Collectively, our study favours blue aleurone as a recently evolved trait resulting from environmental adaptation. Our findings provide an evolutionary explanation for the absence of blue anthocyanins in other cereals and highlight the importance of gene functional divergence for plant diversity and environmental adaptation. 相似文献
Island biodiversity has long fascinated biologists as it typically presents tractable systems for unpicking the eco‐evolutionary processes driving community assembly. In general, two recurring themes are of central theoretical interest. First, immigration, diversification, and extinction typically depend on island geographical properties (e.g., area, isolation, and age). Second, predictable ecological and evolutionary trajectories readily occur after colonization, such as the evolution of adaptive trait syndromes, trends toward specialization, adaptive radiation, and eventual ecological decline. Hypotheses such as the taxon cycle draw on several of these themes to posit particular constraints on colonization and subsequent eco‐evolutionary dynamics. However, it has been challenging to examine these integrated dynamics with traditional methods. Here, we combine phylogenomics, population genomics and phenomics, to unravel community assembly dynamics among Pheidole (Hymenoptera, Formicidae) ants in the isolated Fijian archipelago. We uphold basic island biogeographic predictions that isolated islands accumulate diversity primarily through in situ evolution rather than dispersal, and population genomic support for taxon cycle predictions that endemic species have decreased dispersal ability and demography relative to regionally widespread taxa. However, rather than trending toward island syndromes, ecomorphological diversification in Fiji was intense, filling much of the genus‐level global morphospace. Furthermore, while most endemic species exhibit demographic decline and reduced dispersal, we show that the archipelago is not an evolutionary dead‐end. Rather, several endemic species show signatures of population and range expansion, including a successful colonization to the Cook islands. These results shed light on the processes shaping island biotas and refine our understanding of island biogeographic theory. 相似文献
This study investigated the biomass production process from the laboratory to the pilot scale in order to use the nutrient-rich biomass of the diatom Thalassiosira weissflogii as live feed for white-leg shrimp (Litopenaeus vannamei) at larval stages (zoeal, mysis, and postlarval) and in commercial production in hatcheries in Vietnam. Our results showed that T. weissflogii was successfully cultured in 1–2 L Erlenmeyer flasks, 0.2–3.5 m3 composite tanks, and 6.5 m3 tubular photobioreactors, with the highest cell density of 1.6 × 106 cells mL?1 reached after 6 days of culture. Under optimal culture conditions, the protein, lipid, and carbohydrate contents in this algal biomass were 13.2%, 20.0%, and 10.0% of dry cell weight, respectively. The fatty acid composition contains high amount of palmitic acid (C16:0, 43.11% of total fatty acid), and polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA, C20:5ω-3), approximated 16.5% of total fatty acid. In a 50 L larval rearing tank, at the optimal stocking density of 125 nauplii L?1, the survival percentage (75.55%), the total body length (from 5.376 ± 0.007 to 10.860 ± 0.030 mm), and weight (at from PL1 to PL12 stages) (from 0.145 ± 0.002 to 1.158 ± 0.005 g) of the white-leg shrimp larvae reached the highest values but the metamorphosis time (234 h) was shortest compared with the other stocking densities. Further, adding living T. weissflogii biomass to the diet of white-leg shrimp larvae at the nauplii 6 stage led to an increase in the body length, weight, and survival percentage of white-leg shrimp larvae of 21.17%, 35.7%, and 33% higher compared with those of larvae fed the control diet (without the addition of T. weissflogii), respectively. At the same time, the metamorphosis time of larvae (from Z1 to PL1) decreased by 4 h compared to the control group. In intensive ponds (area of 6400 m2 pond?1), using seed stocks at the postlarvae 12 stage that had been fed T. weissflogii, the final weight, yield, and survival percentage of the shrimp were increased by 7.3%, 14.2%, and 16.3%, respectively, compared with those of the control group. There were no statistically significant differences in the protein and carbohydrate contents in the shrimp flesh among the experimental and control group (p > 0.05). The lipid, omega-3, omega-6, and omega-9 fatty acid contents of shrimp flesh in experiment formula (per 100 g shrimp) were 1.21 g, 72.9 mg, 114 mg, and 86.1 mg, 11%, 29%, 21.6%, and 17.7% higher than that those in control, respectively. The obtained results show the great potential of using T. weissflogii as live feed on white-leg shrimp farms in Vietnam.
The weevil Pagiophloeus tsushimanus Morimoto (Coleoptera: Curculionidae), native to Eastern Asia, is a wood-boring pest that causes severe damage to camphor trees (Cinnamomum sp.) in Shanghai, China. Other Lauraceae tree species that grew sympatrically with this pest in close proximity could face a potential threat. To assess the potential risks of host shift, we explored the phenotypic associations between preference and performance in P. tsushimanus reared on three Lauraceae tree species. In a no-choice experiment offering branches of each plant as diet material and oviposition sites, we found that individuals reared on Cinnamomum camphora (L.) Presl (Laurales: Lauraceae) exhibited the strongest performance with shorter development time, higher survival and growth rate in the immature stage, longer longevity and greater fecundity in adults. In contrast, those on novel Lauraceae tree species (Cinnamomum chekiangensis Nakai and Phoebe chekiangensis Shang) had difficulty completing their whole life cycle due to significantly lower survival and reproduction. In a multiple-choice experiment, C. camphora was established as the preferred host. However, we found that the larval experiences on the non-preferred host plants contributed to an increased preference for that plant species. These results indicated that both the preference-performance hypothesis and the Hopkins’ host selection principle are applicable in this weevil under experimental conditions. It is possible that although the weevil performed poorly on two novel Lauraceae tree species, under favourable conditions their surviving offspring could evolve into a new host-specific population. Consequently, this weevil pest needs to be monitored on these novel Lauraceae tree species. 相似文献