Facet-dependent haloperoxidase-like activities of CeO2 nanoparticles contribute to their excellent biofilm formation suppression abilities.

Biofilms adhering to different surfaces have significant negative impacts in various fields. Cerium oxide nanoparticles can serve as mimics of haloperoxidase for biological biofilm inhibition applications. The regulation of the exposed facet of CeO2 nanoparticles influences their efficiency in various catalytic processes. However, there is still a lack of systematic studies on the facet-dependent haloperoxidase-like activity of CeO2. In the present study, the facet-dependent haloperoxidase activities and antibiofilm performance of CeO2 nanoparticles were elucidated through experiment analysis and density function theory calculation. The as-prepared CeO2 nanoparticles inhibited bacterial survival and catalyzed the oxidative bromination of quorum sensing signaling molecules, achieving biofilm inhibition performance. The antibacterial and biofilm formation suppression abilities were consistent with their haloperoxidase activities. The {111}- and {110}-facet CeO2 nanopolyhedra, as well as the {110}- and {100}-facet CeO2 nanorods, which had higher haloperoxidase activity showed better antibiofilm performance than the {100}-facet CeO2 cubes. The present findings provide a comprehensive understanding of the facet-dependent haloperoxidase-like activity of CeO2. Furthermore, engineering CeO2 morphologies with different crystal facets may represent a novel method for significantly adjusting their haloperoxidase-like activity.

Molecular characterization and expression analysis of nine toll like receptor (TLR) genes in Scortum barcoo under Streptococcus agalactiae infection.

Toll like receptors (TLRs) are important pattern recognition receptors participating in innate immune system. Up to now, no TLR has been identified in Jade perch (Scortum barcoo). In this study, we successfully identified 9 members of TLRs from the Jade perch. Amino acid sequence alignment analysis showed that the whole sequences of these TLRs were highly conserved among different fish species, especially in LRR, TM and TIR domains. Phylogenetic analysis revealed that each SbTLR was successfully grouped into corresponding gene family of teleosts. Expression analysis showed that most SbTLRs mainly expressed in liver, spleen, muscle and skin, while expressed less in brain and stomach. After Streptococcus agalactiae infection, expression of SbTLR2, SbTLR5S and SbTLR22 were significantly upregulated, while SbTLR3, SbTLR5M, SbTLR9, SbTLR13, and SbTLR14 were significantly downregulated. In all, this research first reported molecular characterization and expression profiles of 9 TLRs in Jade perch. These data will make a contribution for better understanding the antibacterial mechanism of TLRs in teleosts.

Research Progress on New Environmentally Friendly Antifouling Coatings in Marine Settings: A Review.

Any equipment submerged in the ocean will have its surface attacked by fouling organisms, which can cause serious damage. Traditional antifouling coatings contain heavy metal ions, which also have a detrimental effect on the marine ecological environment and cannot fulfill the needs of practical applications. As the awareness of environmental protection is increasing, new environmentally friendly and broad-spectrum antifouling coatings have become the current research hotspot in the field of marine antifouling. This review briefly outlines the formation process of biofouling and the fouling mechanism. Then, it describes the research progress of new environmentally friendly antifouling coatings in recent years, including fouling release antifouling coatings, photocatalytic antifouling coatings and natural antifouling agents derived from biomimetic strategies, micro/nanostructured antifouling materials and hydrogel antifouling coatings. Highlights include the mechanism of action of antimicrobial peptides and the means of preparation of modified surfaces. This category of antifouling materials has broad-spectrum antimicrobial activity and environmental friendliness and is expected to be a new type of marine antifouling coating with desirable antifouling functions. Finally, the future research directions of antifouling coatings are prospected, which are intended to provide a reference for the development of efficient, broad-spectrum and green marine antifouling coatings.

Encapsulation of Monodisperse Microdroplets in Nanofibers through a Microfluidic-Electrospinning Hybrid Method.

Fibers with droplets encapsulated in them could build bridges between a 0D dispersed structure and a 1D continuous wire and thus provide optimal solutions requiring high surface-to-volume ratio and strong mechanical properties. However, current methods are mostly focusing on the architectures with the size of droplets smaller than that of fibers; the relatively thick barrier of fibers usually limits the rate of diffusion from inner droplets to the outer environment. Here, we report a hybrid method combining microfluidics and electrospinning to fabricate nanofibers with microdroplets encapsulated in them. Monodisperse microdroplets with controllable sizes from 36 to 95 µm are generated through microfluidic flow-focusing and split into a string of smaller droplets from 1 to 3 µm, respectively, during the electrospinning stretching. The size of encapsulated droplets could be tuned by controlling the flow rate ratio during the microfluidic process, and the shape of that could be varied by changing the viscosity of encapsulated solution. This marriage of microfluidics and electrospinning could be applied to produce a nanofiber-based moisture barrier and drug carrier, also providing efficient tools to study the under-electric-field stretching and splitting of droplets trapped in the polymer network.

Characterization and expression analysis of the interferon regulatory factor (IRF) gene family in zig-zag eel (Mastacembelus armatus) against Aeromonas veronii infection.

Interferon regulatory factors (IRFs) play an important role in innate and adaptive immune system. However, in teleosts, the data on IRFs is still scarce. Here, for the first time, we identified 11 members of IRFs from the zig-zag eel Mastacembelus armatus (MarIRF1-10). The deduced protein sequences are highly conserved among different fish species especially in DBD and IAD domain. Phylogenetic analysis indicated that MarIRFs preferentially grouped with fish species in Synbranchiformes or Perciformes. Expression analysis showed that MarIRFs were expressed in all nine tissues including spleen, gill, muscle and intestine. After infected by Aeromonas veronii, expression of MarIRF2, MaIRF4b and MaIRF5 were significantly upregulated in spleen, MarIRF1, MarIRF2 were significantly upregulated in kidney, but in liver, nearly all MarIRFs were downregulated. Taken together, this study first reported molecular characterization and expression patterns of 11 IRFs in the zig-zag eel. All these results will contribute a lot to better understanding the antibacterial mechanism of IRFs in teleosts.

De Novo Assembly, Characterization and Comparative Transcriptome Analysis of the Mature Gonads in Spinibarbus hollandi.

Spinibarbus hollandi is an important commercial aquaculture species in southeastern China, but with long maturity period and low egg laying amount. However, there has been little study of its gonad development and reproductive regulation, which limits aquaculture production. Here, for the first time, gonadal transcriptomes of male and female S. hollandi were analyzed. A total of 167,152 unigenes were assembled, with only 48,275 annotated successfully. After comparison, a total of 21,903 differentially expressed genes were identified between male and female gonads, of which 16,395 were upregulated and 5508 were downregulated in the testis. In addition, a large number of differentially expressed genes participating in reproduction, gonad formation and differentiation, and gametogenesis were screened out and the differential expression profiles of partial genes were further validated using quantitative real-time PCR. These results will provide basic information for further research on gonad differentiation and development in S. hollandi.