Marine Life Science & Technology最新文献

During a study on the diversity of ciliated protists in Lake Weishan Wetland, the largest wetland in northern China, four epibiotic sessilid peritrichs were isolated from aquatic host animals. Two of them, i.e., Epistylis cambari Kellicott, 1885 and Epistylis lwoffi Fauré-Fremiet, 1943, were known species whereas the other two, i.e., Parapiosoma typicum gen. nov., sp. nov. and Orborhabdostyla gracilis sp. nov., are new to science. The new genus Parapiosoma gen. nov. is characterized by its branched non-contractile stalk, everted peristomial lip, obconical macronucleus and transverse silverlines. Two species are assigned to the new genus, namely Parapiosoma typicum sp. nov. and Parapiosoma gasterostei (Fauré-Fremiet, 1905) comb. nov. Morphologically, P. typicum sp. nov. is recognized by its goblet-shaped zooids, single-layered peristomial lip, dichotomously branched stalk, and infundibular polykinety 3 (P3) containing three equal-length rows. Orborhabdostyla gracilis sp. nov. is characterized by its slender zooid, curved macronucleus, and three equal-length rows in infundibular P3. Improved diagnoses and redescriptions of E. cambari and E. lwoffi are provided including, for the first time, data on the ciliature of E. cambari. Phylogenetic analyses based on SSU rDNA, ITS1-5.8S rDNA -ITS2, and LSU rDNA sequence data strongly support the assertion that the family Epistylididae comprises morphospecies with different evolutionary lineages and indicate that Parapiosoma gen. nov. may represent a new taxon at family level.

In mammals, mitofusin 2 (MFN2) is involved in mitochondrial fusion, and suppresses the virus-induced RIG-I-like receptor (RLR) signaling pathway. However, little is known about the function of MFN2 in non-mammalian species. In the present study, we cloned an MFN2 ortholog (LcMFN2) in large yellow croaker (Larimichthys crocea). Phylogenetic analysis showed that MFN2 emerged after the divergence of amphioxus and vertebrates. The protein sequences of MFN2 were well conserved from fish to mammals. LcMFN2 was expressed in all the tissues/organs examined at different levels, and its expression was upregulated in response to poly(I:C) stimulation. Overexpression of LcMFN2 inhibited MAVS-induced type I interferon (IFN) promoter activation and antiviral gene expression. In contrast, knockdown of endogenous LcMFN2 enhanced poly(I:C) induced production of type I IFNs. Additionally, LcMFN2 enhanced K48-linked polyubiquitination of MAVS, promoting its degradation. Also, overexpression of LcMFN2 impaired the cellular antiviral response, as evidenced by the increased expression of viral genes and more severe cytopathic effects (CPE) in cells infected with spring viremia of carp virus (SVCV). These results indicated that LcMFN2 inhibited type I IFN response by degrading MAVS, suggesting its negative regulatory role in cellular antiviral response. Therefore, our study sheds a new light on the regulatory mechanisms of the cellular antiviral response in teleosts.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-023-00189-8.

Hemorrhage control requires hemostatic materials that are both effective and biocompatible. Among these, diatom biosilica (DBs) could significantly improve hemorrhage control, but it induces hemolysis (the hemolysis rate > 5%). Thus, the purpose of this study was to explore the influence of Ca²⁺ biomineralization on DBs for developing fast hemostatic materials with a low hemolysis rate. Here, CaCl₂ was added to the diatom medium under high light (cool white, fluorescent lamps, 67.5 µmol m^-2 s^-1), producing Ca-DBs-3 with a particle size of 40-50 μm and a Ca²⁺ content of Ca-DBs-3 obtained from the higher concentration CaCl₂ group (6.7 mmol L^-1) of 0.16%. The liquid absorption capacity of Ca-DBs-3 was 30.43 ± 0.57 times its dry weight; the in vitro clotting time was comparable to QuikClot^® zeolite; the hemostatic time and blood loss using the rat tail amputation model were 36.40 ± 2.52 s and 0.39 ± 0.12 g, which were 40.72% and 19.50% of QuikClot^® zeolite, respectively. Ca-DBs-3 showed no apparent toxicity to L929 cells (cell viability > 80%) and was non-hemolysis (the hemolysis rate < 2%). This study prepared Ca-DBs-3 with a rapid hemostatic effect and good biocompatibility, providing a path to develop diatom biosilica hemostatic materials.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-023-00180-3.

Diuron is one of the most frequently applied herbicides in sugarcane farming in southern Japan, and Australia. In addition, it is used as a booster substance in copper-based antifouling paints. Due to these various uses, Diuron is released into the marine environment; however, little information is available on gene expression in corals and their symbiotic algae exposed to Diuron. We investigated the effects of Diuron on stress-responsive gene expression in the hermatypic coral Acropora tenuis and its symbiotic dinoflagellates. After seven days of exposure to 1 µg/L and 10 µg/L Diuron, no significant changes in the body colour of corals were observed. However, quantitative reverse transcription-polymerase chain reaction analyses revealed that the expression levels of stress-responsive genes, such as heat shock protein 90 (HSP90), HSP70, and calreticulin (CALR), were significantly downregulated in corals exposed to 10 µg/L of Diuron for seven days. Moreover, aquaglyceroporin was significantly downregulated in corals exposed to environmentally relevant concentrations of 1 µg/L Diuron. In contrast, no such effects were observed on the expression levels of other stress-responsive genes, such as oxidative stress-responsive proteins, methionine adenosyltransferase, and green/red fluorescent proteins. Diuron exposure had no significant effect on the expression levels of HSP90, HSP70, or HSP40 in the symbiotic dinoflagellates. These results suggest that stress-responsive genes, such as HSPs, respond differently to Diuron in corals and their symbiotic dinoflagellates and that A. tenuis HSPs and CALRs may be useful molecular biomarkers for predicting stress responses induced by the herbicide Diuron.

Supplementary information: The online version contains supplementary material available at 10.1007/s42995-023-00183-0.