Marine Biotechnology最新文献

The marine environment is a rich and diverse habitat, home to numerous organisms that serve as valuable sources of biological and pharmacological compounds. The skeletal structures of many marine invertebrates represent precursors for calcium phosphate (CaP) bioceramics. This study demonstrates hydroxyapatite (HA) synthesis from sea urchin (Echinometra mathaei) shell and spine, a sustainable CaCO₃ source. FTIR and XRD analysis revealed the presence of characteristic peaks associated with hydroxyapatite. SEM-EDS observations indicated that synthesis parameters determined the calcium to phosphorus ratio (Ca/P) and morphology of the derived calcium phosphate bioceramic. HA-based hydrogels play an important role in bone tissue engineering due to their high biocompatibility. The hydrogels were formulated as follows: a control group of oxidized carboxymethyl chitosan/cellulose (O-CMC/CEL), a composite group with commercial hydroxyapatite (O-CMC/CEL/HA), and two experimental composite groups containing HA synthesized from sea urchin spine (O-CMC/CEL/HA (spine-derived)) and shell (O-CMC/CEL/HA (shell-derived)). Four groups of hydrogels melded on 3D print frames to evaluate the osteogenic differentiation of human adipose-derived mesenchymal stem cells (ADSCs). SEM, FTIR, water contact angle, swelling rate, and live/dead assay results indicated that the porous composite hydrogels possessed a suitable microarchitecture, featuring appropriate pore size and interconnectivity, which promotes nutrient permeability, cell attachment, cell survival, and proliferation. Furthermore, real-time PCR analysis indicated an upregulation of key osteogenic markers in ADSCs cultured on these composites, suggesting their potential to support osteogenic differentiation. The collective in vitro evidence indicates that the O-CMC/CEL/HA (spine-derived) composite hydrogel, with its suitable physicochemical properties and positive cellular responses, represents a promising biomaterial for future bone tissue engineering studies.

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This study explores the molecular responses underlying the FOXO/MAPK signaling pathway’s regulation under cold stress in Epinephelus akaara. Using transcriptome sequencing and RT-qPCR analysis, this study elucidates how E. akaara maintains energy balance, immune function, and cellular repair through the regulation of FOXO and MAPK signaling pathways under cold stress. The results demonstrate that several genes involved in energy metabolism and cellular homeostasis regulation, including FOXO1, SGK2, and G6PC, exhibit significant temperature-dependent changes, highlighting the crucial role of these pathways in cold adaptation. The study further reveals that under the suppression of the FOXO pathway, the MAPK pathway compensatorily activates to sustain stress sensing and repair functions, illustrating a multi-pathway signal integration response. Additionally, the expression changes of heat shock proteins further support the cellular adaptation strategies to cold stress. Overall, this study offers a novel molecular perspective on understanding the cold adaptation responses in E. akaara, provides theoretical support for cold-resistant breeding and cold stress mitigation strategies, and lays the groundwork for the sustainable development of the aquaculture industry.

Although the eyestalk-androgenic gland-testis axis (ES-AG-TS axis) has been acknowledged as the core neuro-endocrine regulatory system for sex differentiation and gonad development in decapod crustaceans, the molecular regulatory networks underlying the ES-AG-TS axis remains unclear. In this study, we performed multi-tissue comparative transcriptomic analysis at different testis developmental stages of the giant freshwater prawn Macrobrachium rosenbergii. 116,892 unigenes were obtained from 27 sequencing libraries. Differential gene expression (DEG) analysis identified 7,126 to 27,532 DEGs across the eyestalk ganglia, androgenic gland and testis tissues at different stages. Functional enrichment analysis revealed that in the eyestalk ganglia, gonad inhibitory genes such as GIH were significantly down-regulated, while glucose metabolism-related pathways were markedly activated. The androgenic gland exhibited distinct regulation characteristics, with steroid hormone biosynthesis pathways showing progressive activation at later stages. In the testis tissue, metabolic patterns shifted from predominant oxidation-reduction process to protein phosphorylation. Further inter-tissue comparisons identified 19,652 and 37,075 DEGs in the comparisons of ES-vs-AG and AG-vs-TS, respectively. Based on the results of DEG analysis and functional enrichment, we propose that the calcium signaling-WNT/β-catenin pathway regulates male differentiation through the Sox9-Dmrt-IAG cascade, while the p53-MMPs-TNFα axis mediates testis development. In summary, this study demonstrates that eyestalk ablation triggers reprogramming of glucose metabolism in the eyestalk ganglia, activates the androgenic gland steroid synthesis pathway, and facilitates the timing transition of testis metabolism. These findings enhance our understanding of the ES-AG-TS regulatory axis and provide novel potential targets for sex manipulation in crustacean aquaculture.

Inositol 1,4,5-trisphosphate kinase (IP3K) is a key regulatory enzyme within the phosphatidylinositol signaling pathway, modulating downstream signal transduction via the phosphorylation of inositol trisphosphate (IP3). Our previous comparative transcriptomic analysis of the razor clam (Sinonovacula constricta) under low salinity stress revealed significant enrichment of the phosphatidylinositol pathway. In this study, we characterized the IP3K gene and employed RNA interference (RNAi) to investigate its regulatory role by assessing downstream signaling, oxidative stress, and apoptosis under low-salinity (5 ppt) in S. constricta. The results showed that IP3K has a ubiquitous expression pattern along with significant increases in its expression in the gill under low-salinity stress. IP3K knockdown led to significant decreases in phosphatidylinositol (PI) and IP3 levels, altered Ca²⁺ level, and also triggered accumulation of reactive oxygen species (ROS). Concurrently, inhibition of IP3K significantly reduced the activities of superoxide dismutase (SOD) and catalase (CAT), while significantly increasing the content of malondialdehyde (MDA) (P < 0.01). TUNEL staining confirmed that IP3K suppression exacerbated apoptosis in gill tissues, leading to a marked decline in cell viability. Overall, these findings demonstrate that IP3K plays an essential role in regulating oxidative stress and maintaining cellular homeostasis under low salinity conditions, providing a potential target for improving salinity tolerance in shellfish.

Sea cucumber aquaculture is a cornerstone of the mariculture industry in Liaoning Province, China, contributing significantly to both economic development and​​ coastal marine ecosystems balance. Recent frequent coastal water salinity fluctuations limited the survival, growth, and yield stability of sea cucumbers, and thus posing a challenge to the sustainable development of the sea cucumber aquaculture industry. To address this issue, this study aimed to identify the key molecular regulatory mechanisms underlying sea cucumber response to low-salt environments, thereby providing theoretical support for salt-tolerant sea cucumber breeding. Based on our previous transcriptomic sequencing data of sea cucumbers under low-salt stress, we identified a potential regulatory axis consisting of miR-novel-3 (a novel microRNA), LNC_015168 (a long non-coding RNA), and slc17a9 (a transmembrane transporter gene). Time-course qPCR demonstrated that miR-novel-3 and slc17a9 exhibited inverse expression patterns under salinity stress, peaking at 24 h. The 24 h inflection point in all three molecules highlights its critical role in low-salt acclimatization. Their reciprocal regulation over-expression of miR-novel-3 suppressed slc17a9, whereas LNC_015168 acted as a ​competitive endogenous RNA​​ (ceRNA) to sequester miR-novel-3, thereby enhancing slc17a9 expression. Bioinformatics analysis identified slc17a9 as a hydrophilic transmembrane protein with 76 phosphorylation sites, suggesting its role in ion transport. These findings highlight a ceRNA network as a pivotal mechanism for osmoregulatory plasticity in echinoderms, offering potential targets for breeding salt-tolerant sea cucumbers.

Vitamin C (VC) is an essential micronutrient known to significantly promote growth and enhance immunity in aquatic organisms. For crustaceans, dietary VC is a critical requirement for proper development. To assess the effects of VC supplementation on juvenile Chinese horseshoe crabs (Tachypleus tridentatus), first instar juveniles were subjected to various concentrations of VC in the aquatic environment. The objectives of this study were to determine the optimal VC concentration for the growth and survival of juvenile horseshoe crabs based on experimental records; to investigate the effects of VC on their gene expression through transcriptomic analysis; and to examine the impacts of various VC concentrations by measuring enzyme activities. The experimental results showed that the optimal VC concentration for molting was 30 mg/L (medium concentration), while 90 mg/L (high concentration) was optimal for survival. The effects of VC were specifically manifested by up-regulation of cytochrome c-like and down-regulation of ATP synthase F0 subunit 6 and increased alkaline phosphatase levels, which accelerated energy absorption and promoted rational energy allocation. At moderate-to-high concentrations, VC up-regulated the expression of papain family cysteine protease and partially up-regulated β-actin, while down-regulating ribosomal protein L29 (RPL29) and rho-related proteins. This expression profile ensured the precise execution of apoptosis and cell division/differentiation. Additionally, downregulation of RPL39 by VC enhanced translation efficiency. Concurrently, up-regulation of RPLP2, protein component of the small (40 S) ribosomal subunit, and RPL35, along with elevated alkaline phosphatase levels, collectively improved cellular immunity and repair capacity. Overall, these results confirm that VC promotes the growth and development of T. tridentatus.

Red seaweeds are increasingly recognized as rich sources of bioactive compounds with promising applications in health promotion, yet their mechanisms of action in human systems remain underexplored. This study investigates the safety and immunomodulatory potential of two red seaweed-derived compounds, R-phycoerythrin (R-PE) and floridoside, and phycobiliprotein-rich extracts from two species of red algae, Acrochaetium secundatum and Gracilaria gracilis. In vitro assays were conducted using Caco-2 intestinal epithelial cells and THP-1 macrophages. Assessed endpoints were cell viability (via a panel of three fluorescence-based assays), intracellular reactive oxygen species (ROS) levels, and cytokine secretion (interleukin-6 (IL-6) and interleukin-8 (IL-8)). Both pure compounds and the seaweed extracts exhibited minimal cytotoxicity. R-PE concentration-dependently increased both IL-6 and IL-8 secretion in THP-1 macrophages, starting at our lowest tested concentration of 3.125 µg mL^-1, whereas floridoside had no detectable effect on cytokine levels. Both compounds elevated ROS production in Caco-2 cells under basal conditions at concentrations (ge) 50 µg mL^-1. R-PE content in the seaweed extracts was quantified at 2022 µg g^-1 wet weight (WW) for A. secundatum and 170.6 µg g^-1 WW for G. gracilis. At exposed concentrations of 1000 µg mL^-1, both extracts significantly increased IL-8 secretion in THP-1 macrophages, with A. secundatum inducing a stronger response (127%) compared to G. gracilis (116%) (p = 0.10). These findings suggest limited bioactivity of floridoside under the tested conditions, but support an immunostimulatory potential of R-PE and red seaweed phycobiliprotein extracts. This study emphasizes the value of investigating both isolated compounds and whole seaweed extracts, as seaweed extracts can offer a more accessible, scalable, and cost-effective alternative to purified compounds, particularly for highly abundant bioactives.