Intertidal organisms are more sensitive to temperature stresses (whether high or low temperatures). As an intertidal crustacean, the optimal survival temperature ranges of Charybdis japonica are from 20 to 27°C. In this study, C. japonica was selected as the research species to better explore the molecular regulatory mechanisms of intertidal crustaceans to temperature stresses. The transcriptomes of C. japonica exposed to three temperature gradients (12, 20, and 28°C) were sequenced. A total of 69.22 Gb clean transcriptome reads were obtained from nine libraries and then de novo assembled to 52,972 unigenes with a mean length of 1080.23 bp and an N50 length of 1,775 bp. A total of 20,121 unigenes were successfully matched with at least one protein database. The transcriptome structure was predicted, and 12,125 coding sequences and 12,854 simple sequence repeats (SSRs) were obtained. The gene expression level of C. japonica at 20°C was used as control, and 548 and 90 unigenes were significantly differentially expressed at 28 and 12°C, respectively. A total of 720 unigenes were significantly differentially expressed at 28°C compared with 12°C. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation showed that genes related to cell structure, metabolism, and protein folding and hormone synthesis might be involved in the regulation of temperature stress in C. japonica. Our results reveal for the first time the response of C. japonicas to low- and high- temperature stresses at the transcriptome level. The results provide fundamental information for revealing the temperature regulation mechanisms of C. japonica and other intertidal crustaceans. Furthermore, the present study enhances our understanding of how temperature fluctuations will affect the survival of marine crustaceans.

The identification and visualization of functional elements within biological sequences offers visual presentation for biologists to integrate annotation, and also helps them to produce high-quality figures for publication. Although there are now some standalone tools that can perform this function, these tools generally lack flexibility and cannot meet personalized needs. Based on the advantages of R language in graphic display, we have developed an R package: BioVizSeq (CRAN: https://cran.r-project.org/package=BioVizSeq. Github: https://github.com/zhaosq2022/BioVizSeq). It is designed for visualizing the types and distribution of elements within bio-sequences. These data could come from users or analysis programs, such as, GFF/GTF, MEME, SMART, Plantcare, PFAM, CDD and etc. BioVizSeq can be conducted locally or online, providing great convenience for researchers without coding training. Its user-friendly visualization function can simultaneously meet users’ general needs and personalized exploration.

Mangrove forests, found primarily in tropical and subtropical coastal regions, support diverse microbial communities that are crucial for nutrient cycling and energy flow and then sustain mangrove ecosystem integrity. This study investigated the seasonal dynamics of bacterial communities in mangrove sediments of Shupaisha island (Zhejiang Province, China) through amplifying and high-throughput sequencing bacterial 16S rRNA gene fragments. Proteobacteria (23.59–44.40%), Actinobacteria (4.92–19.01%), and Bacteroidetes (4.31–22.79%) dominated the bacterial phyla in Shupaisha mangrove sediments with the highest diversity indices in winter. Actinobacteria were more abundant during winter (13.27%) and spring (14.36%), while Bacteroidetes abundance was highest in summer, significantly correlating with temperature. Significant differences in bacterial community composition were observed between winter and summer, while spring and autumn exhibited similar distribution, indicating a transitional pattern in bacterial community dynamics, with temperature and sand content being the most influential factors. This study enhances our understanding of the seasonal characteristics of bacterial communities in the mangrove ecosystems, potentially providing valuable insights into monitoring and assessing the health and stability of mangrove ecosystems in Zhejiang Province.

Being the phylum with the second largest biodiversity, mollusks are widely distributed in marine, freshwater, and land, conquered almost all habitats on the earth. Throughout geological time, several molluscan lineages independently colonized freshwater and land, evolving independently in new habitats. Resolving the timing of their colonization for novel environments is the basis of understanding the complex evolution of Mollusca. Herein, we obtained an elaborate single–copy orthologs set including 107 genes with a total length of 3,447,675 amino acid sites across 134 mollusks to reconstruct the phylogeny of Mollusca. The phylogenetic analysis recovered the “Aculifera+ Conchifera” topology with well–supported. By the divergence times estimation with fossil calibration, we revealed Cambrian rapid diversification of all molluscan classes. What’s more, our results provided the times of three major independent colonization of novel environments and consistent with previous studies. The freshwater mussels (Bivalvia: Unionida) colonized freshwater about 233 Mya, ancient origin and late diversification make this order to become the main represent of the freshwater bivalves. The orders Stylommatophora and Basommatophora (Gastropoda: Pulmonata) respectively colonized land and freshwater about 201 Mya, the Triassic–Jurassic mass extinction may have provided the opportunities for their colonization. Ampullariidae (Gastropoda) colonized freshwater about 156 Mya, their lungs may have contributed to the adaption of tropical freshwater environment and make them survive. Our results probably offer the most comprehensive time–scale of molluscan evolution, could provide some insights into the habitat transition and evolution of Mollusca.

Mangrove forests are intertidal ecosystems that harbor diverse microbial communities essential for biogeochemical cycles and energy flow. This study investigated the seasonal and spatial patterns of bacterial communities in the artificially introduced mangrove sediments of the Ao River estuary using 16S rRNA gene amplicon high-throughput sequencing. Alpha diversity analyses indicated that the bacterial community diversity in the mangrove sediments of the Ao River estuary was similar to those of natural-formed mangroves, with the Shannon index ranging from 5.16 to 6.54, which was significantly higher in winter compared to other seasons. The dominant bacterial phyla included Proteobacteria (43.65%), Actinobacteria (11.55%), Desulfobacterota (11.16%), and Bacteroidetes (5.52%), while beta diversity analysis revealed substantial differences in bacterial community structure across different seasons and regions. For instance, the relative abundance of Woeseiaceae and Bacteroidota during the summer was significantly higher than that observed in other seasons. And the relative abundance of Bacillaceae in autumn and winter increased by one order of magnitude compared to spring and summer. Woeseiaceae, Desulfobulbaceae, Thermoanaerobaculaceae, and Sva1033 (family of Desulfobacterota) exhibited significantly higher relative abundance in the unvegetated area, whereas Bacillaceae and S085 (family of Chloroflexi) demonstrated greater abundance in the mangrove area. Seasonal variations in bacterial community structure are primarily attributed to changes in environmental factors, including temperature and salinity. Regional differences in bacterial community structure are primarily associated with environmental stressors, such as wave action, fluctuations in salinity, and organic matter content, which are further complicated by seasonal changes. This study is significant for understanding the microbial diversity and seasonal dynamics of estuarine mangrove wetlands, and it contributes to the assessment of mangrove wetland restoration efforts in Zhejiang Province, providing important guidance for the development of strategies to maintain the health of mangrove ecosystems in the future.