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To investigate the effect of Staphylococcus saprophyticus MF B8 from stinky mandarin fish on the volatile flavor of stinky mandarin fish, four experimental groups were set up using mandarin fish as raw material: fresh mandarin fish (S1), uninoculated fermentation (S2), inoculated fermentation by adding 1% MF B8 (S3) and 2% MF B8 (S4). The volatile flavor components were analyzed using headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS). And combined with chemometrics, identify the characteristic "stink" substances of stinky mandarin fish. The results showed that a total of 87 volatile compounds were identified by GC-MS, including 22 alcohols, 11 aldehydes, 8 ketones, 9 acids, 8 esters, 23 hydrocarbons, 2 sulfur-containing compounds, 2 nitrogen-containing compounds, and 2 other compounds. Compared with the fresh mandarin fish, the amount of aldehydes and hydrocarbons in fermented samples decreased, while the amount of acids, alcohols, esters, ketones, and nitrogen-containing compounds increased. Through orthogonal partial least squares discriminant analysis (OPLS-DA), variable importance in projection (VIP), and odour activity value (OAV), indicated that indole, trimethylamine, acetic acid and dimethyl disulphide, may be the key characteristic "stink" substances in fermented stinky mandarin fish inoculated by Staphylococcus saprophyticus MF B8. The research results provide a theoretical basis for the formation of volatile flavor compounds in fermented fish products.

In this study, the effect of Zanthoxylum bungeanum aqueous extract (ZBAE) with the addition of 0, 0.125%, 0.25%, 0.5% and 1.0% on the characteristics of mandarin fish surimi gel, including water-holding capacity, gel strength, texture, whiteness, secondary structure and microstructure were performed. The results showed that the fish surimi gel's water-holding capacity, gel strength, hardness, and adhesion presented a trend of first increasing and then decreasing with the increasing of ZBAE, which had a maximum value of 0.25%. Also, FTIR analysis showed that α-helix, β-fold, and random coil structure exerted a trend of first increasing and then decreasing, and the content of β-fold and α-helix both reached the highest value at 0.125% and 0.25%, respectively. SEM results showed that when adding 0.25% ZBAE, the network structure was more ordered and denser than that of the non-addition group, and the fractal dimension, average diameter and water holes were also perfect. In addition, low addition (

Geloina erosa is an important benthic animal in the mangrove, serving as an indicator organism for coastal environmental pollution. This study aimed to investigate the tissue-specific expression of miRNAs and their regulatory roles in predicted targets in G. erosa. Through miRNA sequencing and co-expression network analysis, we extensively studied the miRNA expression in three tissues: gills, hepatopancreas, and muscle. The results revealed a total of 1412 miRNAs, comprising 1047 known miRNAs, and 365 newly predicted miRNAs. These miRNAs exhibited distinct tissue-specific expression patterns. In the miRNA target gene prediction, a total of 7404 potential predicted targets were identified, representing approximately 33% of all unique transcripts associated with miRNAs. Further co-expression network analysis revealed nine modules, each showing a positive correlation with specific tissues (gills, hepatopancreas, or muscle). The blue module showed a significant correlation with gills (r = 0.83, p-value = 0.006), the black module was significantly related to the hepatopancreas (r = 0.78, p-value = 0.01), and the purple module was significantly correlated with muscle (r = 0.83, p-value = 0.006). Within these modules, related miRNAs tended to cluster together, while their correlations with other modules were relatively weak. Functional enrichment analysis was performed on miRNAs and their predicted targets in each tissue. In the gills, miRNAs primarily regulate immune-related genes, substance transport, and cytoskeletal organization. In the hepatopancreas, miRNAs suppressed genes involved in shell formation and played a role in cellular motor activity and metabolism. In muscle, miRNAs participate in metabolism and photoreceptive processes, as well as immune regulation. In summary, this study provides valuable insights into the tissue-specific regulation of miRNAs in G. erosa, highlighting their potential roles in immune response, metabolism, and environmental adaptation. These findings offer important clues for understanding the molecular mechanisms and biological processes in G. erosa, laying the foundation for further validation and elucidation of these regulatory relationships.

Littoraria melanostoma (Gray, 1839) is one of the most common species of gastropods in mangroves. They quickly respond during the early stage of mangrove restoration and usually form a dominant community within a certain period. We characterized the complete mitochondrial genome of this species. The whole mitogenome of L. melanostoma was 16,149 bp in length and its nucleotide composition showed a high AT content of 64.16%. It had 37 genes, including 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes, and 1 control region between tRNA-Phe and COX3. The A/T composition in the control region was 74.7%, and is much higher than the overall A/T composition of the mitochondrial genomes. The amino acid composition and codon usage of the mitochondrial genomes from seven superfamilies of Littorinimorpha were analyzed, and the results showed that CUU (Leu), GCU (Ala), AUU (Ile), UCU (Ser), UUA (Leu), GUU (Gly), and UUU (Phe) are the commonly used codons. The maximum likelihood phylogenetic tree reconstructed using 62 species of Littorinimorpha presented consistency between the molecular and morphological classifications, which provide a basis to understand the phylogeny and evolution of this order. In the phylogenetic tree, L. melanostoma is located within Littorinoidea and is closely related to L. sinensis, a rock-dwelling species that is widespread in the coastal intertidal zone of China.

Mollusca is the second largest animal phylum and represents one of the most evolutionarily successful animal groups. Geloina erosa, a species of Corbiculidae, plays an important role in mangrove ecology. It is highly adaptable and can withstand environmental pollution and microbial infections. However, there is no reference genome or full-length transcriptome available for G. erosa. This impedes the study of the biological functions of its different tissues because transcriptome research requires reference genome or full-length transcriptome as a reference to improve accuracy. In this study, we applied a combination of Illumina and PacBio single-molecule real-time sequencing technologies to sequence the full-length transcriptomes of G. erosa tissues. Transcriptomes of nine samples obtained from three tissues (hepatopancreas, gill, and muscle) were sequenced using Illumina. Furthermore, we obtained 87,310 full-length reads non-chimeric sequences. After removing redundancy, 22,749 transcripts were obtained. The average Q score of 30 was 94.48%. In total, 271 alternative splicing events were predicted. There were 14,496 complete regions and 3,870 lncRNAs. Differential expression analysis revealed tissue-specific physiological functions. The gills mainly express functions related to filtration, metabolism, identifying pathogens and activating immunity, and neural activity. The hepatopancreas is the main tissue related to metabolism, it also involved in the immune response. The muscle mainly express functions related to muscle movement and control, it contains more energy metabolites that gill and hepatopancreas. Our research provides an important reference for studying the gene expression of G. erosa under various environmental stresses. Moreover, we present a reliable sequence that will provide an excellent foundation for further research on G. erosa.

Abstract Seagrass meadows are among the four most productive marine ecosystems in the world. Zostera japonica (Z. japonica) is the most widely distributed species of seagrass in China. However, there is no reference genome or transcriptome available for Z. japonica, impeding progress in functional genomic and molecular ecology studies in this species. Temperature is the main factor that controls the distribution and growth of seagrass around the world, yet how seagrass responds to heat stress remains poorly understood due to the lack of genomic and transcriptomic data. In this study, we applied a combination of second- and third-generation sequencing technologies to sequence full-length transcriptomes of Z. japonica. In total, we obtained 58,134 uniform transcripts, which included 46,070 high-quality full-length transcript sequences. We identified 15,411 simple sequence repeats, 258 long non-coding RNAs and 28,038 open reading frames. Exposure to heat elicited a complex transcriptional response in genes involved in posttranslational modification, protein turnover and chaperones. Overall, our study provides the first large-scale full-length trascriptome in Zostera japonica, allowing for structural, functional and comparative genomics studies in this important seagrass species. Although previous studies have focused specifically on heat shock proteins, we found that examination of other heat stress related genes is important for studying response to heat stress in seagrass. This study provides a genetic resource for the discovery of genes related to heat stress tolerance in this species. Our transcriptome can be further utilized in future studies to understand the molecular adaptation to heat stress in Zostera japonica.

The transition from outcrossing to selfing is a common evolutionary trend in flowering plants, and floral traits change significantly with the evolution of selfing. Whether or not plant traits are subjected to selection remains an open question in species with mixed mating systems. We examined phenotypic selection in two populations of Halenia elliptica with different selfing rates. We found that the pollen–ovule ratio, seed size, plant height, spur length, and pollinator visitation rate in the population with the higher selfing rate were lower than those in the population with the lower selfing rate. Selfing provides reproductive assurance for populations when pollinator service is low, and the floral traits that are associated with selfing syndrome are evident in populations with a higher selfing rate but are subjected to weak selection in each of the two populations with different selfing rates. Directional selection for an early flowering time indicated that late blooming flowers could experience a risk of seed development in alpine environments, and for large plants, selection indicated that seed production could be limited by the available resources. The floral traits that are associated with pollinator attraction and specialization could be subjected to weak selection at the plant level as selfing evolves, and the selective pressures that are independent of pollinators might not change significantly; highlighting the selective biotic and abiotic pressures that shape the morphological traits of plant species and their independence from the mating system.

We assembled one mitochondrial genome of Geloina erosa from NovaSeq 6000 sequencing data. The complete mitochondrial genome of G. erosa was 15,041 bp in length, including 36 genes, which are 12 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes ((12S and 16S), which showed the typical marine bivalves mitochondrial gene composition. The overall base composition was 21.16% for A, 46.11% for T, 7.73% for C, and 25% for G. A phylogeny of 13 bivalves showed G. erosa was clustered within Veneroida.

Halenia elliptica is a popular Chinese medicinal herb that is used to treat jaundice disease and virus hepatitis, and its wild populations have been reduced significantly due to overharvesting recently. However, effective conservation could not be implemented because of the lack of genomic information and genetic markers. In this study, a de novo transcriptome of H elliptica was sequenced using the NGS Illumina, and 132 695 unigenes with the length >200 bp (base pairs) were obtained. Among them, a total of 32 109 unigenes were scanned to develop simple sequence repeats (SSRs). Based on NCBI (National Center for Biotechnology Information) nonredundant database (Nr), these SSR sequences were annotated and assigned into gene ontology categories. In addition, we designed 126 pairs of SSR primers for polymerase chain reaction amplification, of which 12 pairs were identified to be polymorphic among 40 individuals from 8 populations. We then used the 12 polymorphic SSRs to construct a UPGMA dendrogram of the 40 individuals. In addition, a significant correlation between the genetic relationship and the geographic distance was found, suggesting a phylogeographic structure in H elliptica . Moreover, 2 of these SSRs were also successfully amplified in a related species Veratrilla baillonii , suggesting their cross-species transferability. Generally, the SSR markers with high polymorphisms identified in this study provide valuable genetic resources and represent an initial step for exploring the genetic diversity and population histories of H elliptica and its related species.

The complete mitogenome of Sphaeroma sp. (Crustacea, Isopod, Sphaeromatidae) was determined in this study. The total length of mitogenome was 15,839 bp, and contained 13 protein-coding genes, 21 tRNA genes, 2 rRNA genes, 1 control region, and 2 unknown fragments which longer than 200 bp. The nucleotide composition was 25.80% A, 16.56% C, 25.94% G and 31.67% T. Six initiation codons (ATA, ATC, ATG, ATT, ACG, GTG) and three termination codons (TAA, TAG, TA–) were used in the protein-coding genes. The length of tRNA genes ranged from 52 to 65 bp, and tRNA-Arg was not identified. The phylogenetic result showed Sphaeroma sp. was closely related to Sphaeroma terebrans with high bootstrap value supported.

In this study, we determined the complete mitogenome of Sphaeroma terebrans (Crustacea, Isopod, Sphaeromatidae), which was the first one in the family Sphaeromatidae. The mitogenome of S. terebrans was 15,540 bp in length and contained 13 protein-coding genes, 21 tRNA genes, 2 rRNA genes, 1 control region, and 2 unknown fragments which is longer than 200 bp. The overall base composition was 30.1% A, 14.9% C, 21.3% G, and 33.7% T. Six start codons (ATA, ATC, ATG, ATT, ACG, GTG) and three stop codons (TAA, TAG, T–) were found in the protein-coding genes. The size of 21 tRNA genes ranged from 51 to 66 bp, tRNA-Gly was not found. All nodes strongly supported that S. terebrans was placed as sister to Sphaeroma serratum in the maximum likelihood tree.