Selenochemical modification of low molecular weight polysaccharides from Grifola frondosa and the mechanism of their inhibitory effects on gastric cancer cells.

An important micronutrient involved in immune response and antitumor is selenium. LMW-GFP, a polysaccharide extracted from Grifola frondosa seed bodies, has a relatively weak antitumor effect on BGC-823 and MFC cells in vitro, whereas selenium binding to LMW-GFP can significantly increase the in vitro antitumor activity of LMW-GFP. In this study, Se-LMW-GFP was prepared by the HNO3-Na2SeO3 method, and the structures of LMW-GFP and Se-LMW-GFP were characterized by UV-visible spectroscopy of absorption, FTIR spectroscopy, and electron scanning microscopy, and these structural analyses showed that selenium was successfully complexed to LMW-GFP. The selenium content of Se-LMW-GFP was measured to be 2.08 % ± 0.08 % by ICP-MS. The anti-tumor activity of LMW-GFP before and after selenium modification was compared by cellular experiments, and the findings indicated that the anti-tumor activity of Se-LMW-GFP was considerably improved over that of LMW-GFP, and inhibited the proliferation of BGC-823 cells and MFC cells through a combination of the Fas/FasL-mediated exogenous death receptor pathway as well as the endogenous mitochondrial pathway. Our results suggest that Se-LMW-GFP not only has great potential for natural health food and anti-gastric cancer drug development but is also a good selenium supplement.

Effects of Long-Term Cryopreservation on the Transcriptomes of Giant Grouper Sperm.

The giant grouper fish (Epinephelus lanceolatus), one of the largest and rarest groupers, is a fast-growing economic fish. Grouper sperm is often used for cross-breeding with other fish and therefore sperm cryopreservation is important. However, freezing damage cannot be avoided. Herein, we performed a transcriptome analysis to compare fresh and frozen sperm of the giant grouper with frozen storage times of 0, 23, 49, and 61 months. In total, 1911 differentially expressed genes (DEGs), including 91 in El-0-vs-El-23 (40 upregulated and 51 downregulated), 251 in El-0-vs-El-49 (152 upregulated and 69 downregulated), and 1569 in El-0-vs-El-61 (984 upregulated and 585 downregulated), were obtained in the giant grouper sperm. DEGs were significantly increased at 61 months of cryopreservation (p < 0.05). GO and KEGG enrichment analyses of the DEGs revealed significant enrichment in the pilus assembly, metabolic process, MAPK signaling pathway, apoptosis, and P53 signaling pathway. Time-series expression profiling of the DEGs showed that consistently upregulated modules were also significantly enriched in signaling pathways associated with apoptosis. Four genes, scarb1, odf3, exoc8, and atp5f1d, were associated with mitochondria and flagella in a weighted correlation network analysis. These genes may play an important role in the response to sperm freezing. The experimental results show that long-term cryopreservation results in freezing damage to the giant grouper sperm. This study provides rich data for studies of the mechanism underlying frozen fish sperm damage as well as a technical reference and evaluation index for the long-term cryopreservation of fish sperm.

Effect of non-permeable cryoprotectant sucrose on the development of spotted knifejaw (Oplegnathus punctatus) embryos.

In this study, the toxicity of sucrose to Oplegnathus punctatus embryos was evaluated. Embryos at the 4-6 somite, tail-bud, heart formation, and heart-beating stages were exposed to 0, 0.5, 1,1.5, 2, 2.5, or 3 M sucrose for 1 h. Survival rates of embryos at the tail-bud, heart formation, and heart-beating stages after rehydration for 1 h were not affected by treatment with 2 M sucrose (the maximum concentration). Embryos at the tail-bud, heart formation, and heart-beating stages were exposed to 2 M sucrose for 0, 30, 60, 90, 120, 150, or 180 min. Long-term developmental indicators, including rates of survival, hatching, swimming, and malformation, were evaluated for 4 days after rehydration. Based on the survival rates 10 min after rehydration, the longest tolerance time for embryos at the three stages was 120 min. Based on long-term developmental indicators, the longest tolerance times were 60 min at the tail-bud, 60 min at the heart formation stage and 30 min at the heart beating stage. The malformation rates increased as the treatment time increased. The malformation rates were 100% when embryos were exposed to sucrose for ≥120 min. Malformation was divided into larval and embryonic abnormality. As the exposure time increased for tail-bud stage embryos, the rate of larval malformation increased. Treatment at heart formation and heart-beating stages resulted in higher rates of failure to hatch at exposure time. Based on these results, toxicity tests of non-permeable cryoprotectant in embryos requires the observation of development for at least 2 days after rehydration. Based on long-term observation, it was concluded that dehydration before freezing was not the direct cause of larvae deformity that hatched from frozen-thawing embryo. These results provide a reference for the singly use of representative non-permeable cryoprotectant sucrose.

A chromosome-level genome assembly of the potato grouper (Epinephelus tukula).

The potato grouper, Epinephelus tukula, is one of the largest coral reef teleost, and it is an important germplasm resource for selection and cross breeding. Here we report a potato grouper genome assembly generated using PacBio long-read sequencing, Illumina sequencing and high-throughput chromatin conformation capture (Hi-C) technology. The genome size was 1.13 Gb, with a total of 508 contigs anchored into 24 chromosomes. The scaffold N50 was 42.65 Mb. For the genome models, our assembled genome contained 98.11% complete BUSCO with the vertebrata_odb9 database. One more copies of Gh and Hsp90b1 were identified in the E. tukula genome, which might contribute to its fast growth and high resistance to stress. In addition, 435 putative antimicrobial peptide (AMP) genes were identified in the potato grouper. This study provides a good reference for whole genome selective breeding of the potato grouper and for future development of novel marine drugs.

Characterization of the complete mitochondrial genome of the hybrid grouper (Cromileptes altivelis♀ × Epinephelus tukula♂) with phylogenetic consideration.

Here we isolated and characterized the complete mitochondrial genome of the hybrid grouper (Cromileptes altivelis♀ × Epinephelus tukula♂). It is 16,503 bp long and contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. The nucleotide composition is 29.08% of A, 29.03% of C, 15.66% of G and 26.23% of T, with 55.31% A + T. The phylogenetic analysis by neighbor-joining (NJ) method reveals that the hybrid offspring has a closer relationship to C. altivelis.

Involvement of glycolysis activation in flatfish sexual size dimorphism: Insights from transcriptomic analyses of Platichthys stellatus and Cynoglossus semilaevis.

The starry flounder (Platichthys stellatus), a flatfish cultured at the margins of the North Pacific, displays an obvious female-biased growth advantage, similar to many other fish species. To reveal the molecular mechanism underlying sexual size dimorphism, a comparative transcriptomic analysis of the somatotropic and reproductive axes was conducted. In total, 156, 67, 3434, and 378 differentially expressed genes (DEGs) between female and male samples were obtained in the brain, liver, gonad, and muscle tissues (q < 0.05). These DEGs were significantly enriched for various GO terms, including ion channel activity, protein binding, lipid transporter activity, and glycolytic process. The significantly enriched KEGG pathways included insulin secretion, axon guidance, and glycolysis/gluconeogenesis. In a detailed analysis of DEGs in these significantly enriched pathways, 35 genes showed higher expression levels in female muscle tissues than in male muscle tissues. A protein-protein interaction network further revealed specific interactions involving the glycolysis related-protein enolase (ENO), triosephosphate isomerase (TPI), Bisphosphoglycerate mutase (BPGM), fructose-bisphosphate aldolase (ALDO), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Interestingly, the role of glycolysis/gluconeogenesis was supported by an analysis of common DEGs between P. stellatus and Chinese tongue sole (Cynoglossus semilaevis). These results indicate that the activation of glycolysis in female muscle tissues contributes to flatfish sexual size dimorphism.

The complete mitochondrial genome of the hybrid offspring Epinephelus awoara♀ × Epinephelus tukula♂.

The complete mitochondrial genome of hybrid grouper from Epinephelus awoara (♀) ×E. tukula (♂) was obtained by PCR amplification. The circular genome was 16,801 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a control region (D-loop region). The overall base composition was as follows: A: 28.46%, T: 27.27%, C: 27.27%, G: 16.49%. The new results may provide valuable data for the genetic and taxonomic research on artificial hybrid grouper.

Optimization of vitrification factors for embryo cryopreservation of kelp grouper (Epinephelus moara).

Cryopreservation of marine fish embryos causes to severe cryogenic damage, and to date, adults have not been reared from embryos that were cryopreserved. Here, we optimized vitrification factors to improve the survival and hatching rate of kelp grouper (Epinephelus moara) embryos after cryopreservation. We screened the effects of 11 vitrification solution concentrations (25-50%) on the survival rate of embryos at four developmental stages (16S, 18S, 22S, TB). We investigated the effects of different equilibration time (25-45min) on the survival rate and the influence of vitrification solutions on embryonic volume. In addition, we tested the effects of treating embryos at five different developmental stages (4-6S, 16S, 22S, TB, HB) with different vitrification solutions (35% PMG3S and 35% PMG3T), prechilling temperature (-5 °C and 4 °C) and prechilling time. In total, 9855 embryos were cryopreserved at 10 developmental stages, from optic capsule stage to pre-hatch stage. We found that kelp grouper embryos performed best at equilibration time of 30 min. Embryos at the tail-bud stage exhibited greater tolerance to vitrification than other stages. Vitrification solutions that contained sucrose showed better survival rates compared to embryos treated with vitrification solutions containing trehalose. Pre-chilling treatment improved viability before freezing, but did not improve viability after freezing. In the most optimal condition we identified in this study, the average survival, normal development and malformation rates of cryopreserved embryos were 6.32%, 2.36% and 3.49%, and 39.85% of the surviving embryos that were cryopreserved hatched. The hatched larvae gradually died at day 12 of cultivation, where the longest surviving individuals lived for 16 days. This study provides valuable data for improving survival and hatching rate of cryopreserved grouper embryos, and provides references for further exploring techniques in fish embryo cryopreservation.

Transcriptome comparative analysis of immune tissues from asymptomatic and diseased Epinephelus moara naturally infected with nervous necrosis virus.

Epinephelus moara is an economically important fish in Southeast Asian countries but is suffering from nervous necrosis virus (NNV) infection. A deeper understanding of the host-NNV interaction mechanisms makes sense for disease control, however, at present, the pathogenesis of natural NNV infection and the resistance mechanism in host remains poorly understood. In this study, asymptomatic and diseased E. moara with clinical symptoms of viral nervous necrosis (VNN) from a grouper farm were both detected with a positive RT-PCR signal of NNV, then transcriptome sequencing of their immune tissues (liver, spleen and kidney) were performed for comparation analysis. The de novo assemblies yielded 53,789 unigenes which had a length varied from 201 to 19,675 bp and a N50 length of 2115 bp, and 29,451 unigenes were functionally annotated, with 83, 250 and 5632 unigenes being differentially expressed in liver, spleen and kidney respectively. KEGG pathway enrichment analysis of the DEGs showed many DEGs were enriched in immune related pathways. Although the expression of class I major histocompatibility complex (MHC) was significantly higher in three immune tissues of the diseased grouper, many immune related genes, including humoral immune molecules (such as antibodies), the cellular mediated cytotoxic molecules (such as perforin) and some adhesion related genes were down regulated in the diseased grouper. Our results provided many unigenes that might play important roles in NNV resistance for further research. Furthermore, a total of 8666 unigenes containing 11,623 simple sequence repeats (SSRs) were identified, which provided useful information for screening molecular markers associated with NNV resistance in E. moara.

The complete mitochondrial genome of the hybrid offspring Epinephelus fuscoguttatus ♀ × Epinephelus tukula ♂.

The hybrid offspring Epinephelus fuscoguttatus ♀ × E. tukula ♂ showed heterosis in terms of growth and disease resistance. The mitochondrial genome is 16,629 bp in length and consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. The difference of total length is mainly caused by the difference of length in non-coding region. The nucleotide base composition is A = 29.15%, G = 15.62%, T = 26.91%, C = 28.32%, A + T = 56.06%, and C + G = 43.94%. The phylogenetic analysis using neighbour-joining (NJ) method showed that the hybrid offspring has a closer relationship to E. fuscoguttatus × E. lanceolatus.

Characterization of the complete mitochondrial genome of the hybrid grouper Epinephelus akaara ♀ × Epinephelus tukula ♂, with its phylogenetic analysis.

Epinephelus akaara ♀ × Epinephelus tukula ♂ is an economically important fish. The mitochondrial genome of the hybrid grouper had a double-stranded DNA molecule with the length of 16,928 bp and consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. The gene composition of the hybrid grouper mitochondrial genome was similar to that of most other vertebrates. Furthermore, phylogenetic analysis by maximum-likelihood (ML) method, based on the nucleotide sequences of 13 protein-coding genes, showed that the hybrid grouper has the closer relationship to Epinephelus akaara and confirmed that the mitochondrial genome is maternally inherited.

Experimental and modeling approaches for food waste composting: a review.

Composting has been used as a method to dispose food waste (FW) and recycle organic matter to improve soil structure and fertility. Considering the significance of composting in FW treatment, many researchers have paid their attention on how to improve FW composting efficiency, reduce operating cost, and mitigate the associated environmental damage. This review focuses on the overall studies of FW composting, not only various parameters significantly affecting the processes and final results, but also a number of simulation approaches that are greatly instrumental in well understanding the process mechanism and/or results prediction. Implications of many key ingredients on FW composting performance are also discussed. Perspects of effective laboratory experiments and computer-based simulation are finally investigated, demonstrating many demanding areas for enhanced research efforts, which include the screening of multi-functional additives, volatile organiccompound emission control, necessity of modeling and post-modeling analysis, and usefulness of developing more conjunctive AI-based process control techniques.