Preliminary analysis of pathways and their implications during salinity stress in abalone.

Transcriptome sequencing has offered immense opportunities to study non-model organisms. Abalone is an important marine mollusk that encounters harsh environmental conditions in its natural habitat and under aquaculture conditions; hence, research that increases molecular information to understand abalone physiology and stress response is noteworthy. Accordingly, the study used transcriptome sequencing of the gill tissues of abalone exposed to low salinity stress. The aim is to explore some enriched pathways during salinity stress and the crosstalk and functions of the genes involved in the candidate biological processes for future further analysis of their expression patterns. The data suggest that abalone genes such as YAP/TAZ, Myc, Nkd, and Axin (involved in the Hippo signaling pathway) and PI3K/Akt, SHC, and RTK (involved in the Ras signaling pathways) might mediate growth and development. Thus, deregulation of the Hippo and Ras pathways by salinity stress could be a possible mechanism by which unfavorable salinities influence growth in abalone. Furthermore, PEPCK, GYS, and PLC genes (mediating the Glucagon signaling pathway) might be necessary for glucose homeostasis, reproduction, and abalone meat sensory qualities; hence, a need to investigate how they might be influenced by environmental stress. Genes such as MYD88, IRAK1/4, JNK, AP-1, and TRAF6 (mediating the MAPK signaling pathway) could be useful in understanding abalone's innate immune response to environmental stresses. Finally, the aminoacyl-tRNA biosynthesis pathway hints at the mechanism by which new raw materials for protein biosynthesis are mobilized for physiological processes and how abalone might respond to this process during salinity stress. Low salinity clearly regulated genes in these pathways in a time-dependent manner, as hinted by the heat maps. In the future, qRT-PCR verification and in-depth study of the various genes and proteins discussed would provide enormous molecular information resources for the abalone biology.

Comparative Responses of Orange-Foot and Common-Foot Haliotis gigantea to Carotenoid-Enriched Diets: Survival, Heat Tolerance, and Bacterial Resistance.

Carotenoids, known to enhance survival, heat tolerance, and bacterial resistance, play an essential role in the nutrition of economically important aquatic animals. This study specifically examined their impact as feed additives on the abalone Haliotis gigantea. We prepared 13 compound feeds with varying levels of astaxanthin, zeaxanthin, and ß-carotene, and administered them to both common-footed and orange-footed H. gigantea. The survival rate of H. gigantea was about 70-80%, with no significant differences in survival observed among the various carotenoid-supplemented feeding groups or when compared with the control group, nor between orange-footed and common-footed individuals. In heat attachment duration experiments, orange-foot abalones exhibited longer attachment durations with certain concentrations of astaxanthin and zeaxanthin, whereas common-foot abalones showed extended durations with astaxanthin, zeaxanthin, and ß-carotene, indicating that common-foot abalones might benefit more from these carotenoids. Additionally, our results showed similar patterns and levels of Vibrio harveyi AP37 resistance in both orange-footed and common-footed H. gigantea, suggesting a uniform response to carotenoid supplementation in their bacterial defense mechanisms. This study suggests the potential benefits of carotenoid supplementation in H. gigantea and contributes to the theoretical basis for developing high-quality artificial compound feeds.

OmicsSuite: a customized and pipelined suite for analysis and visualization of multi-omics big data.

With the advancements in high-throughput sequencing technologies such as Illumina, PacBio, and 10X Genomics platforms, and gas/liquid chromatography-mass spectrometry, large volumes of biological data in multiple formats can now be obtained through multi-omics analysis. Bioinformatics is constantly evolving and seeking breakthroughs to solve multi-omics problems; however, it is challenging for most experimental biologists to analyse data using command-line interfaces, coding, and scripting. Based on experience with multi-omics, we have developed OmicsSuite, a desktop suite that comprehensively integrates statistics and multi-omics analysis and visualization. The suite has 175 sub-applications in 12 categories, including Sequence, Statistics, Algorithm, Genomics, Transcriptomics, Enrichment, Proteomics, Metabolomics, Clinical, Microorganism, Single Cell, and Table Operation. We created the user interface with Sequence View, Table View, and intelligent components based on JavaFX and the popular Shiny framework. The multi-omics analysis functions were developed based on BioJava and 300+ packages provided by the R CRAN and Bioconductor communities, and it encompasses over 3000 adjustable parameter interfaces. OmicsSuite can directly read multi-omics raw data in FastA, FastQ, Mutation Annotation Format, mzML, Matrix, and HDF5 formats, and the programs emphasize data transfer directions and pipeline analysis functions. OmicsSuite can produce pre-publication images and tables, allowing users to focus on biological aspects. OmicsSuite offers multi-omics step-by-step workflows that can be easily applied to horticultural plant breeding and molecular mechanism studies in plants. It enables researchers to freely explore the molecular information contained in multi-omics big data (Source: https://github.com/OmicsSuite/, Website: https://omicssuite.github.io, v1.3.9).

Comparative cytogenetic analysis of diploid and triploid pacific abalone, Haliotis discus hannai.

Cytogenetic analysis of triploid Haliotis discus hannai larvae (produced by chemical treatment) and its diploids were performed. The results showed that triploid H. discus hannai had a chromosome number of 3n = 54, consisting of 30 metacentric (m) and 24 submetacentric (sm) chromosomes, while the diploids had a chromosome number of 2n = 36, consisting of 20 metacentric (m) and 16 submetacentric (sm) chromosomes. Notably, both triploids and diploids displayed variation in the number of NORs and/or their diameter. The average number of NORs was significantly higher in triploids than in diploids (P < 0.05), while there was no significant difference in the average diameter of NORs between the two groups (P > 0.05). Additionally, 5S rDNA localization to 3 submetacentric chromosomes was observed in triploids, compared to 2 submetacentric chromosomes in diploids. The number of 18S rDNA sites displayed positional conservancy and quantitative variability in both diploids and triploids. Specifically, 18S rDNA was found at the end of the chromosome in both groups, with triploids exhibiting a significantly higher number of loci than diploids (P < 0.01). This study provides valuable insights into the cytogenetic characteristics of triploid H. discus hannai, which could facilitate further research on the stability of the chromosome set in this species.

Impact of ocean acidification on shells of the abalone species Haliotis diversicolor and Haliotis discus hannai.

Ocean acidification (OA) results from the absorption of anthropogenic CO2 emissions by the ocean and threatens the survival of many marine calcareous organisms including molluscs. We studied OA effects on adult shells of the abalone species Haliotis diversicolor and Haliotis discus hannai that were exposed to three pCO2 conditions (ambient, ∼880, and ∼1600 µatm) for 1 year. Shell periostracum corrosion under OA was observed for both species. OA reduced shell hardness and altered the nacre ultrastructure in H. diversicolor, making its shells more vulnerable to crushing force. OA exposure did not reduce the shell hardness of H. discus hannai and did not alter nacre ultrastructure. However, the reduced calcification also decreased its resistance to crushing force. Sr/Ca in the shell increased with rising calcification rate. Mg/Ca increased upon OA exposure could be due to a complimentary mechanism of preventing shell hardness further reduced. The Na/Ca distribution between the aragonite and calcite of abalone shells was also changed by OA. In general, both abalone species are at a greater risk in a more acidified ocean. Their shells may not provide sufficient protection from predators or to transportation stress in aquaculture.

Comprehensive Comparison of Effects of Antioxidant (Astaxanthin) Supplementation from Different Sources in Haliotis discus hannai Diet.

Dietary antioxidant supplementation, especially astaxanthin, has shown great results on reproductive aspects, egg quality, growth, survival, immunity, stress tolerance, and disease resistance in aquatic animals. However, the effects of dietary astaxanthin supplementation from different sources are still unknown. A comprehensive comparison of survival, growth, immune response, antioxidant activity, thermal resistance, disease resistance, and intestinal microbial structure was conducted in dietary antioxidant supplementation from the sources of Gracilaria lemaneiformis (GL), industrial synthetic astaxanthin (80 mg/kg astaxanthin actual weight, named as group 'SA80'), Phaffia rhodozyma (80 mg/kg astaxanthin actual weight, named as group 'PR80') and Haematococcus pluvialis (120 mg/kg astaxanthin actual weight, named as group 'HP120') at their optimal supplementation amounts. Furthermore, the SA80, PR80, and HP120 groups performed better in all aspects, including survival, growth, immune response, antioxidant activity, thermal resistance, and disease resistance, compared with the GL group. The PR80 and HP120 group also had a better growth performance than the SA80 group. In terms of heat stress and bacterial challenge, abalone in the PR80 group showed the strongest resistance. Overall, 80 mg/kg astaxanthin supplementation from Phaffia rhodozyma was recommended to obtain a more effective and comprehensive outcome. This study contributes to the discovery of the optimum dietary astaxanthin supplementation source for abalone, which is helpful to improve the production efficiency and economic benefits of abalone. Future research can further explore the action mechanism and the method of application of astaxanthin to better exploit its antioxidant role.

Ecological benefits of artificial light at night (ALAN): Accelerating the development and metamorphosis of marine shellfish larvae.

Urbanization has led to increasing use of artificial light at night (ALAN), which has rapidly become an important source of pollution in many cities. To identify the ALAN effects on the embryonic development of the Pacific abalone Haliotis discus hannai, we first exposed larvae to natural light with a light period of 12 L:12D (control, Group CTR). We then exposed larvae to three different light regimes. Larvae in Group NL were exposed to full spectrum artificial light from 18:00 to 00:00 to simulate the lighting condition at night, whereas Groups BL and YL were illuminated at the same time interval with 450 nm of short-wavelength blue light and 560 nm of long-wavelength orange light, respectively, to simulate billboard lighting at night. There were significantly higher hatching success and metamorphosis rates of larvae in Group BL than in Group YL or CTR (P < 0.05). The larvae in Group YL had the highest abnormality rate and took the longest time to complete metamorphosis. Transcriptomic studies revealed significantly higher expression levels of genes related to RNA transport, DNA replication, and protein processing in endoplasmic reticulum pathways in Group BL compared to the other groups. In the metabolomic analysis, we identified prostaglandin B1, tyramine, d-fructose 6-phosphate, L-adrenaline, leukotriene C4, and arachidonic acid as differential metabolic markers, as they play a vital part in helping larvae adapt to different ALAN conditions. Multi-omics correlation analysis of pairwise comparisons between all of the groups suggested that the biosynthesis of unsaturated fatty acids (FAs) and arachidonic acid metabolism pathways were significantly enriched (P < 0.05). Further quantitative analysis of the fatty acid (FA) contents revealed that 42 out of 50 FAs were down-regulated in Group BL and up-regulated in Group YL, which suggested that the synthesis, catabolism, and metabolism of FAs are crucial for the larval response to different spectral components of ALAN. For the first time, we report positive rather than negative effects of artificial blue light at night on the embryonic development of a benthic marine species. These results are significant for unbiased and full-scale assessment of the ecological effects of ALAN and for understanding the structural stability of the marine benthic community.

Molecular Characterization and Function of Bone Morphogenetic Protein 7 (BMP7) in the Pacific Abalone, Haliotis discus hannai.

Bone morphogenetic proteins (BMPs) play important roles in a lot of biological processes, such as bone development, cell proliferation, cell differentiation, growth, etc. However, the functions of abalone BMP genes are still unknown. This study aimed to better understand the characterization and biological function of BMP7 of Haliotis discus hannai (hdh-BMP7) via cloning and sequencing analysis. The coding sequence (CDS) length of hdh-BMP7 is 1251 bp, which encodes 416 amino acids including a signal peptide (1-28 aa), a transforming growth factor-ß (TGF-ß) propeptide (38-272 aa), and a mature TGF-ß peptide (314-416 aa). The analysis of expression showed that hdh-BMP7 mRNA was widely expressed in all the examined tissues of H. discus hannai. Four SNPs were related to growth traits. The results of RNA interference (RNAi) showed that the mRNA expression levels of hdh-BMPR I, hdh-BMPR II, hdh-smad1, and hdh-MHC declined after hdh-BMP7 was silenced. After RNAi experiment for 30 days, the shell length, shell width, and total weight were found to be reduced in H. discus hannai (p < 0.05). The results of real-time quantitative reverse transcription PCR revealed that the hdh-BMP7 mRNA was lower in abalone of the S-DD-group than in the L-DD-group. Based on these data, we hypothesized that BMP7 gene has a positive role in the growth of H. discus hannai.

Metabolic and transcriptional responses demonstrating enhanced thermal tolerance in domesticated abalone.

Global warming threatens aquatic systems and organisms. Many studies have focused on the vulnerability and stress responses of aquaculture organisms to future thermal conditions. However, it may be of more practical significance to reveal their acclimation potential and mechanisms. In this study, the physiological, metabolic, and transcriptional responses to long-term temperature acclimation of northern and southern populations of Pacific abalone Haliotis discus hannai, a commercially important gastropod sensitive to environmental changes, were compared. This study conducted two common-garden experiments, including a thermostatic experiment in the lab and an aquaculture experiment on the farm. The abalone population cultured in warmer southern waters was tolerant of ongoing high temperatures, whereas the abalone population originally cultured in cooler northern waters exhibited vulnerability to high temperatures but could enhance its thermal tolerance through the process of natural selection in warmer southern waters. This difference was linked to divergence in the metabolic and transcriptional processes of the two populations. The tolerant population exhibited a greater capacity for carbohydrate and amino acid metabolism regulation and energy redistribution to cope with heat stress. This capacity may have been selected for, and accumulated, over many generations because the tolerant population originated from the intolerant population over two decades ago. This work provides insight into the vulnerability and acclimation potential of abalone to heat stress and discloses the molecular and metabolic traits underlying this phenomenon. Future research on the ability of abalone and other commercial shellfish species to acclimate to global warming should take this potential into account.

Reproduction strategy of nocturnal marine molluscs: running for love.

The cost of reproduction is the core driver of life history evolution in animals. This paper demonstrates that the cumulative distance moved and the duration of movement of sexually immature abalones, Haliotis discus hannai, kept in various male and female groups, were significantly higher than those of sexually mature individuals, except when kept in mixed cultures of mature males and females. After mixed-culture, sexually mature males moved significantly further and for a longer duration than mature female abalones, and even more so than mature male abalones of any other group. Examination of the LC-MS metabolomics of mature males cultured with sexually mature females (AM) and those cultured with sexually immature females (JM) showed that cyclic adenosine monophosphate (cAMP) acted as a differential metabolic biomarker. After 24-h uninterrupted sampling, the concentration of 5-HT and the expression levels of the 5-HT2 and 5-HT6 receptors in AM were significantly higher than those in JM. After further injection of 5-HT2 and 5-HT6 receptor antagonists, the concentrations of cAMP and PKA rose again, but the cumulative movement duration and distance of male abalones decreased significantly, showing that 5-HT was involved in the regulation of movement behavior of male abalones through the 5-HT2 and 5-HT6 receptor-activated cAMP-PKA pathways. The results demonstrated a significant increase in the movement endurance of mature male abalones cultured with mature females, providing a theoretical basis for understanding the adaptive life history strategies of abalones and suggesting ways to protect diverse benthic resources for abalones during the reproductive stage.

Divergent Carry-Over Effects of Hypoxia during the Early Development of Abalone.

After being exposed to environmental stimuli during early developmental stages, some organisms may gain or weaken physiological regulating abilities, which would have long-lasting effects on their performance. Environmental hypoxia events can have significant effects on marine organisms, but for breeding programs and other practical applications, it is important to further explore the long-term physiological effects of early hypoxia exposure in economically significant species. In this study, the Pacific abalone Haliotis discus hannai was exposed to moderate hypoxia (∼4 mg/L) from zygote to trochophora, and the assessments of hypoxia tolerance were conducted on the grow-out stage. The results revealed that juvenile abalones exposed to hypoxia at the early development stages were more hypoxia-tolerant but with slower weight growth, a phenomenon called the trade-off between growth and survival. These phenotypic effects driven by the hypoxia exposure were explained by strong selection of genes involved in signal transduction, autophagy, apoptosis, and hormone regulation. Moreover, long non-coding RNA regulation plays an important role modulating carry-over effects by controlling DNA replication and repair, signal transduction, myocardial activity, and hormone regulation. This study revealed that the ability to create favorable phenotypic differentiation through genetic selection and/or epigenetic regulation is important for the survival and development of aquatic animals in the face of rapidly changing environmental conditions.

Effects of one-year exposure to ocean acidification on two species of abalone.

Ocean acidification (OA) resulting from the absorption of excess atmospheric CO2 by the ocean threatens the survival of marine calcareous organisms, including mollusks. This study investigated the effects of OA on adults of two abalone species (Haliotis diversicolor, a subtropical species, and Haliotis discus hannai, a temperate species). Abalone were exposed to three pCO2 conditions for 1 year (ambient, ~ 880, and ~ 1600 µatm), and parameters, including mortality, physiology, immune system, biochemistry, and carry-over effects, were measured. Survival decreased significantly at ~ 800 µatm pCO2 for H. diversicolor, while H. discus hannai survival was negatively affected only at a higher OA level (~ 1600 µatm pCO2). H. diversicolor exhibited depressed metabolic and excretion rates and a higher O:N ratio under OA, indicating a shift to lipids as a metabolism substrate, while these physiological parameters in H. discus hannai were robust to OA. Both abalone failed to compensate for the pH decrease of their internal fluids because of the lowered hemolymph pH under OA. However, the reduced hemolymph pH did not affect total hemocyte counts or tested biomarkers. Additionally, H. discus hannai increased its hemolymph protein content under OA, which could indicate enhanced immunity. Larvae produced by adults exposed to the three pCO2 levels were cultured in the same pCO2 conditions and larval deformation and shell length were measured to observe carry-over effects. Enhanced OA tolerance was observed for H. discus hannai exposed under both of the OA treatments, while that was only observed following parental pCO2 ~ 880 µatm exposure for H. diversicolor. Following pCO2 ~ 1600 µatm parental exposure, H. diversicolor offspring exhibited higher deformation and lower shell growth in all pCO2 treatments. In general, H. diversicolor were more susceptible to OA compared with H. discus hannai, suggesting that H. diversicolor could be unable to adapt to acidified oceans in the future.

Genomic selection applications can improve the environmental performance of aquatics: A case study on the heat tolerance of abalone.

Aquaculture is one of the world's fastest-growing and most traded food industries, but it is under the threat of climate-related risks represented by global warming, marine heatwave (MHW) events, ocean acidification, and deoxygenation. For the sustainable development of aquaculture, selective breeding may be a viable method to obtain aquatic economic species with greater tolerance to environmental stressors. In this study, we estimated the heritability of heat tolerance trait of Pacific abalone Haliotis discus hannai, performed genome-wide association studies (GWAS) analysis for heat tolerance to detect single nucleotide polymorphisms (SNPs) and candidate genes, and assessed the potential of genomic selection (GS) in the breeding of abalone industry. A total of 1120 individuals were phenotyped for their heat tolerance and genotyped with 64,788 quality-controlled SNPs. The heritability of heat tolerance was moderate (0.35-0.42) and the predictive accuracy estimated using BayesB (0.55 ± 0.05) was higher than that using GBLUP (0.40 ± 0.01). A total of 11 genome-wide significant SNPs and 2 suggestive SNPs were associated with heat tolerance of abalone, and 13 candidate genes were identified, including got2,znfx1,l(2)efl, and lrp5. Based on GWAS results, the prediction accuracy using the top 5K SNPs was higher than that using randomly selected SNPs and higher than that using all SNPs. These results suggest that GS is an efficient approach for improving the heat tolerance of abalone and pave the way for abalone selecting breeding programs in rapidly changing oceans.

AMPK regulates behavior and physiological plasticity of Haliotis discus hannai under different spectral compositions.

In natural environments, the spectral composition of incident light is often subject to drastic changes due to the abundance of suspended particles, floating animals, and plants in coastal waters. In this study, after four months of culturing under blue light (NB), orange light (NY), dark environment (ND), and natural light (NN), the shell length and weight-specific growth rate in Pacific abalone, Haliotis discus hannai, were ranked in the following order: NY > NN > ND > NB. To understand the growth differences in abalone under these different light environments, we first performed 24-h video monitoring and found that the cumulative movement distance and duration were lowest in group NB, whereas the cumulative movement distance and duration were significantly higher in group ND than in any other group (P < 0.05). In group NB, the time spent hidden underneath the attachment substrate accounted for 81% of the resting time, but this ratio was lowest in group ND, at only 37% (P < 0.05). Next, LC-MS metabolomics identified 201 and 105 metabolites in NB vs. NN, ND vs. NN, and NY vs. NN under the positive and negative ion modes, respectively. According to the fold changes and annotations for differential metabolites in the KEGG enrichment pathways, adenosine, NAD+, cGMP, and arachidonic acid were used as differential metabolism markers, and the AMPK signaling pathway was enriched in every comparison group, and thus investigated further. The gene sequences of three subtypes of AMPK were obtained by cloning and we found that the expression levels of AMPKα and AMPKγ, and the AMP content were significantly higher in group NB than in any other group (P < 0.05). In addition, the ATP contents and adenylate energy charge values were ranked in the following order: NY > NN > ND > NB. According to in situ hybridization analysis, the three subtype genes were widely expressed in the hepatopancreas. Finally, the contents of many lipid metabolites differed significantly among groups and the expression levels of the triglyceride hydrolysis-related gene hormone sensitive lipase and fatty acid oxidation-related gene carnitine palmitoyltransferase 1 were higher in groups ND and NB than in groups NN and NY according to fluorescence quantification PCR (P < 0.05). The expression levels of fatty acid synthase and acetyl-CoA carboxylase were significantly lower in groups ND and NB than in groups NN and NY (P < 0.05). These findings indicated that differences in the spectral composition of incident light could reshape the behavior and physiological metabolism in abalone by influencing the "energy switch" AMPK, thereby providing some insights into the mechanisms that allow nocturnal marine organisms to adapt to different lighting environments.

Role of Bmal1 in mediating the cholinergic system to regulate the behavioral rhythm of nocturnal marine molluscs.

The circadian rhythm is one of the most general and important rhythms in biological organisms. In this study, continuous 24-h video recordings showed that the cumulative movement distance and duration of the abalone, Haliotis discus hannai, reached their maximum values between 20:00-00:00, but both were significantly lower between 08:00-12:00 than at any other time of day or night (P < 0.05). To investigate the causes of these diel differences in abalone movement behavior, their cerebral ganglia were harvested at 00:00 (group D) and 12:00 (group L) to screen for differentially expressed proteins using tandem mass tagging (TMT) quantitative proteomics. Seventy-five significantly different proteins were identified in group D vs. group L. The differences in acetylcholinesterase (AchE) expression levels between day- and nighttime and the key role in the cholinergic nervous system received particular attention during the investigation. A cosine rhythm analysis found that the concentration of acetylcholine (Ach) and the expression levels of AchE tended to be low during the day and high at night, and high during the day and low at night, respectively. However, the rhythmicity of the diel expression levels of acetylcholine receptor (nAchR) appeared to be insignificant (P > 0.05). Following the injection of three different concentrations of neostigmine methylsulfate, as an AchE inhibitor, the concentration of Ach in the hemolymph, and the expression levels of nAchR in the cerebral ganglia increased significantly (P < 0.05). Four hours after drug injection, the cumulative movement distance and duration of abalones were significantly higher than those in the uninjected control group, and the group injected with saline (P < 0.05). The expression levels of the core diurnal clock Bmal1 over a 24-h period also tended to be high during the day and low at night. First, a co-immunoprecipitation assay demonstrated the binding between Bmal1 and AchE or nAchR. A dual-luciferase gene test and electrophoretic mobility shift assay showed that Bmal1 bound to the promoter regions of AchE and nAchR. Twenty-four hours after silencing the Bmal1 gene, the expression levels of AchE and nAchR decreased significantly compared to those of the dsEGFP and PBS control groups, further showing that Bmal1 mediates the cholinergic system to regulate the behavioral rhythm of abalone. These findings shed light on the endocrine mechanism regulating the rhythmic behavior of abalone, and provide a reference for understanding the life history adaptation strategies of nocturnal organisms and the proliferation and protection of bottom dwelling economically important organisms.

Transcriptome analysis reveals fluid shear stress (FSS) and atherosclerosis pathway as a candidate molecular mechanism of short-term low salinity stress tolerance in abalone.

BACKGROUND: Transcriptome sequencing is an effective tool to reveal the essential genes and pathways underlying countless biotic and abiotic stress adaptation mechanisms. Although severely challenged by diverse environmental conditions, the Pacific abalone Haliotis discus hannai remains a high-value aquaculture mollusk and a Chinese predominantly cultured abalone species. Salinity is one of such environmental factors whose fluctuation could significantly affect the abalone's cellular and molecular immune responses and result in high mortality and reduced growth rate during prolonged exposure. Meanwhile, hybrids have shown superiority in tolerating diverse environmental stresses over their purebred counterparts and have gained admiration in the Chinese abalone aquaculture industry. The objective of this study was to investigate the molecular and cellular mechanisms of low salinity adaptation in abalone. Therefore, this study used transcriptome analysis of the gill tissues and flow cytometric analysis of hemolymph of H. discus hannai (DD) and interspecific hybrid H. discus hannai ♀ x H. fulgens ♂ (DF) during low salinity exposure. Also, the survival and growth rate of the species under various salinities were assessed. RESULTS: The transcriptome data revealed that the differentially expressed genes (DEGs) were significantly enriched on the fluid shear stress and atherosclerosis (FSS) pathway. Meanwhile, the expression profiles of some essential genes involved in this pathway suggest that abalone significantly up-regulated calmodulin-4 (CaM-4) and heat-shock protein90 (HSP90), and significantly down-regulated tumor necrosis factor (TNF), bone morphogenetic protein-4 (BMP-4), and nuclear factor kappa B (NF-kB). Also, the hybrid DF showed significantly higher and sustained expression of CaM and HSP90, significantly higher phagocytosis, significantly lower hemocyte mortality, and significantly higher survival at low salinity, suggesting a more active molecular and hemocyte-mediated immune response and a more efficient capacity to tolerate low salinity than DD. CONCLUSIONS: Our study argues that the abalone CaM gene might be necessary to maintain ion equilibrium while HSP90 can offset the adverse changes caused by low salinity, thereby preventing damage to gill epithelial cells (ECs). The data reveal a potential molecular mechanism by which abalone responds to low salinity and confirms that hybridization could be a method for breeding more stress-resilient aquatic species.

Exploring the Intestinal Microbiota and Metabolome Profiles Associated With Feed Efficiency in Pacific Abalone (Haliotis discus hannai).

Feed efficiency (FE) is critical to the economic and environmental benefits of aquaculture. Both the intestines and intestinal microbiota play a key role in energy acquisition and influence FE. In the current research, intestinal microbiota, metabolome, and key digestive enzyme activities were compared between abalones with high [Residual feed intake (RFI) = -0.029] and low FE (RFI = 0.022). The FE of group A were significantly higher than these of group B. There were significant differences in intestinal microbiota structures between high- and low-FE groups, while higher microbiota diversity was observed in the high-FE group. Differences in FE were also strongly correlated to variations in intestinal digestive enzyme activity that may be caused by Pseudoalteromonas and Cobetia. In addition, Saprospira, Rhodanobacteraceae, Llumatobacteraceae, and Gaiellales may potentially be utilized as biomarkers to distinguish high- from low-FE abalones. Significantly different microorganisms (uncultured beta proteobacterium, BD1_7_clade, and Lautropia) were found to be highly correlated to significantly different metabolites [DL-methionine sulfoxide Arg-Gln, L-pyroglutamic acid, dopamine, tyramine, phosphatidyl cholines (PC) (16:0/16:0), and indoleacetic acid] in the high- and low-FE groups, and intestinal trypsin activity also significantly differed between the two groups. We propose that interactions occur among intestinal microbiota, intestinal metabolites, and enzyme activity, which improve abalone FE by enhancing amino acid metabolism, immune response, and signal transduction pathways. The present study not only elucidates mechanisms of variations in abalone FE, but it also provides important basic knowledge for improving abalone FE by modulating intestinal microbiota.

The Hippo Signaling Core Components YAP and TAZ as New Prognostic Factors in Lung Cancer.

Background: The Hippo pathway is an essential signaling cascade that regulates cell and organ growth. However, there is no consensus about (i) the expression levels of the Hippo signaling core components yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) in lung cancer, especially in small cell lung cancer (SCLC), or (ii) their association with the prognosis of patients with SCLC. Methods: We screened relevant articles and identified eligible studies in the PubMed, EMBASE, COCHRANE, and WanFang databases. A combined analysis was performed to investigate (i) the expression levels of the major effectors, YAP and TAZ, in lung cancer and its subsets and (ii) their prognostic role in lung cancer, especially in SCLC. Results: In total, 6 studies related to TAZ and 13 studies concerning YAP were enrolled in this meta-analysis. We found that high TAZ expression was significantly associated with poor overall survival (OS) of patients with non-small cell lung cancer (NSCLC) in the overall population [P h < 0.001, crude hazard ratio (HR) = 1.629, 95% CI = 1.199-2.214 for TAZ expression; P h = 0.029, adjusted HR = 2.127, 95% CI = 1.307-3.460 for TAZ], the Caucasian population (P h = 0.043, crude HR = 1.233, 95% CI = 1.030-1.477 for TAZ expression), and the Asian population (P h = 0.551, adjusted HR = 2.676, 95% CI = 1.798-3.982 for TAZ). Moreover, there was a significant negative association between YAP expression and an unsatisfactory survival of patients with lung cancer (P h = 0.327, crude HR = 1.652, 95% CI = 1.211-2.253 for YAP expression) and patients with NSCLC [disease-free survival (DFS): Ph = 0.693, crude HR = 2.562, 95% CI = 1.876-3.499 for YAP expression; Ph = 0.920, crude HR = 2.617, 95% CI = 1.690-4.052 for YAP-mRNA; OS: Ph = 0.878, crude HR = 1.777, 95% CI = 1.233-2.562 for YAP expression], especially in the Asian population (DFS: P h = 0.414, crude HR = 2.515, 95% CI = 1.755-3.063; OS: P h = 0.712, crude HR = 1.772, 95% CI = 1.214-2.587). However, no association was observed in the multivariate combined analysis. High YAP expression was significantly associated with short OS of patients with SCLC in our combined multivariate analysis in the Asian population (P h = 0.289, crude HR = 4.482, 95% CI = 2.182-9.209), but not with crude data (P h = 0.033, crude HR = 1.654, 95% CI = 0.434-6.300). Conclusion: The Hippo pathway is involved in carcinogenesis and progression of NSCLC and SCLC, and high expression levels of YAP and TAZ are independent and novel prognostic factors for lung cancer.

Review: Use of Electrophysiological Techniques to Study Visual Functions of Aquatic Organisms.

The light environments of natural water sources have specific characteristics. For the majority of aquatic organisms, vision is crucial for predation, hiding from predators, communicating information, and reproduction. Electroretinography (ERG) is a diagnostic method used for assessing visual function. An electroretinogram records the comprehensive potential response of retinal cells under light stimuli and divides it into several components. Unique wave components are derived from different retinal cells, thus retinal function can be determined by analyzing these components. This review provides an overview of the milestones of ERG technology, describing how ERG is used to study visual sensitivity (e.g., spectral sensitivity, luminous sensitivity, and temporal resolution) of fish, crustaceans, mollusks, and other aquatic organisms (seals, sea lions, sea turtles, horseshoe crabs, and jellyfish). In addition, it describes the correlations between visual sensitivity and habitat, the variation of visual sensitivity as a function of individual growth, and the diel cycle changes of visual sensitivity. Efforts to identify the visual sensitivity of different aquatic organisms are vital to understanding the environmental plasticity of biological evolution and for directing aquaculture, marine fishery, and ecosystem management.

Genomic insights into the adaptation and evolution of the nautilus, an ancient but evolving "living fossil".

The nautilus, commonly known as a "living fossil," is endangered and may be at risk of extinction. The lack of genomic information hinders a thorough understanding of its biology and evolution, which can shed light on the conservation of this endangered species. Here, we report the first high-quality chromosome-level genome assembly of Nautilus pompilius. The assembled genome size comprised 785.15 Mb. Comparative genomic analyses indicated that transposable elements (TEs) and large-scale genome reorganizations may have driven lineage-specific evolution in the cephalopods. Remarkably, evolving conserved genes and recent TE insertion activities were identified in N. pompilius, and we speculate that these findings reflect the strong adaptability and long-term survival of the nautilus. We also identified gene families that are potentially responsible for specific adaptation and evolution events. Our study provides unprecedented insights into the specialized biology and evolution of N. pompilius, and the results serve as an important resource for future conservation genomics of the nautilus and closely related species.