RNA splicing modulates the postharvest physiological deterioration of cassava storage root.

Rapid postharvest physiological deterioration (PPD) of cassava (Manihot esculenta Crantz) storage roots is a major constraint that limits the potential of this plant as a food and industrial crop. Extensive studies have been performed to explore the regulatory mechanisms underlying the PPD processes in cassava to understand their molecular and physiological responses. However, the exceptional functional versatility of alternative splicing (AS) remains to be explored during the PPD process in cassava. Here, we identified several aberrantly spliced genes during the early PPD stage. An in-depth analysis of AS revealed that the abscisic acid (ABA) biosynthesis pathway might serve as an additional molecular layer in attenuating the onset of PPD. Exogenous ABA application alleviated PPD symptoms through maintaining ROS generation and scavenging. Interestingly, the intron retention transcript of MeABA1 (ABA DEFICIENT 1) was highly correlated with PPD symptoms in cassava storage roots. RNA yeast three-hybrid and RNA immunoprecipitation assays showed that the serine/arginine-rich protein MeSCL33 (SC35-like splicing factor 33) binds to the precursor mRNA of MeABA1. Importantly, overexpressing MeSCL33 in cassava conferred improved PPD resistance by manipulating the AS and expression levels of MeABA1 and then modulating the endogenous ABA levels in cassava storage roots. Our results uncovered the pivotal role of the ABA biosynthesis pathway and RNA splicing in regulating cassava PPD resistance and proposed the essential roles of MeSCL33 for conferring PPD resistance, broadening our understanding of SR proteins in cassava development and stress responses.

Identification of Growth-Related Gene BAMBI and Analysis of Gene Structure and Function in the Pacific White Shrimp Litopenaeus vannamei.

As one of the most important aquaculture species in the world, the improvement of growth traits of the Pacific white shrimp (Litopenaeus vannamei), has always been a primary focus. In this study, we conducted SNP-specific locus analysis and identified a growth-related gene, BAMBI, in L. vannamei. We analyzed the structure and function of LvBAMBI using genomic, transcriptomic, metabolomic, and RNA interference (RNAi) assays. The LvBAMBI possessed highly conserved structural domains and widely expressed in various tissues. Knockdown of LvBAMBI significantly inhibited the gain of body length and weight of the shrimp, underscoring its role as a growth-promoting factor. Specifically, knockdown of LvBAMBI resulted in a significant downregulation of genes involved in lipid metabolism, protein synthesis, catabolism and transport, and immunity. Conversely, genes related to glucose metabolism exhibited significant upregulations. Analysis of differential metabolites (DMs) in metabolomics further revealed that LvBAMBI knockdown may primarily affect shrimp growth by regulating biological processes related to lipid and glucose metabolism. These results suggested that LvBAMBI plays a crucial role in regulating lipid metabolism, glucose metabolism, and protein transport in shrimp. This study provides valuable insights for future research and utilization of BAMBI genes in shrimp and crustaceans.

Structure and function analyses of the SRC gene in Pacific white shrimp Litopenaeus vannamei.

SRC gene encodes scavenger receptor class C, a member of the scavenger receptor family, and has only been identified and investigated in invertebrates. Our previous studies have revealed that SRC is a novel candidate gene associated with body weight in Pacific white shrimp (Litopenaeus vannamei). In order to comprehend the underlying mechanism by which LvSRC affects shrimp growth, we analyzed the structure, phylogeny, expression profiles and RNA interference (RNAi) of this gene in L. vannamei. We found that LvSRC contains two CCP domains and one MAM domain, with the highest expression level in the heart and relatively low expression level in other tissues. Notably, LvSRC exhibited significantly higher expression levels in the fast-growing group among groups with different growth rates, suggesting its potential involvement as a gene contributing to the growth of L. vannamei. RNAi of LvSRC inhibited body length and body weight gain compared to the control groups. Moreover, through RNA-seq analysis, we identified 598 differentially expressed genes (DEGs), including genes associated with growth, immunity, protein processing and modification, signal transduction, lipid synthesis and metabolism. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed significant changes in the signaling pathways related to growth, lipid metabolism and immune response, suggesting that LvSRC exhibits the potential to participate in diverse physiological processes and immune regulation. These findings deepen our understanding of the structure and function of the SRC in shrimp and lay the foundation for further research into the regulatory mechanism of LvSRC. Additionally, they provide potential applications in shrimp genetics and breeding.

Identification of the domestication gene GmCYP82C4 underlying the major quantitative trait locus for the seed weight in soybean.

KEY MESSAGE: A major quantitative trait locus (QTL) for the hundred-seed weight (HSW) was identified and confirmed in the two distinct soybean populations, and the target gene GmCYP82C4 underlying this locus was identified that significantly associated with soybean seed weight, and it was selected during the soybean domestication and improvement process. Soybean is a major oil crop for human beings and the seed weight is a crucial goal of soybean breeding. However, only a limited number of target genes underlying the quantitative trait loci (QTLs) controlling seed weight in soybean are known so far. In the present study, six loci associated with hundred-seed weight (HSW) were detected in the first population of 573 soybean breeding lines by genome-wide association study (GWAS), and 64 gene models were predicted in these candidate QTL regions. The QTL qHSW_1 exhibits continuous association signals on chromosome four and was also validated by region association study (RAS) in the second soybean population (409 accessions) with wild, landrace, and cultivar soybean accessions. There were seven genes in qHSW_1 candidate region by linkage disequilibrium (LD) block analysis, and only Glyma.04G035500 (GmCYP82C4) showed specifically higher expression in flowers, pods, and seeds, indicating its crucial role in the soybean seed development. Significant differences in HSW trait were detected when the association panels are genotyped by single-nucleotide polymorphisms (SNPs) in putative GmCYP82C4 promoter region. Eight haplotypes were generated by six SNPs in GmCYP82C4 in the second soybean population, and two superior haplotypes (Hap2 and Hap4) of GmCYP82C4 were detected with average HSW of 18.27 g and 18.38 g, respectively. The genetic diversity of GmCYP82C4 was analyzed in the second soybean population, and GmCYP82C4 was most likely selected during the soybean domestication and improvement process, leading to the highest proportion of Hap2 of GmCYP82C4 both in landrace and cultivar subpopulations. The QTLs and GmCYP82C4 identified in this study provide novel genetic resources for soybean seed weight trait, and the GmCYP82C4 could be used for soybean molecular breeding to develop desirable seed weight in the future.

CRISPR/Cas9-mediated gene mutation of EcIAG leads to sex reversal in the male ridgetail white prawn Exopalaemon carinicauda.

In the culture of crustaceans, most species show sexual dimorphism. Monosex culture is an effective approach to achieve high yield and economic value, especially for decapods of high value. Previous studies have developed some sex control strategies such as manual segregation, manipulation of male androgenic gland and knockdown of the male sexual differentiation switch gene encoding insulin-like androgenic gland hormone (IAG) in decapods. However, these methods could not generate hereditable changes. Genetic manipulation to achieve sex reversal individuals is absent up to now. In the present study, the gene encoding IAG (EcIAG) was identified in the ridgetail white prawn Exopalaemon carinicauda. Sequence analysis showed that EcIAG encoded conserved amino acid structure like IAGs in other decapod species. CRISPR/Cas9-mediated genome editing technology was used to knock out EcIAG. Two sgRNAs targeting the second exon of EcIAG were designed and microinjected into the prawn zygotes or the embryos at the first cleavage with commercial Cas9 protein. EcIAG in three genetic males was knocked out in both chromosome sets, which successfully generated sex reversal and phenotypic female characters. The results suggest that CRISPR/Cas9-mediated genome editing technology is an effective way to develop sex manipulation technology and contribute to monosex aquaculture in crustaceans.

Penaeid Shrimp Chromosome Studies Entering the Post-Genomic Era.

Chromosome studies provide the foundation for comprehending inheritance, variation, systematics, and evolution. Penaeid shrimps are a group of crustaceans with great economic importance. Basic cytogenetic information obtained from these shrimps can be used to study their genome structure, chromosome relationships, chromosome variation, polyploidy manipulation, and breeding. The study of shrimp chromosomes experienced significant growth in the 1990s and has been closely linked to the progress of genome research since the application of next-generation sequencing technology. To date, the genome sequences of five penaeid shrimp species have been published. The availability of these genomes has ushered the study of shrimp chromosomes into the post-genomic era. Currently, research on shrimp cytogenetics not only involves chromosome counting and karyotyping, but also extends to investigating submicroscopic changes; exploring genome structure and regulation during various cell divisions; and contributing to the understanding of mechanisms related to growth, sexual control, stress resistance, and genome evolution. In this article, we provide an overview of the progress made in chromosome research on penaeid shrimp. We emphasize the mutual promotion between studies on chromosome structure and genome research and highlight the impact of chromosome-level assembly on studies of genome structure and function. Additionally, we summarize the emerging trends in post-genomic-era shrimp chromosome research.

An ancient whole-genome duplication in barnacles contributes to their diversification and intertidal sessile life adaptation.

INTRODUCTION: Whole-genome duplication (WGD) is one of the most sudden and dramatic events rarely reported in invertebrates, but its occurrence can lead to physiological, morphological, and behavioral diversification. WGD has also never been reported in barnacles, which is one of the most unique groups of crustaceans with extremely speciallized morphology (calcareous shells) and habits (intertidal sessile lifestyle). OBJECTIVES: To investigate whether WGD has occurred in barnacles and examine its potential role in driving the adaptive evolution and diversification of barnacles. METHODS: Based on a newly sequenced and assembled chromosome-level barnacle genome, a novel WGD event has been identified in barnacles through a comprehensive analysis of interchromosomal synteny, the Hox gene cluster, and synonymous substitution distribution. RESULTS: We provide ample evidences for WGD in the barnacle genomes. Comparative genomic analysis indicates that this WGD event predates the divergence of Thoracicalcarea, occurring more than 247 million years ago. The retained ohnologs from the WGD are primarily enriched in various pathways related to environmental information processing, shedding light on the adaptive evolution and diversification of intertidal sessile lifestyle. In addition, transcriptomic analyses show that most of these ohnologs were differentially expressed following the ebb of tide. And the cytochrome P450 ohnologs with differential expression patterns are subject to subfunctionalization and/or neofunctionalization for intertidal adaptation. Besides WGD, parallel evolution underlying intertidal adaptation has also occurred in barnacles. CONCLUSION: This study revealed an ancient WGD event in the barnacle genomes, which is potentially associated with the origin and diversification of thoracican barnacles, and may have contributed to the adaptive evolution of their intertidal sessile lifestyle.

Structure and function analyses of the Mmd2 gene in pacific white shrimp Litopenaeus vannamei.

Monocyte to macrophage differentiation factor 2 gene (Mmd2) encodes a member of the progestin and adipoQ receptor (PAQR) family, and plays a key role in growth and development. Our previous studies had found Mmd2 (Monocyte to macrophage differentiation factor 2) is a new candidate gene for growth traits in Pacific white shrimp (Litopenaeus vannamei). For the purpose of understanding the underlying mechanism of LvMmd2 affecting the growth of shrimp, we analyzed the gene structure, phylogeny, expression profiles and RNA interference of this gene in L. vannamei. We found the LvMmd2 gene sequence was highly conserved in transmembrane regions, it was widely expressed in different tissues, with the highest expression level in the eye stalk. Knockdown LvMmd2 could significantly promote body length and body weight gain, suggesting it is a growth suppressor. Through transcriptome analysis we identified 422 differentially expressed genes (DEGs) between the dsMmd2 group and control group, among which 337 genes were upregulated in the dsMmd2 group, including numerous muscle-related genes and protein synthesis genes. Further bioinformatics analysis showed that growth, metabolism, and immune-related signal pathway had changed significantly. The above results greatly increase our understanding on the conservative structure and function of LvMmd2 gene, and provide potential application prospects in genetics and breeding.

The Responses of Alternative Splicing during Heat Stress in the Pacific White Shrimp Litopenaeus vannamei.

Heat tolerance is increasingly becoming a crucial trait for aquaculture species in the face of rapidly changing climate conditions. Alternative splicing (AS) is a vital mechanism within cells that modulates gene abundance and functional diversity, enabling organisms to effectively respond to diverse stressful conditions, including thermal stress. However, it is still uncertain whether AS contributes to heat tolerance in shrimp. In this study, we conducted an extensive transcriptome analysis on the Pacific white shrimp, Litopenaeus vannamei, revealing a total of 1267, 987, and 130 differential AS events (DAS) in the gill, hepatopancreas, and muscle, respectively, following exposure to heat stress. Among all of the DAS events, exon skipping (ES) was the predominant form of splicing modification observed. Interestingly, a minor portion of DAS genes exhibited overlap across the three tissues, implying that heat stress exerts unique effects on various tissue types. Moreover, the functional enrichment analysis demonstrated that commonly identified DAS genes were primarily associated with the "spliceosome" pathway, indicating that the AS of splicing-related genes played a crucial role in the response to heat stress. Our findings also revealed that heat stress tended to induce longer mRNA isoforms through differential alternative 3' splice site (A3SS) events. Notably, A3SS events exhibited the highest proportion of maintained open reading frames (ORFs) under heat stress. Interestingly, we observed a limited overlap between the genes exhibiting DAS and those showing differential gene expression (DEG), indicating that AS may function as a distinct regulatory mechanism independent of transcriptional regulation in response to heat stress. This is the first comprehensive study on AS in crustacea species under heat stress, which broadens our understanding of the regulatory mechanisms governing the crustaceans' response to environmental stress, providing valuable insights for the aquaculture breeding of shrimp and other aquatic animals.

ACD-containing chaperones reveal the divergent thermo-tolerance in penaeid shrimp.

The α-crystallin domain-containing (ACD-containing) gene family, which includes typical small heat shock proteins (sHSPs), is the most ubiquitous and diverse family of putative chaperones in all organisms, including eukaryotes and prokaryotes. In the present study, approximately 54-117 ACD-containing genes were identified in five penaeid shrimp species, yielding a significant expansion in comparison with other crustaceans (generally 6-20 ACD-containing genes). Unlike typical sHSPs, which contain a single ACD domain, the ACD-containing genes of penaeid shrimp contain additional ACD domains (3-7 domains, in general), thus having a larger molecular weight and a more complex 3D structure. As indicated by the RNA-seq and qRT-PCR results, the ACD-containing genes of penaeid shrimp showed a strong response to high temperatures. Furthermore, heterologous expression and citrate synthase assays of three representative ACD-containing genes confirmed that their chaperone activity could enhance the thermo-tolerance of E. coli and prevent the aggregation of substrate proteins at high temperatures. Compared with penaeid shrimp species with a relatively low thermo-tolerance (Fenneropenaeus chinensis and Marsupenaeus japonicus), the species with high thermo-tolerance (Litopenaeus vannamei and Fenneropenaeus indicus) contained more ACD-containing genes due to tandem duplication and exhibited biased expression levels under high temperatures. This can explain the divergent thermo-tolerance of different penaeid shrimp species. In conclusion, the ACD-containing genes in penaeid shrimp could be assigned as new chaperones and contribute to their divergent thermo-tolerance phenotypes and adaptations to the ecological environment.

Gene Structure, Expression and Function Analysis of MEF2 in the Pacific White Shrimp Litopenaeus vannamei.

The Pacific white shrimp Litopenaeus vannamei is the most economically important crustacean in the world. The growth and development of shrimp muscle has always been the focus of attention. Myocyte Enhancer Factor 2 (MEF2), a member of MADS transcription factor, has an essential influence on various growth and development programs, including myogenesis. In this study, based on the genome and transcriptome data of L. vannamei, the gene structure and expression profiles of MEF2 were characterized. We found that the LvMEF2 was widely expressed in various tissues, mainly in the Oka organ, brain, intestine, heart, and muscle. Moreover, LvMEF2 has a large number of splice variants, and the main forms are the mutually exclusive exon and alternative 5' splice site. The expression profiles of the LvMEF2 splice variants varied under different conditions. Interestingly, some splice variants have tissue or developmental expression specificity. After RNA interference into LvMEF2, the increment in the body length and weight decreased significantly and even caused death, suggesting that LvMEF2 can affect the growth and survival of L. vannamei. Transcriptome analysis showed that after LvMEF2 was knocked down, the protein synthesis and immune-related pathways were affected, and the associated muscle protein synthesis decreased, indicating that LvMEF2 affected muscle formation and the immune system. The results provide an important basis for future studies of the MEF2 gene and the mechanism of muscle growth and development in shrimp.

Study on Dissociation and Chemical Structural Characteristics of Areca Nut Husk.

From the perspective of full-component utilization of woody fiber biomass resources, areca nut husk is an excellent woody fiber biomass feedstock because of its fast regeneration, significant regeneration ability, sustainability, low cost, and easy availability. In this study, fiber cell morphologies, chemical compositions, lignin structures, and carbohydrate contents of areca nut husks were analyzed and compared with those of rice straw, and the application potentials of these two materials as biomass resources were compared. We found that areca nut husk fibers were shorter and wider than those of rice straw; areca nut husk contained more lignin and less ash, as well as less holocellulose than rice straw; areca nut husk and rice straw lignin were obtained by ball milling and phase separation, and areca nut husk lignin was found to be a typical GHS-type lignin. Herein, the yield of lignocresol was higher than that of milled wood lignin for both raw materials, and the molecular size was more homogeneous. Tricin structural monomers were discovered in the lignin of areca nut husk, similar to those present in other types of herbaceous plants. Structures of areca nut husk MWL (AHMWL) and AHLC were comprehensively characterized by quantitative NMR techniques (that is, 1H NMR, 31P NMR, and 2D NMR). The molecular structure of AHLC was found to be closer to the linear structure with more functional groups exposed on the molecular surface, and the hydroxyl-rich p-cresol grafting structure was successfully introduced into the lignin structure. In addition, the carbohydrate content in the aqueous layer of the phase separation system was close to the carbohydrate content in the raw material, indicating that the phase separation method can precisely separate lignin from carbohydrates. These experimental results indicate that the phase separation method as a method for lignin utilization and structure study has outstanding advantages in lignin structure regulation and yield, and areca nut husk lignin is suitable for application in the same phase separation systems as short-period herbs, such as rice straw and wheat grass, and has the advantages of low ash content and high lignification degree, which will provide guidance for the high-value utilization of areca nut husk in the future.

CRISPR/Cas9-mediated mutation on an insulin-like peptide encoding gene affects the growth of the ridgetail white prawn Exopalaemon carinicauda.

Insulin-like peptides (ILPs) play key roles in animal growth, metabolism and reproduction in vertebrates. In crustaceans, one type of ILPs, insulin-like androgenic gland hormone (IAG) had been reported to be related to the sex differentiations. However, the function of other types of ILPs is rarely reported. Here, we identified another type of ILPs in the ridgetail white prawn Exopalaemon carinicauda (EcILP), which is an ortholog of Drosophila melanogaster ILP7. Sequence characterization and expression analyses showed that EcILP is similar to vertebrate insulin/IGFs and insect ILPs in its heterodimeric structure and expression profile. Using CRISPR/Cas9 genome editing technology, we generated EcILP knockout (KO) prawns. EcILP-KO individuals have a significant higher growth-inhibitory trait and mortality than those in the normal group. In addition, knockdown of EcILP by RNA interference (RNAi) resulted in slower growth rate and higher mortality. These results indicated that EcILP was an important growth regulator in E. carinicauda.

Reference intervals of complete blood count parameters for individuals aged 80 to 89 years in Guizhou, China: A STROBE-compliant retrospective study.

The reference intervals of complete blood count (CBC) parameters were commonly based on healthy individuals aged 20 to 79 years. However, these values are not optimal for correct clinical diagnosis in older individuals (e.g., 80-89 years). Although the reference intervals for this age group have been reported in China, there is no population-based report in Guizhou province. A total of 481 healthy adults (238 males and 243 females) aged 80 to 89 years were recruited from Affiliated Hospital of Zunyi Medical University in Guizhou. The CBC parameters were detected by Sysmex XN-9000 automatic hematology analyzer. The reference intervals of the components were analyzed according to the guidelines of International Federation of Clinical Chemistry. This study reported the reference intervals of CBC parameters. There were significant differences were examined in some reference intervals between the different gender groups, especially for RBC-related parameters. Compared with national standards, the most of all conventional reference intervals for CBC parameters were decreased. The present study provided the local reference intervals of CBC parameters for individuals aged 80 to 89 years in Guizhou, China. Some of our results were sex-specific, and most of our results show lower values while comparing with commonly used reference intervals in China. Therefore, more attentions should be paid to these differences, and accurate reference intervals will facilitate clinical diagnosis and decision-making in these populations.

Convergent evolution of barnacles and molluscs sheds lights in origin and diversification of calcareous shell and sessile lifestyle.

The calcareous shell and sessile lifestyle are the representative phenotypes of many molluscs, which happen to be present in barnacles, a group of unique crustaceans. The origin of these phenotypes is unclear, but it may be embodied in the convergent genetics of such distant groups (interphylum). Herein, we perform comprehensive comparative genomics analysis in barnacles and molluscs, and reveal a genome-wide strong convergent molecular evolution between them, including coexpansion of biomineralization and organic matrix genes for shell formation, and origination of lineage-specific orphan genes for settlement. Notably, the expanded biomineralization gene encoding alkaline phosphatase evolves a novel, highly conserved motif that may trigger the origin of barnacle shell formation. Unlike molluscs, barnacles adopt novel organic matrices and cement proteins for shell formation and settlement, respectively, and their calcareous shells have potentially originated from the cuticle system of crustaceans. Therefore, our study corroborates the idea that selection pressures driving convergent evolution may strongly act in organisms inhabiting similar environments regardless of phylogenetic distance. The convergence signatures shed light on the origin of the shell and sessile lifestyle of barnacles and molluscs. In addition, notable non-convergence signatures are also present and may contribute to morphological and functional specificities.

Uncovering a Phenomenon of Active Hormone Transcriptional Regulation during Early Somatic Embryogenesis in Medicago sativa.

Somatic embryogenesis (SE) is a developmental process in which somatic cells undergo dedifferentiation to become plant stem cells, and redifferentiation to become a whole embryo. SE is a prerequisite for molecular breeding and is an excellent platform to study cell development in the majority of plant species. However, the molecular mechanism involved in M. sativa somatic embryonic induction, embryonic and maturation is unclear. This study was designed to examine the differentially expressed genes (DEGs) and miRNA roles during somatic embryonic induction, embryonic and maturation. The cut cotyledon (ICE), non-embryogenic callus (NEC), embryogenic callus (EC) and cotyledon embryo (CE) were selected for transcriptome and small RNA sequencing. The results showed that 17,251 DEGs, and 177 known and 110 novel miRNAs families were involved in embryonic induction (ICE to NEC), embryonic (NEC to EC), and maturation (EC to CE). Expression patterns and functional classification analysis showed several novel genes and miRNAs involved in SE. Moreover, embryonic induction is an active process of molecular regulation, and hormonal signal transduction related to pathways involved in the whole SE. Finally, a miRNA-target interaction network was proposed during M. sativa SE. This study provides novel perspectives to comprehend the molecular mechanisms in M. sativa SE.

Mortar Designed from Red Mud with Iron Tailings and Moulded by 3D Printing.

A specific mortar material (abbreviated as RFT) was designed from industrial solid wastes, such as red mud, fly ash, and iron tailings. It was mainly developed for 3D printing in this work. Mechanical properties, microstructure and heavy metal leaching properties were discussed. The RFT composed of 15% red mud, 45% iron tailings, 9% fly ash, 30% cement, and 1% FDN water reducing agent attained good mechanical properties. Hydration products including Ca(OH)2, ettringite and C-S-H gel were found in RFT through SEM observation. Iron tailings mainly acted as fine aggregates in RFT, and they were wrapped by the C-S-H gels, producing a strong bonding effect between aggregates and cementitious matrix. The leaching toxicity test results proved that the developed RFT mortar materials were environmentally acceptable. Finally, RFT was subjected to a 3D printing test to verify its feasibility as 3D printable construction material.

Comparative transcriptomic analysis unveils a network of energy reallocation in Litopenaeus vannamei responsive to heat-stress.

Temperature serves as an important environmental factor in ecosystems. Understanding the cooperation of various tissues of animals in response to heat stress is the basis for clarifying the regulation mechanism of different species under heat stress. Herein, a comparative transcriptomic analysis was conducted on three tissues (hepatopancreas, gill and muscle) of the Pacific white shrimp Litopenaeus vannamei under heat stress. Three tissues displayed distinct gene expression patterns, suggesting a cooperation based on division of labor might have occurred among them. In hepatopancreas and gill, genes related to ATP generation and utilization were down-regulated, and energetically expensive protein turnover was almost shut down. While in muscle, genes related to ATP generation and utilization, and those involved in several energy-consuming processes were up-regulated. In consistent, significant accumulation of ATP and decrease of total protein concentration were detected in hepatopancreas and gill, while it was opposite in muscle. Therefore, we suggest that different tissues may cooperate with each other simultaneously via energy reallocation in response to heat stress. Less energy was channeled into protein turnover in gill and hepatopancreas, and more energy was required for muscle. This study not only provides a comprehensive understanding of the molecular mechanism of L. vannamei in response to high temperature, but also lays the foundation of mining thermotolerance genes and proposing effective strategies to cope with the high temperature environment.

Genome of a giant isopod, Bathynomus jamesi, provides insights into body size evolution and adaptation to deep-sea environment.

BACKGROUND: The deep-sea may be regarded as a hostile living environment, due to low temperature, high hydrostatic pressure, and limited food and light. Isopods, a species-rich group of crustaceans, are widely distributed across different environments including the deep sea and as such are a useful model for studying adaptation, migration, and speciation. Similar to other deep-sea organisms, giant isopods have larger body size than their shallow water relatives and have large stomachs and fat bodies presumably to store organic reserves. In order to shed light on the genetic basis of these large crustaceans adapting to the oligotrophic environment of deep-sea, the high-quality genome of a deep-sea giant isopod Bathynomus jamesi was sequenced and assembled. RESULTS: B. jamesi has a large genome of 5.89 Gb, representing the largest sequenced crustacean genome to date. Its large genome size is mainly attributable to the remarkable proliferation of transposable elements (84%), which may enable high genome plasticity for adaptive evolution. Unlike its relatives with small body size, B. jamesi has expanded gene families related to pathways of thyroid and insulin hormone signaling that potentially contribute to its large body size. Transcriptomic analysis showed that some expanded gene families related to glycolysis and vesicular transport were specifically expressed in its digestive organs. In addition, comparative genomics and gene expression analyses in six tissues suggested that B. jamesi has inefficient lipid degradation, low basal metabolic rate, and bulk food storage, suggesting giant isopods adopt a more efficient mechanism of nutrient absorption, storage, and utilization to provide sustained energy supply for their large body size. CONCLUSIONS: Taken together, the giant isopod genome may provide a valuable resource for understanding body size evolution and adaptation mechanisms of macrobenthic organisms to deep-sea environments.

The Role of Insulin-like Peptide in Maintaining Hemolymph Glucose Homeostasis in the Pacific White Shrimp Litopenaeus vannamei.

Insulin-like peptide (ILP) has been identified in various crustaceans, but whether it has a similar function in regulating hemolymph glucose as vertebrate insulin is unclear. We analyzed the components of hemolymph sugar in the Pacific white shrimp, Litopenaeus vannamei, and investigated the changes of hemolymph glucose concentration and the expressions of ILP and glucose metabolism genes under different treatments. We found glucose was a major component of hemolymph sugar in shrimp. Starvation caused hemolymph glucose to rise first and then decline, and the raised hemolymph glucose after exogenous glucose injection returned to basal levels within a short time, indicating that shrimp have a regulatory mechanism to maintain hemolymph glucose homeostasis. In addition, injections of bovine insulin and recombinant LvILP protein both resulted in a fast decline in hemolymph glucose. Notably, RNA interference of LvILP did not significantly affect hemolymph glucose levels, but it inhibited exogenous glucose clearance. Based on the detection of glucose metabolism genes, we found LvILP might maintain hemolymph glucose stability by regulating the expression of these genes. These results suggest that ILP has a conserved function in shrimp similar to insulin in vertebrates and plays an important role in maintaining hemolymph glucose homeostasis.