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Volume 38 ， Issue 2 ， 2020
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- Keywords：upwelling;salinity;temperature4|2|1Updated：2023-04-27
Physics
Chemistry
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- Abstract：Trimethylamine N-oxide (TMAO) is one of the most important nutrients for bacteria in the deep-sea environment and is capable of improving pressure tolerance of certain bacterial strains. To assess the impact of TMAO on marine microorganisms,especially those dwelling in the deep-sea environment,we analyzed the bacterial community structure of deep-sea sediments after incubated under different conditions. Enrichments at 50 MPa and 0.1 MPa revealed that TMAO imposed a greater influence on bacterial diversity and community composition at atmospheric pressure condition than that under high hydrostatic pressure (HHP). We found that pressure was the primary factor that determines the bacterial community. Meanwhile,in total,238 bacterial strains were isolated from the enrichments,including 112 strains affiliated to 16 genera of 4 phyla from the Yap Trench and 126 strains affiliated to 11 genera of 2 phyla from the Mariana Trench. Treatment of HHP reduced both abundance and diversity of isolates,while the presence of TMAO mainly affected the diversity of isolates obtained. In addition,certain genera were isolated only when TMAO was supplemented. Taken together,we demonstrated that pressure primarily defines the bacterial community and culturable bacterial isolates. Furthermore,we showed for the first time that TMAO had distinct influences on bacterial community depending on the pressure condition. The results enriched the understanding of the significance of TMAO in bacterial adaptation to the deep-sea environment.Keywords：deep-sea bacteria;high hydrostatic pressure (HHP);trimethylamine N-oxide (TMAO);community structure4|2|1Updated：2023-04-27
- Abstract：Copper has long been utilized as a disinfectant for bacteria,but its impact on microbial communities attached to the steel surface in seawater remains unknown. In the present study,3 mooring chain steels of different copper contents are subjected to a 3-month marine field exposure,and the corrosion rate increases in the order of BR5 steel (without copper) < BR5CuH steel (0.8% copper) < BR5CuL steel (0.4% copper). The microbial community results show that copper introduction does not result in an obvious change in microbial quantity,but it alters the diversity,richness,and structure of microbial communities due to the variation in copper-resistance of different species. BR5CuH steel holds microbial communities with the highest percentage of some well-known corrosive microbes including sulfate-reducing bacteria,sulfuroxidizing bacteria,and iron-oxidizing bacteria,but possesses the lowest community diversity/richness owing to the toxicity of copper. The microbial community diversity/richness is stimulated by the low-copper content of BR5CuL steel,and this steel also carries an intermediate proportion of such corrosive bacteria. Both well-known corrosive bacteria and microbial community diversity/richness seem to be involved in the corrosion acceleration of copper-bearing mooring chain steels.Keywords：marine corrosion;microbially influenced corrosion;microbial community;mooring chain steel;copper introduction4|2|1Updated：2023-04-27
- Abstract：Saline lakes represent a particularly interesting aquatic environment for harboring high microbial diversity. However,the microbial diversity in different states and locations of saline lake is often overlooked. We studied for the first time the diversity and relative composition of the microbial communities in the Chagan Lake,NE China,and investigated the differences in microbial species and physical and chemical factors in different geographical localities of the lake. After extracting the total DNA of the sample,we tested the library with the established library,sequenced the qualified library with Illumina HiSeq 2500,and studied the bacterial diversity by 16S rRNA targeted metagenomics analysis. Results reveal that the highest microbial abundance in Chagan Lake at genus level was Proteobacterium followed by Actinomycetes and Bacteroides. In addition,we compared the microbial composition within the lake using alpha- and beta-diversity indices,showing that both diversity and evenness were the highest in the middle of the lake and lowest in the west of lake areas,and in the upper,middle,and lower depth of water columns,the low water column had the highest species number in the whole water environment,but the difference was not significant. We believe that physicochemical factors contribute to the formation of microbial community composition and diversity. In aquaculture industry,it is impossible apply horticulture for making full use of the spatial differences in the microbial composition of the water. Therefore,combining cultured aquatic animal with the most suitable microbial species is a good way to boost the breeding effect for greater economic value.Keywords：saline lake;aquatic environment;microbial diversity;physical and chemical factors;Chagan Lake5|3|0Updated：2023-04-27
- Abstract：Geographic isolation is a key factor in shaping the genetic structure of many fish species. Two sympatric species, Culter alburnus and C. mongolicus, are economically important fish that are widely distributed in China and have been recently used as new aquaculture species. We used the mitochondrial DNA control region (CR) as a marker to investigate the genetic structure of the two species. Phylogenetic analysis revealed two major lineages (Lineages I and II) that were highly consistent with geographical patterns for C. alburnus and C. mongolicus. Based on genetic distance, the Zhujiang (Pearl) River Basin (ZRB) populations potentially represented a cryptic subspecies, which might be differentiated as the result of strict geographic isolation, an earlier diverged event, or peripheral areas. Genetic diversity analysis suggested that the Changjiang (Yangtze) River Basin (CRB) populations are located at, or near the core region of their origination, not only due to the larger population size at the CRB, but also their habitat diversity and suitability for its survival, and the genetic diversity differences among basin populations were significant for the two species. Moreover, demographic analysis indicated that the two Culter species and most populations had undergone a period of population expansion during warm interglacial periods. However, the C. alburnus population of Huaihe River Basin (Weishan Lake) exhibited different patterns during the interglacial period, which may due to the latest diverged time of HRB and Weishan Lake located at the permafrost. Notably, the ZRB (in Songtao Reservoir) C. mongolicus population showed no genetic diversity and had a unique haplotype, which could be treated as a special gene pool for species conservation. In summary, geographic isolation is most likely responsible for the two Culter species distribution patterns.Keywords：Culter species;drainage basin;genetic differentiation;geographic isolation4|0|0Updated：2023-04-27
Ecology
- Abstract：Deep-sea organisms survive in an extremely harsh environment. There must be some genetic adaptation mechanisms for them. We systematically characterized and compared the complete mitochondrial genome (mitogenome) of a deep-sea crab (Chaceon granulates) with those of shallow crabs. The mitogenome of the crab was 16 126 bp in length, and encoded 37 genes as most of a metazoan mitogenome, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, and 2 ribosomal RNA (rRNA) genes. The gene arrangement and orientation was conserved in the crabs. However, a unique mitogenome element regulator, the origin of light-strand replication (OL), was firstly predicted in the present crab mitogenome. In addition, further positive selection analysis showed that two residues (33S in ND3 and 502I in ND5) in C. granulates mitogenome were positively selected, indicated the selective evolution of the deep-sea crab. Therefore, the mitogenome of deep-sea C. granulates showed a unique OL element and positive selection. These special features would influence the mitochondrial energy metabolism, and be involved in the adaptation of deepsea environment, such as oxygen deficits and low temperatures.Keywords：deep-sea organisms;mitochondrial genome;adaptation;Chaceon granulates4|0|4Updated：2023-04-27
- Abstract：This study aimed to characterize the morphological changes in the ovary of the female crab Neptunus pelagicus and to identify specific fractions of vitelloginin and vitelline molecules during primary and secondary vitellogenesis. Samples of the blue crab were collected from the Mediterranean Sea of Alexandria monthly during 2017. Ovaries and oocytes in primary and secondary vitellogenesis were detached and treated for histological test. Native polyacrylamide gel electrophoresis (PAGE) Bis-Tris Gels was applied to identify vitelloginin (VN) and vitelline (VL) molecules. Protein Analyses were done by PAGE-SDS. The initial degenerate primers were built regarding the conserved amino acid domains of the yolk proteins. Primary and secondary vitellogeneses consisted of 8 phases. Lipoprotein fraction with molecular weight 550 kDa was identified in the hemolymph in secondary vitellogenesis. Two protein fractions (VLI & VLII) were identified in secondary vitellogenic oocytes. The electrophoresis performed with extract of stage Ⅰ oocyte showed two protein fractions with molecular weights 550 kDa and 460 kDa. In stage Ⅱ and Ⅲ oocyte, 4 subunits were presented of 180, 195, 140 and 120 kDa in VLI and 2 subunits with molecular weight of 110 kDa and 95 kDa in VLII. Another two fractions in stage Ⅴ oocyte presented with molecular weights of 380 kDa and 360 kDa. Western blot analysis proved that both fractions were of four major polypeptide subunits with molecular weight of 180, 125, 90 and 85 kDa in each of the two VLs. The hybridization signal obtained by the Northern blot was detected in the hepatopancreas during ovarian cycle and in the ovary during secondary vitellogenesis. The result of the reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the mRNA that encodes the C-terminal region of the VN cDNA was found in the ovary in secondary vitellogenesis and in the hepatopancreas.Keywords：Neptunus pelagicus;vitellogenesis;vitelloginin and vitelline;native polyacrylamide gel electrophoresis (PAGE) Bis-Tris Gels;PAGE-SDS;western blot analysis;reverse transcriptionpolymerase chain reaction (RT-PCR)4|0|0Updated：2023-04-27
- Abstract：As an aquatic fish, the spotted halibut Verasper variegatus is highly susceptible to bacterial and virus infections. Tumor necrosis factor-alpha (TNF-α) as a cytokine could control the inflammatory responses. The functions of TNF-α in many species have been widely studied, particularly in mammals. However, little is known about the TNF-α functions in V. variegatus. We first cloned and sequenced the TNF-α gene in V. variegatus (VvTNF-α). The two conserved cysteine residues, transmembrane sequence, Thr-Leu motif, and TNF family signature, as well as the TA-rich motifs of its proteins related to inflammatory responses had high similarity to those of the other teleost and mammalian TNF-α. The phylogenetic analysis showed that VvTNF-α was consistent with TNF-α genes of other vertebrates. The VvTNF-α transcripts were extensively distributed in the peripheral blood leukocytes (PBLs), spleen, and gill, indicating that the VvTNF-α had a role in immune function. Furthermore, treatment with pathogen-associated molecular patterns (PAMPs) could induce a rapid and significant increase of VvTNF-α in the PBLs, which reveals that VvTNF-α does participate in the host immune responses against bacterial and viral pathogens. We found that VvTNF-α had an interesting expression pattern during metamorphosis, showing that the flatfish TNF-α may have some novel functions during specific developmental stages. In addition, the 3D structure prediction of VvTNF-α provided an indication of how it is likely to interact with other proteins. Therefore, VvTNF-α has multiple functions, and provides valuable information to explore novel functions of TNF-α.Keywords：tumor necrosis factor-alpha (TNF-α);Verasper variegatus;metamorphosis;peripheral blood leukocytes (PBLs);3D modeling;pathogen-associated molecular patterns (PAMPs)4|0|0Updated：2023-04-27
Biology
- Abstract：Turbot harbor a relatively remarkable ability to adapt to opposing osmotic challenges and are an excellent model species to study the physiological adaptations of flounder associated with osmoregulatory plasticity. The kidney transcriptome of turbot treated 24 h in water of hypo-salinity (salinity 5) and seawater (salinity 30) was sequenced and characterized. In silico analysis indicated that all unigenes had significant hits in seven databases. The functional annotation analysis of the transcriptome showed that the immune system and biological processes associated with digestion, absorption, and metabolism played an important role in the osmoregulation of turbot in response to hypo-salinity. Analysis of biological processes associated with inorganic channels and transporters indicated that mineral absorption and bile secretion contributed to iono-osmoregulation resulting in cell volume regulation and cell phenotypic plasticity. Moreover, we analyzed and predicted the mechanisms of canonical signaling transduction. Biological processes involved in renin secretion, ECM-receptor interaction, adherens junction, and focal adhesion played an important role in the plasticity phenotype in hypo-stress, while the signal transduction network composed of the MAPK signaling pathway and PI3K-Akt signaling pathway with GABAergic synapse, worked in hypoosmoregulation signal transduction in the turbot. In addition, analysis of the tissue specificity of targeted gene expression using qPCR during salinity stress was carried out. The results showed that the kidney, gill, and spleen were vital regulating organs of osmotic pressure, and the osmoregulation pattern of euryhaline fish differed among species.Keywords：osmoregulation mechanisms;Scophthalmus maximus;hypo-saline;signal transduction;cell volume regulation;gene expression4|0|1Updated：2023-04-27
- Abstract：Trachinotus blochii is one of the important commercial fish species. In this study, we aim to confirm the reliability reference genes in T. blochii during different bacterial challenge through quantitative real-time PCR (qRT-PCR). The expression of the seven selected genes in four immune organs (i.e., spleen, kidney, intestine, and gill) stimulated with Vibrio harveyi, Edwardsiella tarda, and Streptococcus agalactiae were determined by qRT-PCR. The PCR data was analyzed using the geNorm and NormFinder algorithms. The results showed the selection of the internal controls should be tissue specific when studying gene expression in response to bacterial stimulation. After 48 h of stimulation with V. harveyi, geNorm ranked EF1A/Actin, 18S rRNA/B2M, UBCE/B2M, and 18S rRNA/B2M, as the most stably expressed genes in spleen, kidney, intestine, and gill, respectively. After 48 h of stimulation with E. tarda, geNorm ranked 18S rRNA/EF1A, 18S rRNA/B2M, B2M/RPL13, and 18S rRNA/EF1A, as the most stably expressed genes in spleen, kidney, intestine, and gill, respectively. After 48 h of stimulation with S. agalactiae, 18S rRNA/ EF1A, 18S rRNA/B2M, B2M/Actin, and 18S rRNA/B2M were ranked as the most stably expressed genes in spleen, kidney, intestine, and gill, respectively. Compared to the results analyzed by geNorm, reference genes received similar rankings when using NormFinder software. The results showed that the reference genes appeared to be not only tissue specific, but also specific to the infecting species of bacteria. If one gene is preferred when T. blochii were infected by bacteria, 18S rRNA, B2M, B2M, 18S rRNA may be used in spleen, kidney, intestine, and gill, respectively.Keywords：Trachinotus blochii;housekeeping gene;expression stability;reference gene4|0|1Updated：2023-04-27
- Abstract：A complete mitogenome of T. lineatus from Lake Turkana in the Kenyan part was determined. It had a length of 16 470 bp, including 37 genes as found in teleosts with the typical gene order in these fishes. Mitogenomic comparison and phylogenetic analysis supported not only the morphology-based recognition of the pufferfish specimen from Lake Turkana as the Nile pufferfish, but also the identification of the Chinese specimen recently recorded as T. lineatus and its African source. The mitochondrial genome here amplified for the sample of T. lineatus from Lake Turkana also provides conclusive molecular evidence for the monophyletic nature of Tetraodon s.s., as it serves as a reference genome of this species used to clarify ambiguity in its identification in previous molecular studies.Keywords：Tetraodon lineatus;Kenya;mtDNA;phylogenetic analysis4|0|0Updated：2023-04-27
- Abstract：Korean freshwater snails of the genus Semisulcospira are widely distributed across East Asia. It has been a very popular nutritional food in Korea, and is an ecologically important water quality indicator because it lives only in clean water. However, no microsatellite markers have been generated to study the population genetic diversity of this genus. In the present study, we developed and characterized 18 novel microsatellite loci from Semisulcospira coreana genomic DNA. The microsatellites were isolated using 454 GS-FLX titanium sequencing and 18 markers were used for genotyping in S. coreana. In addition, we also tested the cross-species transferability of the microsatellite markers in four additional Semisulcospira spp. We identified 18 polymorphic loci and the number of alleles per loci, and their polymorphism information content values ranged from 2 to 17 and 0.203 to 0.902, respectively. The observed and expected heterozygosities of the loci ranged from 0.063 to 0.924 and 0.226 to 0.924, respectively. According to the analysis of the cross-species transferability of these markers, four species, S. forticosta, S. gottschei, S. tegulata, and S. libertina, showed a very high transferability (80%-85%). These results show that this set of nuclear markers could be useful for population genetics studies of this species and closely related species.Keywords：Semisulcospira;next-generation sequencing (NGS);microsatellite markers;cross-species transferability4|0|0Updated：2023-04-27
- Abstract：To explore effective physiological indexes to distinguish the resistant lines and susceptible lines of Pythium porphyrae, the causal agent of red rot disease of Pyropia yezoensis, and establish the disease-resistance breeding strategy, we obtained and analyzed the candidate resistant and susceptible lines by population selection. Gametophytes of the candidate lines were cultured in seawater containing Pyt. porphyrae zoospores. Antioxidase activities, including superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO), were measured and compared between the two lines before and after infection. In the resistant lines, SOD and POD activities increased and then decreased, but PPO activity rose with the prolongation of the infection time. The phenylalanine ammonia lyase (PAL) activities also increased and then decreased after infection, but it had significantly different expression in the two lines without pathogen attack. The synthesis rates of β-1, 3-glucanase, and cell-wall degrading enzyme were different from each other between the two lines after infection of Pyt. porphyrae. Comparison in the contents of malondialdehyde (MDA) and reactive oxygen species (ROS) in the two lines showed that, the two contents varied synchronously in response to the pathogen attack. Changes of these enzymes activities or contents demonstrated that Pyr. yezoensis could resist against the pathogen of Pyt. porphyrae with the antioxidant defense capacity. In addition, β-1.3-glucanase content showed extremely significant difference between the two lines, and the PAL had consistent expression difference. Therefore, phenylalanine ammonia lyase (PAL) and β-1, 3-glucanase can be considered as an effective index to distinguish susceptible line and resistant line, with which the workload of the resistant breeding could be reduced in the future.Keywords：population selection;resistant lines;susceptible lines;Pyropia yezoensis;Pythium porphyrae4|0|2Updated：2023-04-27
- Abstract：The unicellular green alga, Chlamydomonas reinhardtii is a model organism for studying various biological processes, such as photosynthesis, flagellar motility, and lipid metabolism. To find some novel genes regulating the lipid metabolism under various stress conditions, the paromomycin resistance gene aphVⅢ was transferred into the genome of C. reinhardtii to establish a mutant library. Two genes mutated in two of the TAG-reduced mutants (Cre06.g278111 in M2 mutant, Cre06.g278110 in M6 mutants) were neighboring in the genome, and their expression levels were down-regulated in their corresponding mutants in parallel with their reduced TAG levels following N deprivation. The proteins encoded by these two genes (KCN11 by Cre06.g278111, ACYC3 by Cre06.g278110) contained a conversed cyclic mononucleotide phosphate (cNMP) binding protein and an adenylate domain, respectively. Since cNMP binding protein and adenylate domain have been known as important components of cyclic adenosine monophosphate (cAMP) signaling pathway, suggesting that these two genes might affect cellular TAG biosynthesis through cAMP signal pathway.Keywords：Chlamydomonas reinhardtii;mutant;lipid droplet (LD);triacylglycerol (TAG);cyclic adenosine monophosphate (cAMP)4|0|0Updated：2023-04-27
- Abstract：The recombinant expression of phycocyanobilin (PCB) was carried out in Escherichia coli, and the best fermentation conditions of recombinant E. coli biosynthesized PCB are optimized in the response surface methodology to improve PCB production. The recombinant PCB is extracted, isolated, and purified by methanol and chloroform extraction. Recombinant PCB is validated in UV-vis spectroscopy, high-pressure liquid chromatography, and mass spectrometry. In addition, the anti-oxidant activities of the recombinant PCB are determined. The best induction conditions that optimized by Design Expert 8.0 software include:lactose concentration 4 mmol/L, induction temperature 24.69℃, induction time 4.6 h, and induction duration 13.57 h, under which the PCB expression level reached approximately 13 mg PCB/L, which is more than four times of previously reported 3 mg PCB/L. The maximum absorption peak of the recombinant PCB is located at 680 nm with a high fluorescence intensity of 470 nm. The recombinant PCB has a good ability to scavenge 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radicals.Keywords：combinational biosynthesis;phycocyanobilin;response surface methodology;antioxidant4|3|0Updated：2023-04-27
- Abstract：A new free-living marine nematode species of the genus Sabatieria was documented from the sediment of the Jiaozhou Bay, Qingdao, China, and it has been named Sabatieria sinica sp. nov. It is characterized by homogeneous cuticle without lateral differentiation, relatively short cephalic setae, spiral amphideal fovea with 2-2.25 turns; thick spicules with a mid constriction or joint, gubernaculum with a long straight dorso-caudal apophyses, and 6-7 prominent papillar precloacal supplements. This new species could be distinguished from other congener species by the combination of its characteristics:body size, length of cephalic setae, number of amphid turns, structures of spicules and gubernaculum, and type and number of precloacal supplements. An update dichotomous key is provided for nine species of pulchra group of Sabatieria including the new species.Keywords：new species;free-living marine nematode;taxonomy;Jiaozhou Bay4|2|1Updated：2023-04-27
- Abstract：A new free-living marine nematode species of the genus Rhinema belonging to the family Monoposthiidae was collected from marine sediments in the Qiongzhou Strait of the South China Sea, and it is described here as Rhinema longispicula sp. nov. The new species is characterized by coarsely annulated cuticle with 12 longitudinal ridges (alae) marked as reversed V-shaped. The first and second annuli broader and form a kind of a cephalic capsule. The amphideal fovea circular, situated in the middle of the broad second annulus, not surrounded by dense annulations. Buccal cavity cylindrical with a large dorsal tooth. Pharynx with a prominent anterior pharyngeal bulb and an elongated terminal bulb. Elongate spicules strongly curved, with cephalated proximal end and pointed distal end. Gubernaculum boat-shaped, without apophysis. A long and blunt precloacal seta present. Female with two opposed, outstretched ovaries.Keywords：Rhinema longispicula sp.nov.;free-living marine nematode;taxonomy4|0|1Updated：2023-04-27
- Abstract：Antibiotics are widespread in various environmental media, and may pose a potential threat to aquatic ecosystems and non-target aquatic organisms. Florfenicol (FLO) is one of the most commonly used antibiotics in aquaculture, and extensively used to substitute chloramphenicol with its strong sterilization and low adverse effect. In this study, flounder Paralichthys olivaceus, an important economic fish species in seawater was used as an experimental subject. Five exposure concentrations of FLO (including environmentrelated concentrations) were set at 0, 0.01, 0.1, 1, and 10 mg/L. Effects of FLO exposure for 168 h on growth and development, motor behavior, antioxidant enzyme activity, malondialdehyde (MDA) content, and thyroid hormone level of P. olivaceus larvae were studied in pre-larvae (1 dpf) and post-larvae (20 dpf). The results show that the short-term FLO exposure could promote the larvae growth to some degrees, but inhibit them as the exposure time prolonged. For pre-larvae, FLO at 0.01 mg/L could stimulate the motor nerve system and increase the swimming ability, but inhibited it at 1 mg/L. With the increasing dosage of FLO, the superoxide dismutase (SOD) and MDA contents were elevated, reaching the maximum in the 1 mg/L FLO group. The pre-larvae were more sensitive than the post-larvae to FLO in the environment, and the growth and immune resistance could be damaged with long exposure. Post-larvae were more tolerant to external pollutants, FLO at 1 mg/L could promote the motor behavior and reduce SOD and MDA contents. Therefore, FLO can be used as an antibiotic at a proper concentration but as a drug to prevent disease in a long-term way.Keywords：florfenicol;Paralichthys olivaceus larvae;growth and development;motor behavior;antioxidant capacity4|0|2Updated：2023-04-27
- Abstract：In this study, we established a new cell line (Cynoglossus semilaevis kidney cells, CSK) from kidney of the half-smooth tongue sole (Cynoglossus semilaevis). The cells were subcultured over 1 000 days and passaged for more than 100 times. Additionally, CSK cells were optimally maintained in Dulbecco's modified Eagle medium nutrient mixture F-12 supplemented with HEPES, antibiotics, fetal bovine serum, 2-mercaptoethanol, and basic fibroblast growth factor. The optimum growth temperature for CSK cells was 25℃, and the cells showed a fibroblast-like phenotype. Chromosome analysis revealed that CSK cells had a normal diploid karyotype with 2n=42. CSK cells were susceptible to Grouper nervous necrosis virus (NNV), and cytopathic effects were observed at 3-5 days postinfection. The NNV sensitivity of CSK cells was related to the high abundance of virions in the cytoplasm, as observed by electron microscopy. Additionally, CSK cells could be successfully transfected with a green fluorescent protein reporter plasmid, and fluorescent signals were easily observed. Finally, immunocytochemistry analysis showed that CSK cells were supporting cells. Overall, we established this new cell line, which may have potential applications in the identification of viral pathogens affecting the half-smooth tongue sole.Keywords：kidney cell line;Cynoglossus semilaevis;viral multiplication4|0|0Updated：2023-04-27
- Abstract：Gene expression variation can be considered as a phenotype, and it plays an important role in both acclimation and adaption. However, genetic variation of gene expression received much less attention than traditional commercial traits in aquaculture. To estimate the genetic variation and heritability of gene transcription in clam Meretrix petechialis, five Vibrio resistance-related genes were selected for gene expression analysis in the digestive gland, and an animal linear model was used to analyze data from quantitative real-time PCR (qRT-PCR). Among the five genes, BIRC7 showed significant additive genetic variations, the heritability of this gene of 12-month- and 15-month-old clams were 0.84±0.32 and 0.91±0.34, respectively. The heritability of other four genes (Bax, NFIL3, Big-Def, and CTL9) expression were low-tomoderate but not significantly expressed. Additionally, no significant phenotypic and genetic correlations between the BIRC7 transcription trait and body size were detected. This study highlights that certain gene expression variation is heritable and provides a reference for indirect selection of M. petechialis with high Vibrio resistance.Keywords：Meretrix petechialis;transcription trait;body size;heritability;genetic correlation4|0|0Updated：2023-04-27
- Abstract：Vibrio harveyi is a pathogen of various aquatic organisms that has been recently associated with massive mortality episodes in the aquaculture industry. Recurrent outbreaks of vibriosis are closely correlated with the capacity of this bacterial species to survive long-term starvation conditions. To study the regulation mechanism of gene expression at the transcriptional level in V. harveyi under starvation conditions,the transcriptomic response profiles were determined of the Portunus trituberculatus pathogen V. harveyi strain DY1 under normal conditions and after four weeks of starvation. A total of 4 679 and 4 661 genes were expressed in the non-starved and starved cells,respectively. The significantly differentially expressed genes (DEGs) between non-starved and starved groups were identified,in which 255 genes were up-regulated and 411 genes were down-regulated. GO analysis and KEGG enrichment analysis were used to analyze the DEGs and revealed the involvement of these DEGs in many pathways,including ABC transporters,flagellum assembly,and fatty acid metabolism. Several DEGs were randomly selected and their expression levels were confirmed by quantitative real-time PCR (qRT-PCR). This is the first comprehensive transcriptomic analysis of starvation effects in V. harveyi. Our findings will facilitate future study on stress adaptation and survival mechanisms of V. harveyi.Keywords：Vibrio harveyi;starvation stress;transcriptome sequencing;differentially expressed genes;adaptation and survival mechanisms4|0|0Updated：2023-04-27
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Aquaculture and Fisheries
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