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Growing evidence suggests a close relationship between gut microbiota and infectious diseases. However, the specific role of gut microbiota in host-pathogen interactions during aquaculture-related infections remains poorly understood. This study investigated the diversity and composition of gut microbiota communities in Aeromonas veronii-infected Lateolabrax maculatus using high-throughput sequencing. The results revealed significant changes in the structure and composition of L. maculatus gut microbiota after A. veronii infection. Over time, Bacteroidetes and Firmicutes decreased significantly, while Proteobacteria increased significantly after A. veronii infection. Most intestinal bacteria showed a decline in abundance over time, with probiotics (such as Lactobacillus) experiencing a significant decrease and pathogens (such as Aeromonas) showing a significant increase. Conversely, no differences were observed in the structure and composition of gut microbiota between healthy L. maculatus and those infected with A. veronii after treatment with Lactobacillus plantarum; no changes in relative abundances of other bacterial phyla or genera except for Aeromonas. Furthermore, intestinal flora's structural diversity and composition differed significantly from untreated L. maculatus infected with A. veronii. These findings suggest alterations in the structure and composition of gut microbiota following A. veronii infection. L. plantarum can maintain a dynamic balance within the intestinal flora, reducing the potential risk of pathogen infections. [ABSTRACT FROM AUTHOR]

Spotted seabass (Lateolabrax maculatus) is a popular food fish in Asian countries. Not only does the fish tasted well, but it is also widely utilized as nutraceuticals. However, the knowledge about the composition of the fish is lack. In this work, the proximate composition of spotted seabass flesh was determined. The content of proximate composition (moisture, proteins, fat, and ash) of spotted seabass flesh was fell within the range of other reported fish species, while it was a high-quality food fish with low oil-very high protein. The ratio of essential amino acids (EAAs) to nonessential amino acids (NEAAs) was 0.74, and the amount of EAAs accounted for approximately 42.34% of the total amino acids. Unsaturated fatty acids composed the majority of the fatty acid components, with linoleic acid was the predominate one. The content of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were abundant in spotted seabass flesh. The proximate composition of the dorsal, ventral, lateral, and tail flesh was similar, except for the ventral flesh exhibited a higher content of fatty acids and lower content of moisture. Our research will be helpful for the general population to know the nutritional traits of spotted seabass. [ABSTRACT FROM AUTHOR]

The spotted sea bass (Lateolabrax maculatus) is an economically valuable cultured fish species in China. In this study, 20 novel polymorphic microsatellite loci of L. maculatus were isolated from genomic data and characterized using 40 wild individuals. The number of alleles and the effective number of alleles ranged from 2 to 12 (average of 5.1000) and from 1.180 to 8.000 (average of 3.3097). The observed and expected heterozygosities ranged from 0.083 to 0.875 (average of 0.4405) and from 0.153 to 0.875 (average of 0.5633), respectively. Deviation from the Hardy-Weinberg equilibrium was observed in 11 loci (P < 0.05). Polymorphism information content ranged from 0.141 to 0.862 (average of 0.5265) and most loci were heterozygous. Crossamplification trials in two cryptic congeneric species, the largemouth bass, Micropterus salmoides, and the barramundi, Lates calcarifer, achieved successful amplification of 16 primers. The microsatellite markers developed in this study could be used for research on genetic breeding of L. maculatus and genetic relationships among tested taxa. [ABSTRACT FROM AUTHOR]

The Chinese sea bass (Lateolabrax maculatus) is one of the most important marine aquaculture fish in China. Hypoxia represents a growing threat to L. maculatus in intensive mariculture. Here, effects of hypoxia and re-oxygenation conditions on physiological, biochemical responses and apoptosis-related genes expressions in L. maculatus were investigated. The results showed that the asphyxiation point and critical non-equilibrium point of adult L. maculatus were 0.39 mg/L and 1.17 mg/L dissolved oxygen, respectively. The concentrations of four inorganic ions (Na+, K+, Cl-, Ca2+) in serum and four red blood cell parameters levels (HCT, MCV, MCHC, RDW-CV) were significantly changed in hypoxic and re-oxygenated fish. The concentration of hepatic glycogen was decreased dramatically in re-oxygenated fish compared with control and hypoxic fish, which is contrary to the result of glucose, total cholesterol and triglyceride in serum. Moreover, the activities of certain myocardial enzymes (LDH, CK, CK-MB) were significantly increased in the serum occurred in cardiomyocytes during re-oxygenated condition, speculating that hypoxia/reoxygenation injury might be occurred in cardiomyocytes. The result of six apoptosisrelated genes expressions in heart of L. maculatus showed that pro-apoptotic genes (Cytc, Caspase3, Bax, Stat3) were significantly up-regulated in re-oxygenated condition whereas anti-apoptotic genes were (TET1, SGK1) expressed lower in re-oxygenated condition than that in normal. The experimental results suggested that hypoxia and re-oxygenation had a serious impact on L. maculatus, such as ion balance destroying, innate immune decreasing, oxygen carrying capacity changing, cardiomyocyte apoptosis. Especially, cardiomyocyte injury caused by hypoxia and re-oxygenation after hypoxia is very severely. These findings might be helpful for breeding management and future hypoxia stress study in L. maculatus. [ABSTRACT FROM AUTHOR]

Cyclin H is an important cell protein that plays a crucial role in cell division. In the present study, the cDNA of cyclin H (designated as Pmcyclin H) was identified from black tiger shrimp (Penaeus monodon) by expressed sequence tag (EST) analysis, and RACE techniques. The full length cDNA of Pmcyclin H is 1280bp, including a 5'-terminal un-translated region (5'UTR) of 63 bp, a 3'UTR of 218 bp with a poly (A) tail, and an open reading frame (ORF) of 999 bp encoding a polypeptide of 332 amino acids with a predicted molecular weight of 39 kDa, predicted pI of 6.39. Both Blast, and phylogenetic analysis, confirmed that Pmcyclin H is a new member of the shrimp cyclin H family. Using real-time PCR the mRNA expression of Pmcyclin H in eight tissues was examined, and mRNA transcript of Pmcyclin H was predominantly detectable in ovarian tissue, and to a lesser degree in the tissues of intestine, testis, stomach, and heart, but almost undetectable in the tissues of liver (hepar), brain, and muscle. The temporal expression of Pmcyclin H in different developmental stages of the ovaries was investigated by real-time PCR. During the six stages of ovarian development, one peak expression of Pmcyclin H was detected in stage II. All these results indicated that Pmcyclin H might be involved in the regulation of cell cycle and ovarian development of P. monodon. [ABSTRACT FROM AUTHOR]