Litopenaeus vannamei is one of the most economically valuable aquaculture species. In recent years, the shrimp industry has experienced considerable economic losses due to various diseases such as acute hepatopancreatic necrosis disease (AHPND). AHPND is a disease caused by certain strain of Vibrio parahaemolyticus carrying a specific plasmid pVA1. The pVA1 plasmid contains the pirA and pirB genes, which encode the main virulence factors of AHPND. In light of the dearth of effective treatment options, the development of expeditious, precise, and effective methodologies for detecting AHPND pathogens is imperative to prevent the onset of disease in shrimp farming. However, current nucleic acid based and antibody-based detection methods sometimes produce false positive results, affecting the reliability of diagnosis. This study aims to make a comparison of the content of the pirA and pirB virulence factors at the DNA, RNA, and protein levels in order to investigate whether there is a corresponding relationship between the pathogenic factors of AHPND at the nucleic acid and protein levels, which will provide a foundation for the selection of pathogen detection methods for shrimp. At the mRNA level, the expression level of pirA is significantly higher than that of pirB. Conversely, at the protein level, the expression level of PirB protein is much higher than that of PirA protein, indicating that the results of the two different detection methods are contradictory. Therefore, relying solely on nucleic acid or protein testing may not accurately assess whether shrimp are diseased. In the future, a combined nucleic acid and protein testing strategy could be implemented to enhance diagnostic accuracy and ensure the sustainable development of the shrimp farming industry.
Penaeus vannamei is an important aquaculture species, but disease outbreaks posed a serious threat to the sustainable development of shrimp farming. In recent years, a fatal disease known as translucent post-larvae disease (TPD) has emerged in many farms, characterized by the vacuolization of the hepatopancreas and the pallor or colorlessness of the intestine. In this study, we obtained a strain of Vibrio parahaemolyticus, named H1, that could cause TPD in both juvenile and adult shrimps. V. parahaemolyticus H1 could cause gradual atrophy of the hepatopancreas, deepening of the intracellular material color, and eventually complete vacuolization. Antibiotic susceptibility tests revealed that V. parahaemolyticus H1 was resistant to chloramphenicol, ceftriaxone, and sulfamethoxazole trimethoprim, but exhibited resistance to tetracycline. The 2b-RAD-M analysis showed that V. parahaemolyticus H1 could disrupt the shrimp intestinal microbiota and lead to a loss of resistance to environmental bacteria. These results identified a pathogenic V. parahaemolyticus causing TPD from P. vannamei.
The suppression of malaria parasites in the presence of an existing microsporidian infection of Vavraia culicis, was examined using fluorescent Plasmodium berghei. Younger hosts infected with V. culicis had a greater suppressive effect on the subsequent development of P. berghei than older infected hosts. This effect was density dependant on the numbers of microsporidian spores present, consequently it was also dependant on the age at which mosquitoes were infected with microsporidia, as larvae infected later harboured comparatively fewer V. culicis spores. The timing of primary and secondary infections of larval and adult mosquitoes (host age) with different parasites affects parasite development and hence disease outcomes. The use of green, fluorescent P. berghei enabled easier and rapid visualisation and separation of malaria oocysts from V. culicis spores. Different degrees of melanisation of V. culicis spores were seen in a number of hosts and merits further investigation.
DEAD-box RNA helicase 21 (DDX21) is a widely expressed protein in cells, involved in almost all RNA-related cellular processes, and plays a significant role in disease prevention and defense within organisms. This study characterized a DDX21 in Pacific oyster Magallana gigas (MgDDX21), and investigated its association of single nucleotide polymorphisms with susceptibility/resistance of oyster to Halomonas sp. 7T. MgDDX21 contains three conserved domains (DEADc, HELICc, and GUCT), and shares highly conserved key functional sites with other organisms. High-temperature and Lipopolysaccharide (LPS) treatment both significantly upregulated the mRNA expression level of MgDDX21 (P < 0.05). The promoter sequence of MgDDX21 gene from the bacterial-resistant population and the common population was cloned, and the polymorphisms within this region were investigated by sequencing to analyze their association with bacterial resistance. A total of 25 single nucleotide polymorphism (SNP) sites were identified, and 21 SNPs and one haplotype TACACTAACT were significantly associated with the bacterial resistance trait of Pacific oyster, which could be used as potential markers for oyster selection breeding with higher bacterial resistance. These results lay the foundation for further investigation into the role of DDX21 in the response of Pacific oyster to bacterial resistance and provide candidate molecular markers for breeding new varieties of oysters with excellent disease resistance traits.
Glycogen synthase kinase-3 beta (GSK3 beta), a conserved regulator involved in glycogen metabolism and signal transduction, was identified in Yesso scallop (Patinopecten yessoensis) as PyGSK-3 beta, containing a conserved S_TKc domain and phosphorylation sites at Ser9 and Tyr216. The gene expression, protein phosphorylation and apoptosis under high temperature (HT) stress were assessed by using quantitative real-time PCR, Western blotting, and immunohistochemistry. PyGSK-3 beta mRNA was ubiquitously expressed in all the examined tissues and haemocytes. HT stress significantly upregulated the mRNA level of PyGSK-3 beta (Tyr216) and PyJNK (Thr183) in gills, and decreased the mRNA expression of PyBCL-2. Furthermore, the GSK-3 inhibitor SB216763 significantly suppressed the mRNA expression of PyGSK-3 beta, PyGRP78, PyJNK and PyCaspase-3, decreased the phosphorylation level of PyGSK-3 beta However, SB216763 had no effect on the mRNA expression of PyBCL-2. These findings highlight the pivotal role of PyGSK-3 beta in ER stress-mediated apoptosis and offer insights into scallop high temperature stress adaptation, suggesting its potential as a molecular target for breeding or further functional studies in aquaculture.
Penaeus vannamei is a high-value aquaculture species. However, with the expansion in farming area and the rise in stocking density, the disease problems of P. vannamei have grown increasingly severe. Given the pivotal role of intestinal microbiota in regulating host health, including digestion, immune function, and metabolic homeostasis, understanding microbial dynamics is critical for disease control. Notably, although pronounced sexual dimorphism exists in P. vannamei, gender-specific microbiota variations remain uncharacterized. This study intends to evaluate the impact of gender variations on the intestinal microbiota of P. vannamei, using the 2bRAD-M technique. The results showed that the average growth rate of female shrimp was significantly higher than that of male shrimp. The Chao 1 index and Simpson index of female shrimp were greater than those of male shrimp. beta diversity research suggested that the female group samples might contain more microbial variety. At the phylum level, the microbial composition of the female and male shrimp groups is similar, with Pseudomonadota, Bacillota_A, Bacteroidota, Actinomycetota, and Planctomycetota being the dominating phyla. At the species level, the female group is predominantly formed of Phaeobacteritalicus, NSJ_50_sp014385105, Pseudoalteromonas spongiae, and Xanthomarina gelatinilytica, while the male group contains a larger abundance of Vibrio parahaemolyticus and Vibrio cholerae. These data indicated that female P. vannamei not only display faster growth rates, but also possess a more complex and diverse intestinal microbiota, which may contribute to their higher disease resistance compared to male ones.
The flour moth, Ephestia kuehniella, is a common storage pest worldwide. One of the most commonly used methods for controlling storage pests is fumigation using synthetic chemical compounds, which have serious negative impacts. In this study, the fumigant toxicity effects of Artemisia annua essential oil and 1,8-cineole, two environmentally safe substances, were investigated on larvicidal activity, developmental stages, cellular immunity, and enzymatic activities of E. kuehniella larvae. The results of fumigation assays on 3(rd) instar larvae after 24 and 48 h was estimated for A. annua essential oil and 1,8-cineole and lethal concentration (LC) values was calculated. The results indicated higher toxicity of 1,8-cineole over A. annua essential oil. Moreover, prolongation of larval developmental duration and a decrease in pupation period were observed at LC30-treated larvae with A. annua essential oil as well as 1,8-cineole. A significant reduction of total hemocyte count (THC) and differential hemocyte count (DHC), including the number of plasmatocytes and granulocytes was also observed at LC30 and LC50 concentrations, 24 and 48 h post-treatment. The antioxidant enzymes including catalase and peroxidase were significantly increased compared to the control. Similarly, the metabolic enzymes including alanine aminotransferase, aspartate aminotransferase, acid phosphatase, alkaline phosphatase, lactate dehydrogenase were enhanced. The evaluation of detoxifying enzymes like glutathione S-transferase using DCNB and CDNB substrates, showed a significant increase compared to the control. Conversely, the activity of acetylcholinesterase was significantly decreased compared to the control. The results are indicative of the potentiality of these natural compounds as alternative to classical control measure against this important storage product pest.
In this study, we examined the harmful effects of magnetic iron oxide nanoparticles (Fe3O4 NPs) on were administered Fe3O4 nanoparticles (NPs) at concentrations of 0.4, 2, 10, 50, and 250 mu g/10 mu l. Subsequently, the impact of these concentrations on total hemocyte counts (THCs) and various hemocyte indices, namely viable, mitotic, apoptotic, necrotic, and micronucleated cells, was assessed using hematoxylin and eosin (H&E) staining. Compared to the control group, G. mellonella larvae exposed to Fe3O4 NPs at concentrations of 10, 50, and 250 mu g/10 mu l exhibited a statistically significant reduction in THCs. Additionally, in these experimental groups exposed to different concentrations of Fe3O4 NPs, the percentage of viable cells significantly decreased, while the percentage of apoptotic cells increased in comparison to the control group. Likewise, the percentage of necrotic hemocytes was significantly higher in the larvae exposed to 50 and 250 mu g/10 mu l Fe3O4 NPs than that in the control group. Furthermore, the frequency of micronucleated hemocytes was significantly elevated at Fe3O4 NP doses of 10 and 50 mu g/10 mu l when compared to the control group.
