Autophagy and white spot syndrome virus infection in crustaceans

Study on the mechanism of miR-7562 regulating ATG5 and ATG12 genes in Penaeus monodon under Vibrio harveyi infection

MicroRNAs (miRNAs) play a fundamental role in the post-transcriptional regulation of genes and are pivotal in modulating immune responses in marine species, particularly during pathogen assaults. This study focused on the function of miR-7562 and its regulatory effects on autophagy against Vibrio harveyi infection in the black tiger shrimp (Penaeus monodon), an economically important aquatic species. We successfully cloned and characterized two essential autophagy-related genes (ATGs) from P. monodon, PmATG5 and PmATG12, and then identified the miRNAs potentially involved in co-regulating these genes, which were notably miR-7562, miR-8485, and miR-278. Subsequent bacterial challenge experiments and dual-luciferase reporter assays identified miR-7562 as the principal regulator of both genes, particularly by targeting the 3'UTR of each gene. By manipulating the in vivo levels of miR-7562 using mimics and antagomirs, we found significant differences in the expression of PmATG5 and PmATG12, which corresponded to alterations in autophagic activity. Notably, miR-7562 overexpression resulted in the downregulation of PmATG5 and PmATG12, leading to a subdued autophagic response. Conversely, miR-7562 knockdown elevated the expression levels of these genes, thereby enhancing autophagic activity. Our findings further revealed that during V. harveyi infection, miR-7562 continued to influence the autophagic pathway by specifically targeting the ATG5-ATG12 complex. This research not only sheds light on the miRNA-dependent mechanisms governing autophagic immunity in shrimp but also proposes miR-7562 as a promising target for therapeutic strategies intended to strengthen disease resistance within the crustacean aquaculture industry.

Functionality of probiotics on the resistance capacity of shrimp against white spot syndrome virus (WSSV)

Shrimp aquaculture is currently regarded as a significant commercial and food production sector due to its growing importance as a source of human-consumable protein, As shrimp farming has become more intensive, disease outbreaks have become more common, necessitating the overuse of antimicrobial drugs, which has had a number of unintended consequences. The white spot syndrome virus (WSSV) is now recognized as one of the world's most pervasive and potentially fatal diseases affecting shrimp. However, there is currently no cure to prevent the disease's uncontrolled incidence and spread. Probiotics are currently favoured over these antimicrobial substances because of their ability to stimulate disease resilience in shrimp farms by strengthening the immune systems naturally. Probiotics for bacterial infections such as vibriosis are well documented, whereas research is still required to identify the legitimate strains for viral diseases. The utilization of these probiotics as a therapy for and preventative measure against WSSV in shrimp farming is a cutting-edge method that has proven to be effective. Some probiotic strains, such as Bacillus spp, Lactobacillus, and Pediococcus pentosaceus, have been displayed to enhance the innate immunity of shrimp against WSSV, reduce viral load, increase digestibility and growth, and support the gut microbiome of the host in multiple investigations. The present review explores recent developments regarding the function of probiotics in shrimp, with a focus on their anti-WSSV activity.

Immune Defense in Hypoxic Waters: Impacts of CO2 Acidification

AbstractPeriodic episodes of low oxygen (hypoxia) and elevated CO₂ (hypercapnia) accompanied by low pH occur naturally in estuarine environments. Under the influence of climate change, the geographic range and intensity of hypoxia and hypercapnic hypoxia are predicted to increase, potentially jeopardizing the survival of economically and ecologically important organisms that use estuaries as habitat and nursery grounds. In this review we synthesize data from published studies that evaluate the impact of hypoxia and hypercapnic hypoxia on the ability of crustaceans and bivalve molluscs to defend themselves against potential microbial pathogens. Available data indicate that hypoxia generally has suppressive effects on host immunity against bacterial pathogens as measured by in vitro and in vivo assays. Few studies have documented the effects of hypercapnic hypoxia on crustaceans or bivalve immune defense, with a range of outcomes suggesting that added CO₂ might have additive, negative, or no interactions with the effects of hypoxia alone. This synthesis points to the need for more partial pressure of O₂ × low pH factorial design experiments and recommends the development of new host∶pathogen challenge models incorporating natural transmission of a wide range of viruses, bacteria, and parasites, along with novel in vivo tracking systems that better quantify how pathogens interact with their hosts in real time under laboratory and field conditions.