Immune Priming Induced by Heat-inactivated White Spot Syndrome Virus (WSSV) in Fenneropenaeus chinensis Cultured at Different Temperature

[ Objective] This study was designed to explore whether heat-inactivated white spot syndrome virus （ WSSV ） could induce immune priming in Fenneropenaeus chinensis. [Method] Shrimps cultured at 15 （group E15℃ ）, 23 （group E23℃ ）, 28 （group E28℃ ） and 32 （group E32℃ ）℃ were fed for six successive days with the meat of WSSV-infected shrimps, which had been treated at 60℃ for 1 h. Meanwhile, the shrimps of positive control were fed with a diet containing active WSSV at 23℃ （ group C23℃ ）, and the shrimps of negative control were fed with commercial compound feed only at 23℃ （ group CF23℃ ）. On Day 13 of the experiment, the survivors were re-challenged with active WSSV, and then the survival time, survival rate, mortality rate and viral load in each group were measured. The results showed that no death occurred among the shrimps fed with a diet containing heat-inactivated WSSV before the secondary challenge, while all the shrimps fed with a diet containing active WSSV （ group CF23℃ ） died, suggesting that WSSV was completely inactivated by treatment at 60℃ for 1 h. On day 19 of the experiment, the survival rate in groups E15℃ , E23℃, E28℃, E32℃ and CF23℃ was 80.41% , 33.29%, 8.47% , 16.43% and 8.89%, respectively. There was an extremely significant difference in survival rate between group E15℃ and other groups （ P 〈 0.01 ）, a significant difference in survival rate between group E23℃ and CF23℃ , E28℃, E32℃ （P 〈 0. 05）, and no significant difference in survival rate between groups E28℃ and E32℃ （ P 〉 0. 05 ）. RT-qPCR revealed WSSV replicated most rapidly at 28℃ after the secondary challenge, while high （32℃） and low （ 15℃ ） temperature inhibited the multiplication of WSSV. In summary, heat-inactivated WSSV can induce immune priming response and provide some protection to shrimps against WSSV infection. The multiplication rate of WSSV is closely related to water temperature.

Active DNA demethylation regulates MAMP-triggered immune priming in Arabidopsis

Plants recognize microbe-associated molecular patterns(MAMPs)to activate immune responses and defense priming to defend against pathogen infections.Transcriptional regulation of gene expression is crucial for plant immunity and is mediated by multiple factors,including DNA methylation.However,it remains unknown whether and how DNA demethylation contributes to immune responses in MAMPtriggered immunity.Here,we report that active DNA demethylation is required for MAMP-triggered immunity to bacterial pathogens.The rdd-2 triple mutant carrying mutations in ROS1,DML2,and DML3 that encode DNA glycosylases,which are key DNA demethylation enzymes,exhibits compromised immune responses triggered by the MAMPs fig22 and elf18.Genome-wide methylome analysis reveals that fig22 induces rapid and specific DNA demethylation in an RDD-dependent manner.The expression levels of salicylic acid signaling-related and phytoalexin biosynthesis-related genes are tightly associated with the fig22-induced promoter demethylation.The compromised accumulation of priming compounds and antimicrobial metabolites ultimately leads to a defense priming defect in the rdd-2 mutant.Our results reveal the critical role of active DNA demethylation in the MAMP-triggered immune response and provide unique insight into the molecular mechanism of fig22-modulated DNA demethylation.

Neutrophil programming dynamics and its disease relevance

Neutrophils are traditionally considered as first responders to infection and provide antimicrobial host defense. However, recent advances indicate that neutrophils are also critically involved in the modulation of host immune environments by dynamically adopting distinct functional states. Functionally diverse neutrophil subsets are increasingly recognized as critical components mediating host pathophysiology. Despite its emerging significance, molecular mechanisms as well as functional relevance of dynamically programmed neutrophils remain to be better defined. The increasing complexity of neutrophil functions may require integrative studies that address programming dynamics of neutrophils and their pathophysiological relevance. This review aims to provide an update on the emerging topics of neutrophil programming dynamics as well as their functional relevance in diseases.

Previous encapsulation response enhances within individual protection against fungal parasite in the mealworm beetle Tenebrio mofitor

Immune defenses of insects show either broad reactions or specificity and durability of induced protection against attacking parasites and pathogens. In this study, we tested whether encapsulation response against nylon monofilament increases between two attempts of activation of immune system in mealworm beetles Tenebrio molitor, and whether previous exposure to nylon monofilament may also increase protection against an entomopathogenic fungus. We found that survival of beetles subjected to immune activation by nylon implant and subsequent fungal exposure a week later was significantly higher than survival of beetles which had been subjected to fimgal infection only. This result suggests that previous immune activation by the nylon implant may be considered as broad spectrum ＂immune priming＂ which helps to fight not only the same intruder but also other parasites.