Transcriptome analysis of hepatopancreas of Chinese grass shrimp, Palaemonetes sinensis, infected by Enterocytospora artemiae

Non-coding RNAs and regulatory networks involved in the Ameson portunus (Microsporidia)-Portunus trituberculatus interaction

Ameson portunus, the causative agent of "toothpaste disease" in Portunus trituberculatus and "slurry-like syndrome" in Scylla paramamosain, has resulted in considerable economic losses in the marine crab aquaculture industry in China. Practical control strategies are yet unavailable. Non-coding RNAs (ncRNAs) are crucial components of gene regulation of intracellular parasites, however, their roles in regulating the microsporidia-host interaction remain limited. Here we conducted a whole-transcriptome RNA-seq analysis to identify ncRNAs and to establish the interaction regulatory networks to get further insights into the A. portunus-P. trituberculatus interaction. Totally, 2805 mRNAs, 484 lncRNAs, 5 circRNAs, and 496 miRNAs were identified from A. portunus. These ncRNAs are possibly important regulators for its own energy and substrate metabolism, thereby supporting the intracellular survival and proliferation of A. portunus. DNA replication-associated mRNAs were significantly up-regulated after P. trituberculatus infection with A. portunus. It can be hypothesized that up-regulated lncRNAs may be responsible for the up-regulation of these DNA replication-related genes by miRNAs in P. trituberculatus. The downregulation of metabolic pathways is one of possible strategies of P. trituberculatus to respond the infection of A. portunus. Cross-species miRNAs were suggested to play important roles in the cross-talk of P. trituberculatus-A. portunus, e.g. the disruption of the cytoskeletal organization and normal cell function of host by this microsporidian. The results enrich the knowledge of ncRNAs in microsporidia and offer new insights into microsporidia-host interactions.

Biochar alters the soil fauna functional traits and community diversity: A quantitative and cascading perspective

With the widespread use of biochar, the cascading effects of biochar exposure on soil fauna urgently require deeper understanding. A meta-analysis quantified hierarchical changes in functional traits and community diversity of soil fauna under biochar exposure. Antioxidant enzymes (24.1 %) did not fully mitigate the impact of MDA (13.5 %), leading to excessive DNA damage in soil fauna (21.2 %). Concurrently, reproduction, growth, and survival rates decreased by 20.2 %, 8.5 %, and 21.2 %, respectively. Due to a 39.7 % increase in avoidance behavior of soil fauna towards biochar, species richness ultimately increased by 80.2 %. Compared to other feeding habits, biochar posed a greater threat to the survival of herbivores. Additionally, macrofauna were the most sensitive to biochar. The response of soil fauna also depended on the type, size, concentration, and duration of biochar exposure. It should be emphasized that as exposure concentration increased, the damage to soil fauna became more severe. Furthermore, the smaller the biochar sizes, the greater the damage to soil fauna. To mitigate the adverse effects on soil fauna, this study recommens applying biochar at appropriate times and selecting large sizes in low to medium concentrations. These findings confirm the threat of biochar to soil health from the perspective of soil fauna.

High temperatures and low humidity promote the occurrence of microsporidians (Microsporidia) in mosquitoes (Culicidae)

BACKGROUND

In the context of climate change, a growing concern is that vector-pathogen or host-parasite interactions may be correlated with climatic factors, especially increasing temperatures. In the present study, we used a mosquito-microsporidian model to determine the impact of environmental factors such as temperature, humidity, wind and rainfall on the occurrence rates of opportunistic obligate microparasites (Microsporidia) in hosts from a family that includes important disease vectors (Culicidae).

METHODS

In our study, 3000 adult mosquitoes collected from the field over 3 years were analysed. Mosquitoes and microsporidia were identified using PCR and sequencing of the hypervariable V5 region of the small subunit ribosomal RNA gene and a shortened fragment of the cytochrome c oxidase subunit I gene, respectively.

RESULTS

DNA metabarcoding was used to identify nine mosquito species, all of which were hosts of 12 microsporidian species. The prevalence of microsporidian DNA across all mosquito samples was 34.6%. Microsporidian prevalence in mosquitoes was more frequent during warm months (> 19 °C; humidity < 65%), as was the co-occurrence of two or three microsporidian species in a single host individual. During warm months, microsporidian occurrence was noted 1.6-fold more often than during the cold periods. Among the microsporidians found in the mosquitoes, five (representing the genera Enterocytospora, Vairimorpha and Microsporidium) were positively correlated with an increase in temperature, whereas one (Hazardia sp.) was significantly correlated with a decrease in temperature. Threefold more microsporidian co-occurrences were recorded in the warm months than in the cold months.

CONCLUSIONS

These results suggest that the susceptibility of mosquitoes to parasite occurrence is primarily determined by environmental conditions, such as, for example, temperatures > 19 °C and humidity not exceeding 62%. Collectively, our data provide a better understanding of the effects of the environment on microsporidian-mosquito interactions.

Comparative Transcriptome Analysis of the Hepatopancreas from Macrobrachium rosenbergii Exposed to the Heavy Metal Copper

The contamination of aquatic ecosystems by the heavy metal copper (Cu) is an important environmental issue and poses significant risks to the physiological functions of aquatic organisms. Macrobrachium rosenbergii is one of the most important freshwater-cultured prawns in the world. The hepatopancreas of crustaceans is a key organ for immune defense, heavy metal accumulation, and detoxification, playing a pivotal role in toxicological research. However, research on the molecular response of the hepatopancreas in M. rosenbergii to Cu exposure is still lacking. In this study, the transcriptomic response in the hepatopancreas of M. rosenbergii was studied after Cu exposure for 3 and 48 h. Compared with the control group, 11,164 (7288 up-regulated and 3876 down-regulated genes) and 10,937 (6630 up-regulated and 4307 down-regulated genes) differentially expressed genes (DEGs) were identified after 3 and 48 h exposure, respectively. Most of these DEGs were up-regulated, implying that gene expressions were largely induced by Cu. Functional enrichment analysis of these DEGs revealed that immunity, copper homeostasis, detoxification, DNA damage repair, and apoptosis were differentially regulated by Cu. Seven genes involved in immunity, detoxification, and metabolism were selected for validation by qRT-PCR, and the results confirmed the reliability of RNA-Seq. All these findings suggest that M. rosenbergii attempts to resist the toxicity of Cu by up-regulating the expression of genes related to immunity, metabolism, and detoxification. However, with the excessive accumulation of reactive oxygen species (ROS), the antioxidant enzyme system was destroyed. As a result, DNA damage repair and the cellular stress response were inhibited, thereby exacerbating cell damage. In order to maintain the normal function of the hepatopancreas, M. rosenbergii removes damaged cells by activating the apoptosis mechanism. Our study not only facilitates an understanding of the molecular response mechanisms of M. rosenbergii underlying Cu toxicity effects but also helps us to identify potential biomarkers associated with the stress response in other crustaceans.

Differential molecular responses of hemolymph and hepatopancreas of swimming crab, Portunus trituberculatus, infected with Ameson portunus (Microsporidia)

Ameson portunus (Microsporidia) has caused serious economic losses to the aquaculture industry of swimming crab, Portunus trituberculatus. The hemolymph and hepatopancreas are the main immune organs of P. trituberculatus, and the main sites of A. portunus infection. Elucidating the response characteristics of hemolymph and hepatopancreas to microsporidian infection facilitates the development of microsporidiosis prevention and control strategy. This study performed comparative transcriptomic analysis of hemolymph (PTX/PTXA) and hepatopancreas (PTG/PTGA) of P. trituberculatus uninfected and infected with A. portunus. The results showed that there were 223 and 1309 differentially expressed genes (DEGs) in PTX/PTXA and PTG/PTGA, respectively. The lysosome pathway was significantly enriched after the invasion of the hemolymph by A. portunus. Also, immune-related genes were all significantly up-regulated in the hemolymph and hepatopancreas, suggesting that the invasion by A. portunus may activate host immune responses. Unlike hemolymph, antioxidant and detoxification-related genes were also significantly up-regulated in the hepatopancreas. Moreover, metabolism-related genes were significantly down-regulated in the hepatopancreas, suggesting that energy synthesis, resistance to pathogens, and regulation of oxidative stress were suppressed in the hepatopancreas. Hemolymph and hepatopancreas have similarity and tissue specificity to microsporidian infection. The differential genes and pathways identified in this study can provide references for the prevention and control of microsporidiosis.

Analysis of differentially expressed proteins after EHP-infection and characterization of caspase 3 protein in the whiteleg shrimp (Litopenaeus vannamei)

Whiteleg shrimp (Litopenaeus vannamei) is the most important species of shrimp farmed worldwide in terms of its economic value. Enterocytozoon hepatopenaei (EHP) infects the hepatopancreas, resulting in the hepatopancreatic microsporidiosis (HPM) of the host, which causes slow growth of the shrimp and poses a threat to the farming industry. In this study, differentially expressed proteins (DEPs) between EHP-infected and uninfected shrimp were investigated through proteomics sequencing. A total of 9908 peptides and 2092 proteins were identified. A total of 69 DEPs were identified in the hepatopancreas (HP), of which, 28 were upregulated and 41 were downregulated. Our results showed that the differences among the level of multiple proteins involved in the apoptosis were significant after the EHP infection, which indicated that the apoptosis pathway was activated in whiteleg shrimp. In addition, expression leve of caspase 3 gene were identified related to the EHP infection. Furthermore, predictions of spatial structure, analysis of phylogeny and chromosome-level linearity of the caspase 3 protein were performed as well. In conclusion, a relatively complete proteomic data set of hepatopancreas tissues in whiteleg shrimp were established in this study. Findings about genes involved in the apoptosis here will provide a further understanding of the molecular mechanism of EHP infection in the internal immunity of whiteleg shrimp.