Effects of stand ages on soil enzyme activities in Chinese fir plantations and natural secondary forests.

Forest type and stand age are important biological factors affecting soil enzyme activities. However, the changes in soil enzyme activities across stand ages and underlying mechanisms under the two forest restoration strate-gies of plantations and natural secondary forests remain elusive. In this study, we investigated the variations of four soil enzyme activities including cello-biohydrolase (CBH), ß-1,4-glucosidase (ßG), acid phosphatase (AP) and ß-1,4-N-acetylglucosaminidase (NAG), which were closely associated with soil carbon, nitrogen, and phosphorus cycling, across Cunninghamia lanceolata plantations and natural secondary forests (5, 8, 21, 27 and 40 years old). The results showed that soil enzyme activities showed different patterns across different forest types. The acti-vities of AP, ßG and CBH in the C. lanceolata plantations were significantly higher than those in the natural secon-dary forests, and there was no significant difference in the NAG activity. In the plantations, AP activity showed a decreasing tendency with the increasing stand ages, with the AP activity in the 5-year-old plantations significantly higher than other stand ages by more than 62.3%. The activities of NAG and CBH decreased first and then increased, and ßG enzyme activity fluctuated with the increasing stand age. In the natural secondary forests, NAG enzyme activity fluctuated with the increasing stand age, with that in the 8-year-old and 27-year-old stand ages being significantly higher than the other stand ages by more than 14.9%. ßG and CBH enzyme activities increased first and then decreased, and no significant difference was observed in the AP activity. Results of the stepwise regression analyses showed that soil predictors explained more than 34% of the variation in the best-fitting models predicting soil enzyme activities in the C. lanceolata plantations and natural secondary forests. In conclusion, there would be a risk of soil fertility degradation C. lanceolata plantations with the increasing stand age, while natural secondary forests were more conducive to maintaining soil fertility.

Effects of elevated carbon dioxide (CO2)and ozone (O3)concentrations on ectoenzyme activities in rice rhizospheric soil.

Rising atmospheric carbon dioxide (CO2) and ozone (O3) concentrations are the main global change drivers. Soil ectoenzymes play an important role in maintaining soil ecosystem services. Exploring the responses of soil ectoenzymes to elevated CO2 and O3 concentrations is important for combating global climate change. In this study, we simulated elevated CO2 concentrations (+200 µmol·mol-1, eCO2), elevated O3 concentrations (0.04 µmol·mol-1, eO3), and their combination (eCO2+eO3) in open-top chambers (OTCs), and investigated the responses of rhizospheric soil ectoenzyme activities. The results showed that eCO2 significantly increased the ß-D-Glucosidase (ßG) activity by 73.0%, and decreased that of polyphenol oxidase (PHO), peroxidase (PEO), and acid phosphatase (AP) by 48.9%, 46.6% and 72.9% respectively, but did not affect that of cellulose hydrolase (CBH) and ß-N-Acetylglucosaminidase (NAG). eO3 significantly reduced the activities of CBH and AP by 34.2% and 30.4%, respectively. The activities of PHO and AP were reduced by 87.3% and 32.3% under the eCO2+eO3 compared with the control, respectively. Results of the principal coordinate analysis, permutation multivariate analysis of variance and redundancy analysis showed that both elevated CO2 and O3 significantly affected soil ectoenzyme activities, with stronger effects of elevated CO2 than elevated O3. Root nitrogen content, root carbon to nitrogen ratio, soil microbial biomass carbon and nitrate nitrogen were the main drivers of soil ectoenzyme activities under elevated CO2 and O3. Elevated O3 could partially neutralize the effects of elevated CO2 on soil ectoenzyme activities. In conclusion, elevated CO2 and O3 restrained the activities of most soil ectoenzyme, suggesting that climate change would threat soil ecosystem services and functions in the agroecosystem.

Scavenger receptor B2, a type III membrane pattern recognition receptor, senses LPS and activates the IMD pathway in crustaceans.

The immune deficiency (IMD) pathway is critical for elevating host immunity in both insects and crustaceans. The IMD pathway activation in insects is mediated by peptidoglycan recognition proteins, which do not exist in crustaceans, suggesting a previously unidentified mechanism involved in crustacean IMD pathway activation. In this study, we identified a Marsupenaeus japonicus B class type III scavenger receptor, SRB2, as a receptor for activation of the IMD pathway. SRB2 is up-regulated upon bacterial challenge, while its depletion exacerbates bacterial proliferation and shrimp mortality via abolishing the expression of antimicrobial peptides. The extracellular domain of SRB2 recognizes bacterial lipopolysaccharide (LPS), while its C-terminal intracellular region containing a cryptic RHIM-like motif interacts with IMD, and activates the pathway by promoting nuclear translocation of RELISH. Overexpressing shrimp SRB2 in Drosophila melanogaster S2 cells potentiates LPS-induced IMD pathway activation and diptericin expression. These results unveil a previously unrecognized SRB2-IMD axis responsible for antimicrobial peptide induction and restriction of bacterial infection in crustaceans and provide evidence of biological diversity of IMD signaling in animals. A better understanding of the innate immunity of crustaceans will permit the optimization of prevention and treatment strategies against the arising shrimp diseases.

Soil nitrification and denitrification in Cunninghamia lanceolata plantations with different stand ages.

The variations in soil nitrification and denitrification processes, together with the abundances of functional microbes were investigated in Cunninghamia lanceolata plantations with different stand ages of 5, 8, 21, 27, and 40 years old. The results showed that the net nitrification rate fluctuated with increasing forest ages, with that of 8-year- and 27-year-old C. lanceolata plantations being significantly lower than other stand ages. The abundance of ammonia-oxidizing archaea (AOA) amoA in the 27-year-old plantation was significantly lower than that of the 40-year-old plantation, while there was no significant difference among the other stand ages. There was no significant difference in the abundance of AOB amoA gene, denitrifying functional genes or soil denitrification potential among different stand ages. The results of stepwise regression analysis showed that the abundance of AOA amoA gene was not significantly affected by soil physical and chemical properties. In addition, the abundance of AOB was positively associated with soil total carbon content and soil pH. The abundance of denitrifying functional genes including narG, nirK and nosZ increased with increasing soil pH. The abundance of nirK and nirS was influenced by soil total carbon. Stand age influenced soil net nitrification rate through the AOA amoA abundance. Moreover, soil denitrification potential was directly affected by stand age, or indirectly affected by stand age through soil microbial biomass carbon, soil pH and denitrifying gene abundance of narG and nirK. Compared with the denitrification process, soil nitrification and associated AOA amoA gene abundance were more sensitive to the development of C. lanceolata plantations. The rotation period sould be appropriately extended to reduce the risk of nitrogen losses resulting from soil nitrification.

Effects of common afforestation tree species on soil bacterial community and microbial functional guilds in subtropical forests.

To understand the effects of common afforestation tree species on soil microbial community in subtropical forests, seven different tree species were selected as the research object, including Pinus massoniana, Mytilaria laosensis, Liquidambar formosana, Ilex chinensis, Michelia macclurei, Quercus acutissima and Betula luminifera. Based on 16S rRNA high-throughput sequencing and real-time quantitative PCR techniques, we explored the effects of different tree species on soil bacterial community composition, diversity and microbial functional guilds. The results showed that Acidobacteria, Proteobacteria, and Actinobacteria were the dominant bacterial phyla, and that there was no significant difference in bacterial diversity or richness index among different tree species. Results of redundancy analysis suggested that soil bulk density, soil C/N, litter nitrogen content, and litter C/N were the predominant factors determining soil bacterial community composition. The afforestation tree species had significant effects on functional gene abundances of ammonia oxidizing archaea, ammonia oxidizing bacteria and complete ammonia oxidation. Comammox were dominant in abundance. Ammonia oxidizing archaea amoA gene was the only type whose abundance showed significant correlation with soil nitrate content, suggesting that ammonia oxidizing archaea could play a dominant role in the autotrophic nitrification in the acidic subtropical forest soils. The afforestation tree species had significant effects on functional gene abundances of ammonia oxidizing microorganisms. Results of correlation analysis showed that litter nitrogen content was the driving factor for the abundance of ammonia oxidizing microorganisms. Our study provided strong evidence that the responses of soil microbial functional guilds to tree species were more sensitive than bacterial community composition. Future studies should explore the mechanisms of tree plantations on forest ecosystem functioning from the perspective of microbial functional guilds.

The sORF-Encoded Peptides, ATP Synthase Subunits, Facilitate WSSV Duplication in Shrimp.

Short open reading frames (sORFs) are a newly identified family of genes, and the functions of most sORF genes and their encoded peptides (SEPs) are still unknown. In this study, two ATP synthase subunits were identified in kuruma shrimp (Marsupenaeus japonicus) as SEPs, namely MjATP5I and MjATP5L. They were widely distributed in all of the tested tissues of shrimp and upregulated in hemocytes and intestines in response to WSSV challenge. The injection of recombinant proteins (rMjATP5I and rMjATP5L) increased the expression of Ie1 and Vp28, while the knockdown of MjATP5I and MjATP5L decreased the expression of Ie1 and Vp28. All of the results suggest that MjATP5I and MjATP5L were beneficial for WSSV replication. Further exploration found that MjATP5I and MjATP5L RNAi significantly improved the shrimp survival rates, reduced ATP production, and upregulated the expression of antimicrobial peptide genes post viral challenge, and the two ATPase subunits and Relish negatively regulated each other. These results reveal that MjATP5I and MjATP5L facilitated WSSV duplication by regulating the production of ATP contents and the expression of antimicrobial peptide genes in shrimp.

[Effects of root growth on leaf litter decomposition and enzyme activity in litter layer]. / æ ¹ç³»åœ¨å‡‹è½ç‰©å±‚ç”Ÿé•¿å¯¹å‡‹è½å¶åˆ†è§£åŠé ¶æ´»æ€§çš„å½±å“.

The growth of roots towards aboveground litter layer is a common phenomenon in forest ecosystems. It is of great significance to examine the effects of root presence on litter decomposition for understanding nutrient cycling in forest ecosystems. We explored the effects of root growth on leaf litter decomposition, nutrient release and enzyme activities by establishing treatments with and without root with a one year field decomposition experiment in Phoebe zhennan and Castanopsis kawada-mii forests at Sanming, Fujian. The results showed that after 360 days decomposition, leaf litter mass remaining ratio in the treatment with root was 8.4% and 19.7% lower than control, respectively. The presence of root exhibited significant effect on litter decomposition during the 90-180 days. Compared with the control, the remaining ratio of leaf litter carbon, nitrogen and phosphorus were 6.0%, 19.1% and 20.6% lower in the treatment with root in the P. zhennan forest, and were 21.3%, 23.2% and 20.5% lower in the C. kawadamii forest, respectively. During the whole decomposition process, root presence did not affect the hydrolytic enzyme activity. After 180 days decomposition, the peroxidase activities in the treatment with root were 111.4% and 92.4% higher than control in the P. zhennan and C. kawadamii forests, respectively. The remaining ratio of leaf litter carbon, nitrogen and phosphorus were negatively correlated with the activities of cellobiohydrolase, ß-glucosidase, acid phosphatase, and peroxidase. Root presence in litter layer could accelerate litter decomposition and nutrient release through nutrient uptake and stimulation of oxidase activity.

Health literacy of junior high school students in Jiaxing and its influencing factors / 预防医学

Objective@#To learn the health literacy level and its influencing factors among junior high school students in Jiaxing, so as to provide basis for health promotion of adolescents. @*Methods@#The junior high school students who had been studying and living in Jiaxing for more than six months were selected by multistage cluster random sampling method. A questionnaire survey was conducted to collect general information and health literacy level (including basic knowledge and concept, healthy lifestyle and behaviors, and basic skills) of these selected students. The multivariate logistic regression model was used to analyze the influencing factors for health literacy.@*Results @#Of 1 773 questionnaires collected, 1 738 were valid, accounting for 98.03%. The level of health literacy in the junior high school students in Jiaxing was 22.84% ( 95%CI: 20.87%-24.82% ), The levels of basic knowledge and concept, healthy lifestyle and behaviors, and basic skills were 55.29% ( 95%CI: 52.95%-57.63% ), 21.75% ( 95%CI: 19.81%-23.69% ), 53.05% ( 95%CI: 50.70%-55.40%), respectively. Multivariate logistic regression analysis showed that the second grade and above ( OR: 1.609-1.835, 95%CI: 1.195-2.459 ), mother's educational level of technical secondary school/senior high school and above ( OR: 1.965-1.976, 95%CI: 1.276-3.357 ), and self-rated academic achievement of medium and above ( OR: 1.881-2.441, 95%CI: 1.359-3.335 ) were the promoting factors for health literacy level of junior high school students; self rated health status as unhealthy ( OR=0.254, 95%CI: 0.089-0.721 ) was an obstructive factor.@*Conclusions@#The health literacy level of the junior high school students in Jiaxing was 22.84%. The level of healthy lifestyle and behaviors was the lowest in three aspects. Grade, mother's educational level, self-rated academic performance and self-rated health status may have impacts on health literacy level of junior high school students.

Mitochondrial ATPase inhibitor factor 1, MjATPIF1, is beneficial for WSSV replication in kuruma shrimp (Marsupenaeus japonicus).

ATPase Inhibitory Factor 1 (IF1) is a mitochondrial protein that functions as a physiological inhibitor of F1F0-ATP synthase. In the present study, a mitochondrial ATPase inhibitor factor 1 (MjATPIF1) was identified from kuruma shrimp (Marsupenaeus japonicus), which was demonstrated to participate in the viral immune reaction of white spot syndrome virus (WSSV). MjATPIF1 contained a mitochondrial ATPase inhibitor (IATP) domain, and was widely distributed in hemocytes, heart, hepatopancreas, gills, stomach, and intestine of shrimp. MjATPIF1 transcription was upregulated in hemocytes and intestines by WSSV. WSSV replication decreased after MjATPIF1 knockdown by RNA interference and increased following recombinant MjATPIF1 protein injection. Further study found that MjATPIF1 promoted the production of superoxide and activated the transcription factor nuclear factor kappa B (NF-κB, Dorsal) to induce the transcription of WSSV RNAs. These results demonstrate that MjATPIF1 benefits WSSV replication in kuruma shrimp by inducing superoxide production and NF-κB activation.

Thymosins participate in antibacterial immunity of kuruma shrimp, Marsupenaeus japonicus.

Thymosins ß are actin-binding proteins that play a variety of different functions in inflammatory responses, wound healing, cell migration, angiogenesis, and stem cell recruitment and differentiation. In crayfish, thymosins participate in antiviral immunology. However, the roles of thymosin during bacterial infection in shrimp remain unclear. In the present study, four thymosins were identified from kuruma shrimp, Marsupenaeus japonicus, and named as Mjthymosin2, Mjthymosin3, Mjthymosin4, and Mjthymosin5 according the number of their thymosin beta actin-binding motifs. Mjthymosin3 was selected for further study because its expression level was the highest in hemocytes. Expression analysis showed that Mjthymosin3 was upregulated in hemocytes after challenged by Vibrio anguillarum or Staphylococcus aureus. The recombinant Mjthymosin3 protein could inhibit the growth of certain bacteria in an in vitro antibacterial test. Mjthymosins could facilitate external bacterial clearance in shrimp, and were beneficial to shrimp survival post V. anguillarum or S. aureus infection. The results suggested that Mjthymosins played important roles in the antibacterial immune response of kuruma shrimp.

Activation of Toll Pathway Is Different between Kuruma Shrimp and Drosophila.

The Toll pathway is essential for inducing an immune response to defend against bacterial invasion in vertebrates and invertebrates. Although Toll receptors and the transcription factor Dorsal were identified in different shrimp, relatively little is known about how the Toll pathway is activated or the function of the pathway in shrimp antibacterial immunity. In this study, three Tolls (Toll1-3) and the Dorsal were identified in Marsupenaeus japonicus. The Toll pathway can be activated by Gram-positive (G+) and Gram-negative (G-) bacterial infection. Unlike Toll binding to Spätzle in Drosophila, shrimp Tolls could directly bind to pathogen-associated molecular patterns from G+ and G- bacteria, resulting in Dorsal translocation into nucleus to regulate the expression of different antibacterial peptides (AMPs) in the clearance of infected bacteria. These findings suggest that shrimp Tolls are pattern recognition receptors and the Toll pathway in shrimp is different from the Drosophila Toll pathway but identical with the mammalian Toll-like receptor pathway in its activation and antibacterial functions.

Myeloid leukemia factor functions in anti-WSSV immune reaction of kuruma shrimp, Marsupenaeus japonicus.

Myeloid leukemia factor (MLF) plays an important role in development, cell cycle, myeloid differentiation, and regulates the RUNX transcription factors. However, the function of MLF in immunity is still unclear. In this study, an MLF was identified and characterized in kuruma shrimp Marsupenaeus japonicus, and named as MjMLF. The full-length cDNA of MjMLF contained 1111 nucleotides, which had an opening reading frame of 816 bp encoding a protein of 272 amino acids with an MLF1-interacting protein domain. MjMLF could be ubiquitously detected in different tissues of shrimp at the transcriptional level. The expression pattern analysis showed that MjMLF could be upregulated in shrimp hemocytes and hepatopancreas after white spot syndrome virus challenge. The RNA interference and protein injection assay showed that MjMLF could inhibit WSSV replication in vivo. Flow cytometry assay showed that MjMLF could induce hemocytes apoptosis which functioned in the shrimp antiviral reaction. All the results suggested that MjMLF played an important role in the antiviral immune reaction of kuruma shrimp. The research indicated that MjMLF might function as a novel regulator to inhibit WSSV replication in shrimp.

Scavenger receptor C promotes bacterial clearance in kuruma shrimp Marsupenaeus japonicus by enhancing hemocyte phagocytosis and AMP expression.

Scavenger receptors (SRs) comprise a large family of structurally diverse glycoproteins located on the cell membrane and function as pattern-recognition receptors (PRRs) participating in innate immunity in different species. Class C scavenger receptor (SRC) has been only identified in invertebrates and its biological functions still need to be researched. In this study, we characterized the anti-bacterial function of a SRC from kuruma shrimp Marsupenaeus japonicus (MjSRC). The mRNA level of MjSRC was up-regulated significantly in hemocytes of kuruma shrimp challenged by Vibrio anguillarum or Staphylococcus aureus. The recombinant extracellular domains (MAM and CCP domains) of MjSRC have the ability of binding different bacteria and glycans in vitro. After knockdown of MjSRC, the bacterial clearance ability and phagocytic rate of hemocyte decreased significantly in vivo. Meanwhile, overexpression of MjSRC in shrimp enhanced the clearance ability and phagocytic rate of hemocytes. Further study found that MjSRC could regulate the expression of several antimicrobial peptides (AMPs). All these results indicate that MjSRC plays important roles in antibacterial immunity in kuruma shrimp by enhancing hemocyte phagocytosis and AMP expression.

Long-Term Nickel Contamination Increases the Occurrence of Antibiotic Resistance Genes in Agricultural Soils.

Heavy metal contamination is assumed to be a selection pressure on antibiotic resistance, but to our knowledge, evidence of the heavy metal-induced changes of antibiotic resistance is lacking on a long-term basis. Using quantitative PCR array and Illumina sequencing, we investigated the changes of a wide spectrum of soil antibiotic resistance genes (ARGs) following 4-5 year nickel exposure (0-800 mg kg-1) in two long-term experimental sites. A total of 149 unique ARGs were detected, with multidrug and ß-lactam resistance as the most prevailing ARG types. The frequencies and abundance of ARGs tended to increase along the gradient of increasing nickel concentrations, with the highest values recorded in the treatments amended with 400 mg nickel kg-1 soil. The abundance of mobile genetic elements (MGEs) was significantly associated with ARGs, suggesting that nickel exposure might enhance the potential for horizontal transfer of ARGs. Network analysis demonstrated significant associations between ARGs and MGEs, with the integrase intI1 gene having the most frequent interactions with other co-occurring ARGs. The changes of ARGs were mainly driven by nickel bioavailability and MGEs as revealed by structural equation models. Taken together, long-term nickel exposure significantly increased the diversity, abundance, and horizontal transfer potential of soil ARGs.

Leucine-rich repeats containing protein functions in the antibacterial immune reaction in stomach of kuruma shrimp Marsupenaeus japonicus.

Leucine rich repeat (LRR) motif exists in many immune receptors of animals and plants. Most LRR containing (LRRC) proteins are involved in protein-ligand and protein-protein interaction, but the exact functions of most LRRC proteins were not well-studied. In this study, an LRRC protein was identified from kuruma shrimp Marsupenaeus japonicus, and named as MjLRRC1. MjLRRC1 was consistently expressed in different tissues of normal shrimp with higher expression in gills and stomach. At the transcriptional level, there were no significant changes of MjLRRC1 after injection of Vibrio anguillarum or Staphylococcus aureus in gills and hepatopancreas. While in V. anguillarum oral infection, MjLRRC1 was upregulated in stomach but not in intestine. The recombinant MjLRRC1 protein could bind to Gram-positive and Gram-negative bacteria, bacterial cell wall components including peptidoglycan, lipoteichoic acid, and lipopolysaccharide. MjLRRC1 regulated the expression of some antimicrobial peptide (AMP) genes and participated in bacteria clearance of stomach. All these results suggested that MjLRRC1 might play important roles in antibacterial immune response of kuruma shrimp.

Scavenger Receptor C Mediates Phagocytosis of White Spot Syndrome Virus and Restricts Virus Proliferation in Shrimp.

Scavenger receptors are an important class of pattern recognition receptors that play several important roles in host defense against pathogens. The class C scavenger receptors (SRCs) have only been identified in a few invertebrates, and their role in the immune response against viruses is seldom studied. In this study, we firstly identified an SRC from kuruma shrimp, Marsupenaeus japonicus, designated MjSRC, which was significantly upregulated after white spot syndrome virus (WSSV) challenge at the mRNA and protein levels in hemocytes. The quantity of WSSV increased in shrimp after knockdown of MjSRC, compared with the controls. Furthermore, overexpression of MjSRC led to enhanced WSSV elimination via phagocytosis by hemocytes. Pull-down and co-immunoprecipitation assays demonstrated the interaction between MjSRC and the WSSV envelope protein. Electron microscopy observation indicated that the colloidal gold-labeled extracellular domain of MjSRC was located on the outer surface of WSSV. MjSRC formed a trimer and was internalized into the cytoplasm after WSSV challenge, and the internalization was strongly inhibited after knockdown of Mjß-arrestin2. Further studies found that Mjß-arrestin2 interacted with the intracellular domain of MjSRC and induced the internalization of WSSV in a clathrin-dependent manner. WSSV were co-localized with lysosomes in hemocytes and the WSSV quantity in shrimp increased after injection of lysosome inhibitor, chloroquine. Collectively, this study demonstrated that MjSRC recognized WSSV via its extracellular domain and invoked hemocyte phagocytosis to restrict WSSV systemic infection. This is the first study to report an SRC as a pattern recognition receptor promoting phagocytosis of a virus.

Involvement of a LysM and putative peptidoglycan-binding domain-containing protein in the antibacterial immune response of kuruma shrimp Marsupenaeus japonicus.

Lysin motif (LysM) is a peptidoglycan and chitin-binding motif with multiple functions in bacteria, plants, and animals. In this study, a novel LysM and putative peptidoglycan-binding domain-containing protein was cloned from kuruma shrimp (Marsupenaeus japonicus) and named as MjLPBP. The cDNA of MjLPBP contained 1010 nucleotides with an open reading frame of 834 nucleotides encoding a protein of 277 amino acid residues. The deduced protein contained a Lysin motif and a transmembrane region, with a calculated molecular mass of 31.54 kDa and isoelectric point of 8.61. MjLPBP was ubiquitously distributed in different tissues of shrimp at the mRNA level. Time course expression assay showed that MjLPBP was upregulated in hemocytes of shrimp challenged with Vibrio anguillarum or Staphylococcus aureus. MjLPBP was also upregulated in hepatopancreas after white spot syndrome virus and bacteria challenge. The recombinant protein of MjLPBP could bind to some Gram-positive and Gram-negative bacteria and yeast. Further study found that rMjLPBP bound to bacterial cell wall components, including peptidoglycans, lipoteichoic acid, lipopolysaccharide, and chitin. The induction of several antimicrobial peptide genes and phagocytosis-related gene, such as anti-lipopolysaccharide factors and myosin, was depressed after knockdown of MjLPBP. MjLPBP could facilitate V. anguillarum clearance in vivo. All the results indicated that MjLPBP might play an important role in the innate immunity of shrimp.

Dual oxidases participate in the regulation of intestinal microbiotic homeostasis in the kuruma shrimp Marsupenaeus japonicus.

The metazoan gut lumen harbors numerous microbial communities. Tolerance for high bacterial counts and maintenance of microbiota homeostasis remain insufficiently studied. In this study, we identified a novel dual oxidase (MjDUOX2) involved in reactive oxygen species (ROS) production in the kuruma shrimp Marsupenaeus japonicus. MjDUOX2 is a transmembrane protein with an N-signal peptide region (19 aa) and a peroxidase homology domain (PHD, 554 aa) in the extracellular region; seven transmembrane regions; and three EF (calcium-binding region) domains (110 aa), a FAD-binding domain (104 aa), and a NAD-binding domain (156 aa) in the intracellular region. The novel MjDUOX2 exhibits a relatively low similarity (26.84% identity) to a previously reported DUOX in the shrimp (designated as MjDUOX1). The mRNA of MjDUOXs was widely distributed in the hemocytes, heart, hepatopancreas, gills, stomach, and intestine. Oral infection of the shrimp with pathogenic bacteria upregulated the mRNA expression of MjDUOXs and increased the ROS level in the intestine. However, High ROS level could inhibit the expression of MjDUOXs in shrimp after Vibrio anguillarum infection. Knockdown of MjDUOXs by RNA interference (RNAi) decreased the ROS level, increased the bacterial count in the intestine, and decreased the survival rate of the MjDUOX-RNAi shrimp infected with V. anguillarum. These results suggest that MjDUOXs play an important role for microbiota homeostasis in intestine of shrimp.

ß-Arrestins Negatively Regulate the Toll Pathway in Shrimp by Preventing Dorsal Translocation and Inhibiting Dorsal Transcriptional Activity.

The Toll signaling pathway plays an important role in the innate immunity ofDrosophila melanogasterand mammals. The activation and termination of Toll signaling are finely regulated in these animals. Although the primary components of the Toll pathway were identified in shrimp, the functions and regulation of the pathway are seldom studied. We first demonstrated that the Toll signaling pathway plays a central role in host defense againstStaphylococcus aureusby regulating expression of antimicrobial peptides in shrimp. We then found that ß-arrestins negatively regulate Toll signaling in two different ways. ß-Arrestins interact with the C-terminal PEST domain of Cactus through the arrestin-N domain, and Cactus interacts with the RHD domain of Dorsal via the ankyrin repeats domain, forming a heterotrimeric complex of ß-arrestin·Cactus·Dorsal, with Cactus as the bridge. This complex prevents Cactus phosphorylation and degradation, as well as Dorsal translocation into the nucleus, thus inhibiting activation of the Toll signaling pathway. ß-Arrestins also interact with non-phosphorylated ERK (extracellular signal-regulated protein kinase) through the arrestin-C domain to inhibit ERK phosphorylation, which affects Dorsal translocation into the nucleus and phosphorylation of Dorsal at Ser(276)that impairs Dorsal transcriptional activity. Our study suggests that ß-arrestins negatively regulate the Toll signaling pathway by preventing Dorsal translocation and inhibiting Dorsal phosphorylation and transcriptional activity.

Impacts of reclaimed water irrigation on soil antibiotic resistome in urban parks of Victoria, Australia.

The effluents from wastewater treatment plants have been recognized as a significant environmental reservoir of antibiotics and antibiotic resistance genes (ARGs). Reclaimed water irrigation (RWI) is increasingly used as a practical solution for combating water scarcity in arid and semiarid regions, however, impacts of RWI on the patterns of ARGs and the soil bacterial community remain unclear. Here, we used high-throughput quantitative PCR and terminal restriction fragment length polymorphism techniques to compare the diversity, abundance and composition of a broad-spectrum of ARGs and total bacteria in 12 urban parks with and without RWI in Victoria, Australia. A total of 40 unique ARGs were detected across all park soils, with genes conferring resistance to ß-lactam being the most prevalent ARG type. The total numbers and the fold changes of the detected ARGs were significantly increased by RWI, and marked shifts in ARG patterns were also observed in urban parks with RWI compared to those without RWI. The changes in ARG patterns were paralleled by a significant effect of RWI on the bacterial community structure and a co-occurrence pattern of the detected ARG types. There were significant and positive correlations between the fold changes of the integrase intI1 gene and two ß-lactam resistance genes (KPC and IMP-2 groups), but no significant impacts of RWI on the abundances of intI1 and the transposase tnpA gene were found, indicating that RWI did not improve the potential for horizontal gene transfer of soil ARGs. Taken together, our findings suggested that irrigation of urban parks with reclaimed water could influence the abundance, diversity, and compositions of a wide variety of soil ARGs of clinical relevance. ONE-SENTENCE SUMMARY: Irrigation of urban parks with treated wastewater significantly increased the abundance and diversity of various antibiotic resistance genes, but did not significantly enhance their potential for horizontal gene transfer.