Future range dynamics of Asian yellow-legged hornets (Vespa velutina) and their range overlap with Western honey bees (Apis mellifera) reveal major challenges for bee conservation in Europe

BACKGROUND

The invasion of Asian yellow-legged hornets (Vespa velutina) has significantly affected Western honey bees (Apis mellifera) and apiculture in Europe. However, the range dynamics of this hornet and its range overlap with the bees under future change scenarios have not yet been clarified. Using land-use, climate, and topographical datasets, we projected the range dynamics of this hornet and Western honey bees in Europe and the future overlap of their ranges.

RESULTS

We found that climatic factors had stronger effects on the potential ranges of the hornets compared with land-use and topographical factors. A considerable range expansion of this hornet was predicted, and an increase in the overlap between this pest and the bees was primarily caused by future decreases in temperature seasonality. Additionally, we detected future range expansions of the hornet in the UK and France; future range overlap between this pest and Western honey bees in the UK, Ireland, Portugal, and France; and future overlap between the ranges of this pest and bees but not under recent conditions was mainly projected in Germany, Denmark, and the UK.

CONCLUSION

Mitigating future climate change might effectively control the proliferation of the hornets and their effects on the bees. Strategies for preventing the invasion of this pest and developing European apiculture should be developed and implemented in these regions where future range overlap between them was projected. Given that climate-change scenarios may result in uncertainty in our projections, further investigation is needed to clarify future range changes of our target species. © 2024 Society of Chemical Industry.

IFN-υ and its receptor subunits, IFN-υR1 and IL10RB in mallard Anas platyrhynchos

Type IV interferon (IFN) has been shown to be a cytokine with antiviral activity in fish and amphibian. But, it has not been cloned and characterized functionally in avian species. In this study, type IV IFN, IFN-υ, and its 2 possible receptors, IFN-υR1 and IL10RB, were identified from an avian species, the mallard (Anas platyrhynchos). Mallard IFN-υ has a 531 bp open reading frame (ORF), encoding 176 amino acids (aa), and has highly conserved features as reported in different species, with an N-terminal signal peptide and a predicted multi-helix structure. The IFN-υR1 and IL10RB contain 528 and 343 aa, respectively, with IFN-υR1 protein containing JAK1 and STAT binding sites, and IL10RB containing TYK2 binding site. These 2 receptor subunits also possess 3 domains, the N-terminal extracellular domain, the transmembrane domain, and the C-terminal intracellular domain. Expression analysis indicated that IFN-υ, IFN-υR1 and IL10RB were widely expressed in examined organs/tissues, with the highest level observed in pancreas, blood, and kidney, respectively. The expression of IFN-υ, IFN-υR1 and IL10RB in liver, spleen or kidney was significantly upregulated after stimulation with polyI:C. Furthermore, recombinant IFN-υ protein induced the expression of ISGs, and the receptor of IFN-υ was verified as IFN-υR1 and IL10RB using a chimeric receptor approach in HEK293 cells. Taken together, these results indicate that IFN-υ is involved in the host innate immune response in mallard.

Characterization of type II IFNs and their receptors in a cyprinid fish, the blunt snout bream Megalobrama amblycephala

Type II interferons (IFNs) are a key class of molecules regulating innate and adaptive immunity in vertebrates. In the present study, two members of the type II IFNs, IFN-γ and IFNγ-rel, were identified in the blunt snout bream (Megalobrama amblycephala). The open reading frame (ORF) of IFN-γ and IFNγ-rel was found to have 564 bp and 492 bp, encoding 187 and 163 amino acids, with the first 26 and 24 amino acids being the signal peptide, respectively. IFN-γ and IFNγ-rel genes showed a high degree of similarity to their zebrafish homologues, being 76.9 % and 58.9 %, respectively. In the phylogenetic tree, IFN-γ and IFNγ-rel were clustered with homologous genes in cyprinids. In blunt snout bream, IFN-γ and IFNγ-rel were constitutively expressed in trunk kidney, head kidney, spleen, liver, heart, muscle, gill, intestine and brain and were significantly up-regulated by poly (I:C) induction in head kidney, spleen, liver, gill and intestine. Using recombinant proteins of IFN-γ and IFNγ-rel, the surface plasmon resonance (SPR) results showed that IFN-γ was bound to CRFB6, CRFB13 and CRFB17, but mainly to CRFB6 and CRFB13, whereas IFN-γrel bound mainly to CRFB17 and had no affinity with CRFB6. These results contribute to a better understanding on type II IFNs and their receptor usage in teleost fish.

Niche and Range Shifts of Aedes aegypti and Ae. albopictus Suggest That the Latecomer Shows a Greater Invasiveness

The yellow fever (Aedes aegypti) and Asian tiger (Ae. albopictus) mosquitos are major vectors of global mosquito-borne pathogens. However, their niche and range shifts, the underlying mechanisms, and related relative invasion rates remain scarcely known. We examined the niche and range shifts between the native and invasive Ae. aegypti and Ae. albopictus populations through dynamic niche and range models and the largest occurrence record datasets to date. We detected substantial niche and range expansions in both species, probably because the introduced populations have more opportunities to acclimate to diverse environmental conditions than their native counterparts. Mitigating climate change could effectively control their future invasions, given that future climate changes could promote their invasiveness. Additionally, compared to the introduced Ae. aegypti, the more recent invader Ae. albopictus had greater niche and range expansion over its shorter invasion history. In terms of the range shifts, Ae. albopictus had an invasion rate approximately 13.3 times faster than that of Ae. aegypti, making it a more invasive vector of global mosquito-borne pathogens. Therefore, considering its higher invasion rate, much more attention should be paid to Ae. albopictus in devising our strategies against prevailing global mosquito-borne pathogens than Ae. aegypti. Since small niche shifts could result in their large range shifts, niche shifts might be a more important indicator for biological invasion assessments.

Climatic niche and range shifts of grey squirrels (Sciurus carolinensis Gmelin) in Europe: An invasive pest displacing native squirrels

BACKGROUND

As an invasive pest from North America, grey squirrels (GSs; Sciurus carolinensis Gmelin) are displacing native squirrels in Europe. However, the climatic niche and range dynamics of GSs in Europe remain largely unknown. Through niche and range dynamic models, we investigated climatic niche and range shifts between introduced GSs in Europe and native GSs in North America.

RESULTS

GSs in North America can survive in more variable climatic conditions and have much wider climatic niche breadth than do GSs in Europe. Based on climate, the potential range of GSs in Europe included primarily Britain, Ireland, and Italy, whereas the potential range of GSs in North America included vast regions of western and southern Europe. If GSs in Europe could occupy the same climatic niche space and potential range as GSs in North America, they would occupy an area ca. 2.45 times the size of their current range. The unfilling ranges of GSs in Europe relative to those of GSs in North America were primarily in France, Italy, Spain, Croatia, and Portugal.

CONCLUSION

Our observations implied that GSs in Europe have significant invasion potential, and that range projections based on their occurrence records in Europe may underestimate their invasion risk. Given that small niche shifts between GSs in Europe and in North America could lead to large range shifts, niche shifts could be a sensitive indicator in invasion risk assessment. The identified unfilling ranges of the GS in Europe should be prioritized in combating GS invasions in the future. © 2023 Society of Chemical Industry.

A CT-based radiomics nomogram for distinguishing between malignant and benign Bosniak IIF masses: a two-centre study

AIM

To establish and assess a computed tomography (CT)-based radiomics nomogram for identifying malignant and benign Bosniak IIF masses.

MATERIALS AND METHODS

In total, 150 patients with Bosniak IIF masses were separated into a training set (n=106) and a test set (n=44) in a ratio of 7:3. A radiomics signature was calculated based on extracted features from the three phases of CT images. A clinical model was constructed based on clinical characteristics and CT features, and a nomogram incorporating the radiomics signature and independent clinical variables was established. The calibration ability, discrimination accuracy, and clinical value of the nomogram model were assessed.

RESULTS

Twelve features derived from CT images were applied to establish the radiomics signature. The performance levels of three machine-learning models were improved by adding the synthetic minority oversampling technique algorithm. The optimised machine learning model was a combination of the minimum redundancy maximum relevance-least absolute shrinkage and selection operator feature screening method + logistic regression classifier + synthetic minority oversampling technique algorithm, which demonstrated excellent identification ability on the test set (area under the curve [AUC], 0.970; 95% confidence interval [CI], 0.940-1.000). The nomogram model displayed outstanding discrimination ability on the test set (AUC, 0.972; 95% CI, 0.942-1.000).

CONCLUSIONS

The CT-based radiomics nomogram was useful for discriminating between malignant and benign Bosniak IIF masses, which improved the precision of preoperative diagnosis.

Dung treated by high-temperature composting is an optimal bedding material for suckling calves according to analyses of microbial composition, growth performance, health status, and behavior

Bedding materials are important for suckling buffalo calves. Treated dung has been used as a bedding material for dairy cows but the lack of an appropriate safety assessment limits its application. In this study, we evaluated the feasibility of treated dung (TD) as a bedding material for suckling calves by comparing TD with rice husk (RH) and rice straw (RS) bedding materials. The TD was prepared through high-temperature composting by Bacillus subtilis. Thirty-three newborn suckling buffalo calves (Bubalus bubalis, 40.06 ± 5.79 kg) were randomly divided into 3 bedding material groups (TD, RH, and RS) and bedded with 1 of the 3 bedding materials for 60 d. We compared cost, moisture content, bacterial counts, and microbial composition of the 3 bedding materials, and investigated growth performance, health status, behavior, rumen fermentation, and blood parameters of bedded calves. The results showed that TD contained the fewest gram-negative bacteria and coliforms on d 1 and 30 and the lowest relative abundance of Staphylococcus throughout the experiment. The RH and TD bedding materials had the lowest cost. Calves in the TD and RS groups showed a higher dry matter intake, and final body weight and average daily gain in the TD and RS groups tended to be higher than in the RH group. Calves in the TD and RS groups had a lower disease incidence (diarrhea and fever), fewer antibiotic treatments, and lower fecal score than calves in the RH group. Higher contents of IgG, IgA, and IgM were observed in calves of the TD and RS groups than in calves of the RH group on d 10, indicating higher immune ability in TD and RS groups. Furthermore, TD bedding increased the butyric acid content in the calf's rumen, whereas RS bedding increased the acetate content, which might be attributed to the longer time and higher frequency of eating bedding material in the RS group. Considering all of the above indicators, we concluded that TD is the optimal bedding material for calves based on economics, bacterial count, microbial diversity, growth performance, and health status. Our findings provide a valuable reference for bedding material choice and calf farming.

Molecular characterization of nineteen cytokine receptor family B (CRFB) members, CRFB1, CRFB2, CRFB4-17, with three CRFB9 and two CRFB14 in a cyprinid fish, the blunt snout bream Megalobrama amblycephala

The class II cytokine receptor family members are receptors of class 2 helical cytokines in mammals, and are named cytokine receptor family B (CRFB) in fish. In zebrafish, sixteen members, including CRFB1, CRFB2 and CRFB4-17 were reported. With the availability of genome sequence, a total of nineteen CRFBs was identified in the blunt snout bream (Megalobrama amblycephala), including CRFB1, CRFB2, CRFB4-17 with the presence of three CRFB9 isoforms, and two CRFB14 isoforms. These CRFB molecules contain well conserved features, such as fibronectin type III (FNIII) domain, transmembrane and intracellular domains as other class II cytokine receptors, and are phylogenetically grouped into thirteen clades with their homologues from other species of fish. The CRFB genes were constitutively expressed in organs/tissues examined in the fish. The finding of more CRFB members in the bream may provide clues to understand possible receptor-ligand interaction and their diversity from an evolutionary point of view.

Niche and Range Shifts of the Fall Webworm (Hyphantria cunea Dury) in Europe Imply Its Huge Invasion Potential in the Future

The fall webworm (Hyphantria cunea Dury) has a strong impact on agricultural systems in Europe. However, its invasive potential, which was inherited from its native niche in North America, remains unknown. Here, we investigated the climatic niche and range shifts of the fall webworm in Europe and compared them with those in native North America, then assessed the worms' invasive potential in Europe. Compared with the fall webworm in Europe, those in North America survived in more diverse climatic conditions, which was closely associated with their broader niche and larger potential ranges in Europe. If the fall webworm in Europe could exploit the native niche inherited from those in North America to adapt to climatic conditions in Europe, their potential ranges in Europe could be 5.5-fold those based on the niche as introduced in Europe. The potentially unfilled ranges of the fall webworm in Europe were mainly detected in vast regions of Europe, excluding Norway, Sweden, Finland, North Russia, Hungary, Croatia, Romania, and Ukraine, suggesting that, without strict control, these vast regions might be preferably invaded by the fall webworm in Europe in the future. Therefore, strict control against its invasion is needed. Given that small niche shifts in this invasive insect could result in large range shifts, the niche shifts represent a more sensitive indicator of invasion risk than range shifts.

Functional characterization of IL-18 receptor subunits, IL-18Rα and IL-18Rβ, and its natural inhibitor, IL-18 binding protein (IL-18BP) in rainbow trout Oncorhynchus mykiss

As an important proinflammation and immunomodulatory cytokine, IL-18 has been reported in several species of fish, but its receptor subunits, IL-18Rα and IL-18Rβ, and its decoy receptor, IL-18BP, have not been functionally characterized in fish. In the present study, IL-18Rα, IL-18Rβ and IL-18BP were cloned from rainbow trout Oncorhynchus mykiss, and they possess common conserved domains with their mammalian orthologues. In tested organs/tissues, IL-18Rα and IL-18Rβ exhibit basal expression levels, and IL-18BP has a pattern of constitutive expression. When transfected with different combinations of chimeric receptors in HEK293T cells, recombinant IL-18 (rIL-18) can induce the activation of NF-κB only when pcDNA3.1-IL-18Rα/IL-1R1 and pcDNA3.1-IL-18Rβ/IL-1RAP were both expressed. On the other hand, recombinant receptors, including rIL-18BP, rIL-18Rα-ECD-Fc and rIL-18Rβ-ECD-Fc can down-regulate significantly the activity of NF-κB, suggesting the participation of IL-18Rα, IL-18Rβ and IL-18BP in rainbow trout IL-18 signal transduction. Co-IP assays indicated that IL-18Rβ may form a complex with MyD88, IRAK4, IRAK1, TRAF6 and TAB2 in HEK293T cells, indicating that IL-18Rβ, in IL-18 signalling pathway, is associated with these signalling molecules. In conclusion, IL-18Rα, IL-18Rβ and IL-18BP in rainbow trout are conserved in function and signalling pathway with their mammalian orthologues.

Identification of type II interferons and receptors in an osteoglossiform fish, the arapaima Arapaima gigas

In mammals, type II interferon (IFN; i.e. IFN-γ) signalling transduces through its specific receptors IFN-γR1 and IFN-γR2. In an osteoglossiform fish, the arapaima Arapaima gigas, three type II IFNs, IFN-γ-like, IFN-γ and IFN-γrel, and their four possible receptor subunits IFN-γR1-1, IFN-γR1-2, IFN-γR2-1 and IFN-γR2-2 were identified in this study. The three type II IFN genes are composed of four exons and three introns, and they all contain IFN-γ signature motif and signal peptide, with the presence of potential nuclear localization signal (NLS) in IFN-γ-like and IFN-γ. The IFN-γR1-1, IFN-γR1-2, IFN-γR2-1 and IFN-γR2-2 are composed of seven exons and six introns, with predicted IFN-γR1-1 and IFN-γR1-2 proteins containing JAK1 and STAT1 binding sites, and IFN-γR2-1 and IFN-γR2-2 containing JAK2 binding sites. Gene synteny analysis showed that the type II IFN and their receptor loci are duplicated in arapaima. All these genes were expressed constitutively in all organs/tissues examined, and responded to the stimulation of polyI:C. The prokaryotic recombinant IFN-γ-like, IFN-γ and IFN-γrel proteins can significantly induce the upregulation of immune-related genes in trunk kidney leucocytes. The ligand-receptor relationship analyses revealed that recombinant IFN-γ-like, IFN-γ, and IFN-γrel transduce downstream signalling through IFN-γR1-1/IFN-γR2-1, IFN-γR1-2/IFN-γR2-2, and IFN-γR1-1, respectively, in xenogeneic cells with the overexpression of original or chimeric receptors. In addition, tyrosine (Y) 366 and Y377 in the intracellular region may be essential for the function of IFN-γR1-2 and IFN-γR1-1, respectively. The finding of type II IFN system in A. gigas thus provides different knowledge in understanding the diversity and evolution of type II IFN ligand-receptor relationships in vertebrates.

Global niche and range shifts of Batrachochytrium dendrobatidis, a highly virulent amphibian-killing fungus

Batrachochytrium dendrobatidis (Bd) is one of the world's most invasive species, and is responsible for chytridiomycosis, an emerging infectious disease that has caused huge losses of global amphibian biodiversity. Few studies have investigated invasive Bd's niche and range relative to those of native Bd. In the present study, we applied niche and range dynamic models to investigate global niche and range dynamics between native and invasive Bd. Invasive Bd occupied wider and different niche positions than did native Bd. Additionally, invasive Bd was observed in hotter, colder, wetter, drier, and more labile climatic conditions. Contrast to most relevant studies presuming Bd's niche remaining stable, we found that invasive Bd rejected niche conservatism hypotheses, suggesting its high lability in niche, and huge invasion potential. Bd's niche non-conservatism may result in range lability, and small niche expansions could induce large increases in range. Niche shifts may therefore be a more sensitive indicator of invasion than are range shifts. Our findings indicate that Bd is a high-risk invasive fungus not only due to its high infection and mortality rates, but also due to its high niche and range lability, which enhance its ability to adapt to novel climatic conditions. Therefore, invasive Bd should be a high-priority focus species in strategizing against biological invasions.

Molecular characterization and transcriptional conservation of N-myc-interactor, Nmi, by type I and type II IFNs in mandarin fish Siniperca chuatsi

N-myc-interactor (Nmi) belongs to interferon (IFN) stimulated genes (ISGs) and is involved in the regulation of physiological processes including viral infection, inflammatory response, apoptosis and tumorigenesis in mammals. However, the function of Nmi in teleost fish remains to be explored. In this study, an Nmi homologue was characterized from mandarin fish Siniperca chuatsi. The mandarin fish Nmi shares two conserved functional Nmi/IFP35 homology domains (NIDs) with mammalian Nmi protein in its C-terminal domain and a coiled coil region (CC) in its N-terminal domain, with its genomic DNA sequence consisting of nine exons and eight introns. Subcellular localization analysis shows that mandarin fish Nmi is a cytoplasmic protein and that its localization is dependent on the CC and NID1 regions. High and constitutive mRNA level of Nmi was observed in all examined tissues, with the highest level being observed in blood. In addition, the Nmi gene was significantly induced in various organs/tissues following the infection of infectious spleen and kidney necrosis virus (ISKNV), and its mRNA and protein level was also significantly induced in vitro after the treatment of IFNh, IFNc, as well as IFN-γ. The dual luciferase activity analysis indicated that the Nmi promoter was activated by the three type I IFNs through interferon-stimulated response element (ISRE) sites, and it can be also transcriptionally activated by IFN-γ via IRF1 which can activate the expression of Nmi through ISRE. Taken together, it is demonstrated in this study that the transcription of Nmi in mandarin fish can be regulated by type I and type II IFNs, thus confirming that Nmi in fish is also an ISG, and is involved in antiviral and IFN-induced innate immunity.

Presence of two RIG-I-like receptors, MDA5 and LGP2, and their dsRNA binding capacity in a perciform fish, the snakehead Channa argus

Fish retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) are critical RNA sensors in cytoplasm and are involved in antiviral innate immunity. However, some species of fish lack RIG-I gene, and the function of RLR members in RIG-I-absent fish is poorly understood. In the present study, MDA5, LGP2 and MAVS genes were identified in commercially important snakehead Channa argus. But, RIG-I gene was not found in this fish, and a systematic analysis of RLRs in available genome database of fish indicated the absence of RIG-I in the Acanthomorphata, Clupeiformes and Polypteriformes, suggesting that loss events of RIG-I gene may have occurred independently three times in the evolutionary history of fish. The MDA5, LGP2 and MAVS in snakehead have conserved protein domains and genomic location based on sequence, phylogenetic and syntenic analyses. These genes are constitutively expressed in healthy fish and can be induced by polyinosinic and polycytidylic acid (poly(I:C)) stimulation in vitro. It is further revealed that the snakehead MDA5 and LGP2 have binding capacity with dsRNA, such as poly(I:C), and MDA5 can interact with MAVS, implying the antiviral function of MDA5 in the RIG-I-absent fish.

Four type I IFNs, IFNa1, IFNa2, IFNb, IFNc, and their receptor usage in an osteoglossomorph fish, the Asian arowana, Scleropages formosus

In fish, type I IFNs are classified into three groups, i.e. Group I, Group II and Group III, which are further divided into seven subgroups according to the number of conservative cysteines, phylogenetic relationship, and probably their receptor complexes. In the present study, four type I IFNs and four cytokine receptor family B members (CRFBs) were identified in the Asian arowana, Scleropages formosus, an ancient species in the Osteoglossomorpha with commercial and conservation values. According to multiple sequence alignment and phylogenetic relationship, the four type I IFNs are named as IFNa1, IFNa2, IFNb and IFNc, with the former two belonging to Group I, and the latter two to Group II. The four receptors are named as CRFB1, CRFB2, CRFB5a and CRFB5b. The IFNs and their possible receptor genes are widely expressed in examined organs/tissues, and are induced following the stimulation of polyinosinic polycytidylic acid (polyI:C) in vivo. It was found that IFNa1, IFNa2, IFNb and IFNc use preferentially the receptor complexes, CRFB1 and CRFB5b, CRFB1 and CRFB5b, CRFB2 and CRFB5a, and CRFB2 and CRFB5b, respectively, indicating the evolutionary diversification in the interaction of type I IFNs and their receptors in this ancient fish species, S. formosus.

Transcriptional and subcellular characterization of interferon induced protein-35 (IFP35) in mandarin fish, Siniperca chuatsi

Interferon (IFN)-stimulated genes (ISGs) exert multiple functions in immune system, and IFN-induced protein 35 (IFP35), which is a member of ISG, has been suggested to be involved in numerous cellular activities including the regulation of antiviral immunity in mammals. However, the role of IFP35 in fish innate immunity remains largely unknown. In the present study, we characterized the IFP35 gene in mandarin fish Siniperca chuatsi, which contains two conserved Nmi/IFP35 homology domains (NIDs) at C-terminus, but no leucine zipper motif, with its genomic DNA sequence consisting of eight exons and seven introns. High and constitutive mRNA level of IFP35 was observed in all examined tissues, with the highest level being observed in gills. Moreover, the IFP35 gene was significantly induced in vivo for 120 h following the infection of infectious spleen and kidney necrosis virus (ISKNV), and its mRNA and protein level was also significantly induced in vitro following the treatment of poly I:C, IFNh, IFNc, as well as IFN-γ. The subcellular localization results indicated that exogenous IFP35 protein was mainly located in cytoplasm, while endogenous IFP35 protein was transferred into, or aggregated around, the nucleus with the induction of poly I:C or IFNs. The dual luciferase activity analysis indicated that the IFP35 promoter was activated by type I and type II IFNs through ISRE site. It is considered that IFP35 in fish is involved in antiviral, as well as in IFN-induced innate immunity.

IRF11 regulates positively type I IFN transcription and antiviral response in mandarin fish, Siniperca chuatsi

In vertebrates, a total of eleven interferon (IFN) regulatory factors (IRFs), IRF1 to IRF11 are reported, with the conserved presence of IRF1 to IRF9 in all classes of vertebrates. However, IRF10 has been reported only in fish and birds, and IRF11 seems to be a fish specific IRF member. In this study, IRF11 in mandarin fish Siniperca chuatsi was found upregulated following virus infection, and IRF11 was localized constitutively in nucleus as revealed through immunofluorescence test. The overexpression and/or luciferase reporter assays showed that IRF11 can induce transcriptionally the ISRE activity, and the expression of type I IFNs, IFNc and IFNh, as well as the IFN-stimulated gene, Mx, thus inhibiting the Siniperca chuatsi rhabdovirus (SCRV) replication as indicated in the reduced expression of virus protein genes. It is thus suggested that IRF11 in mandarin fish and probably in other teleost fish can exert its antiviral effect through the upregulation of type I IFNs and ISGs.

Cloning and functional characterization of IRAK1 from rainbow trout (Oncorhynchus mykiss)

As a key molecule in innate immune signalling pathway, interleukin (IL)-1 receptor-associated kinase 1 (IRAK1) mediates downstream signalling cascades in immune response. In the present study, an IRAK1 orthologue was characterized from rainbow trout (Oncorhynchus mykiss), with a 2115 bp open reading frame (ORF), encoding a protein of 704 amino acids (aa). Multiple alignments showed that IRAK1 contains highly conserved features among different species, with a conservative N-terminal death domain (DD) and a C-terminal conserved serine/threonine protein kinase (STKc) domain. Expression analysis indicated that IRAK1 was widely expressed in examined organs/tissues, with the highest level observed in muscle and lowest in stomach. In RTG-2 cell line, the induced expression of IRAK1 was observed following the stimulation by the fish bacterial pathogen Flavobacterium columnare. Luciferase activity assays revealed that IRAK1 induced significantly the activity of NF-κB in Human embryonic kidney 293T (HEK293T) cell line; but after co-transfected with rainbow trout IL-1 receptor-associated kinase 4 (IRAK4), the induction was significantly down-regulated when compared with the expression of IRAK1 alone. Co-immunoprecipitation (Co-IP) assays indicated that IRAK1 was associated with rainbow trout myeloid differentiation factor 88 (MyD88), IRAK4 and TNF receptor associated factor 6 (TRAF6) in transfected HEK293T cells, and may form a complex with MyD88, IRAK4 and TRAF6 during the signalling pathway.

Radiomics-based machine-learning method for prediction of distant metastasis from soft-tissue sarcomas

AIM

To construct and validate a radiomics-based machine-learning method for preoperative prediction of distant metastasis (DM) from soft-tissue sarcoma.

MATERIALS AND METHODS

Seventy-seven soft-tissue sarcomas were divided into a training set (n=54) and a validation set (n=23). The performance of three feature selection methods (ReliefF, least absolute shrinkage and selection operator [LASSO], and regularised discriminative feature selection for unsupervised learning [UDFS]) and four classifiers, random forest (RF), logistic regression (LOG), K nearest neighbour (KNN), and support vector machines (SVMs), were compared for predicting the likelihood of DM. To counter the imbalance in the frequencies of DM, each machine-learning method was trained first without subsampling, then with the synthetic minority oversampling technique (SMOTE). The performance of the radiomics model was assessed using area under the receiver-operating characteristic curve (AUC) and accuracy (ACC) values.

RESULTS

The performance of the LASSO and SVM algorithm combination used with SMOTE was superior to that of the algorithm combination alone. The combination of SMOTE with feature screening by LASSO and SVM classifiers had an AUC of 0.9020 and ACC of 91.30% in the validation dataset.

CONCLUSION

A machine-learning model based on radiomics was favourable for predicting the likelihood of DM from soft-tissue sarcoma. This will help decide treatment strategies.

Expression and antibacterial analysis of galectin-8 and -9 genes in mandarin fish, Siniperca chuatsi

Galectin-8 and galectin-9 belong to tandem repeat-type galectins, and in the present study, these two genes were cloned in mandarin fish Siniperca chuatsi. The open reading frame (ORF) of the mandarin fish galectin-8 and galectin-9 contains 942, and 1008 bp, encoding 313 and 335 amino acids, respectively. As a conserved feature, an N-terminal carbohydrate recognition domain (CRD), and a C-terminal CRD were observed in each of the two galectins in mandarin fish. In healthy fish, galectin-8 and -9 were constitutively expressed in all organs/tissues examined, and their expression can be induced following the stimulation of LPS and poly(I:C). It is obvious that galectin-8 had a higher increase at mRNA level following the stimulation of poly(I:C). It is further demonstrated that mandarin fish galectin-8 inhibited the growth of Flavobacterium columnare and Streptococcus agalactiae, and in addition to the two species of bacteria, galectin-9 inhibited also the growth of Edwardsiella piscicida, which provides the basis for further understanding their antibacterial role in immune response of mandarin fish.

Identification of type I IFNs and their receptors in a cyprinid fish, the topmouth culter Culter alburnus

In fish, type I IFNs are classified into three groups, i.e. group one, group two and group three, and further separated into seven subgroups based on the number of conserved cysteines and phylogenetic relationships. In the present study, four type I IFNs, named as IFNϕ1, IFNϕ2, IFNϕ3, IFNϕ4, as reported in zebrafish, were identified in a cyprinid, the topmouth culter, Culter alburnus, a species introduced recently into China's aquaculture. These IFNs may be classified as IFNa, IFNc, IFNc and IFNd in a recent nomenclature, with IFNa and IFNd having two cysteines in group one, and IFNc four cysteines in group two. These IFNs, together with their possible receptors, IFNϕ1, IFNϕ2, IFNϕ3, IFNϕ4, and CRFB1, CRFB2 and CRFB5 have an open reading frame (ORF) of 540, 552, 567, 516 bp, and 1572, 1392, 1125 bp, respectively. These IFNs have high amino acid sequence identities, being 91.1-93.6% and 66.9-77.3%, with those in grass carp and zebrafish, respectively, and are expressed constitutively in organs/tissues examined in the fish. The expression of these IFNs can be further induced following poly (I:C) stimulation. However, the possible function of these IFNs and their signalling pathway are of interest for further research.

Myxovirus resistance (Mx) gene and its differential expression regulated by three type I and two type II IFNs in mandarin fish, Siniperca chuatsi

Interferons (IFNs) can induce the expression of IFN-stimulated genes (ISGs), such as myxovirus resistance (Mx) protein, to inhibit virus replication. In this study, the expression of Mx gene in mandarin fish, and the IFN-sensitive response elements (ISREs) and gamma-interferon activated sites (GASs) in the promoter of Mx gene were analyzed in relation to the stimulation of three distinct type I IFNs, IFNc, IFNd and IFNh, and two type II IFNs, IFN-γ and IFN-γ related molecule (IFN-γrel). A single Mx gene was found in mandarin fish, and its expression was highly and constitutively observed in all organs/tissues examined. The Mx gene was significantly induced in vivo for 120 h following infectious spleen and kidney necrosis virus (ISKNV) infection. Furthermore, the overexpression and recombinant of IFNh, IFNc, as well as IFN-γ can significantly induce Mx expression in MFF-1 cells at transcript and protein levels, although all the three type I IFNs and the two type II IFNs can activate the Mx promoter. In addition, ISRE1 which is the proximal one among the three predicted ISREs seems to be the important ISRE for the higher and efficient activation of the Mx promoter. However, the possible interaction between the GASs and type II IFN signalling molecules require further study.

Identification of a novel splice variant isoform of interferon regulatory factor 10, IRF10, in orange spotted grouper Epinephelus coioides

Interferon regulatory factors (IRFs) are a family of transcription factors essential to the control of antiviral immune response, cell growth, differentiation and apoptosis. IRF10 was originally found in chicken, which was induced by the v-Rel oncoprotein in lymphoid cell lines and involved in the upregulation of major histocompatibility complex (MHC) class I and guanylate-binding protein. In fish, IRF10 plays negative roles in regulation of the interferon (IFN) response. Here, we identified a splice variant of IRF10, named as EcIRF10-SF in orange spotted grouper, which shares the first three exons with the long form (EcIRF10-LF) and retains part of intron 3, creating a premature termination codon. Furthermore, we observed that the EcIRF10-SF exhibits similar expression pattern compared to its native counterparts. Functional studies demonstrate that the two EcIRF10 isoforms repress DrIFNϕ1 and DrIFNϕ3 promoter activity and negatively regulate fish antiviral gene expression. Subcellular localization analysis shows that the amino acids from 57 to 86 within DBD are required for IRF10 nuclear import. Overall, our description of transcript diversification of IRF10 in the grouper provides a coherent framework to further dissect its roles in immune response.

Identification of a novel RIG-I isoform and its truncating variant in Japanese eel, Anguilla japonica

Retinoic acid-inducible gene-I (RIG-I) is a cytoplasmic viral RNA sensor that triggers the production of type I interferons (IFNs) and proinflammatory cytokines during viral infection. RIG-I gene has been identified previously in Japanese eel, Anguilla japonica. In the present study, we have characterized a novel isoform of RIG-I (designated as AjRIG-Ib) and its truncated variant (AjRIG-Ibv). The AjRIG-Ib encodes 940 amino acids (aa) consisting of two N-terminal caspase activation and recruitment domains (CARDs), a DEX(D/H) box RNA helicase domain, and a C-terminal regulatory domain (CTD). The AjRIG-Ibv encodes a protein of 843 aa, that shares similar structural organization with AjRIG-Ib, but lacking CTD. The gene expression analyses showed that AjRIG-Ib and AjRIG-Ibv were detectable in all tissues/organs examined, and AjRIG-Ib was the predominant form. The mRNA level of AjRIG-Ibv was upregulated rapidly at 8 h after the Poly I:C injection, and the significant increase of AjRIG-Ib was observed at 16 and 24 h post-injection (hpi). Laser confocal microscopy showed that AjRIG-Ib and AjRIG-Ibv were both located in cytoplasm. In addition, the overexpression of AjRIG-Ib or AjRIG-Ibv led to the increased activity of IFN promoter in transient transfection assay. Taken together, our results indicated that AjRIG-Ib and AjRIG-Ibv may play cooperative or somewhat complementary roles in coordinating the antiviral response in fish.

Receptor complex and signalling pathway of the two type II IFNs, IFN-γ and IFN-γrel in mandarin fish or the so-called Chinese perch Siniperca chuatsi

IFN-γ, as the sole member of mammalian type II IFN, is a multifunctional cytokine which exerts its effects through two distinct IFN-γ receptors, IFNGR1 and IFNGR2. However, in teleost fish, another IFN-γ homologous gene, namely IFN-γ related gene (IFN-γrel), has been identified. Although IFN-γ and IFN-γrel genes have been described in some fish species, many important aspects remain poorly understood in relation with their signalling and function. In the present study, IFN-γ and IFN-γrel, as well as their receptors, cytokine receptor family B (CRFB) 17, CRFB13, two of which are homologous to IFNGR1 in mammals, and CRFB6, homolomous to IFNGR2, have been characterized in mandarin fish, Siniperca chuatsi. It was revealed that the two type IFN members exhibit antiviral activity, and IFN-γ transduces downstream signalling through CRFB13 and CRFB6, while IFN-γrel interacts with CRFB17 to activate downstream signalling. Moreover, IFN-γ and IFN-γrel have been shown to exert antiviral biological activity in a STAT1-dependent manner. Intracellular domain analysis of CRFB17 and CRFB13 demonstrated that the Y386 tyrosine residue of CRFB13 is required for the activation of the IFN-γ-mediated biologic response, and the Y324 and Y370 residues in CRFB17 are required to activate IFN-γrel signalling.

Identification of four type I IFNs from Japanese eel with differential expression properties and Mx promoter inducibility

Type I IFNs are a family of cytokines with antiviral, anti-proliferative and immune-modulatory functions. In this study, four type I IFNs (termed AjIFN1-4) have been cloned from the Japanese eel, Anguilla japonica. The open reading frames of AjIFN1-4 are 552, 534, 546 and 561 bp in length, encoding 183, 177, 181, and 186 amino acids (aa), respectively. Sequence comparison and phylogenetic analysis results revealed that AjIFN1 and AjIFN2 belong to group one (2C-containing) IFNs, while AjIFN3 and AjIFN4 belong to group two (4C-containing) IFNs. Syntenic comparison showed that chromosome block duplication and rearrangement events might have occurred at IFN loci in different teleost lineages. Expression analysis revealed the rapid induction of AjIFNl and AjIFN2 in response to poly I:C stimulation, while AjIFN3 and AjIFN4 were predominantly expressed at later time points. Two Mx promoter reporter assays were conducted to assess the Mx-inducing capability of AjIFN1-4. It is shown that the overexpression of AjIFN1-4 all promoted the luciferase activity of MxB reporter, but the activity of MxC reporter increased only in cells transfected with AjIFN1. Collectively, it is suggested that teleost IFNs were evolved independently in different lineages of fish and may function differently in teleost antiviral immunity.

Characterization of MyD88 in Japanese eel, Anguilla japonica

Myeloid differentiation factor 88 (MyD88) is a key adaptor protein required for the signaling of all Toll-like receptors except TLR3, which results to the interaction of activated TLR complexes via C-terminal TIR domain and the binding of downstream kinase via N-terminal death domain. In this study, the MyD88 gene from the Japanese eel (Anguilla japonica) was identified. The open reading frame of AjMyD88 was 918 bp in length, encoding a protein composed of conserved N-terminal death domain and C-terminal TIR domain, respectively. Multiple alignment revealed highly conserved sites across all examined vertebrate lineages in death and TIR domains. Site-directed mutagenesis and luciferase analysis revealed that the W78A, L91A and L95A mutations in death domain had modest impairment of their ability in activating NF-κB promoter. The expression level of AjMyD88 was investigated by real-time PCR in response to poly I:C stimulation and Edwardsiella tarda infection. Significantly increased MyD88 expression was observed at early phase in all tested tissues/organs in response to E. tarda infection and slight increase was detected in intestine and gill at 16 hpi and in head kidney, spleen and liver at 24 hpi after poly I:C stimulation. Immunofluorescence staining revealed that AjMyD88 is present as condensed forms in the cytoplasm. Taken together, sequence characterization, gene expression and cellular distribution data obtained in this study suggest that AjMyD88, similar to its mammalian ortholog, plays an important role in eel immune response against bacteria.

Contrast-enhanced CT findings of intravenous leiomyomatosis

AIM

To characterise the contrast-enhanced computed tomography (CT) imaging findings of nine patients with intravenous leiomyomatosis (IVL).

MATERIALS AND METHODS

The contrast-enhanced CT imaging findings of nine patients with histopathologically proven IVL were examined. The location, morphology, extension pathway, adhesion, and degree and pattern of enhancement of the tumour were assessed.

RESULTS

Four patients had tumours located within the inferior vena cava, and five had tumours that involved the right heart. Seven patients with residual uterus myoma showed enhanced heterogeneous contrast of the uterus. Eight tumours extended into the inferior vena cava through the iliac veins and one through the bilateral iliac veins. All the IVLs demonstrated heterogeneous enhancement on contrast-enhanced CT and appeared to have lower density than the contrast-enhanced venous blood. On the coronal and sagittal images, tumours were continuous and, when the right heart was involved, the lesions displayed a characteristic "walking stick head" or "snake head" appearance. The lesion looked similar to a "sieve" on axial contrast-enhanced CT images, and a "luffa sponge" on post-processing coronal or sagittal images.

CONCLUSION

Contrast-enhanced CT imaging has unique advantages in the diagnosis of IVL, namely, luffa sponge and sieve appearance, which can be helpful for differential diagnosis. Contrast-enhanced CT can demonstrate tumour location and full-scale extension pathway, which are important for diagnosis, surgical planning, and follow-up of the tumour.

Composition and transcription of all interferon regulatory factors (IRFs), IRF1‒11 in a perciform fish, the mandarin fish, Siniperca chuatsi

Interferon regulatory factors (IRFs) are a family of mediators in various biological processes including immune modulation of interferon (IFN) and proinflammatory cytokine expression. However, the data on the complete composition of IRFs is rather limited in teleost fish. In the present study, all IRF members, i.e. IRF1‒11 with two IRF4, IRF4a and IRF4b have been characterised in an aquaculture species of fish, the mandarin fish, Siniperca chuatsi, in addition to the previous report of IRF1, IRF2, IRF3 and IRF7 from the fish. These IRFs are constitutively expressed in various organs/tissues of the fish, and their expression can be induced following the stimulation of polyinosinic:polycytidylic acid (poly(I:C)) and the infection of infectious spleen and kidney necrosis virus (ISKNV), a viral pathogen of mandarin fish in aquaculture. The ISKNV infection induced the significant increase in the expression of some IRF genes, i.e. IRF2, IRF4a, IRF7, IRF9, IRF10 at 24 or 36 h post-infection (hpi) in spleen and head-kidney, and the significant increase of some other IRF genes, e.g. IRF1, IRF3, IRF4b, IRF5, IRF6, IRF8 at later stage of infection from 72, or 96, or even 120 hpi, which may imply the inhibitory effect of ISKNV on fish immune response. It is considered that the present study provides the first detailed analysis on all IRF members in an aquaculture species of fish, and can be served as the base for further investigation on the role of IRFs in teleost fish.

[The role and significance of digital reconstruction technique in liver segments based on portal vein structure]

Objective: To study the segment of liver according to the large amount of three-dimensional(3D) reconstructive images of normal human livers and the vascular system, and to recognize the basic functional liver unit based on the anatomic features of the intrahepatic portal veins. Methods: The enhanced CT primitive DICOM files of 1 260 normal human livers from different age groups who treated from October 2013 to February 2017 provided by 16 hospitals were analyzed using the computer-aided surgery system.The 3D liver and liver vascular system were reconstructed, and the digital liver 3D model was established.The vascular morphology, anatomical features, and anatomical distributions of intrahepatic portal veins were statistically analyzed. Results: The digital liver model obtained from the 3D reconstruction of CAS displayed clear intrahepatic portal vein vessels of level four.Perform a digital liver segments study based on the analysis of level four vascular distribution areas.As the less anatomical variation of left hepatic portal vein, the liver was classified into four types of liver segmentation mainly based on right hepatic portal vein.Type A was similar to Couinaud or Cho's segmentation, containing 8 segments(537 cases, 42.62%). Type B contained 9 segments as there are three ramifications of right-anterior portal vein(464 cases, 36.82%). The main difference for Type C was the variation of right-posterior portal vein which was sector shape(102 cases, 8.10%). Type D contained the cases with special portal vein variations, which needs three-dimensional simulation to design individualized liver resection plan(157 cases, 12.46%). These results showed that there was no significant difference in liver segmental typing between genders(χ(2)=2.179, P=0.536) and did not reveal any significant difference in liver segmental typing among the different age groups(χ(2)=0.357, P=0.949). Conclusions: The 3D digital liver model can demonstrate the true 3D anatomical structures, and its spatial vascular variations.The observation of anatomic features, distribution areas of intrahepatic portal veins and individualized liver segmentation achieved via digital medical 3D visualization technology is of great value for understand the complexity of liver anatomy and to guide the precise hepatectomy.

Molecular cloning and expression analysis of a fish specific interferon regulatory factor, IRF11, in orange spotted grouper, Epinephelus coioides

Interferon regulatory factors (IRFs) are transcription mediators which play vital roles in multiple biological processes, such as antiviral defense, immune response, cell growth regulation and apoptosis. A fish specific IRF, termed IRF11, has been identified in previous study through searching fish genome databases. Herein, a transcript of IRF11, EcIRF11 was cloned from orange-spotted grouper, Epinephelus coioides. The EcIRF11 cDNA sequence has 1573 bp in length, encoding a putative protein of 261 amino acids, with a high degree of similarity found between EcIRF11 and its teleost counterparts. Comparative analyses in teleost genomes revealed that IRF11 may have an ancient origin at least 450 million years ago, and the locus harbouring IRF11 might have experienced chromosomal rearrangement and/or inversion during evolution. Expression analysis revealed that the other two members, IRF1 and IRF2 also in the IRF1 subgroup (SG) as IRF11, exhibited high expression levels in early experimental infection phase in response to viral stimulation of poly I:C and to bacterial stimulation of Vibrio parahaemolyticus infections in the fish, while EcIRF11 is not transcriptionally modulated at the examined time points except in kidney at 6 h following poly I:C stimulation. Taken together, the results obtained in this study indicate that IRF11 might have been originated from the same ancestor as IRF1 and IRF2, but exhibits distinct basal and induced expression, implying its different function which needs further characterization.

Computational hemodynamics of portal vein hypertension in hepatic cirrhosis patients

Portal vein hypertension generally occurs in liver diseases like hepatic cirrhosis. It causes hemodynamic changes that are closely related to liver disease. At advanced stages of hepatic cirrhosis, portal vein hypertension leads to the atrophy of the right lobe of the liver and the hypertrophy of the left lobe through a process that has not yet been fully explained. Based on the hemodynamic changes that are known to occur, we hypothesize that liver volume is related to the distribution of blood flowing from the splenic vein (SV) that carries hepatotrophic factors from the spleen and pancreas. We studied blood flow in the portal vein system to validate this hypothesis through in vitro experimentation and a computational fluid dynamics (CFD) analysis involving both simplified and patient-specific models based on four healthy subjects and two patients with liver cirrhosis. The results confirmed the hypothesis that right-lobe atrophy is significantly influenced by the distribution of blood from the SV. Moreover, the patients with liver cirrhosis had a significantly larger mass fraction of spleen-derived blood in the left portal vein branch (LPV) than healthy subjects, a result consistent with right-lobe atrophy and left-lobe hypertrophy.

TBK1-like transcript negatively regulates the production of IFN and IFN-stimulated genes through RLRs-MAVS-TBK1 pathway

TANK-binding kinase 1 (TBK1) is an essential serine/threonine-protein kinase required for Toll-like receptor (TLR)- and retinoic acid-inducible gene I (RIG-I) -mediated induction of type I IFN and host antiviral defense. In the present study, TBK1-like transcript, namely TBK1L, was cloned from zebrafish. Compared with TBK1, TBK1L contains an incomplete S_TKc domain, and lacks UBL_TBK1_like domain. Realtime PCR showed that TBK1L was constitutively produced in embryos, early larvae and ZF4 cells, and unchanged in ZF4 cells following SVCV infection. Overexpression of TBK1 but not TBK1L resulted in significant activation of zebrafish IFN1 and IFN3 promoters. Similarly, TBK1L had little impact on the antiviral state of the cells. However, the overexpression of TBK1L negatively regulated the induction of zebrafish IFN1 and/or IFN3 promoters mediated by the retinoic acid-inducible gene I-like receptors (RLRs), MAVS and TBK1. In addition, the overexpression of TBK1L in zebrafish embryos led to the decreased production of many IFN-stimulated genes induced by TBK1. Collectively, these data support that zebrafish TBK1L negatively regulates RLRs-MAVS-TBK1 pathway.

MRI findings in intraspinal mature teratoma

AIM

To characterise and evaluate magnetic resonance imaging (MRI) images for their clinical value in diagnosing and assessing intraspinal mature teratoma.

MATERIALS AND METHODS

MRI images obtained from eight patients with a histopathologically verified intraspinal mature teratoma were analysed retrospectively regarding tumour location, size, and margins. Additionally, the signal intensity and enhancement pattern on MRI and other associated malformations were also assessed.

RESULTS

Three cases that contained fatty tissue showed markedly heterogeneous hyperintense signalling on T1-weighted images, and mixed hyperintense and hypointense signalling on T2-weighted images and fat-suppression sequences. All three of those cases showed an irregular peripheral fatty tissue signal, and one case showed additional patches of an interspersed calcification signal. The remaining five cases without fatty tissue displayed heterogeneous hyperintense signalling on T1-weighted images and T2-weighted images, and also on fat-suppression sequences. Four of the five cases showed additional patches of interspersed nodular calcification signals. Contrast-enhanced MRI images showed only slight enhancement (n=3).

CONCLUSIONS

MRI is regarded as the reference standard diagnostic technique to reveal the location of teratomas and the degree of spinal cord involvement. In most cases, MRI provides accurate anatomical and histological information, which is necessary for patients with suspected intraspinal mature teratoma.

Interferon regulatory factor 10 (IRF10): Cloning in orange spotted grouper, Epinephelus coioides, and evolutionary analysis in vertebrates

IRF10 gene was cloned in orange spotted grouper, Epinephelus coioides, and its expression was examined following poly(I:C) stimulation and bacterial infection. The cDNA sequence of grouper IRF10 contains an open reading frame of 1197 bp, flanked by 99 bp 5'-untranslated region and 480 bp 3'- untranslated region. Multiple alignments showed that the grouper IRF10 has a highly conserved DNA binding domain in the N terminus with characteristic motif containing five tryptophan residues. Quantitative real-time PCR analysis revealed that the expression of IRF10 was responsive to both poly(I:C) stimulation and Vibrio parahemolyticus infection, with a higher increase to poly(I:C), indicating an important role of IRF10 in host immune response during infection. A phyletic distribution of IRF members was also examined in vertebrates, and IRF10 was found in most lineages of vertebrates, not in modern primates and rodents. It is suggested that the first divergence of IRF members might have occurred before the evolutionary split of vertebrate and cephalochordates, producing ancestors of IRF (1/2/11) and IRF (4/8/9/10)[(3/7) (5/6)], and that the second and/or third divergence of IRF members occurred following the split, thus leading to the subsets of the IRF family in vertebrates.

High-pitch spiral CT with 3D reformation: an alternative choice for imaging vascular anomalies with affluent blood flow in the head and neck of infants and children

OBJECTIVE

To evaluate the feasibility of high-pitch spiral CT in imaging vascular anomalies (VAs) with affluent blood flow in the head and neck of infants and children.

METHODS

For patients with suspected VAs and affluent blood flow pre-detected by ultrasound, CT was performed with high-pitch mode, individualized low-dose scan protocol and three-dimensional (3D) reformation. A five-point scale was used for image quality evaluation. Diagnostic accuracy was calculated with clinical diagnosis with/without pathological results as the reference standard. Radiation exposure and single-phase scan time were recorded. Treatment strategies were formulated based on CT images and results and were monitored through follow-up results.

RESULTS

20 lesions were identified in 15 patients (median age of 11 months). The mean score of image quality was 4.13 ± 0.74. 7 patients (7/15, 46.67%) were diagnosed with haemangiomas, 6 patients (6/15, 40%) were diagnosed with venous malformations and 2 patients (2/15, 13.33%) were diagnosed with arteriovenous malformations. The average effective radiation doses of a single phase and of the total procedure were 0.27 ± 0.08 and 0.86 ± 0.21 mSv. The average scanning time of a single phase was 0.46 ± 0.09 s. After treatment, 13 patients (13/15, 86.67%) achieved excellent results, and 2 patients (2/15, 13.33%) showed good results in follow-up visits.

CONCLUSION

High-pitch spiral CT with an individualized low-dose scan protocol and 3D reformation is an effective modality for imaging VAs with affluent blood flow in the head and neck of infants and children when vascular details are needed and ultrasound and MRI could not provide the complete information.

ADVANCES IN KNOWLEDGE

This study proposes an alternative modality for imaging VAs with affluent blood flow.

Establishment and characterization of a head kidney cell line from large yellow croaker Pseudosciaena crocea

A continuous cell line, LYCK, derived from the head kidney of large yellow croaker Pseudosciaena crocea was established and characterized. The LYCK cell line multiplied well in Leibovitz's-15 (L-15) medium supplemented with 10% foetal bovine serum (FBS) at 28° C. This cell line, with a population doubling time of 29·5 h at passage 35, has been subcultured for >70 passages. Microscopically, LYCK cells were fibroblast-like. Chromosomal analysis revealed that the modal diploid chromosome number of LYCK cells was 48, which was identical to that of the P. crocea kidney. The cellular fluorescence could be observed in LYCK cells at 48 h after being transfected with pEGFP-N1 plasmid DNA, indicating that LYCK cells were competent for target gene expression in vitro. The expression of mRNA transcripts of the antiviral immune-related molecules interferon regulatory factor-3 I(ir3), interferon regulatory factor-7 (irf7), melanoma differentiation-associated protein 5 (mda5) was obviously up-regulated in LYCK cells in response to the stimulation with poly (I:C), whereas the expression of mRNA transcripts of the inflammatory cytokines tumour necrosis factor-α2 (tnfTNF-α2), interleukin-8 (il8), CC chemokine (lycCC) was up-regulated by lipopolysaccharide. These results indicated that the LYCK cell line could serve as a valuable tool for studies on immune-related gene functions in vitro.

Cloning and expression analyses of interferon regulatory factor (IRF) 3 and 7 genes in European eel, Anguilla anguilla with the identification of genes involved in IFN production

Interferon regulatory factor (IRF) 3 and IRF7 have been identified as regulators of type I interferon (IFN) gene expression in mammals. In the present study, the two genes were cloned and characterized in the European eel, Anguilla anguilla. The full-length cDNA sequence of IRF3 and IRF7 in the European eel, named as AaIRF3 and AaIRF7 consists of 2879 and 2419 bp respectively. Multiple alignments showed that the two IRFs have a highly conserved DNA binding domain (DBD) in the N terminus, with the characteristic motif containing five tryptophan residues, which is a feature present in their mammalian homologues. But, IRF7 has only four of the five residues in other species of fish. The expression of AaIRF3 and AaIRF7 both displayed an obvious dose-dependent manner following polyinosinic:polycytidylic acid (PolyI:C) challenge. In vivo expression analysis showed that the mRNA level of AaIRF3 and AaIRF7 was significantly up-regulated in response to PolyI:C stimulation in all examined tissues/organs except in muscle, with a lower level of increase observed in response to lipopolysaccharide (LPS) challenge and Edwardsiella tarda infection, indicating that AaIRF3 and AaIRF7 may be more likely involved in antiviral immune response. In addition, some pattern recognition receptors genes related with the production of type I IFNs and those genes in response to type I IFNs were identified in the European eel genome database, indicating a relatively conserved system in the production of type I IFN and its signalling in the European eel.

Molecular cloning and functional characterization of peptidoglycan recognition protein 6 in grass carp Ctenopharyngodon idella

Peptidoglycan recognition proteins (PGRPs) are pattern recognition molecules of innate immunity. In this study, a long-form PGRP, designated as gcPGRP6, was identified from grass carp Ctenopharyngodon idella. The deduced amino acid sequence of gcPGRP6 is composed of 464 residues with a conserved PGRP domain at the C-terminus. The gcPGRP6 gene consists of four exons and three introns, spacing approximately 2.7 kb of genomic sequence. Phylogenetic analysis demonstrated that gcPGRP6 is clustered closely with zebrafish PGLYRP6, and formed a long-type PGRP subfamily together with PGLYRP2 members identified in teleosts and mammals. Real-time PCR and Western blotting analyses revealed that gcPGRP6 is constitutively expressed in organs/tissues examined, and its expression was significantly induced in liver and intestine of grass carp in response to PGN stimulation and in CIK cells treated with lipoteichoic acid (LTA), polyinosinic polycytidylic acid (Poly I:C) and peptidoglycan (PGN). Immunofluorescence microscopy and Western blotting analyses revealed that gcPGRP6 is effectively secreted to the exterior of CIK cells. The over-expression of gcPGRP6 in CIK cells leads to the activation of NF-κB and the inhibition of intracellular bacterial growth. Moreover, cell lysates from CIK cells transfected with pTurbo-gcPGRP6-GFP plasmid display the binding activity towards Lys-type PGN from Staphylococcus aureus and DAP-type PGN from Bacillus subtilis. Furthermore, proinflammatory cytokine IL-2 and intracellular PGN receptor NOD2 had a significantly increased expression in CIK cells overexpressed with gcPGRP6. It is demonstrated that the PGRP6 in grass carp has a role in binding PGN, in inhibiting the growth of intracellular bacteria, and in activating NF-κB, as well as in regulating innate immune genes.

Complementary DNA sequences of the constant regions of T-cell antigen receptors α, β and γ in mandarin fish, Siniperca chuatsi Basilewsky, and their transcriptional changes after stimulation with Flavobacterium columnare

In this study, the constant-region genes (Cα, Cβ and Cγ) that encode the T-cell antigen receptor (TCR) α, β and γ chains were cloned from mandarin fish, Siniperca chuatsi Basilewsky, an important freshwater fish species in China. The complementary DNA sequences of Cα, Cβ and Cγ were 843, 716 and 906 base pairs (bp) in length and had a 465-, 289- and 360-bp 3' untranslated region, encoding 125, 142 and 182 amino acids, respectively. The amino-acid sequences of the constant regions of mandarin fish TCR α, β and γ chains (encoded by Cα, Cβ and Cγ, respectively) were most similar to those of their teleost counterparts, showing 60% similarity with pufferfish, 48% similarity with Atlantic salmon and 57% similarity with flounder, respectively. The phylogenetic analysis revealed that the mandarin fish Cα, Cβ and Cγ were clustered, respectively, with their vertebrate counterparts. The mandarin fish Cα, Cβ and Cγ could also be separated into four domains: immunoglobulin; connecting peptide (CP); transmembrane (TM); and cytoplasmic tail. Several conserved features in mammalian TCRs were also found in those of mandarin fish, such as a conserved cysteine residue in the CP domain of Cα, necessary for creating an interchain disulphide bond with the TCR β chain, and a conserved antigen receptor TM motif in Cα and Cβ. Meanwhile, transcripts of Cα, Cβ and Cγ were detectable in all examined organs, with a stronger signal observed in lymphoid organs. In addition, the temporal transcriptional changes for Cα and Cγ were investigated, 1, 2, 3, 4, 5, 6 and 8 weeks after stimulation with Flavobacterium columnare, in head kidney, spleen, blood, thymus, gill and intestine, using real-time polymerase chain reaction. The results demonstrated stimulation-dependent up-regulations in almost all tissues examined, which indicates that T cells may play important roles in preventing mandarin fish from bacterial invasion. In particular, apart from thymus, T cells were distributed mainly in gill and intestine, where striking up-regulation of Cγ was also observed. These results will facilitate functional studies of teleost TCRs and T cells.

IFN-γ and its receptors in a reptile reveal the evolutionary conservation of type II IFNs in vertebrates

In this study, interferon gamma (IFN-γ) and interferon gamma receptor (IFN-γR) genes have been identified in non-avian reptile, the North American green anole lizard (Anolis carolinensis). Like their counterparts from other jawed vertebrates, lizard IFN-γ, IFN-γR1 and IFN-γR2 show conserved features in genomic organizations, gene loci and protein sequences. The IFN-γ gene has the full cDNA sequence of 936 bp, with 522 bp open reading frame (ORF) encoding 174 amino acids, and has the genomic organization of four exons and three introns as observed in IFN-γ genes of other classes of vertebrates. The receptors, IFN-γR1 and IFN-γR2 have the ORF of 1278 and 984 bp, coding for 425 and 327 aa, respectively, with the genome organization of seven exons and six introns. In the gene loci of IFN-γ, DYRK2, IL22, IL26 and MDM1 are found with conserved synteny in vertebrates, and similar genes adjacent to IFN-γR1 and IFN-γR2 were also found. These receptors also contain conserved motifs, such as the membrane-proximal region and the C-terminal five residue motif in IFN-γR1, and intracellular conservative sequence in IFN-γR2, which have been confirmed to mediate down-stream JAK-STAT signaling pathway in mammals. IFN-γ and its receptors, IFN-γR1 and IFN-γR2 were constitutively expressed in organs/tissues examined in the lizard, and up-regulated expression of IFN-γ was observed in organs/tissues examined following the poly(I:C) stimulation, suggesting its antiviral role in lizards. The conserved features of IFN-γ and its receptors, IFN-γR1 and IFN-γR2, in gene organization and gene locus as well as in functional domain or motif may imply that the function of type II IFN system is evolutionarily conserved in the green anole lizard, as observed in other classes of vertebrates.

Histological characteristics of induced membranes in subcutaneous, intramuscular sites and bone defect

BACKGROUND

The induced membrane technique was proposed as a treatment of large segmental bone defects. The influence of the surrounding tissues on its characteristics remains unknown. It is therefore not known which kind of plastic surgery procedure (muscular or facio-cutaneous flap) would optimize bone osteointegration within a bone defect reconstructed using the induced-membrane technique.

HYPOTHESIS

We hypothesized that membrane characteristics could be influenced by the soft-tissue environment either subcutaneous or muscular.

OBJECTIVE

To evaluate the histological characteristics of poly-methylmethacrylate (PMMA) induced membranes in intramuscular, subcutaneous and bony environment (radius defects) at 2 steps: spacer implantation; secondary bone graft and its subsequent osteintegration after spacer removal.

METHODS

PMMA-induced membranes were obtained in the three sites of 15 rabbits. Subsequent new bone formation was studied in the same environments in 24 other rabbits. Six weeks after the initial implantation, PMMA spacers were replaced with iliac autografts. Animals were euthanized at 2, 4, and 8 weeks postoperatively. Tissue samples were harvested and stained with hematoxylin and eosin. The histological characteristics of the membrane (thickness and microvessel density) and the newly-formed bone (cortical thickness) were quantitatively analyzed.

RESULTS

The membranes in the subcutaneous sites developed quicker, were thicker and had the lowest microvessel density (P<0.01). The membranes in the intramuscular sites developed later and were thinner (P<0.01). The membranes in the osseous defects had the greatest microvessel density (P<0.01). After bone grafting, induced membranes became thinner and their microvessel density decreased substantially, but maintained better in osseous site. The newly-formed bone that developed in the radius defects, had the thickest cortices (P<0.01).

CONCLUSIONS

The evolution of membranes induced in the intramuscular and subcutaneous environments was close to that of the bone defect model, although bone formation appeared weaker.

Characterization of four Mx isoforms in the European eel, Anguilla anguilla

Mx protein is known to play an important role in vertebrate immune response to viral infection. In this study, cDNA sequences of four Mx isoforms, designated as MxA, B, C and D were characterized in the European eel, Anguilla anguilla. These sequences contained an open reading frame of 1899, 1896, 1866, 1779 bp, flanked by 95, 53, 138, 69 bp of 5' untranslated region and 389, 241, 136, 124 bp of 3' untranslated region, respectively. A phylogenetic tree constructed with Mx peptide sequences from vertebrates revealed that MxA, C and D in the European eel formed into a clade containing zebrafish MxA and MxB and Mx proteins in other teleosts, whereas MxB in the eel was clustered together with zebrafish MxD, MxG and MxF. The transcription level of all Mx isoforms increased in a poly I:C dose-dependent manner in peripheral blood leukocytes of eels, as revealed by real-time PCR. A further experiment was conducted to reveal the temporal change in expression of these isoforms in various organs/tissues following poly I:C stimulation, and significant increase in expression was observed at various degrees in different organs or in different sampling occasions within the 12 h experimental period. In particular, MxA had the highest level of increase, while MxB had the lowest; and three isoforms, MxA, MxB and MxD had the highest increase in intestine, while the highest increase of MxC expression was observed in liver. These four isoforms of eel Mx are thus expressed differentially, and further work is certainly required to clarify the activity of promoter elements and antiviral activity of these Mx isoforms.

Functional characterization of a short peptidoglycan recognition protein, PGRP5 in grass carp Ctenopharyngodon idella

Peptidoglycan recognition proteins (PGRPs), which are evolutionarily conserved from insects to mammals, recognize bacterial peptidoglycan (PGN) and function in antibacterial innate immunity. In this study, a short-form PGRP, designated as gcPGRP5 was identified from grass carp Ctenopharyngodon idella. The deduced amino acid sequence of gcPGRP5 is composed of 180 residues with a conserved PGRP domain at the C-terminus. The gcPGRP5 gene consists of four exons and three introns, spacing approximately 2.3 kb in genomic sequence. Phylogenetic analysis demonstrated that the gcPGRP5 is clustered with other PGRP-S identified in teleost fish. The gcPGRP5 is constitutively expressed in all organs/tissues examined, and its expression was significantly induced in CIK cells treated with lipoteichoic acid (LTA), polyinosinic polycytidylic acid (Poly I:C) and PGN. Fluorescence analysis showed that gcPGRP5 is distributed in cytoplasm of CIK cells, and cell lysates from CIK cells transfected with pTurbo-gcPGRP5-GFP and ptGFP1-gcPGRP5 plasmids display the binding activity and peptidoglycan-lytic amidase activity toward Lys-PGN from Staphylococcus aureus and Dap-PGN from Bacillus subtilis. Furthermore, heat-shock protein70 (Hsp70), and MyD88, an adaptor molecule in Toll-like receptor pathway, had an increased expression in CIK cells overexpressed with gcPGRP5. It is thus indicated that gcPGRP5 exhibits amidase activity, and also possesses roles in anti-stress, and in Toll-like receptor signaling pathway.

Roles of plasmid-encoded proteins, EseH, EseI and EscD in invasion, replication and virulence of Edwardsiella ictaluri

Native plasmids pEI1 and pEI2 were detected in Edwardsiella ictaluri HSN-1 isolated from diseased yellow catfish (Pelteobagrus fulvidraco). EseH encoded by pEI1 and other two proteins, EseI and EscD, encoded by pEI2, were found with homology to type III secretion system (T3SS) proteins. To investigate their roles in pathogenesis, the native plasmids were cured based on plasmid incompatibility by introducing a Kan positive and SacB negative selection marker into gene spacer of the native plasmids. Mutants with the deletion of the target genes were obtained by reverse PCR and self-ligation, and all mutants were examined for their virulence effect in yellow catfish. Compared with the HSN-1 strain, the two mutants ΔeseH and ΔeseI were attenuated, while mutant ΔescD had increased virulence with higher Competitive Index (CI) value. The adherence and invasion assays on fish EPC cells indicated that ΔeseH and ΔeseI had decreased ability in adherence. Using E. tarda as surrogate, EseH and EseI were detected in culture supernatants, but EscD was not, with the secretion of EseH depending on T3SS. In addition, EseH and EseI were found translocated into host cells, and by means of subcellular fractionation, EseH was localized in membrane fraction of ZF4 cells, and EseI in the cytosol fraction. Hence, the role of these three genes in adherence, invasion and cellular replication was revealed from the pathogenic bacterium E. ictaluri.

Characterization and expression of Cd8 molecules in mandarin fish Siniperca chuatsi

The full-length complementary DNA (cDNA) sequences encoding cd8α and cd8β molecules were sequenced and characterized from mandarin fish Siniperca chuatsi. Conserved motifs and residues were found to be present in derived peptides of the Cd8 molecules. For example, WXR motif, DXGXYXC motif, and four cysteine residues were present in the extracellular region of the Cd8 protein. Threonine, serine and proline residues involved in multiple O-linked glycosylation events were located in the membrane proximal hinge region. The common CPH motif in the cytoplasmic tail was detected similar to other teleost Cd8 molecules. Different from those in mammals, S. chuatsi Cd8 sequences have many extra cysteine residues (C149 in Cd8α sequence and C46, C51 and C158 in Cd8β sequence), which also exist in other teleost Cd8 molecules. Real-time polymerase chain reaction (RT-PCR) and Western blot analyses revealed that the thymus had the highest expression of cd8 messenger (m)RNA and protein. After stimulated with phytohaemagglutinin, polyriboinsine-polyribocyaidylic acid and concanavalin A (ConA), the expression level of cd8 mRNA increased significantly in head-kidney lymphocytes at 4 and 8 h, but decreased to normal level at 12 h. Similarly, stimulation with ConA in vivo also led to an increase in the cd8 mRNA level in the spleen. Immunohistochemistry analysis demonstrated that Cd8α-positive cells can be detected in the thymus, spleen and intestine by using polyclonal anti-Cd8α antibody.

Type I restriction-modification system and its resistance in electroporation efficiency in Flavobacterium columnare

Flavobacterium columnare, the causative agent of columnaris disease, infects freshwater fish worldwide. However, the pathogenicity of this bacterium is poorly understood due possibly to the lack of an efficient in-frame knockout technique. In order to improve electroporation efficiency, the type I restriction-modification system (R-M system) was cloned and its role in electroporation was examined in F. columnare G(4) strain. The complete sequence of type I R-M system in the bacterium, designated as Fcl, contains all three subunits of type I R-M system, named as fclM, fclS, fclR, respectively, with the identification of a hypothetical gene, fclX. Constitutive transcription of the three genes was observed in F. columnare G(4) by RT-PCR. The ORF of fclM and fclS was cloned into the plasmid pACYC184 and transformed into Escherichia coli TOP10. The resultant E. coli strain, designated as E. coli TOPmt, was transformed with the integrative plasmid pGL006 constructed for F. columnare G(4). The integrative plasmid was re-isolated from TOPmt and incubated with the lysate of F. columnare G(4). The re-isolated integrative plasmid, designated as pGL006', showed higher resistance than pGL006. With pGL006', the electroporation efficiency of the strain G(4) increased 2.6 times, while that of F. columnare G(18) was not obviously improved. Furthermore, a method to improve the electroporation efficiency of F. columnare G(4) was developed using the integrative plasmid methylated by E. coli TOPmt which contains the fclM and fclS gene of F. columnare G(4). Further analyses showed that the fcl gene cluster may be a unique type I R-M system in F. columnare G(4). It will be of significant interest to examine the composition and diversity of R-M systems in strains of F. columnare in order to set up a suitable genetic manipulation system for the bacterium.