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Summary Purpose The aim of this study was to determine whether the neutrophil to lymphocyte ratio (NLR) can predict severe Coronavirus disease 2019 (COVID-19). Patients and methods A multicenter case-control study was conducted to investigate whether the NLR can help predict the severity of COVID-19. Patients confirmed to have COVID-19 between 16 January 2020 and 15 March 2020 were enrolled. Furthermore, meta-analyses were conducted based on both previous studies and our case-control study. Results In the case-control study, 213 patients (severe: 81) were included. The results suggested that the NLR was an independent risk factor (odds ratio [OR], 1.155, 95% confidence interval [95% CI]: 1.043–1.279, P = 0.006) and a great predictor (the area under the ROC curve was 0.728, 95% CI: 0.656–0.800) for severe COVID-19. In total, 18 datasets from 16 studies combined with our case-control study (severe: 1211; non-severe: 5838) were included in the meta-analyses and the results showed that the NLR of the severe COVID-19 group was significantly higher than that of the non-severe group (SMD = 1.10, 95% CI: 0.90–1.31, P Conclusion Based on a multicenter case-control study and a meta-analysis, we found that the initial NLR was a great predictor of severe COVID-19.

The aim of this work is to study the effect of solution treatment time on the Ti2Ni second phase morphology, phase transformations, mechanical properties and superelastic behavior of plasma arc deposited (PAD) nitinols. The results demonstrate that the Ti2Ni second phases are significantly affected by the solution treatment time. The Ti2Ni second phase is dissolved into the TiNi matrix phase gradually, and its size and volume fraction also gradually decreases with increasing solution treatment time. Additionally, the solution treatment time exhibits a visible influence on the phase transformation, mechanical properties and superelasticity of the PAD nitinol, but the degree of influence depends on the size, volume fraction and distribution of the Ti2Ni second phase. With increasing solution treatment time, the phase transformation temperatures gradually increase, and the phase transformation peaks decrease in width and become sharp with a single transformation. Besides, the compressive strength first increases and then decreases, while the plasticity increases with solution treatment time increases from 0 to 8 h. Moreover, the superelastic stability of the PAD nitinol is improves as the solution treatment time increases from 0 to 6 h and then decreases. This phenomenon is closely related to the critical stress for dislocation slip, which depends on the change in the Ti2Ni second phase.

Objective Patients with severe brain injury is usual at high risk of extubation failure, despite of those with no/minor primary respiratory problem, majority of them still needs long term respiratory support and has severe pulmonary complications. This retrospective study aimed to compare the effect of noninvasive ventilation (NIV) and tracheotomy on the prognosis in critically ill mechanically ventilated neurosurgical patients. Methods This is a single center, retrospective observe cohort study. Postoperative patients with brain injury consecutively admitted to ICU from November 1st, 2015 through February 28th, 2017, who had received invasive mechanical ventilation more than 48 h were screened, those who received NIV or tracheotomy procedure, meanwhile with Glasgow Coma Scale (GCS) score between 8 and 13 points before using NIV or undergoing tracheotomy, were retrospectively included in this study. The demographic data and clinical main outcomes such as ICU and hospital mortality, time of mechanical ventilation, length of ICU and hospital were collected. The primary outcome was the incidence of postoperative pulmonary infection between two groups. Results 77 patients were included in this study. 33 patients received NIV, and 44 patients received tracheotomy through the ICU duration. The incidence of postoperative pulmonary infection in NIV group was significantly lower than that in tracheotomy group (54.5% VS 84.1%, P

The requirement of repairing damaged surface of nickel aluminum bronze (NAB) parts from underwater environment is urgent in recent years. In this paper, a novel approach to underwater laser cladded NAB by adding Ti and applying Zn protective layer has been reported. The materials fabricated underwater from this approach possess desirable performance. Ti additives increases the surface tension in melting pool, and prevents the high-speed water jet from invading the melting pool. Therefore, pores are almost disappearing. Due to the fast heat loss during underwater laser cladding process, the microstructure of underwater laser cladded nickel aluminum with adding titanium is fine, homogeneous and stable, in addition, the heat affected zone is small. Electrochemical results shows that the corrosion resistance of underwater laser cladded nickel aluminum bronze with adding titanium is better than that of substrate. In this study, the underwater environment is favorable for manufacturing a good material by using laser processing technology. The results of this study will provide meaningful reference to repairing NAB parts in underwater environment.

Background Acute kidney injury (AKI) is a serve and harmful syndrome in the intensive care unit. Our previous study has shown that patients who will progress to AKI 3 stage are considered to receive RRT. This study aimed to develop a prediction model that can predict whether progression to AKI stage 3. Methods Patients with AKI stage 1/2, when they were first diagnosed with AKI in the Medical Information Mart for Intensive Care (MIMIC-III), were included. Patients who receive RRT or progress to AKI 3 stage within 72 hours of first AKI diagnosis were excluded. We build two predictive models, respectively using machine learning extreme gradient boosting (XGBoost) and logistic regression, to predict patients who will progress to AKI stage 3. Established models were evaluated by cross-validation and area under receiver operating characteristic curve (AU-ROC). Results Of the 29238 patients included in the analysis, 3237 (11.1%) patients progressed to AKI stage 3. Creatinine, blood urea nitrogen (BUN), sepsis and respiratory failure were the important predictors of AKI progression. The machine learning XGBoost model has a better performance than the Cox regression model on predicting AKI stage 3 progression (AU-ROC, 0.860 vs. 0.728, respectively). Conclusions The XGBoost model was able to identify patients with AKI progression better than the Cox regression model. Machine learning techniques may improve predictive modeling in medical research.

In mammals, PIAS proteins are important SUMO E3 ligases and act as versatile regulators of over sixty different proteins, including components from the NF-κB pathways. But the PIAS functions are not well-understood due to complicated molecular mechanisms and multiple gene paralogs with overlapping roles, which is especially true in lower vertebrates where dedicated studies are scarce. As a basal chordate with a single PIAS gene, amphioxus is a convenient model to study PIAS from the evolutionary perspective. TRAF6 is a critical adaptor of the NF-κB pathways but it is not known whether TRAF6 is regulated by PIAS. Here we discover that in mammalian cells, amphioxus PIAS inhibited NF-κB activation by co-localizing and binding with TRAF6. The interaction relied on the N-terminal SAP and PINIT domains of PIAS. TRAF6 is an E3 ubiquitin ligase, which initiates downstream NF-κB signaling by promoting its self-ubiquitination. Both amphioxus SUMO1 and Ubc9 (SUMO E2 ligase) could suppress TRAF6 self-ubiquitination and NF-κB activation, suggesting that the SUMOylation activity competed away the ubiquitination activity of TRAF6. However, we show that the wild-type PIAS and the mutant PIAS without SUMO E3 ligase activity both could inhibit TRAF6-mediated NF-κB activation by reducing TRAF6 self-ubiquitination. This implies that SUMO ligase activity is not the only mechanism for PIAS to negatively regulate TRAF6. Finally, we tested the interactions between human PIAS1-4 and TRAF6. It reveals that human PIAS1, 3 and 4, but not 2, were able to repress NF-κB activation by reducing TRAF6 self-ubiquitination. Taken together, our study discovers a conserved regulatory interaction between chordate PIAS and TRAF6. It therefore sheds light on the complicated role of PIAS in immune regulation, and may help to understand the PIAS functions in other lower chordate taxa, such as jawless and jawed fishes.

The fracture behavior of high-profile high-entropy alloy coating was characterized by in-situ TEM tensile testing. The samples for in-situ TEM tensile testing were obtained by FIB technology. The results show that irrelevant to phase constitution, the Young's module, fracture strength and ultimate elongation are measured as ∼107 GPa, ∼2.70 GPa and ∼2.6%, respectively. Transcrystalline fracture and cleavage fracture with the cleavage plane of {112} are observed evidentially and the evolution of the dislocation motion in the material could be directly connected with the fracture behavior from the recorded movies obtained by a Gatan CCD camera. The engineering stress-strain curve is nearly linearity, however, a slight deviation away from linearity could be noted in the end of engineering stress-strain curve, which is attributed that the extra elastic deformation results in part of continued deformation.

IL-1R–associated kinases (IRAK) are important regulators in the TLR/IL-1R pathways, but their function appears inconsistent between Drosophila, bony fishes, and vertebrates. This causes a difficulty to understand the IRAK functions. As a step to reveal the evolution of IRAKs, in this study, we performed comparative and functional analysis of IRAKs by exploiting the amphioxus, a pivotal taxon connecting invertebrates and vertebrates. Sequence and phylogenetic analysis indicated three major IRAK lineages: IRAK1/2/3 is a vertebrate-specific lineage, IRAK4 is an ancient lineage conserved between invertebrate and vertebrates, and Pelle is another ancient lineage that is preserved in protostomes and invertebrate deuterostomes but lost in vertebrate deuterostomes. Pelle is closer neither to IRAK4 nor to IRAK1/2/3, hence suggesting no clear functional analogs to IRAK1/2/3 in nonvertebrates. Functional analysis showed that both amphioxus IRAK4 and Pelle could suppress NF-κB activation induced by MyD88 and TRAF6, which are unlike mammalian and Drosophila IRAKs, but, surprisingly, similar to bony fish IRAK4. Also unlike Drosophila IRAKs, no interaction was detected between amphioxus IRAK4 and Pelle, although both of them were shown capable of binding MyD88. These findings, together with previous reports, show that unlike other signal transducers in the TLR/IL-1R pathways, such as MyD88 and TRAF6, the functions of IRAKs are highly variable during evolution and very specialized in different major animal taxa. Indeed, we suggest that the functional variability of IRAKs might confer plasticity to the signal transduction of the TLR/IL-1R pathways, which in return helps the species to evolve against the pathogens.

This study proposes a quick and effective algorithm for screening severe N − 2 contingency, thus avoiding exhausting analysis of all conceivable N − 2 contingencies. First, the index of overload contribution rate (OCR) is developed on the basis of distribution factor, which is discovered to be long-tailed distributed by statistics. Then, by fully exploiting the discovered feature, the so-called technique of combination of partitioned data sets (TCPDS) is designed and described. The core of the contingency screening algorithm is to apply the TCPDS to the OCR. Moreover, an index system is established to evaluate the proposed algorithm. Finally, the proposed algorithm is proved to be effective and efficient by the index system when applied to some practical power systems.

The supersonic fine particles bombarding (SFPB) pretreatment is adopted to assist vacuum carburizing for refining the microstructure and improving the mechanical properties of carburized layer. The microstructures, micrhardness and tribology properties of SFPB carburized sample and vacuum carburized sample were studied. The results showed that SFPB pretreatment could form random oriented, ultrafine-grained microstructure and high density dislocations in AISI 9310 steel, leading to the increase of case depth of carburized layer, the refinement of grain size and the promotion of the formation of twin martensite and carbides in carburized layer. Besides, the surface microhardness, maximum residual compressive stress and wear rate of carburized layer were enhanced by SFPB pretreatment, which was attributed to the formation of twin martensite, grain refinement, dispersion strengthening of carbides and the increase of high misorientation angle grain boundary.

La ion pre-implantation was successfully used to obtain vacuum carburized layer with ultrafine microstructure and higher case depth of AISI 9310 alloy steel. The effect of La ion pre-implantation on microstructure, case depth and hardness of carburized layer was investigated in detail. The results showed that the La2O3, BCC structure solution of La and lattice defects were introduced into AISI 9310 alloy steel by La pre-implantation. Meanwhile, the pre-implantation can effectively refine microstructure and dramatically improve diffusion coefficient of carbon and hardness of carburized layer. The La2O3 and LaC2 in situ produced during carburizing can act as potential heterogeneous nucleation sites for γ-Fe phase to refine grain. The higher carbon concentration gradient caused by the inhibition effect of La on C–C bond formation and induction of Cottrell can increase the amount of carbides in carburized layer. The excellent microstructure and higher carbon concentration gradient can enhance short-circuit diffusion to accelerate the carbon diffusion coefficient inducing the increase of hardness of carburized layer.

The Hongshan quartz monzonite porphyry is one of the Yanshanian intrusions in the southern part of the Yudun Arc. Detailed zircon U–Pb data of four samples yielded ages of 78.8–80.7 Ma, indicating that the Hongshan intrusion was emplaced during the late stage of Late Cretaceous. The Hongshan intrusion shows shoshonitic and high-K calc-alkaline, with A/CNK = 0.64–1.14. The rocks show an obvious fractionation between light and heavy rare-earth elements (average [La/Yb]N = 38.85), with negative Eu anomalies (Eu/Eu* = 0.60–0.87), enrichment in large-ion lithophile elements (Rb, Th, U and K) and depletion in high field-strength elements (Nb, Ta and P). Rocks have high Sr and low Y content which are characteristics of adakitic rocks, suggesting magma derivation from thickened lower crust. In order to evaluate the nature of the source region, Hf isotope data of zircons were acquired through LA-MC-ICPMS. The negative and variable eHf(t) values demonstrate that the Hongshan intrusion was derived from ancient crust, without mantle-derived components and is significantly different from the Triassic intrusions in the southern part of the Yudun Arc. The three Yanshanian intrusions in Hongshan, Relin and Tongchangou are remarkably similar in terms of geochronology, geochemistry and Hf isotopes. We therefore infer that these intrusions had the same magmatic source and we correlate the tectonics with northward subduction of Tethys underneath the Asian continent. Copyright © 2015 John Wiley & Sons, Ltd.

Both amphioxus and the sea urchin encode a complex innate immune gene repertoire in their genomes, but the composition and mechanisms of their innate immune systems, as well as the fundamental differences between two systems, remain largely unexplored. In this study, we dissect the mucosal immune complexity of amphioxus into different evolutionary-functional modes and regulatory patterns by integrating information from phylogenetic inferences, genome-wide digital expression profiles, time course expression dynamics, and functional analyses. With these rich data, we reconstruct several major immune subsystems in amphioxus and analyze their regulation during mucosal infection. These include the TNF/IL-1R network, TLR and NLR networks, complement system, apoptosis network, oxidative pathways, and other effector genes (e.g., peptidoglycan recognition proteins, Gram-negative binding proteins, and chitin-binding proteins). We show that beneath the superficial similarity to that of the sea urchin, the amphioxus innate system, despite preserving critical invertebrate components, is more similar to that of the vertebrates in terms of composition, expression regulation, and functional strategies. For example, major effectors in amphioxus gut mucous tissue are the well-developed complement and oxidative-burst systems, and the signaling network in amphioxus seems to emphasize signal transduction/modulation more than initiation. In conclusion, we suggest that the innate immune systems of amphioxus and the sea urchin are strategically different, possibly representing two successful cases among many expanded immune systems that arose at the age of the Cambrian explosion. We further suggest that the vertebrate innate immune system should be derived from one of these expanded systems, most likely from the same one that was shared by amphioxus.

It has been speculated that before vertebrates evolved somatic diversity-based adaptive immunity, the germline-encoded diversity of innate immunity may have been more developed. Amphioxus occupies the basal position of the chordate phylum and hence is an important reference to the evolution of vertebrate immunity. Here we report the first comprehensive genomic survey of the immune gene repertoire of the amphioxus Branchiostoma floridae. It has been reported that the purple sea urchin has a vastly expanded innate receptor repertoire not previously seen in other species, which includes 222 toll-like receptors (TLRs), 203 NOD/NALP-like receptors (NLRs), and 218 scavenger receptors (SRs). We discovered that the amphioxus genome contains comparable expansion with 71 TLR gene models, 118 NLR models, and 270 SR models. Amphioxus also expands other receptor-like families, including 1215 C-type lectin models, 240 LRR and IGcam-containing models, 1363 other LRR-containing models, 75 C1q-like models, 98 ficolin-like models, and hundreds of models containing complement-related domains. The expansion is not restricted to receptors but is likely to extend to intermediate signal transducers because there are 58 TIR adapter-like models, 36 TRAF models, 44 initiator caspase models, and 541 death-fold domain-containing models in the genome. Amphioxus also has a sophisticated TNF system and a complicated complement system not previously seen in other invertebrates. Besides the increase of gene number, domain combinations of immune proteins are also increased. Altogether, this survey suggests that the amphioxus, a species without vertebrate-type adaptive immunity, holds extraordinary innate complexity and diversity.

A novel F4-carbohydrate recognition domain (CRD) – linker –F3-CRD-type bi-CRD Branchiostoma belcheri tsingtauense galectin (BbtGal)-L together with its alternatively spliced mono-CRD isoform BbtGal-S from amphioxus intestine was encoded by a 9488-bp unique gene with eight exons and seven introns. The recombinant proteins of BbtGal were found to have b-galactosidebinding activity, indicating that BbtGal was a member of the galectin family. Phylogenetic analysis of this gene along with its splicing form and genome structure suggested that the BbtGal gene was the primitive form of the chordate galectin family. Real-time polymerase chain reaction analyses (PCR) indicated that BbtGal mRNA was expressed during all stages of embryonic development. In terms of tissue distribution, BbtGal-L mRNA was mainly expressed in the immunity-related organs, such as hepatic diverticulum, intestine, and gill, but BbtGal-S was ubiquitously expressed in all tissues. The expression of BbtGal-L mRNA was elevated after acute challenge with various microorganisms, but BbtGal-L only bound to specific bacteria. The immune function of BbtGal was consistent with its localization both outside and inside the cell. Our study on amphioxus galectin may help further understanding of the evolution of chordate galectin in terms of host – pathogen interaction in the immune system.

Cone snails are attracting increasing scientific attention due to their unprecedented diversity of invaluable channel-targeted peptides. As arguably the largest and most successful evolutionary genus of invertebrates, Conus also may become the model system to study the evolution of multigene families and biodiversity. Here, a set of 897 expressed sequence tags (ESTs) derived from a Conus litteratus venom duct was analyzed to illuminate the diversity and evolution mechanism of conotoxins. Nearly half of these ESTs represent the coding sequences of conotoxins, which were grouped into 42 novel conotoxin cDNA sequences (seven superfamilies), with T-superfamily conotoxins being the dominant component. The gene expression profile of conotoxin revealed that transcripts are expressed with order-of-magnitude differences, sequence divergence within a superfamily increases from the N to the C terminus of the open reading frame, and even multiple scaffold-different mature peptides exist in a conotoxin gene superfamily. Most excitingly, we identified a novel conotoxin superfamily and three novel cysteine scaffolds. These results give an initial insight into the C. litteratus transcriptome that will contribute to a better understanding of conotoxin evolution and the study of the cone snail genome in the near future.

The coding regions of many of the major histocompatibility complex (MHC) (human leukocyte antigen [HLA] in humans) molecules are believed to be subject to balancing selection. But it is less certain whether the regulatory regions of such coding sequences are also subject to the same type of selection. Here, we studied the polymorphism of the regulatory regions of the HLA-DPA1 and HLA-DPB1 genes among ethnic minorities in southwestern China. Phylogenetic analysis revealed two deep clades >10 million years old. There is almost complete linkage disequilibrium between the regulatory and coding regions of HLA-DPA1, which hints at coadaptive balancing selection on the entire region. Thus, the molecular mechanism of balancing selection in MHC may involve expression modulation in addition to coding-region polymorphisms. Although the frequency of clade II is >30% in some ethnic minorities, it decreases to

Vertebrates diverged from other chordates ~500 Myr ago and experienced successful innovations and adaptations, but the genomic basis underlying vertebrate origins are not fully understood. Here we suggest, through comparison with multiple lancelet (amphioxus) genomes, that ancient vertebrates experienced high rates of protein evolution, genome rearrangement and domain shuffling and that these rates greatly slowed down after the divergence of jawed and jawless vertebrates. Compared with lancelets, modern vertebrates retain, at least relatively, less protein diversity, fewer nucleotide polymorphisms, domain combinations and conserved non-coding elements (CNE). Modern vertebrates also lost substantial transposable element (TE) diversity, whereas lancelets preserve high TE diversity that includes even the long-sought RAG transposon. Lancelets also exhibit rapid gene turnover, pervasive transcription, fastest exon shuffling in metazoans and substantial TE methylation not observed in other invertebrates. These new lancelet genome sequences provide new insights into the chordate ancestral state and the vertebrate evolution., The lancelet, or amphioxus, is an extant basal chordate that diverged from other chordate lineages about 550 million years ago. Here the authors sequence and assemble the diploid genome of a male adult of the Chinese lancelet, B. belcheri, and highlight genomic features that may have played an important role in the origin and evolution of vertebrates.

In seeking evidence of the existence of adaptive immune system (AIS) in ancient chordate, cDNA clones of six libraries from a protochordate, the Chinese amphioxus, were sequenced. Although the key molecules such as TCR, MHC, Ig, and RAG in AIS have not been identified from our database, we demonstrated in this study the extensive molecular evidence for the presence of genes homologous to many genes that are involved in AIS directly or indirectly, including some of which may represent the putative precursors of vertebrate AIS-related genes. The comparative analyses of these genes in different model organisms revealed the different fates of these genes during evolution. Their gene expression pattern suggested that the primitive digestive system is the pivotal place of the origin and evolution of the AIS. Our studies support the general statement that AIS appears after the jawless/jawed vertebrate split. However our study further reveals the fact that AIS is in its twilight in amphioxus and the evolution of the molecules in amphioxus are waiting for recruitment by the emergence of AIS.

Macrophage migration inhibitory factor (MIF) is an important cytokine related to host defenses and autoimmune diseases. Here, we reported two full-length cDNA clones isolated from Chinese amphioxus (Branchiostoma belcheri tsingtaunese). Amino acid sequences analysis and structure prediction of these two molecules, called Bbt-MIF-I and Bbt-MIF-II, respectively, indicated that several conservative domains existed in the two amphioxus MIFs and their sequences were highly homologous to their counterparts of other species. Intriguingly, the Bbt-MIFs gene is present in multi-copy per haploid genome, which is very unusual compared with vertebrate's MIF gene given the known genome duplication theory. The genomic copy number, expression pattern of MIF gene and phylogenetic analysis of MIF proteins all suggested that a leap forward happened for MIF gene during the evolution from invertebrate to vertebrate. Considering the crucial role of MIF in innate immunity, MIF might serve as one of key molecular markers of evolution of immune system.

The TNF-associated factor (TRAF) family, the crucial adaptor group in innate immune signaling, increased to 24 in amphioxus, the oldest lineage of the Chordata. To address how these expanded molecules evolved to adapt to the changing TRAF mediated signaling pathways, here we conducted genomic and functional comparisons of four distinct amphioxus TRAF groups with their human counterparts. We showed that lineage-specific duplication and rearrangement were responsible for the expansion of amphioxus TRAF1/2 and 3 lineages, whereas TRAF4 and 6 maintained a relatively stable genome and protein structure. Amphioxus TRAF1/2 and 3 molecules displayed various expression patterns in response to microbial infection, and some of them can attenuate the NF-κB activation mediated by human TRAF2 and 6. Amphioxus TRAF4 presented two unique functions: activation of the NF-κB pathway and involvement in somite formation. Although amphioxus TRAF6 was conserved in activating NF-κB pathway for antibacterial defense, the mechanism was not the same as that observed in humans. In summary, our findings reveal the evolutionary uniqueness of the TRAF family in this basal chordate, and suggest that genomic duplication and functional divergence of the TRAF family are important for the current form of the TRAF-mediated signaling pathways in humans.

To investigate the evolution and immune function of C-type lectin in amphioxus, the primitive representative of the chordate phylum, we identified three C-type lectins consisting solely of a carbohydrate recognition domain and N-terminal signal peptide and found that they had distinct express patterns in special tissues and immune response to stimulations analyzed by quantitative real-time PCR. We characterized the biochemical and biological properties of AmphiCTL1, which was dramatically up-regulated in amphioxus challenged with Staphylococcus aureus, Saccharomyces cerevisiae, and zymosan. Immunohistochemistry demonstrated that the localization of AmphiCTL1 protein was exclusively detected in the inner folding tissues of the hepatic diverticulum. Recombinant AmphiCTL1 was characterized as a typical Ca2+-dependent carbohydrate-binding protein possessing hemagglutinating activity, preferentially bound to all examined four Gram-positive bacteria and two yeast strains, but had little binding activity toward four Gram-negative bacteria we tested. It aggregated S. aureus and S. cerevisiae in a Ca2+-dependent manner and specifically bound to insoluble peptidoglycan and glucan, but not to LPS, lipoteichoic acid, and mannan. Calcium increased the intensity of the interaction between AmphiCTL1 and those components, but was not essential. This lectin directly killed S. aureus and S. cerevisiae in a Ca2+-independent fashion, and its binding to microorganism cell wall polysaccharides such as peptidoglycan and glucan preceded microbial killing activity. These findings suggested that AmphiCTL1 acted as a direct microbial killing C-type lectin through binding microbial targets via interaction with peptidoglycan and glucan. Thus, AmphiCTL1 may be an evolutionarily primitive form of antimicrobial protein involved in lectin-mediated innate immunity.

To seek evidence of a primitive adaptive immune system (AIS) before vertebrate, we examined whether lymphocytes or lymphocyte-like cells and the related molecules participating in the lymphocyte function existed in amphioxus. Anatomical analysis by electron microscopy revealed the presence of lymphocyte-like cells in gills, and these cells underwent morphological changes in response to microbial pathogens that are reminiscent of those of mammalian lymphocytes executing immune response to microbial challenge. In addition, a systematic comparative analysis of our cDNA database of amphioxus identified a large number of genes whose vertebrate counterparts are involved in lymphocyte function. Among these genes, several genes were found to be expressed in the vicinity of the lymphocyte-like cells by in situ hybridization and up-regulated after exposure to microbial pathogens. Our findings in the amphioxus indicate the twilight for the emergency of AIS before the invertebrate-vertebrate transition during evolution.

Amphioxus is traditionally considered as the living invertebrate most closely related to vertebrate. However, no systematic study was performed about how the amphioxus defends against the microbial invasion. Here we reported a profile of gene transcription after Staphylococcus aureus (S.c) and Vibrio parahaemolyticus (V.p) challenged by suppression subtractive hybridization (SSH). When compared with mammals, amphioxus has the same acute immune defense genes (lectins, metalloproteinase, lysozymes and antimicrobial peptide, etc.) as well as a similar pattern and level of temporal gene expression. In contrast, amphioxus was demonstrated to have some novel acute immune response genes in response to the microbial challenge, such as apextrin and dermatopontin, which have a 3500-fold and 900-fold induction after the V.p infection, respectively, suggesting new functions in early immune system for these two genes. Our results reported for the first time a profile of primitive immune system defense against infection in protochordate.

A cDNA library of male Chinese seahorse (Hippocampus kuda Bleeker) was constructed to investigate the molecular profile of seahorse as one of the most famous traditional Chinese medicine materials, and to reveal immunological and physiological mechanisms of seahorse as one of the most primitive vertebrates at molecular level. A total of 3372 expressed sequence tags (ESTs) consisting of 1911 unique genes (345 clusters and 1566 singletons) were examined in the present study. Identification of the genes related to immune system, paternal brooding and physiological regulation provides not only valuable insights into the molecular mechanism of immune system in teleost fish but also plausible explanations for pharmacological activities of Chinese seahorse. Furthermore, the occurrence of high prevalent C-type lectins suggested that a lectin-complement pathway might exert a more dominant function in the innate immune system of teleost than mammal. Carbohydrate recognition domain (CRD) without a collagen-like region in the lectins of seahorse was likely an ancient characteristic of lectins similar to invertebrates.

In animals, the tetraspanins are a large superfamily of membrane proteins that play important roles in organizing various cell–cell and matrix–cell interactions and signal pathways based on such interactions. However, their origin and evolution largely remain elusive and most of the family's members are functionally unknown or less known due to difficulties of study, such as functional redundancy. In this study, we rebuilt the family's phylogeny with sequences retrieved from online databases and our cDNA library of amphioxus. We reveal that, in addition to in metazoans, various tetraspanins are extensively expressed in protozoan amoebae, fungi, and plants. We also discuss the structural evolution of tetraspanin's major extracellular domain and the relation between tetraspanin's duplication and functional redundancy. Finally, we elucidate the coevolution of tetraspanins and eukaryotes and suggest that tetraspanins play important roles in the unicell-to-multicell transition. In short, the study of tetraspanin in a phylogenetic context helps us understand the evolution of intercellular interactions.

In this research a series of Hf-Si-N composite films with different Si contents are prepared by magnetron sputtering on titanium alloy surface. The element valences of the films are studied by using of X-ray photoelectron spectroscopy (XPS). The tribological property, nano-mechanical performance, biocompatibility of the films is examined through ball-on-disk tester, nano- mechanical test system and platelet adhesion experiment, respectively, and the effect of Si contents on the performance is investigated. The results show that the Hf-Si-N film has good wear resistance, nano-mechanical properties and biocompatibility. The film is mainly composed of HfN and Si3N4. Its nano-hardness first increases then decreases along with the addition of Si and the film achieves the maximum hardness and the minimum friction coefficient when the content of Si is 6.99 at. %.