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The incidence rate of breast cancer is the highest in the world, and major problem in the clinical treatment is the therapy resistance of breast cancer stem cells (CSCs). Thus, new therapeutic approaches targeting breast CSCs are needed. Our previous study demonstrated cancer-derived sialylated IgG (SIA-IgG) is highly expressed in cancer cells with stem/progenitor features. Furthermore, a high frequency of SIA-IgG in breast cancer tissue predicted metastasis and correlated with poor prognosis factors, and depletion of IgG in breast cancer leads to lower malignancy of cancer cells, suggesting SIA-IgG could be a potential therapeutic target in breast cancer. In this study, we first investigated the relationship of SIA-IgG expression with the clinicopathological characteristics and clinical prognosis of breast carcinoma patients, and the data confirmed that the expression of SIA-IgG confers poor prognosis in breast cancer. Successively, by using a monoclonal antibody specifically against SIA-IgG, we targeted SIA-IgG on the surface of MDA-MB-231 cells and detected their functional changes, and the results suggested SIA-IgG to be a promising antibody therapeutic target in breast cancer. In addition, we explored the mechanism of action at the molecular level of SIA-IgG on breast cancer cell, the findings suggest that SIA-IgG promotes proliferation, metastasis, and invasion of breast cancer cells through the

The slow-evolving invertebrate amphioxus has an irreplaceable role in advancing our understanding of the vertebrate origin and innovations. Here we resolve the nearly complete chromosomal genomes of three amphioxus species, one of which best recapitulates the 17 chordate ancestor linkage groups. We reconstruct the fusions, retention, or rearrangements between descendants of whole-genome duplications, which gave rise to the extant microchromosomes likely existed in the vertebrate ancestor. Similar to vertebrates, the amphioxus genome gradually establishes its three-dimensional chromatin architecture at the onset of zygotic activation and forms two topologically associated domains at the Hox gene cluster. We find that all three amphioxus species have ZW sex chromosomes with little sequence differentiation, and their putative sex-determining regions are nonhomologous to each other. Our results illuminate the unappreciated interspecific diversity and developmental dynamics of amphioxus genomes and provide high-quality references for understanding the mechanisms of chordate functional genome evolution.

The slow-evolving invertebrate amphioxus has an irreplaceable role in advancing our understanding into the vertebrate origin and innovations. Here we resolve the nearly complete chromosomal genomes of three amphioxus species, one of which best recapitulates the 17 chordate ancestor linkage groups. We reconstruct the fusions, retention or rearrangements between descendants of whole genome duplications (WGDs), which gave rise to the extant microchromosomes likely existed in the vertebrate ancestor. Similar to vertebrates, the amphioxus genome gradually establishes its 3D chromatin architecture at the onset of zygotic activation, and forms two topologically associated domains at the Hox gene cluster. We find that all three amphioxus species have ZW sex chromosomes with little sequence differentiation, and their putative sex-determining regions are nonhomologous to each other. Our results illuminate the unappreciated interspecific diversity and developmental dynamics of amphioxus genomes, and provide high-quality references for understanding the mechanisms of chordate functional genome evolution.

Vertebrate evolution was accompanied by two rounds of whole-genome duplication followed by functional divergence in terms of regulatory circuits and gene expression patterns. As a basal and slow-evolving chordate species, amphioxus is an ideal paradigm for exploring the origin and evolution of vertebrates. Single-cell sequencing has been widely used to construct the developmental cell atlas of several representative species of vertebrates (human, mouse, zebrafish, and frog) and tunicates (sea squirts). Here, we perform single-nucleus RNA sequencing (snRNA-seq) and single-cell assay for transposase accessible chromatin sequencing (scATAC-seq) for different stages of amphioxus (covering embryogenesis and adult tissues). With the datasets generated, we constructed a developmental tree for amphioxus cell fate commitment and lineage specification and characterize the underlying key regulators and genetic regulatory networks. The data are publicly available on the online platform AmphioxusAtlas.

Stroke is a public health threat that requires urgent attention in China. Nutrients have individual significant impacts on the prevalence of stroke. However, little research has been conducted on the impact of dietary knowledge on stroke and whether the impact is potentially heterogeneous under the effect of socioeconomic status. This study used the 2015 Chinese Health and Nutrition Survey to explore the impact of dietary knowledge and socioeconomic factors on populations suffering from stroke. Results indicated that risk of stroke decreased significantly with increasing dietary knowledge score. Additionally, the impact of dietary knowledge scores on the prevalence of stroke has obvious heterogeneity. First, dietary knowledge scores significantly influenced low-income groups and individuals with low educational levels. Second, the risk of stroke in females is more affected by dietary knowledge. Third, for people living in different areas, dietary knowledge determines whether rural populations suffer from stroke.

Vertebrate evolution was accompanied with two rounds of whole genome duplication followed by functional divergence in terms of regulatory circuits and gene expression patterns. As a basal and slow-evolving chordate species, amphioxus is an ideal paradigm for exploring the origin and evolution of vertebrates. Single cell sequencing has been widely employed to construct the developmental cell atlas of several key species of vertebrates (human, mouse, zebrafish and frog) and tunicate (sea squirts). Here, we performed single-nucleus RNA sequencing (snRNA-seq) and single-cell assay for transposase accessible chromatin sequencing (scATAC-seq) for different stages of amphioxus (covering embryogenesis and adult tissues). With the datasets generated we constructed the developmental tree for amphioxus cell fate commitment and lineage specification, and revealed the underlying key regulators and genetic regulatory networks. The generated data were integrated into an online platform, AmphioxusAtlas, for public access at http://120.79.46.200:81/AmphioxusAtlas.

Goldfish have been subjected to over 1,000 y of intensive domestication and selective breeding. In this report, we describe a high-quality goldfish genome (2n = 100), anchoring 95.75% of contigs into 50 pseudochromosomes. Comparative genomics enabled us to disentangle the two subgenomes that resulted from an ancient hybridization event. Resequencing 185 representative goldfish variants and 16 wild crucian carp revealed the origin of goldfish and identified genomic regions that have been shaped by selective sweeps linked to its domestication. Our comprehensive collection of goldfish varieties enabled us to associate genetic variations with a number of well-known anatomical features, including features that distinguish traditional goldfish clades. Additionally, we identified a tyrosine-protein kinase receptor as a candidate causal gene for the first well-known case of Mendelian inheritance in goldfish-the transparent mutant. The goldfish genome and diversity data offer unique resources to make goldfish a promising model for functional genomics, as well as domestication.

The emergence of adaptive immunity in jawed vertebrates depended on the appearance of variable immune receptors, BCRs and TCRs, which exhibit variable-J–constant (VJ-C)–type Ig superfamily folds. Hitherto, however, the structures of IgV-J-IgC–type molecules had never been characterized in invertebrates, leaving the origin of BCR/TCR-type molecules unknown. Using x-ray crystallography, the structure of a VJ-C2 molecule, named AmpIgVJ-C2, was determined in amphioxus (Branchiostoma floridae). The first domain shows typical V folding, including the hydrophobic core, CDR analogs, and eight conserved residues. The second domain is a C2-type Ig superfamily domain, as defined by its short length and the absence of β-strand D- and C1-typical motifs. AmpIgVJ-C2 molecules form homodimers, using “three-layer packing dimerization,” as described for TCRs and BCRs. The AmpIgVJ-C2 V domain harbors a diglycine motif in β-strand G and forms a β-bulge structure participating in V–V intermolecular interaction. By immunohistochemistry, AmpIgVJ-C2 molecules were primarily found in mucosal tissues, whereas PCR and sequence analysis indicated considerable genetic variation at the single-gene level; these findings would be consistent with an immune function and a basic ability to adapt to binding different immune targets. Our results show a BCR/TCR-ancestral like molecule in amphioxus and help us to understand the evolution of the adaptive immune system.

The survey shows that most of the potential cloud users worry about the trustworthiness problem of cloud computing service, and this problem has become one of the most important reasons to hinder development of cloud computing. Therefore, it is very necessary to measure and evaluate the trustworthy degree of cloud service provider (CSP). In consideration of lacking the trustworthiness evaluation and measurement studies for CSP, besides this, a few research results have not considered uncertainty and relevance among trustworthiness factors in the measuring process. So, this paper summarizes factors affecting cloud service trustworthiness in terms of six aspects: controllability, visualization, security, reliability, provider viability and user satisfaction, constructs the trustworthy cloud service attribute model, based on this model, proposes to use the Information Entropy and Markov Chain as the trustworthiness evaluation method to establish a model and proves the scientificity and rationality of this method, as well as verifies the feasibility through case analysis.

CD27 and its ligand, CD70, are major costimulatory molecules whose interaction can regulate the expansion and differentiation of effector and memory T-cell populations. Their abnormal expression can disturb the immune response and lead to an increased risk of cancer. This study aims to evaluate the associations between single nucleotide polymorphisms (SNPs) in CD27/CD70 gene and breast cancer susceptibility. Five tagSNPs and one coding polymorphism in CD27, as well as three tagSNPs in CD70, were genotyped in a case-control study of 610 breast cancer patients and 617 healthy controls. In CD27, rs3136550 CT and rs2267966 AT genotypes were associated with a decreased risk of breast cancer (P = 0.03, OR = 0.76; P = 0.02, OR = 0.75, respectively). In CD70, AG and GG genotypes in rs1862511 and CC genotype in rs2059154 also showed significant associations with a decreased risk of breast cancer (P = 2.00 × 10(-3), OR = 0.69; P = 0.03, OR = 0.62; P = 2.00 × 10(-3), OR = 0.53; respectively). Significant associations were also found in the dominant and recessive models for rs2059154 and dominant model for rs1862511. In haplotype analysis, CCGAG haplotype in CD27 and TAA haplotype in CD70 conferred an increased risk of breast cancer (P = 5.60 × 10(-3); P = 7.75 × 10(-5), respectively), but TGC, TAC and TGA haplotypes in CD70 were associated with a decreased risk of breast cancer (P = 0.01; P = 5.2 × 10(-3); P = 2.00 × 10(-3), respectively). The associations of CCGAG, TAA, TAC and TGA haplotypes remained significant after correcting P value for multiple testing. Significant associations were shown between the SNPs of CD27 and lymph node metastasis, and ER and PR statuses. These results indicate that CD27 and CD70 gene polymorphisms may affect the risk of breast cancer and show that some SNPs are associated with breast cancer characteristics in a northern Chinese population.

Cytotoxic T lymphocyte antigen-4 (CTLA-4) is an inhibitory molecule that plays a pivotal role in downregulating T-cell mediated immune responses. To determine the role of CTLA-4 in tumor immunity, and to validate previous results as well, we investigated four tag single nucleotide polymorphisms (SNPs) of CTLA-4 in a relatively large Chinese Han cohort from northeastern China. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 581 patients and 566 age-matched controls. Our data indicated that compared with the common genotype and allele of each SNP, the -1722 CC genotype and C allele showed an increased risk of breast cancer (P = 0.030, odds ratio (OR) = 1.457, 95% confidence internal (CI) 1.036-2.051; P = 0.024, OR = 1.214, 95% CI 1.026-1.436, respectively). The -1661 GG genotype and G allele were also associated with an increased risk of breast cancer (P = 0.018, OR = 1.396, 95% CI 1.058-1.843; P = 0.013, OR = 1.353, 95% CI 1.066-1.717, respectively). In the haplotype analysis, the CAAA haplotype showed a higher frequency in cases (P = 0.004), and this association remained significant after correcting the P value for multiple testing. Associations were shown between the SNPs of CTLA-4 and lymph node metastasis, estrogen receptor (ER), progesterone receptor (PR) and P53 statuses. These results indicate that some SNPs in the CTLA-4 gene may affect the risk of breast cancer and show that some SNPs are associated with breast cancer characteristics in Han women in northeastern China.

Novel biodegradable amphiphilic graft copolymers containing hydrophobic poly(ester-carbonate) backbone and hydrophilic poly(ethylene glycol) (PEG) side chains were synthesized by a combination of ring-opening polymerization and “click” chemistry. First, the ring-opening copolymerization of 5,5-dibromomethyl trimethylene carbonate (DBTC) and e-caprolactone (CL) was performed in the presence of stannous octanoate [Sn(Oct)2] as catalyst, resulting in poly(DBTC-co-CL) with pendant bromo groups. Then the pendant bromo groups were completely converted into azide form, which permitted “click” reaction with alkyne-terminated PEG by Huisgen 1,3-dipolar cycloadditions to give amphiphilic biodegradable graft copolymers. The graft copolymers were characterized by proton nuclear magnetic resonance (1H NMR), Fourier transform infrared spectra and gel permeation chromatography measurements, which confirmed the well-defined graft architecture. These copolymers could self-assemble into micelles in aqueous solution. The size and morphologies of the copolymer micelles were measured by transmission electron microscopy and dynamic light scattering, which are influenced by the length of PEG and grafting density. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.

Alginate with long strictly alternating sequences of mannuronic (M) and guluronic (G) acid residues, F(G) = 0.47 and F(GG) = 0.0, was prepared by incubating mannuronan with the recombinant C-5 epimerase AlgE4. By partial acid hydrolysis of this PolyMG alginate at pH values from 2.8 to 4.5 at 95 degrees C, alpha-L-GulpA-(1--4)-beta-D-ManpA (G-M) linkages were hydrolyzed far faster than beta-D-ManpA-(1--4)-alpha-L-GulpA (M-G) linkages in the polymer chain. The ratio of the rates (kG-M/kM-G) decreased with increasing pH. The dominant mechanism for hydrolysis of (1--4)-linked PolyMG in weak acid was thus proved to be an intramolecular catalysis of glycosidic cleavage of the linkages at C-4 by the undissociated carboxyl groups at C-5 in the respective units. The higher degradation rate of G-M than M-G glycosidic linkages in the polymer chain of MG-alginate at pH 3.5 and 95 degrees C was exploited to make oligomers mainly consisting of M on the nonreducing and G on the reducing end and, thus, a majority of oligomers with an even number of residues. The ratio of the rate constants kG-M/kM-G at this pH was 10.7. The MG-hydrolysate was separated by size exclusion chromatography and the MG oligosaccharide fractions analyzed by electrospray ionization-mass spectrometry together with 1H and 13C NMR spectroscopy. Chemical shifts of MG-oligomers (DP2-DP5) were elucidated by 2D 1H and 13C NMR.

It was demonstrated that macroscopic structural changes of polysaccharide chains, such as random coil–helix transition and aggregation of helices, accompanied with the sol–gel and the gel–sol transition can be monitored by numerically analyzing the temperature dependence of the observed water proton spin–spin relaxation time ( T 2obs ) modified by the chemical exchange between water proton and labile proton on the chain. According to the numerical analysis of T 2obs , typical profiles of T 2obs against the temperature were simulated with various parameters of the relaxation time ( T 2 i ) and the mean residence time ( τ i ) of water and the labile protons on the random coil and the ordered chain as well as the activation energy ( E i , E ex, i ) for the motion and the chemical exchange of the respective proton. The difference of structural change of kappa- , iota- , and lambda-carrageenan aqueous systems in the cooling and the heating process was analyzed. In conclusion, (1) the characteristic profile of the temperature dependence of T 2obs , commonly observed in the temperature-induced gelling process, is attributable to the variation of fraction of the ordered chain and the relative rate of chemical exchange to the relaxation rate of labile protons on polysaccharide (1/ T 2p ); (2) the loose aggregated or associated structure is detected for iota-carrageenan system; and (3) the thermally stable junction zones formed by well aggregated helices of kappa-carrageenan in the gel state provokes a thermal hysteresis in the temperature-induced structural change (experimentally, in T 2obs ). It is clarified by the numerical simulation that the aggregated helices formed during further cooling down to the temperature below T sg results in the T 2obs shifts to a longer value in the heating process as compared with that in the cooling process.

In this work, two series of ethylene–dimethylaminoethylmethacrylate (EDAM) and ethylene–methyl acrylate copolymers (EMA) with different comonomer content were studied by high-resolution solid-state 13 C NMR spectroscopy. Biexponential 13 C spin–lattice relaxation behaviors of the crystalline region were observed for all copolymer samples either melt-quenched or isothermally crystallized. The relative content of the shorter 13 C T 1 component to that of the longer 13 C T 1 component was found to increase with comonomer content. By employing a new pulse sequence which can be considered as a combination of Goldman–Shen's and Torchia's pulse sequences, it was demonstrated that the shorter 13 C T 1 component is corresponding to the intermediate part of the crystalline region. The thickness of the intermediate part is estimated to be about 0.85 nm.

The phase structure of a series of ethylene-vinyl acetate copolymers has been investigated by solid-state wide-line 1H NMR and solid-state high-resolution 13C NMR spectroscopy. Not only the degree of crystallinity but the relative contents of the monoclinic and orthorhombic crystals within the crystalline region varied with the vinyl acetate (VA) content. Biexponential 13C NMR spin–lattice relaxation behavior was observed for the crystalline region of all samples. The component with longer 13C NMR spin–lattice relaxation time (T1) was attributed to the internal part of the crystalline region, whereas the component with shorter 13C NMR T1 to the mobile crystalline component was located between the noncrystalline region and the internal part of the crystalline region. The content of the mobile crystalline component relative to the internal part of the crystalline region increased with the VA content, showing that the 13C NMR spin–lattice relaxation behavior is closely related to the crystalline structure of the copolymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2199–2207, 2002

The crystalline structures of ethylene-dimethylaminoethyl methacrylate (EDAM) copolymers, which were either melt-quenched (mq) or isothermally crystallized (iso), were studied by solid-state high-resolution 13 C NMR spectroscopy. It revealed that the crystalline structures of EDAM copolymers are greatly dependent on the comonomer content, crystallization condition and the storage time after treatment. The ratio of monoclinic to orthorhombic crystal (M/O) increases with the increase in the dimethylaminoethyl methacrylate content. Higher crystallinity and lower monoclinic content were observed for iso samples compared to the mq ones. The monoclinic crystal was found to melt at lower temperatures compared to the orthorhombic one during the heating process. The degree of crystallinity as well as the contents of monoclinic and orthorhombic crystals and the M/O value are found to increase after storage at room temperature for a month.

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 this paper, by using the literature analysis, current research literatures on influential factors of effective instruction in China are divided into two categories: one focus on the theoretical a nalysis, the other focus on empirical research, and the literatures are combed through and analysed. On this basis, this paper conducts a summary and reflection, and points out the lack of the research in the field and the direction of its development, with the aim to offer a reference for the evaluation standards and theoretical research of effective instruction, and to offer a basis and reference for teachers to implement effective instruction. Index Terms - effective instruction, influential factors, teachers, students, literature analysis

Background Inducible costimulator (ICOS), a costimulatory molecular of the CD28 family, provides positive signal to enhance T cell proliferation. Its abnormal expression can disturb the immune response and entail an increased risk of cancer. To investigate whether single nucleotide polymorphisms (SNPs) in the ICOS gene are associated with sporadic breast cancer susceptibility and progression in Chinese women, a case-control study was conducted. Methods In the study cohort, we genotyped five SNPs (rs11889031, rs10932029, rs4675374, rs10183087 and rs10932037) in ICOS gene among 609 breast cancer patients and 665 age-matched healthy controls. Furthermore, the positive results were replicated in an independent validation cohort of 619 patients and 682 age-matched healthy controls. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine the genotypes. Results In rs10932029, compared with TT genotype and T allele, the CT genotype and C allele showed a significantly increased risk of breast cancer (P = 0.030, OR = 1.467, 95% CI 1.037-2.077; P = 0.017, OR = 1.481, 95% CI 1.070-2.049, respectively), and the associations were also significant in the validation cohort (P = 0.002, OR = 1.693, 95% CI 1.211-2.357; P = 0.003, OR = 1.607, 95% CI 1.171-2.204, respectively). Haplotype analysis showed that CTCAC haplotype containing rs10932029 T allele had a lower frequency in cases than in controls (P = 0.015), whereas haplotype CCCAC containing rs10932029 C allele was more common in cases than in controls (P = 0.013). In the analysis of clinicopathologic features, rs11889031 CT genotype and T allele were associated with progesterone receptor (PR) status and lymph node metastasis, which were further supported by our validation cohort. Moreover, some haplotypes were associated with estrogen receptor (ER) and PR statuses. Conclusions These results indicate that ICOS gene polymorphisms may affect the risk of breast cancer and show that some SNPs are associated with breast cancer characteristics in a northern Chinese population.

This paper introduces the independent innovation research fund management system of the key university, and analyzes the problems and difficulties during the development process in terms of web server performance utilization and software architecture. A solution to improve the performance of a web server by means of software realization is proposed in the reseach. A load balance technology based on software realization is adopted according to the actual situation, the Application Center Cluster is introduced, and the advantage of the new solution is obvious by analysis. The experiment shows that the resource occupancy of the server in the new solution is reduced compared to the old ones when the number of concurrent users increases.

To some extent, the academic scores of students reflect the teaching level of a school. Taking the students taught by me in 2010 as study objects, from the teaching perspective the paper studies the factors affecting the exam scores in advanced mathematics by using the method of multiple liner regression. The study result shows: although there are some differences in mathematics foundation among students, yet they can still make a great progress in mathematics study and they will have no difference in exam scores , as long as they are willing to spend time, willing to study hard. Meanwhile, the class atmosphere and the learning atmosphere can also play an important role in improving student exam scores.

To study the anti-tumor activity of Scurrula parasitica polysaccharides (SP). Water extraction and ethanol precipitation were used to isolate SP from S. parasitica leaf. S180, K562 and HL-60 cell lines proliferation inhibition by SP were detected by MTT assay. The expressions of Ki-67, Cyclin D1, Bax and Bcl-2 protein in the sarcoma S180 tissues were detected by immunohistochemistry technique to approach the anti-tumor mechanism of SP+ SP could not inhibit cancer cell proliferation. SP ip could inhibit the growth of sarcoma S180 in mice, 100 mg x kg(-1) x d(-1). SP ip was the optimal dose on inhibiting S180 growth, with the tumor inhibition rate of 54%. The expression of Ki-67, Cyclin D1, Bax and Bcl-2 protein in the sarcoma S180 tissues were detected by immunohistochemistry technique to approach the anti-tumor mechanism of SP. The result showed that SP could down-regulate the expression of Ki-67, CyclinD1 and Bcl-2 protein, and up-regulate the expression of Bax protein. It indicted that inhibiting cancer cell proliferation and promoting cancer cell apoptosis in vivo maybe one of the anti-cancer mechanisms of SP.

For many years, the lancelet Branchiostoma belcheri had been considered a widely distributed species throughout the West Pacific Ocean. Several recent studies divided it into two separate species based on significant morphological and genetic divergence. However, this taxonomic subdivision has not yet been fully accepted by the scientific community. In order to further clarify the taxonomic status of the West Pacific lancelets, we present here complete mitochondrial genomes (mitogenomes) of two species and compare them at both genomic and phylogenetic levels. These comparisons reveal a significant genetic differentiation and show a deep phylogenetic division. Moreover, to get more insights into the phylogeography of this species complex, we sampled lancelets from Qingdao and Maoming (China) and sequenced their 12S rRNA gene, then combined the data with those from Xiamen and Japan lancelets for phylogenetic analysis. The results were consistent with our previous identification and proved that the lancelets distributed in Qingdao and Japan as well as B.japonicum in Xiamen waters belong to the same species, and those in Maoming and B. belcheri in Xiamen waters are different. Finally, we discuss the implications of these findings on the distribution of lancelets in the West Pacific Ocean.

Biodegradable antimicrobial poly(ester-carbonate)s were prepared facilely via a simple two-step process with low cost. First, poly(5,5-dibromomethyl trimethylene carbonate-co-e-caprolactone) (PDBTCL) with pendant bromo groups was synthesized by the direct ring-opening copolymerization of 5,5-dibromomethyl trimethylene carbonate (DBTC) and e-caprolactone (CL) in the presence of stannous octanoate (Sn(Oct)2) as catalyst. Then, the quaternization reaction between PDBTCL and a series of N,N-dimethyl alkylamines was performed under mild conditions, resulting in biodegradable poly(ester-carbonate)s with pendant ammonium salts (QPDBTCL). The chemical structure and composition of QPDBTCLs were characterized by 1H NMR. The influences of alkyl chain length and charge density on the antimicrobial activity of QPDBTCLs against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria were evaluated by OD600 and zone of inhibition methods. It was observed that QPDBTCLs with long alkyl chain on the ammonium groups exhibit significantly higher antimicrobial activity than those with short alkyl chain for both Gram-negative and Gram-positive bacteria. QPDBTCL with quaternary N,N-dimethyldodecylammonium groups shows strong antimicrobial activity even with very low charge density (4.3 mol%). This kind of biodegradable antimicrobial material may have potential applications as biomaterials.