Purification and characterization of a chimeric bifunctional antibody specific for human carcinoembryonic antigen and indium-benzyl-EDTA

We describe the purification and characterization of a genetically engineered mouse/human chimeric bifunctional antibody specific for human carcinoembryonic antigen and indium-benzyl-EDTA. A clone expressing the bifunctional antibody has been previously described by our group and was found in this investigation also to express monospecific antibodies as well as Ig forms with mismatched light and heavy chains. The physicochemical properties of these various chimeric immunoglobulins were nearly identical. Isoelectric focusing showed that all these immunoglobulins have pI values between 8.47 and 8.80. A purification method that separates the bifunctional antibody from other Ig forms expressed in the same clone has been devised by relying on a unique interaction between the metal chelate binding region of these antibodies and the sulfopropyl functional group of a TSK SP 5-PW column.     

Biased ligand bonds to make right calls—laboratory of signal transduction reveals molecular mechanism for functional selectivity of GPCR

<正>In a recent study,Professor Rui-Ping Xiao and her research group at Institute of Molecular Medicine of Peking University has provided an essential experimental evidence to support the new paradigm of functional selectivity for G protein-coupled receptor(GPCR)signal transduction.The study was published online on May 15 in The Journal of Biological Chemistry[1].The GPCR superfamily,a class of membrane proteins     

Structural basis for the Smad5 MH1 domain to recognize different DNA sequences

Smad proteins are important intracellular mediators of TGF-β signalling, which transmit signals directly from cell surface receptors to the nucleus. The MH1 domain of Smad plays a key role in DNA recognition. Two types of DNA sequence were identified as Smad binding motifs: the Smad binding element (SBE) and the GC-rich sequence. Here we report the first crystal structure of the Smad5 MH1 domain in complex with the GC-rich sequence. Compared with the Smad5-MH1/SBE complex structure, the Smad5 MH1 domain contacts the GC-rich site with the same β-hairpin, but the detailed interaction modes are different. Conserved β-hairpin residues make base specific contacts with the minimal GC-rich site, 5′-GGC-3′. The assembly of Smad5-MH1 on the GC-rich DNA also results in distinct DNA conformational changes. Moreover, the crystal structure of Smad5-MH1 in complex with a composite DNA sequence demonstrates that the MH1 domain is targeted to each binding site (GC-rich or SBE) with modular binding modes, and the length of the DNA spacer affects the MH1 assembly. In conclusion, our work provides the structural basis for the recognition and binding specificity of the Smad MH1 domain with the DNA targets.     

Expression of the MSI-99m Gene in Transgenic Potato Plants Confers Resistance to Phytophthora infestans and Ralstonia solanacearum

Magainins are a class of antimicrobial peptides isolated from skin secretions of the African clawed frog Xenopus laevis. MSI-99 is a synthesized magainin II analogue with high inhibitory effects to a wide spectrum of microbial organisms, including bacteria, fungi and viruses. To verify the resistance conferred by the MSI-99m gene (a MSI-99 synthetic gene with codon usage adapted for expression in potato) to potato pathogens and to generate multi-resistant potato materials, we transferred the MSI-99m gene into potato plants using Agrobacterium-mediated transformation. PCR and Southern blot analyses of eight kanamycin-resistant plants showed that MSI-99m gene was present and expressed in five independent transgenic lines. These five transgenic plants exhibited enhanced resistance to Phytophthora infestans and Ralstonia solanacearum. The results demonstrate that the MSI-99m gene can be used to potentially improve potato disease resistance genetically.     

Immunity Elicited by an Experimental Vaccine Based on Recombinant Flagellin-Porcine Circovirus Type 2 Cap Fusion Protein in Piglets

In a recent study, we reported that a recombinant protein from fusion expression of flagellin to porcine circovirus type 2 (PCV2) Cap induced robust humoral and cell-mediated immunity that afforded full protection for PCV2 infection using BALB/c mice. Here, we further evaluated the immunogenicity and protection of the recombinant protein using specific pathogen free (SPF) pigs. Twenty-five 3-week-old piglets without passively acquired immunity were divided into 5 groups. All piglets except negative controls were challenged with a virulent PCV2 at 21 days after booster vaccination and necropsied at 21 days post-challenge. Vaccination of piglets with the recombinant protein without adjuvant induced strong humoral and cellular immune responses as observed by high levels of PCV2-specific IgG antibodies and neutralizing antibodies, as well as frequencies of PCV2-specific IFN-γ-secreting cells that conferred good protection against PCV2 challenge, with significant reduced PCV2 viremia, mild lesions, low PCV2 antigen-positive cells, as well as improved body weight gain, comparable to piglets vaccinated with a commercial PCV2 subunit vaccine. These results further demonstrated that the recombinant flagellin-Cap fusion protein is capable of inducing solid protective humoral and cellular immunity when administered to pigs, thereby becoming an effective PCV2 vaccine candidate for control of PCV2 infection.     

Is There a Relationship between Research Sponsorship and Publication Impact? An Analysis of Funding Acknowledgments in Nanotechnology Papers

This study analyzes funding acknowledgments in scientific papers to investigate relationships between research sponsorship and publication impacts. We identify acknowledgments to research sponsors for nanotechnology papers published in the Web of Science during a one-year sample period. We examine the citations accrued by these papers and the journal impact factors of their publication titles. The results show that publications from grant sponsored research exhibit higher impacts in terms of both journal ranking and citation counts than research that is not grant sponsored. We discuss the method and models used, and the insights provided by this approach as well as it limitations.     

Nanosecond pulsed electric fields prime mesenchymal stem cells to peptide ghrelin and enhance chondrogenesis and osteochondral defect repair in vivo

Science China Life Sciences - Mesenchymal stem cells (MSCs) are important cell sources in cartilage tissue development and homeostasis, and multiple strategies have been developed to improve MSCs...     

Generation of an Frs2alpha conditional null allele

The fibroblast growth factor (FGF) signaling family controls a broad spectrum of cellular processes in development and adult tissue homeostasis and function, which is expressed in almost all tissues at all stages. FGF receptor substrate 2 alpha (FRS2alpha) is an adaptor protein that recruits downstream substrates to the FGF receptor (FGFR) tyrosine kinase. Disruption of Frs2alpha gene in mice abrogates activation of the mitogen-activated protein kinase pathway by the FGFR and leads to embryonic lethality at day E7.5 post copulation. To circumvent the embryonic lethality resulting from disruption of the Frs2alpha gene, which hinders further characterization of the role of FRS2alpha in adult tissue function and homeostasis, we generated an Frs2alpha conditional null allele for temporally- and tissue-specific disruption of the Frs2alpha gene. Using gene targeting in mouse embryonic stem cells, we introduced two loxP sites flanking the largest coding exon, exon 5, in the Frs2alpha allele. Our results indicate that the floxed Frs2alpha (Frs2alpha(flox)) allele is a true conditional null allele that encodes wildtype activity and is converted to a null allele after Cre recombinase mediated recombination.     

Prostate cancer identification: quantitative analysis of T2-weighted MR images based on a back propagation artificial neural network model

Computer-aided diagnosis (CAD) systems have been proposed to assist radiologists in making diagnostic decisions by providing helpful information. As one of the most important sequences in prostate magnetic resonance imaging (MRI), image features from T2-weighted images (T2WI) were extracted and evaluated for the diagnostic performances by using CAD. We extracted 12 quantitative image features from prostate T2-weighted MR images. The importance of each feature in cancer identification was compared in the peripheral zone (PZ) and central gland (CG), respectively. The performance of the computer-aided diagnosis system supported by an artificial neural network was tested. With computer-aided analysis of T2-weighted images, many characteristic features with different diagnostic capabilities can be extracted. We discovered most of the features (10/12) had significant difference (P<0.01) between PCa and non-PCa in the PZ, while only five features (sum average, minimum value, standard deviation, 10th percentile, and entropy) had significant difference in CG. CAD prediction by features from T2w images can reach high accuracy and specificity while maintaining acceptable sensitivity. The outcome is convictive and helpful in medical diagnosis.     

Near‐Infrared Light‐Induced Photocurrent from a (NaYF4:Yb‐Tm)/(Cu2O) Composite Thin Film

Utilization of photons of sub‐bandgap energy, mostly near‐infrared (NIR) photo­ns, is highly desirable for photovoltaic devices. We show that (NaYF₄:Yb‐Tm)/(Cu₂O) composite films formed by electrodeposition exhibit robust photoactive current generation under NIR light excitation. The composite films consist of homogeneous crystalline particles of the fluoride and Cu₂O in sub‐micrometer size. From spectroscopic characterization, it is found that the NaYF₄:Yb‐Tm layer in the composite film converts NIR radiation by up‐conversion into visible emission, which is efficiently absorbed by the covering semiconducting Cu₂O film, producing photoelectrons. Accordingly, the composite films exhibit highly photoactive current generation by means of a photoelectrochemical process driven by NIR irradiation. The methodology demonstrated here may have certain implications for the utilization of NIR radiation in solar cells, photocatalysts, and infrared photodetectors.