A conjugate of an anti-midkine single-chain variable fragment to doxorubicin inhibits tumor growth

Doxorubicin (DOX) was conjugated to a single-chain variable fragment (scFv) against human midkine (MK), and the conjugate (scFv-DOX) was used to target the chemotherapeutic agent to a mouse solid tumor model in which the tumor cells expressed high levels of human MK. The His-tagged recombinant scFv was expressed in bacteria, purified by metal affinity chromatography, and then conjugated to DOX using oxidative dextran (Dex) as a linker. The molecular formula of this immunoconjugate was scFv(Dex)1.3(DOX)20. In vitro apoptosis assays showed that the scFv-DOX conjugate was more cytotoxic against MK-transfected human adenocarcinoma cells (BGC823-MK) than untransfected cells (55.3 ± 2.4 vs 22.4 ± 3.8%) for three independent experiments. Nude mice bearing BGC823-MK solid tumors received scFv-DOX or equivalent doses of scFv + DOX for 2 weeks and tumor growth was more effectively inhibited by the scFv-DOX conjugate than by scFv + DOX (51.83% inhibition vs 40.81%). Histological analysis of the tumor tissues revealed that the highest levels of DOX accumulated in tumors from mice treated with scFv-DOX and this resulted in more extensive tumor cell death than in animals treated with the equivalent dose of scFv + DOX. These results show that the scFv-DOX conjugate effectively inhibited tumor growth in vivo and suggest that antigen-specific scFv may be competent drug-carriers

The complete mitochondrial genome and phylogenetic analysis of Nerita yoldii (Gastropoda: Neritidae)

The complete mitochondrial genome of Nerita yoldii has been determined. The whole sequence was 15,719 bp in length and included 13 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes (12S rRNA and 16S rRNA). The overall base composition is A 29.5%, C 13.8%, G 21.5%, and T 35.2%. In 13 protein-coding genes, the nad2, nad5, and nad6 gene start with ATT, whereas nad4 started with ATA, the other nine genes start with ATG. For the stop codon, COX1, COX3, nad3, and atp8 end with TAG, other nine genes end with TAA. Phylogenetic tree was constructed based on 13 protein-coding genes sequences of Archaeogastropoda species, and the result showed that N. yoldii is most closely related to Clithon retropictus. These mitogenome sequence data will be useful for population genetics and phylogenetic analysis of the family Neritidae

Reduction mechanisms for dislocation densities in GaN heteroepitaxy over Si substrate patterned with a serpentine channel structure

Abstract Heteroepitaxial growth of gallium nitride (GaN) over patterned Silicon (Si) substrates using serpentine channel structure was demonstrated and studied with transmission electron microscopy (TEM). Cross‐sectional TEM images showed that the dislocations were filtered out effectively, through two 90° turns in GaN growth front with the unique serpentine channel structure, resulting in high crystal quality GaN materials over the top mask layer. Dislocation behaviours at different parts of the structure were investigated to understand the mechanism of dislocation density reduction

Synthesis, performance and growth mechanism of silver nanoparticle coated SERS fiber probe

Surface-enhanced Raman Scattering (SERS) fiber probe provides abundant interaction area between light and materials, permits detection within limited space and is especially useful for remote or in situ detection. A silver decorated SERS fiber optic probe was prepared by hydrothermal method. This method manages to accomplish the growth of silver nanoparticles and its adherence on fiber optic tip within one step, simplifying the synthetic procedure. The effects of reaction time on phase composition, surface plasmon resonance property and morphology were investigated by X-ray diffraction analysis (XRD), ultraviolet-visible absorption spectrum (UV-VIS absorption spectrum) and scanning electron microscope (SEM). The results showed that when reaction time is prolonged from 4–8 hours at 180 °C, crystals size and size distribution of silver nanoparticles increase. Furthermore, the morphology, crystal size and distribution density of silver nanoparticles evolve along with reaction time. A growth mechanism based on two factors, equilibrium between nucleation and growth, and the existence of PVP, is hypothesized. The SERS fiber probe can detect rhodamin 6G (R6G) at the concentration of 10−6 M. This SERS fiber probe exhibits promising potential in organic dye and pesticide residue detection

The complete mitochondrial genome and phylogenetic analysis of Apogonichthys lineatus（Osteichthyes: Apogonidae）

The complete mitochondrial genome of the Apogonichthys lineatus has been determined in this study. The complete genome (mtDNA) is 16,510 base pairs in length and contains 13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes. The overall base composition of the genome in descending order was28.4% C, 27.3% A, 26.7% T, 17.6% G. In 13 protein-coding genes, most of the protein-coding genes start with ATG, except ND1 start with ATA, COX3 and ND5 start with ATT. For the stop codon, nine protein-coding genes end with TAA, two protein-coding genes end with TAG (ND3 and ND1) and two protein-coding genes end with TGA (ND4 and COX2). Phylogenetic analysis indicated that A. lineatus is close to Pterapogon kauderni families. This study was determined the complete mitochondrial genome of Apogonidae species. It would be a supplement for the genetic analysis of A. lineatus and promote the phylogenetic of Apogonidae

The complete mitochondrial genome and phylogenetic analysis of Chasmagnathus convexus (Crustacea: Grapsidae)

The complete mitochondrial genome of the Chasmagnathus convexus has been determined in this study. The complete genome (mtDNA) was 15,107 bp in length and contained 13 protein-coding genes, 1 rRNA genes, and 22 tRNA genes. The overall base composition of the genome in descending order was 34.2% T, 32.8% A, 20.9% C, and 12.1% G. In 13 protein-coding genes, most of the protein-coding genes start with ATG (COX1, COX2, COX3 and ATP8) and ATT (NAD5, NAD4, NAD4L, NAD6, ATP6 and NAD2), only CYTB, NAD3, and NAD1 genes start with ATA. For the stop codon, only NAD2 end with TAG, the other 12 genes end with TAA. Phylogenetic analysis indicated that C. convexus is closely related to Hemigrapsus penicillatus family. It would be a supplement for the genetic analysis of C. convexus and promote the phylogenesis of Grapsidae