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Although laparoscopic cholecystectomy is a well‐established surgical procedure, an accessory hepatic duct (AcHD) entering the cystic duct is poorly understood. A 77‐year‐old woman with symptomatic cholecystlithiasis was referred to our hospital. Abdominal ultrasonography indicated several small stones in the gall bladder. Magnetic resonance cholangiopancreatography (MRCP) did not reveal an anomalous cystic duct. Dissecting the gall bladder bed at operation, AcHD entering the cystic duct was suspected. Intraoperative cholangiography revealed that B5 branch entered the cystic duct. We ligated the AcHD, and divided it. Laparoscopic cholecystectomy was completed, and the patient was discharged without any complication. A week after the operation, MRCP showed that ventral branch of B5 was dilated. The patient showed no symptom for more than a year. The present case exhibited extremely rare AcHD entering the cystic duct, which was hardly recognized before surgery. It is possible to recognize such anomalous variants with standard laparoscopic approach based on 2018 Tokyo Guidelines and with attention to the possibilities of AcHD entering the cystic duct. [ABSTRACT FROM AUTHOR]

Budded viruses (BVs) of baculovirus such as Autographa californica nucleopolyhedrovirus (AcNPV) have recently been studied as biological nanomaterials, and methods for their longer-term storage without deterioration would be desirable. The cryopreservation of virions with a naturally occurring saccharide like trehalose as a cryoprotectant is known to be useful for maintaining the viral structure and function. In this study, we examined how useful trehalose is as protectant for BV cryopreservation during repeated freeze-thaw cycles: 1) membrane fusion between liposomes (multilamellar vesicles, MLVs) and BVs, 2) infection of insect culture cells (Sf9 cells) by RFP-expressing BVs, and 3) morphologies of these BVs were investigated by fluorescent dequenching assay, fluorescence microscopy, and transmission electron microscopy (TEM), respectively. The results suggest that the BVs deteriorate in quality with each freeze-thaw cycle, and this deterioration can be diminished with the use of trehalose to an extent similar to that seen with storage on ice. Trehalose serves as a cryoprotectant on baculovirus budded virus particles during repeated freeze-thaw cycles. [ABSTRACT FROM AUTHOR]

A highly sensitive biosensor electrode was designed using a novel mesoporous carbon (MPC)-sheet. In this study, the MPC-sheet was prepared by the hard-template method using a mesoporous silica (MPS) sheet. The MPS sheet has unique characteristics such as thin shape, porous structure, and highly capacity as an absorbing material. The shape of synthesized carbon materials was similar with the template MPS sheet which was approximately 1–2 μm width and 100 nm a folded thickness. Surprisingly, the physicochemical properties of MPC-sheet were demonstrated different characteristics depending on the template materials. The MPC-sheet-modified electrode demonstrated excellent electrocatalytic activity for the simultaneous determination of biological compounds. [ABSTRACT FROM AUTHOR]

A notably high-capacity antibody adsorbent was prepared using dispersed gold nanoparticles immobilised on a mesoporous silica sheet. The mesoporous silica sheet (MPS sheet) was prepared via a dual-templating method using tetraethoxysilane and 3-aminopropyltriethoxysilane as the silica framework materials. Gold nanoparticles were loaded onto the amino-functionalised surface of the MPS sheet via deposition–precipitation using HAuCl4 as the Au colloid precursor and then crystallised via calcination. The properties of the gold nanoparticle–silica composite and the dispersion of the nanoparticles were characterised using transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. The surface characteristics of gold nanoparticle composite materials calcined at different temperatures were also evaluated using Fourier transform-infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetry data. The silica–gold nanoparticle composite sheet crystallised at 550 °C (sheet-Au-550) was mesoporous in character (pore diameter = 3.8 nm) with a BET surface area of 258.0 m2 g−1. With respect to antibody adsorption, the sheet materials had a relatively higher capacity than the typical cylindrical mesoporous silica, and sheet-Au-550 exhibited a strong performance (maximum adsorption quantity QMax = 0.26 mg IgG per mg carrier). In addition, the IgG adsorption equilibrium for sheet-Au-550 fits the Langmuir isotherm model better than the Freundlich plot model. These results will be very useful for the design of adsorption materials for biomolecules, such as antibodies. [ABSTRACT FROM AUTHOR]

Abstract: It has been reported that the activity of protein improved when it was adsorbed inside the pores of mesoporous silica (MPS). The current study investigated the activity of immobilized avidin to the biotin on MPS with various pore sizes (diameter=2.4–45.0nm). The binding amount of immobilized avidin to biotin is 123 to 160ng biotin/10μg avidin on 2.7- to 5.4-nm pore MPS, but that on 12- to 45-nm pore MPS was markedly decreased (33–42ng biotin/10μg). Moreover, the binding amount was approximately 2- and 3-fold higher on the glycidoxypropyl (Gly)-functionalized 5.4- and 45-nm pore MPS in comparison with methyl (Me)-functionalized 5.4- and 45-nm pore MPS, respectively. Furthermore, avidin immobilized in native and Gly-grafted 45-nm pore MPS retained more than 70% and 50% binding activity to biotin, respectively, after incubating at 90°C for 3h. In contrast, the activity was greatly reduced in the native and Gly-grafted 5.4-nm pore MPS under the same conditions (<36.9%). The immobilization also protected against effects of 0.01M HCl and 50% MeOH; all of immobilized avidin proteins showed high activity (>50%) with biotin compared with that observed with free avidin (MeOH [<18.2%] and HCl [<32.7%]). [Copyright &y& Elsevier]

Abstract: Cholesterol esterase (CE, cholesteryl ester hydrolase, EC 3.1.1.13) from porcine pancreas (molecular weight 400–500kDa) exhibits hydrolytic activity toward various toxic organic phthalate esters. CE was confined in the nanospace (diameter 3–30nm) of five types of mesoporous silica (MPS) that differ in structural properties such as pore diameter, pore volume, and particle morphology. These structural properties were characterized by transmission electron microscopy, small-angle X-ray diffraction, N2 adsorption–desorption experiments, solid-state 13C nuclear magnetic resonance (NMR), and solid-state 29Si NMR. Catalytic activities of immobilized and free CE were evaluated by the hydrolysis of diethyl phthalate in phosphate buffer solutions containing an organic cosolvent. Optimal activity recovery was achieved when CE was immobilized in n-decane-functionalized MPS, which had a large pore size (22.5nm). The immobilization also protected against effects of temperature within the range 30°C–60°C; CE immobilized in n-decyl-functionalized MPS exhibited better thermal stability than in non-functionalized MPS or free CE. Moreover, it retained approximately 60% of its catalytic activity even after six catalytic cycles. [Copyright &y& Elsevier]

Abstract: Regenerative medicine for repairing damaged body tissues has recently become critically important. Cell culture scaffolds are required for the control of cell attachment, proliferation, and differentiation in in vitro cell cultures. A new strategy to control cell adhesion, morphology, and proliferation was developed by culturing mouse osteoblast-like MC3T3-E1 cells on novel cell culture scaffolds fabricated using ordered nanometer-sized pores (100, 300, 500, and 1000nm). Results of this study indicate that after 72h of incubation, the number of cells cultured on a silica film with a pore size of 1000nm was similar to or slightly lower than that cultured on a non-porous control silica film. Films with 100–500nm pore sizes, however, resulted in the cell growth inhibition. Morphology of the cultured cells revealed increased elongation and the formation of actin stress fibers was virtually absent on macroporous silica films with 100–500nm pore size. Vinculin molecules expressed in cells cultured on the non-porous silica films showed many clear focal adhesions, whereas focal contacts were insufficiently formed in cells cultured on macroporous films. The influence of hydroxyapatite (HAp) and alumina scaffolds on the behavior of MC3T3-E1 cells was also evaluated. The proliferation rate of MC3T3-E1 cells cultured on HAp films with 1000nm pore size was increased to approximately 20% above than that obtained of cells cultured on non-porous HAp films. These results demonstrate that the pore size and constituents of films play a role in controlling the morphology and proliferation rate of MC3T3-E1cells. [Copyright &y& Elsevier]

Previously, we established a method to produce recombinant proteins (r-proteins) in cocoons of germline transgenic silkworms, and showed that a step(s) in post-transcription processes was rate-limiting in obtaining a high yield of r-proteins. In this study, we examined whether the 5′-untranslated region (5′-UTR) of the polyhedrin gene (pol) of nucleopolyhedrovirus (NPV) has a translational enhancer activity in the r-protein expression by middle silk gland (MSG) cells of silkworm Bombyx mori (Bm). Sericin 1 gene (ser1) promoter-driven transformation vectors were constructed in which pol5′-UTRs of NPVs isolated from four different species, Bm, Spodoptera frugiperda, Ectropis oblique, and Malacosoma neustria, were each placed upstream of a reporter gene. Transient expression assays in MSGs showed that these pol5′-UTRs all enhanced the protein expression of reporter genes, and the pol5′-UTR of Bm NPV (pol5′-UTR/Bm) was the most effective among them. Thus, transgenic silkworms were generated, which bore the ser1 promoter-driven His-tagged secretory EGFP (sEGFP-His) gene under the control of pol5′-UTR/Bm. The synthesis of sEGFP-His proteins in MSGs of the transgenic worms was approximately 1.5-fold higher than that in those bearing null vectors. However, its mRNA expression levels were 67% of the control worms, indicating that the pol5′-UTR/Bm specifically enhanced the translational level. In conclusion, pol5′-UTR/Bm increased the yield of r-protein production in transgenic silkworms by enhancing the translational activity and this 5′-UTR could be useful for the mass production of r-proteins in germline transgenic silkworms. [Copyright &y& Elsevier]

Abstract: In this study we produced germline transgenic silkworms that spin cocoons containing recombinant human serum albumin (rHSA) in the sericin layer. A piggyBac-based transformation vector was constructed that carried HSA cDNA driven by sericin-1 gene promoter, viral enhancer hr3, and gene encoding viral trans-activator IE1. Isolated silk glands were bombarded with the vector and transplanted into host larvae. Three days later, the transplants were immunohistochemically analyzed, which showed that middle silk gland (MSG) cells expressed rHSA and secreted it into the MSG lumen. Then, silkworm eggs were injected with the vector and developed to larvae. The obtained transgenic silkworms spun silk threads whose sericin layers contained rHSA at 3.0μg/mg of cocoons. Most (83%) of the rHSA in cocoons was extracted with phosphate buffered saline, which was then subjected to ammonium sulfate precipitation and affinity chromatography. Finally, we obtained 2.8mg of 99%-pure rHSA from 2g of cocoons. Measurements of circular dichroism spectra of rHSA, and equilibrium dissociation constants of rHSA to warfarin and naproxen indicated that rHSA was conformationally and functionally identical to natural plasma HSA. Germline transgenic silkworms will be useful for producing various recombinant proteins in the sericin layer of cocoons. [Copyright &y& Elsevier]

Abstract: We generated germline transgenic silkworms bearing a fibroin light chain (FL) promoter-driven FL gene whose 3′-end was flanked with human basic fibroblast growth factor (bFGF) gene, FL/bFGF gene. The cocoons from transgenic worms were trypsinized to remove sericin layers, and treated with solution containing CaCl2, ethanol, and water at a molar ratio of 1:2:8 (CaCl2/ethanol/water) to solubilize fibroin layers. Western blot analysis showed that the recombinant protein, r(FL/bFGF), was solubilized with CaCl2/ethanol/water, but not with trypsin, indicating that r(FL/bFGF) was in fibroin layers. Thus, it was concluded that the worms spun cocoons whose fibroin layers were composed of the inherent gene-derived natural fibroin (nF) and r(FL/bFGF). The mixture of nF and r(FL/bFGF) was dubbed r(FL/bFGF)nF. The solubilized r(FL/bFGF)nF was refolded using the glutathione redox system. Human umbilical vein endothelial cells (HUVECs) grew in the refolded r(FL/bFGF)nF-containing culture media, showing that bFGF in r(FL/bFGF) was biologically active. r(FL/bFGF)nF immobilized on a culture dish also supported the growth of HUVECs in bFGF-free media, suggesting the usefulness of r(FL/bFGF)nF as a new biomaterial for tissue engineering. The currently developed transgenic silkworms will be suitable for mass production of fibroins bearing a variety of biological activities. [Copyright &y& Elsevier]

Abstract: Prolyl 4-hydroxylase (P4H) is a heterotetramer enzyme consisting of α-subunits (P4Hα) and β-subunits (P4Hβ), and is required for collagen biosynthesis. Previously, we generated transgenic silkworms that produced human type III collagen fragments (mini-collagens) in the posterior silk gland (PSG). However, prolyl 4-hydroxylation did not occur on the mini-collagens, because in spite of an abundant expression of P4Hβ in PSGs, P4Hα expression was quite low there, thus resulting in an insufficient activity of P4H. In this study we aimed at generating hybrid transgenic silkworms whose PSGs are capable of producing mini-collagens and enough P4H for their prolyl 4-hydroxylation. Isolated PSGs were bombarded with fibroin L-chain gene promoter-driven vectors containing Bombyx mori P4Hα (BmP4Hα) cDNAs and were transplanted into the hemolymphatic cavity. The P4H activity in the PSG cells significantly increased, indicating that the expressed BmP4Hα formed active tetramers with endogenous BmP4Hβ. Using germ-line transgenesis technology, silkworms were generated that synthesized BmP4Hα in PSG cells. The P4H activity in the transgenic silkworms was 130-fold higher than that of wild-type counterparts. Finally, we generated hybrid transgenic silkworms that expressed cDNAs of both BmP4Hα and mini-collagen in PSG cells. They spun cocoons that contained mini-collagens whose appropriate proline residues had been adequately hydroxylated. [Copyright &y& Elsevier]

On the basis of immunofluorescence analysis, an entire pathway of B-cell targeting was successfully identified, which can drive selective production of monoclonal antibodies with high efficiency and selectivity. The technique comprises three critical steps, antigen-based preselection of B lymphocytes, formation of antigen-selected B lymphocyte and myeloma cell complexes, and selective fusion of B-cell-myeloma cell complexes with electrical pulses. Intriguingly, expression of surface immunoglobulin receptors on B lymphocytes was recognized even after immunization in vitro. The number of the antigen-selected B lymphocytes after in vitro immunization was in fact higher than that obtained after in vivo immunization, suggesting that such short term immunization is applicable for B-cell targeting. Immunofluorescence analysis revealed the targeting technique to demonstrate fivefold to tenfold higher efficiency for formation of hybridoma cells than a polyethylene glycol (PEG)-mediated method. This efficiency is in good agreement with production of hybridoma cells secreting desired monoclonal antibodies determined by an enzyme-linked immunosorbent assay (ELISA). The addition of a low concentration of PEG brought about enhanced fusion efficiency and reduced cell damage at even electric intensities as high as 4.0 kV/cm and 5.0 kV/cm. Here we demonstrate that immunofluorescence analysis can successfully clarify an entire pathway of B-cell targeting and provide advantages over the PEG-mediated method. This advanced technology may be applicable for rapid production of monoclonal antibodies based on in vitro immunization. [ABSTRACT FROM AUTHOR]

Abstract: The present study shows that hemocytic granular cells synthesize and secrete type IV collagen (ColIV) in the silkworm Bombyx mori (B. mori) and suggests that these cells play roles in the formation of basement membrane, the encapsulation of foreign bodies, and the metamorphic remodeling of the gut. The full- and partial-length cDNA of B. mori prolyl 4-hydroxylase α subunit (BmP4Hα) and B. mori ColIV (BmColIV) were cloned, respectively. In situ hybridization and immunocytochemistry on larval tissues and cells identified hemocytic granular cells as the cells that express mRNAs and proteins of both BmP4Hα and BmColIV. Immunohistochemistry and immunocytochemistry demonstrated that BmColIV was present in the basement membrane and in the secretory granules of granular cells, respectively. Granular cells in culture secreted BmColIV without accompanying the degranulation and discharged it from the granules when the cells were degranulated. Nylon threads were inserted into the hemocoel of larvae. Granular cells concentrated around the nylon threads and encapsulated them as a self-defense reaction. BmColIV was found to be a component of the capsules. Furthermore, the present study showed that actively BmColIV-expressing granular cells accumulated around the midgut epithelium and formed BmColIV-rich thick basal lamina-like structures there in larval to pupal metamorphosis. [Copyright &y& Elsevier]

We describe the generation of transgenic silkworms that produce cocoons containing recombinant human collagen. A fusion cDNA was constructed encoding a protein that incorporated a human type III procollagen mini-chain with C-propeptide deleted, a fibroin light chain (L-chain), and an enhanced green fluorescent protein (EGFP). This cDNA was ligated downstream of the fibroin L-chain promoter and inserted into a piggyBac vector. Silkworm eggs were injected with the vectors, producing worms displaying EGFP fluorescence in their silk glands. The cocoons emitted EGFP fluorescence, indicating that the promoter and fibroin L-chain cDNAs directed the synthesized products to be secreted into cocoons. The presence of fusion proteins in cocoons was demonstrated by immunoblotting, collagenase-sensitivity tests, and amino acid sequencing. The fusion proteins from cocoons were purified to a single electrophoretic band. This study demonstrates the viability of transgenic silkworms as a tool for producing useful proteins in bulk. [ABSTRACT FROM AUTHOR]

The article focuses on a research regarding the mechanism of proteoglycan (PG) absorption in small intestine of rats. According to the research, everted intestinal sac method revealed that jejunum has the highest capacity for PG transport but an inhibitor of clathrin-mediated endocytosis plays an important role in the reduction of PG transport in jejunum. It also mentions that small intestinal transport of PG is dependent on clathrin-mediated endocytosis.

Liver transplantation (LT) is the only life-saving option when acute-on-chronic liver failure (ACLF) does not improve with conservative therapy. Acute pancreatitis (AP) can cause chronic liver disease progression to ACLF. However, deceased donor LT for patients with AP has had mixed results, and no consensus has been established regarding the indication for LT. We report the first successful living donor LT (LDLT) for ACLF caused by severe AP. The 38-year-old patient with alcoholic liver disease was transferred to our institute with worsening refractory ascites. During the pretransplant workup, she developed severe acute necrotizing pancreatitis, resulting in grade 3 ACLF. The patient's clinical course was further complicated by high levels of donor-specific antibodies and immune thrombocytopenia. The AP gradually improved after intensive care combined with artificial liver support. The patient successfully underwent urgent LDLT with upfront splenectomy and desensitization therapy, including plasm exchange, high-dose intravenous immunoglobulin, and anti-thymocyte globulin. No infection or recurrence of AP was observed postoperatively. We conclude that LDLT is a feasible option for ACLF patients caused by severe AP if a deceased donor is not readily available. [ABSTRACT FROM AUTHOR]

Until now, various kinds of monoclonal antibodies have been raised against many antigens. Nevertheless, the production of these monoclonal antibodies was usually limited to only one antigen. If simultaneous generation of monoclonal antibodies against multiple antigens were available at one time, we could reduce not only laborious work, but also experimental animals. Here, we developed a multitargeting (MT) method that enables simultaneous production of monoclonal antibodies against multiple antigens on the basis of strict selection of sensitized B lymphocytes by the target antigens via B-cell receptors. After immunization using multiple antigens, monoclonal antibodies against four different antigens containing lower antigenic one were successfully generated only in one experiment. At maximum, more than 90 % of ELISA-positive wells to hybridoma-positive ones was obtained by this advanced technology. This must be attributed to strict selection of sensitized B lymphocytes by different antigens. In the MT method, sensitized B lymphocytes were selected by means of each desired antigen regardless of their antigenic differences. Selective fusion of B cell–myeloma cell complexes by electrical pulses was also of critical importance for efficient generation of hybridoma cells secreting desired monoclonal antibodies. This study strongly suggests that simultaneous production of novel monoclonal antibodies directed against multiple antigens of interest by the MT method can be feasible. [ABSTRACT FROM AUTHOR]

Giant proteoliposomes are generally useful as artificial cell membranes in biochemical and biophysical studies, and various procedures for their preparation have been reported. We present here a novel preparation technique that involves the combination of i) cell-sized lipid vesicles (giant unilamellar vesicles, GUVs) that are generated using the droplet-transfer method, where lipid monolayer-coated water-in-oil microemulsion droplets interact with oil/water interfaces to form enclosed bilayer vesicles, and ii) budded viruses (BVs) of baculovirus ( Autographa californica nucleopolyhedrovirus) that express recombinant transmembrane proteins on their envelopes. GP64, a fusogenic glycoprotein on viral envelopes, is activated by weak acids and is thought to cause membrane fusion with liposomes. Using confocal laser scanning microscopy (CLSM), we observed that the single giant liposomes fused with octadecyl rhodamine B chloride (R18)-labeled wild-type BV envelopes with moderate leakage of entrapped soluble compounds (calcein), and the fusion profile depended on the pH of the exterior solution: membrane fusion occurred at pH ∼4–5. We further demonstrated that recombinant transmembrane proteins, a red fluorescent protein (RFP)-tagged GPCR (corticotropin-releasing hormone receptor 1, CRHR1) and envelope protein GP64 could be partly incorporated into membranes of the individual giant liposomes with a reduction of the pH value, though there were also some immobile fluorescent spots observed on their circumferences. This combination may be useful for preparing giant proteoliposomes containing the desired membranes and inner phases. [ABSTRACT FROM AUTHOR]

Antibodies have received significant attention for use as antibody drugs, because they bind the objective protein (antigen) via antigen–antibody reactions. Recently, many reports have appeared on various monoclonal antibodies that recognize a single antigen. In this study, monoclonal antibodies are used as adsorbates on mesoporous silica (MPS) for affinity chromatography. MPS has high surface area and large pore volume; moreover, pore diameter, pore structure, and particle morphology are relatively easy to tune by adjusting the conditions of synthesis. The pore structure (two-dimensional (2D) hexagonal and three-dimensional cubic) and particle morphology (spherical and polyhedral) of MPS are optimized for use in a monoclonal antibody/MPS composite. When anti-IgG (one of the monoclonal antibodies) adsorbs on the MPS material and IgG (antigen) binds to anti-IgG/MPS composites, MCM-41p with a 2D-hexagonal pore structure and polyhedral particle morphology has the highest IgG binding efficiency. In addition, the antibody/MPS composites remain stable in chaotropic and low-pH solutions and can be cycled at least five times without decreasing IgG elution. In purification and removal tests, the use of the antibody/MPS composites allows only the objective protein from protein mixtures to be bound and eluted. [ABSTRACT FROM AUTHOR]

In general, it is difficult to raise novel monoclonal antibodies against relatively low-molecular weight antigen, and particularly those with high homology for the mouse protein. The optimized B-cell targeting (BCT) technique can overcome this limitation. The point of this advanced technology is the selection of sensitized B lymphocytes by the antigen through B-cell receptors (BCRs). This strict selection by specific and strong interaction between antigen and antibody enables the efficient production of monoclonal antibodies with high specificity and affinity. It also offers the condensation of sensitized target B lymphocytes to selectively generate hybridoma cells secreting desired monoclonal antibodies. In this study, several kinds of biotinylated human myoglobin (hMyo) were prepared to select sensitized B lymphocytes via BCRs. Biotinylated hMyo prepared by a 3.75- and 7.5-fold molar excess of N -hydroxysuccinimide (NHS)-biotin provided high antigenicity of 68–88%. B lymphocytes selected by these biotinylated antigens had an ELISA-positive rate >17 times higher than that with usual biotinylated antigen. Monoclonal antibodies generated by the optimized BCT technology by preselecting sensitized B lymphocytes with the target antigen were identified to specifically recognize lower antigenic epitopes in hMyo with high affinity, while this would be impossible by the polyethylene glycol (PEG) method. Furthermore, combination of these high-affinity monoclonal antibodies gave the best binding rate in an epitope binning assay. These outcomes could be attributed to the unique characteristic that BCRs on sensitized B lymphocytes themselves can select the target epitopes in the antigen. The BCRs may act as a strict sensor of B lymphocytes to precisely select the target epitopes, even though the number of immunized B lymphocytes is low. [Display omitted] • We have successfully developed optimized B-cell targeting (BCT) technique. • B-cell receptors can work as a strict sensor for selecting target epitopes. • B lymphocytes themselves can select target epitopes through B-cell receptors. • Improved antigen-based hybridoma technology applicable to lower antigenic sites. • Optimized BCT method can generate advanced diagnostic novel monoclonal antibodies. [ABSTRACT FROM AUTHOR]

Recently, deoxyribonucleic acid (DNA) adsorption on solid materials has been reported for applications such as genetic diagnosis of diseases, gene delivery, and biosensors. Mesoporous silica (MPS) is an excellent carrier because of its high surface area and large pore volume. Functionalization of the MPS surface can be controlled by silane coupling reagents, and the MPS particle morphology can be easily changed by the synthetic conditions. In this study, to evaluate the ability of DNA adsorption on MPS, the MPS surface was functionalized using four reagents, 3-aminopropyltriethoxysilane (−NH 2 ), N -(2-aminoethyl)-3-aminopropyltriethoxysilane (−2ENH 2 ), N -(6-aminohexyl)aminopropyltrimethoxysilane (−2HNH 2 ), and (3-trimethoxysilylpropyl)diethylenetriamine (−3NH 2 ), each having a different number of amino groups and alkyl chain lengths. Moreover, we prepared three types of MPSs with different particle morphologies: sheet-type structure (MPS sheet), spherical MPS (MCM-41s), and nonporous spherical silica. A high adsorption capacity was observed in MPS sheets with −2HNH 2 (sheet-2HNH 2 ) and −3NH 2 (sheet-3NH 2 ), as well as MCM-41s with −3NH 2 (41s-3NH 2 ). The adsorption and desorption rates of DNA on these three MPSs were then examined and the best results were obtained with 41s-3NH 2 . These results demonstrate that the amino functionalized MPS materials are useful DNA adsorbents. [ABSTRACT FROM AUTHOR]

The ability to encapsulate variousmolecules including proteinswithin giant liposomes is needed for studies on model cell membranesand artificial cells. In this report, we demonstrate how to improvethe efficiency of protein entrapment with the gentle hydration (naturalswelling) method, which is a well-known protocol for the preparationof giant liposomes. We found that when the initial pH of a solutionwas kept below the pI of a target protein during hydration and thenchanged to above the pI, the protein could be entrapped more efficientlycompared to the sample that was kept at above the pI during the hydration.An examination of the ratio of the mass of entrapped protein to themoles of phospholipid in liposomes (dioleoylphosphatidylcholine (DOPC)/dioleoylphosphatidylglycerol(DOPG)) indicated that entrapment of target proteins like bovine serumalbumin, myoglobin, and lysozyme could be improved using this procedure,and this trend was consistent with microscopic observations at thelevel of a single giant liposome. The conditions that resulted ingood efficiencies were affected by the NaCl concentration and thetemperature of the hydration solution, implying that protein entrapmentin giant liposomes may be enhanced by associative interaction betweenlipid lamellar membranes and target proteins. [ABSTRACT FROM AUTHOR]

Giant liposomes are often used as models for studies on cell membranes. We embedded giant liposomes in agarose gel to fix them for assays. Giant liposomes of dioleoylphosphatidylcholine were embedded in 1% ( w/ v) agarose gel with a low melting temperature: While only 20-25% of giant liposomes survived embedment, their size distribution was unaffected. Using a confocal laser scanning microscope, we monitored dynamic changes in individual agarose gel-embedded giant liposomes induced by the addition of a surfactant (Triton X-100). The permeation and collapse could be clearly discriminated from each other. Invaginated buds on liposome membranes could also be captured as intermediate structures. Additionally, an enzymatic (β-glucosidase) reaction encapsulated within the target liposome was triggered by the external addition of a non-fluorescent substrate and successfully monitored. These results suggest that embedment in agarose gel is useful for the simple fixation of giant liposomes for biochemical and biophysical assays. [ABSTRACT FROM AUTHOR]

Abstract: Histidine-tagged proteins have been purified with immobilized nickel affinity chromatography. This method, however, bears some serious disadvantages, including carcinogenicity and potential leakage of the nickel and the handling and disposal costs. We developed a novel purification process for water-soluble histidine-tagged green fluorescent protein from the cocoons of transgenic silkworms, unlike conventional E. coli expression system which sometimes produced insoluble and inactive inclusion bodies. 60.3% extraction efficiency was achieved with 50mM Tris containing 150mM NaCl, pH 7.5. The extract was purified in one step on zinc-immobilized hydroxyapatite eluted with phosphate buffer. Purity was 91.2% with a recovery of 30.0μg from 160mg of silk fiber. This purification method may provide a simple non-toxic alternative to nickel-immobilized metal affinity chromatography for purification of other histidine-tagged proteins. [Copyright &y& Elsevier]

Abstract: Giant liposomes, or giant vesicles, are cell-size (∼5–100μm) compartments enclosed with phospholipid bilayers, and have often been used in biological research. They are usually generated using hydration methods, “electroformation” and “gentle hydration (or natural swelling)”, in which dry lamellar films of phospholipids are hydrated with aqueous solutions. In gentle hydration, however, giant liposomes are difficult to prepare from an electrostatically neutral phospholipid because lipid lamellae cannot repel each other. In this study, we demonstrate the efficient formation of giant liposomes using the gentle hydration of neutral phospholipid (dioleoyl phosphatidylcholine, DOPC) dry films doped with nonelectrolytic monosaccharides (glucose, mannose, and fructose). A mixture of DOPC and such a sugar in an organic solvent (chloroform/methanol) was evaporated to form the films, which were then hydrated with distilled water or Tris buffers containing sodium chloride. Under these conditions, giant liposomes spontaneously formed rapidly and assumed a swollen cell-sized spherical shape with low lamellarity, whereas giant liposomes from pure DOPC films had multilamellar lipid layers, miscellaneous shapes and smaller sizes. This observation indicates that giant unilamellar vesicles (GUVs) of DOPC can be obtained efficiently through the gentle hydration of sugar-containing lipid dry films because repulsion between lipid lamellae is enhanced by the osmosis induced by dissolved sugar. [Copyright &y& Elsevier]

• We have successfully developed optimized stereospecific targeting (SST) technique. • DNA immunization selectively generates stereospecific antibody-producing B cells. • Antigen-expressing myeloma cells can select DNA sensitized target B cells via BCR. • Stereospecific monoclonal antibodies exhibit specific affinity for native GPCR. It is quite difficult to generate monoclonal antibodies that recognize the three-dimensional structures of the antigens of interest. To address this limitation, we developed a new hybridoma technology termed "optimized stereospecific targeting (SST)". Here we aimed at generating stereospecific monoclonal antibodies against a G protein-coupled receptor (GPCR). The optimized SST technique enabled the efficient production of conformation-specific monoclonal antibodies against human corticotropin-releasing hormone receptor 1 (huCRHR1). Hybridoma cells secreting stereospecific monoclonal antibodies were selectively cloned by a limiting dilution method and the target monoclonal antibodies were purified by protein A column chromatography. They specifically cross-reacted with native huCRHR1 expressed on the surface of CHO cells, whereas they showed no affinity for MDA-MB-231 cancer cells, which abundantly express EphA2 on the cell surface. Furthermore, immunofluorescence analysis revealed that treatment of huCRHR1-expressing CHO cells with 4% paraformaldehyde led to a decrease in the affinity of purified monoclonal antibodies for intact huCRHR1 on the cell surface. In addition, purified monoclonal antibodies showed no cross-reactivity with huCRHR1 expressed on Sf9 insect cells. These results strongly suggest that monoclonal antibodies generated by the optimized SST technique feature specific binding to the intact form of the target GPCR on mammalian cells. [ABSTRACT FROM AUTHOR]

A voltage‐applicable heating specimen holder is developed to observe solid oxide fuel cells (SOFCs) in an environmental transmission electron microscope. An SOFC specimen can be heated and has a voltage applied in an oxygen gas atmosphere using the holder. Oxygen ion migration and redox reactions in the specimen could also be realized. The heating unit, which consists of nickel–chromium alloy mounted on the tip of the developed specimen holder, can heat the specimen up to 1200 K in an oxygen gas atmosphere. A specimen preparation method for the SOFC structure is also established using a focused ion beam technique. The holder has high stability for high‐resolution imaging and electron energy loss spectroscopy under the in situ condition. The mechanical and electrical stabilities are estimated from high‐resolution images and electron energy loss spectra of the heated and voltage‐applied specimen in an oxygen gas atmosphere. The developed holder is a powerful tool to reveal the microstructural and electronic structural changes that occur by electrochemical reactions at the interfaces of an SOFC. [ABSTRACT FROM AUTHOR]

Microscopic polyangiitis (MPA) is a systemic small vessel vasculitis, which, although primarily associated with necrotizing and crescentic glomerulonephritis and pulmonary capillaritis, often has cutaneous and musculoskeltal features. Although the skin is affected in 20–70% of patients, the precise description has been limited. This retrospective study analyzed clinical manifestations in patients of MPA with skin eruptions. [ABSTRACT FROM AUTHOR]

Background: The generation of recombinant proteins for commercialisation must be cost-effective. Despite the cost-effective production of recombinant feline interferon (rFeIFN) by a baculovirus expression system, this rFeIFN carries insect-type N-glycans, with core α 1,3 fucosyl residues that act as potential allergens. An alternative method of production may yield recombinant glycoproteins with reduced antigenicity. Results: A cDNA clone encoding the fifteenth subtype of FeIFN-α (FeIFN-α15) was isolated from a Japanese domestic cat. This clone encoded a protein of 189 amino acids with a molecular mass of 21.1 kDa. The rFeIFN-α15 was expressed using a transgenic silkworm system, which was expected to yield an N-glycan structure with reduced antigenicity compared with the protein produced by the baculovirus system. The resulting rFeIFN-α15 accumulated in the sericin layer of silk fibres and was easily extracted and purified by column chromatography. The N-terminal amino acid sequence of purified rFeIFN-α15 was identical to the mature form of natural sequence. Moreover, its N-glycans did not include detectable core α 1,3 fucosyl residues. Its anti-vesicular stomatitis virus activity (2.6 × 108 units/mg protein) was comparable to that of the baculovirus-expressed rFeIFN. Conclusions: The lower allergy risk of rFeIFN produced by the transgenic silkworm system than by the baculovirus expression system is due to the former lacking core α 1,3 fucosyl residues in its N-glycans. The rFeIFN-α15 produced by the transgenic silkworm system may be a prospective candidate for the next generation of rFeIFN in veterinary medicine. [ABSTRACT FROM AUTHOR]

Close homolog of L1 (CHL1) and its truncated form mainly play crucial roles in mouse brain development and neural functions. Herein, we newly identified that truncated form of CHL1 is produced and released from lung tumor tissue in a mouse model expressing human EML4-ALK fusion gene. Both western blot and direct ELISA analysis revealed that mouse CHL1 level in serum (including serum extracellular vesicles) was significantly elevated in EML4-ALK transgenic mice. The correlation between the tumor size and the amount of CHL1 secretion could be examined in this study, and showed a significant positive correlation in a tumor size-dependent manner. Considering these results, the measurement of circulating CHL1 level may contribute to assess a tumor progression in human lung tumor patients. [ABSTRACT FROM AUTHOR]

Giant vesicles (GVs) are commonly used as artificial membranes and microcompartments in biochemical and biophysical studies. The efficiency and/or yield of their production can be strongly affected by the conditions and procedures used, and thus many protocols have been developed. A reverse-phase protocol has been used to prepare liposomes for decades, and is reported to be suitable for preparing GVs. By revisiting a reverse-phase (W/O/W emulsification) mechanism, in this study we verified how simply and efficiently GVs could be generated using the following alternative method. First, phospholipid/diethyl ether was mixed with an aqueous solution containing sucrose to form an emulsion, and the mixture was centrifuged. The resulting GVs together with tubular and sheet aggregates in the lower water phases could be purified by a second centrifugation after the addition of a glucose aqueous solution. This “reverse-phase/centrifugation” method provided a large amount of GVs of ∼20 μm in diameter from egg phosphatidylcholine as well as multiple lipid components. Spherical GVs were obtained in the presence of physiological salt concentrations (phosphate-buffered saline, PBS) when phosphatidylglycerol was included. The appearance of microdomains on the vesicle membranes may indicate that giant unilamellar vesicles (GUVs) can form through this process. [ABSTRACT FROM AUTHOR]

The spherical aberration corrector for high-resolution electron microscopes has been newly designed and constructed. This aberration correction device is formed by an electrostatic lens consisted of only two electrodes having annular and circular holes and a constant-voltage supply. We call it 'annular and circular electrodes (ACE) corrector'. The ACE corrector has big advantages in easy alignment and very low-cost over the conventional Cs-correctors. In this study, we have constructed the corrector for the scanning transmission electron microsope (STEM) probe-forming optical system. The developed device is very small (less than several tens millimeter) so that this can be assembled at the tip of the conventional aperture holder and installed in a 200kV-STEM column. In experiments using specimens of nanocrystals, we have successfully controlled the spatial resolution of the dark-field STEM images by changing the voltage applied to the corrector and also have imaged lattice fringes. These results clearly demonstrate that our developed device can correct effectively the inherent aberration of the objective lens of the STEM. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Many therapeutic antibodies have been developed, and IgG antibodies have been extensively generated in various cell expression systems. IgG antibodies contain N-glycans at the constant region of the heavy chain (Fc domain), and their N-glycosylation patterns differ during various processes or among cell expression systems. The Fc N-glycan can modulate the effector functions of IgG antibodies, such as antibody-dependent cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC). To control Fc N-glycans, we performed a rearrangement of Fc N-glycans from a heterogeneous N-glycosylation pattern to homogeneous N-glycans using chemoenzymatic approaches with two types of endo-β-N-acetyl glucosaminidases (ENG’ases), one that works as a hydrolase to cleave all heterogeneous N-glycans, another that is used as a glycosynthase to generate homogeneous N-glycans. As starting materials, we used an anti-Her2 antibody produced in transgenic silkworm cocoon, which consists of non-fucosylated pauci-mannose type (Man2-3GlcNAc2), high-mannose type (Man4-9GlcNAc2), and complex type (Man3GlcNAc3-4) N-glycans. As a result of the cleavage of several ENG’ases (endoS, endoM, endoD, endoH, and endoLL), the heterogeneous glycans on antibodies were fully transformed into homogeneous-GlcNAc by a combination of endoS, endoD, and endoLL. Next, the desired N-glycans (M3; Man3GlcNAc1, G0; GlcNAc2Man3GlcNAc1, G2; Gal2GlcNAc2Man3GlcNAc1, A2; NeuAc2Gal2GlcNAc2Man3GlcNAc1) were transferred from the corresponding oxazolines to the GlcNAc residue on the intact anti-Her2 antibody with an ENG’ase mutant (endoS-D233Q), and the glycoengineered anti-Her2 antibody was obtained. The binding assay of anti-Her2 antibody with homogenous N-glycans with FcγRIIIa-V158 showed that the glycoform influenced the affinity for FcγRIIIa-V158. In addition, the ADCC assay for the glycoengineered anti-Her2 antibody (mAb-M3, mAb-G0, mAb-G2, and mAb-A2) was performed using SKBR-3 and BT-474 as target cells, and revealed that the glycoform influenced ADCC activity. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous silica (MPS) thin film biosensor platforms were established. MPS thin films were prepared from tetraethoxysilane (TEOS) via using sol–gel and spin-coating methods using a poly-(ethylene oxide)-block-poly-(propylene oxide)-block-poly-(ethylene oxide) triblock polymer, such as P123 ((EO)20(PO)70(EO)20) or F127 ((EO)106(PO)70(EO)106), as the structure-directing agent. The MPS thin film prepared using P123 as the mesoporous template and treated via vacuum ultraviolet (VUV) irradiation to remove the triblock copolymer had a more uniform pore array than that of the corresponding film prepared via thermal treatment. Protein adsorption and enzyme-linked immunosorbent assay (ELISA) on the synthesized MPS thin films were also investigated. VUV-irradiated MPS thin films adsorbed a smaller quantity of protein A than the thermally treated films; however, the human immunoglobulin G (IgG) binding efficiency was higher on the former. In addition, protein A–IgG specific binding on MPS thin films was achieved without using a blocking reagent; i.e., nonspecific adsorption was inhibited by the uniform pore arrays of the films. Furthermore, VUV-irradiated MPS thin films exhibited high sensitivity for ELISA testing, and cytochrome c adsorbed on the MPS thin films exhibited high catalytic activity and recyclability. These results suggest that MPS thin films are attractive platforms for the development of novel biosensors. [Copyright &y& Elsevier]

Pythium species, isolated from seedlings of Glycyrrhiza uralensis with blight, were identified as P. myriotylum, P. aphanidermatum, and P. spinosum on the basis of morphological characteristics and sequences of the internal transcribed spacer regions of rDNA. In pathogenicity tests, the isolates of the three Pythium species caused blight, producing the original disease symptoms. The primary inoculum source was determined using a multiplex PCR to detect the pathogen. All the Pythium species were detected in the soils of fields with the diseased plants and in soils of adjacent field soils. [ABSTRACT FROM AUTHOR]

Abstract: Human FcγRI is a high affinity receptor for the Fc portion of human immunoglobulin G (IgG), and has extracellular, transmembrane and cytoplasmic regions. The extracellular region of human FcγRI, which is the part that interacts with human IgG, is comprised of three immunoglobulin-like domains. Unlike low affinity Fcγ receptors (FcγRII and FcγRIII), FcγRI has a unique third extracellular domain (D3). This study investigated the contribution of D3 to the binding between recombinant human FcγRI (rhFcγRI) and human IgG. The three extracellular domains and the first and second extracellular domains of human FcγRI were expressed by Escherichia coli as rhFcγRI and rhFcγRI-D1D2, respectively. The binding specificity of rhFcγRI-D1D2 to human IgG subclasses was the same as that of rhFcγRI. From surface plasmon resonance analysis, the binding affinity of rhFcγRI-D1D2 for human IgG1/κ was high (the equilibrium dissociation constant: K D =8.04×10−10 M), but slightly lower than that of rhFcγRI (K D =2.59×10−10 M). While the association of rhFcγRI-D1D2 with human IgG1/κ was same as that of rhFcγRI, the dissociation of rhFcγRI-D1D2 was faster than that of rhFcγRI. From these results, D3 of rhFcγRI would not contribute directly to the binding specificity and association of rhFcγRI, but to the holding bound human IgG. [Copyright &y& Elsevier]

Human FcγRI is a high-affinity receptor for human IgG. On the basis of its binding activity, recombinant human FcγRI (rhFcγRI) has several possible applications, including as a therapeutic reagent to treat immune complex-mediated disease and as a ligand in affinity chromatography for purification of human IgG. As the stability and production rate of rhFcγRI are low, it would need to be engineered for use in such applications. In this study, we demonstrated engineering of rhFcγRI by directed evolution through random mutagenesis and integration of mutations. Engineered rhFcγRI was expressed by Escherichia coli. Screening identified 19 amino acid mutations contributing to the thermal stability and production rate of rhFcγRI. By integration of these mutations, engineered rhFcγRI containing all 19 amino acid mutations (enFcRd) was constructed and showed markedly enhanced thermal stability (transition midpoint temperature [Tm] = 65.6°C) and production rate (3.27 mg L-medium–1 OD600–1) compared with wild-type rhFcγRI (Tm = 48.5°C; production rate, 0.07 mg L-medium–1 OD600–1) without a change in the specificities of binding to human IgG subclasses. Moreover, the binding affinity of enFcRd for human IgG1/к (equilibrium dissociation constant [KD] = 0.80 × 10–10 M) was higher than that of wild-type rhFcγRI (KD = 1.23 × 10–10 M). Our study showed that substantial engineering of rhFcγRI is possible. [ABSTRACT FROM PUBLISHER]

Abstract: Urease templated precipitation of silica synthesized by sol–gel chemistry produces a composite material allowing high urease activity. This study investigates the structural properties of the composite material that allow for the retention of the urease hydrolysis activity. Scanning (SEM) and transmission (TEM) electron microscopy reveal that the composite has a mesoporous structure composed of closely packed spherical structures ∼20–50nm in diameter. Brunauer–Emmett–Teller (BET) analysis revealed that the surface area and pore volume of the composite prepared under the conditions of 50mM urea and 25°C is relatively high (324m2/g and 1.0cm3/g). These values are equivalent to those of usual mesoporous silica materials synthesized from the self-assembly of triblock copolymers as organic templates. In addition, after encapsulating in a sol–gel silica matrix, urease retained high activity (∼90% of the activity compared with native urease). Our results suggest a new method for synthesizing mesoporous silica materials with highly tunable pore sizes and shapes under mild conditions. [Copyright &y& Elsevier]

Abstract: The introduction of bioactive molecules into three-dimensional porous scaffolds to mimic the in vivo microenvironment is a promising strategy for tissue engineering and stem cell research. In this study, bone morphogenetic protein-4 (BMP4) was spatially immobilized in a collagen-PLGA hybrid scaffold with a fusion BMP4 composed of an additional collagen-binding domain derived from fibronectin (CBD-BMP4). CBD-BMP4 bound to the collagen-PLGA hybrid scaffold and the BMP4-immobilized hybrid scaffold supported cell adhesion and proliferation. The osteogenic induction effect of the immobilized CBD-BMP4 was investigated with three-dimensional culture of human bone marrow-derived mesenchymal stem cells in the BMP4-immobilized collagen-PLGA hybrid scaffold. The in vivo implantation experiment demonstrated that the immobilized CBD-BMP4 maintained its osteoinductive activity, being capable of up-regulating osteogenic gene expression and biomineralization. The strong osteoinductivity of the BMP4-immobilized scaffold suggests it should be useful for bone tissue engineering, stem cell function manipulation and bone substitutes. [Copyright &y& Elsevier]

Abstract: The extracellular domain of human FcγRI which interacts with a human IgG was expressed as recombinant soluble human FcγRI (rshFcγRI) by Chinese hamster ovary (CHO) cell. Stable CHO cell clones with efficient expression of rshFcγRI were established based on a dihydrofolate reductase (DHFR)/methotrexate (MTX) gene-amplification system. The CHO clones efficiently produced rshFcγRI under high-density continuous culture in a bioreactor. After 53days of culture, the number of cells had reached approximately 4×106 cells/mL in the bioreactor and the average production of rshFcγRI had reached 7.4mgL-medium−1 day−1. Secreted rshFcγRI was purified to a homogeneous state using cation exchange and affinity chromatographies. The binding affinities of rshFcγRI to human IgG subclasses were determined using surface plasmon resonance analysis. The binding affinities of rshFcγRI to human IgG1/κ and IgG3/κ were high (1.59×10−10 and 2.81×10−10 M, respectively), whereas that of rshFcγRI to human IgG4/κ was lower binding affinity (1.41×10−8 M). Binding to IgG2/κ was not detectable. Examination of circular dichroism spectra indicated that rshFcγRI was rich in β-structures and loop or turn structures, but there were few α-helices. These results may be valuable for further studies of the structure and function of human FcγRI. [Copyright &y& Elsevier]

Abstract: The aim of the project is to develop a novel method estimating granulocyte–macrophage colony-stimulating factor (GM-CSF) neutralizing capacity with high-throughput and good reproducibility. For that purpose, we designed a cell-free receptor binding assay consisting of a solid-phase recombinant soluble GM-CSF receptor α (GMRα) and a biotinylated GM-CSF (bGM-CSF). Using this system, competitive inhibition of bGM-CSF binding to soluble GM-CSF receptor α (sGMRα) by GM-CSF autoantibody or IgG fractions from the sera of patients with pulmonary alveolar proteinosis was examined, resulting in excellent reproducibility. Binding inhibition was correlated with growth inhibition of TF-1 cells, a GM-CSF dependent cell line. These results suggest that our cell-free system can be applied to estimate the neutralizing capacity of GM-CSF autoantibodies ex vivo. [ABSTRACT FROM AUTHOR]

In the present study, we describe the production of transgenic silkworms expressing a recombinant mouse mAb in their cocoons. Two transgenic lines, L- and H-, were generated that carried cDNAs encoding the L- and H-chains of a mouse IgG mAb, respectively, under the control of the enhancer-linked sericin-1 promoter. Cocoon protein analysis indicated that the IgG L- or H-chain was secreted into the cocoons of each line. We also produced a transgenic line designated L/H, which carried both cDNAs, by crossing the L- and H-lines. This line efficiently produced the recombinant mAb as a fully assembled H2L2 tetramer in its cocoons, with negligible L- or H-chain monomer and H-chain dimer production. Thus, the H2L2 tetramer was synthesized in, and secreted from, the middle silk gland cells. Crossing of the L/H-line with a transgenic line expressing a baculovirus-derived trans-activator produced a 2.4-fold increase in mAb expression. The recombinant mAb was extracted from the cocoons with a buffer containing 3 m urea and purified by protein G affinity column chromatography. The antigen-binding affinity of the purified recombinant mAb was identical to that of the native mAb produced by a hybridoma. Analysis of the structure of the N-glycans attached to the recombinant mAb revealed that the mAb contained high mannose-, hybrid- and complex-type N-glycans. By contrast, insect-specific paucimannose-type glycans were not detected. Fucose residues α-1,3- and α-1,6-linked to the core N-acetylglucosamine residue, both of which are found in insect N-glycans, were not observed in the N-glycans of the mAb. [ABSTRACT FROM AUTHOR]

Abstract: We studied the promoter activity of a 5′-flanking region from −5000 to +24 (−5000/+24) in Bombyx mori fibroin heavy chain gene (fibH), fibH(−5000/+24). A luciferase reporter vector carrying fibH(−5000/+24) was bombarded to isolated posterior silk glands (PSGs). The PSGs showed a high luciferase activity when transplanted to larvae, indicating its potent promoter activity. Deletion experiments showed the requirement of fibH(−5000/−3844) and fibH(−2211/−542) for the promoter activity. These two regions and fibH(−541/+24) that contained the basal promoter were tandem fused to yield fibH(−5000/−3844:−2211/−542:−541/+24), which was found to retain 88% of the activity of fibH(−5000/+24). Germline transgenic silkworms bearing fibH(−5000/−3844:−2211/−542:−541/+24) as a promoter and enhanced green fluorescent protein (EGFP) gene as a reporter efficiently secreted EGFP in cocoons. The promoter activity of fibH(−2211/−542) was further investigated, because this contained a DNase I-hypersensitive site. The transient expression assay demonstrated that the activity of fibH(−2211/−542) required fibH(−1659/−1590), which contained the homeodomain protein-binding motif. Mutation experiments suggested a critical role of the motif for the promoter activity. Electrophoretic mobility shift assay (EMSA) demonstrated that a nuclear protein of PSGs bound to the motif. We propose fibH(−1659/−1590) as a novel transcription enhancer that plays a key role for the expression by recruiting a homeodomain protein. [Copyright &y& Elsevier]

Abstract: The silkworm Nd-sD mutant is silk fibroin-secretion deficient. In the mutant, a disulfide linkage between the heavy (H) and light (L) chains, which is essential for the intracellular transport and secretion of fibroin, is not formed because of a partial deletion of the L-chain gene. To utilize the inactivity of the mutant L-chain, we investigated the possibility of using the Nd-sD mutant for the efficient production of recombinant proteins in the silkworm. A germ line transformation of the mutant with a normal L-chain-GFP fusion gene was performed. In the transgenic mutant, normal development of the posterior silk gland (PSG) was restored and it formed a normal cocoon. The biochemical analysis showed that the transgenic silkworms expressed the introduced gene in PSG cells, produced a large amount of the recombinant protein, secreted it into the PSG lumen, and used it to construct the cocoon. The molar ratio of silk proteins, H-chain:L-chain-GFP:fibrohexamerin, in the lumen and cocoon in the transgenic silkworm was 6:6:1, and the final product of the fusion gene formed about 10% of the cocoon silk. This indicates that the transgenic mutant silkworm possesses the capacity to produce and secrete the recombinant proteins in a molar ratio equal to that of the fibroin H-chain, contributing around half molecules of the total PSG silk proteins. [Copyright &y& Elsevier]