Continuous production of fructooligosaccharides using fructosyltransferase immobilized on ion exchange resin

A continuous production of fructooligosaccharides from sucrose was investigated by fructosyltransferase immobilized on a high porous resin, Diaion HPA 25. The optimum pH (5.5) and temperature (55°C) of the enzyme for activity was unaltered by immobilization, and the immobilized enzyme became less sensitive to the pH change. The optimal operation conditions of the immobilized enzyme column for maximizing the productivity were as follows: 600 g/L of sucrose feed concentration, flow rate of superficial space velocity 2.7 h^?1. When the enzyme column was run at 50°C, about 8% loss of the initial activity of immobilized enzyme was observed after 30 days of continuous operation, during which high productivity of 1174 g/L·h was achieved. The kinds of products obtained using the immobilized enzyme were almost the same as those using soluble enzymes or free cells.     

Theoretical calculation of the sugar concentrations during enzymatic production of fructooligosaccharides

Summary In a batch production of fructooligosaccharides from sucrose, the concentrations of residual sucrose, glucose and fructooligosaccharides at a given reaction time(t) and initial sucrose concentration(S₀) were theoretically calculated by the following correlation equations: Glucose(t) = 0.0653 S₀ × ln(t); Fructooligosaccharides(t) = 0.1636 S₀ × ln(t); Sucrose(t)=S₀ - Glucose(t) + FOS(t).     

Ecology of Hantaan virus at Twin Bridges Training Area,Gyeonggi Province,Republic of Korea, 2005–2007

The Twin Bridges Training Area (TBTA) in the Republic of Korea consists of dirt roads, barren training areas, and forested hillsides adjacent to linear and broad expanses of tall grasses, herbaceous, and scrub vegetation. Of the six species of small mammals, the striped field mouse, Apodemus agrarius, was the most frequently captured (96.1%). Apodemus agrarius capture rates varied from 17.7 to 33.2% during three trapping periods. Gravid females were observed during November‐December 2006 (8.4%) and March 2007 (5.1%). In 2005, the overall seroprevalence of Hantaan virus (HTNV) was high (34.4%) and lower during surveys in 2006 (14.2%) and 2007 (13.8%). Seroprevalence was directly correlated with weight increase of A. agrarius.     

Two uvs genes of Aspergillus nidulans with different functions in error-prone repair: uvsI, active in mutation-specific reversion, and uvsC, a recA homolog, required for all UV mutagenesis

Two genes of Aspergillus nidulans are known to function in UV mutagenesis, but have been assigned to different epistasis groups: uvsC, which is also required for meiosis and mitotic recombination, and uvsI, which may have no other function. To clarify their role in error-prone repair and to investigate their interaction, uvsI and uvsC single and uvsI;uvsC double mutant strains were further tested for mutagen sensitivities and characterized for effects on mutation. Spontaneous and induced frequencies were compared in forward and reverse mutation assays. All results confirmed that uvsI and uvsC are members of different epistasis groups, and demonstrated that these uvs mutants have very different defects in UV mutagenesis. The uvsI strains showed wild-type frequencies in all forward mutation tests, but greatly reduced spontaneous and UV-induced reversion of some, but not other, point mutations. In contrast, uvsC had similar effects in all assay systems: namely pronounced mutator effects and greatly reduced UV mutagenesis. Interestingly, the uvsI;uvsC double mutant strains differed from both single mutants; they clearly showed synergism for all types of reversion tested: none were ever obtained spontaneously, nor after induction by UV or EMS (ethylmethane sulfonate). Based on these results, we conclude that uvsI is active in a mutation-specific, specialized error-prone repair process in Aspergillus. In contrast, uvsC, which is now known to show sequence homology to recA, has a basic function in mutagenic UV repair in addition to recombinational repair, similar to recA of Escherichia coli.     

Comparison of Fat–Water MRI and Single‐voxel MRS in the Assessment of Hepatic and Pancreatic Fat Fractions in Humans

The ability to accurately and noninvasively quantify fatty infiltration in organs such as the liver and the pancreas remains a critical component in understanding the link between obesity and its comorbidities such as type 2 diabetes and fatty liver disease. Single‐voxel (¹H) proton magnetic resonance spectroscopy (MRS) has long been regarded as the gold‐standard noninvasive technique for such measurements. Recent advances in three‐dimensional fat–water magnetic resonance imaging (MRI) methods have led to the development of rapid, robust, and quantitative approaches that can accurately characterize the proportion of fat and water content in underlying tissues across the full imaging volume, and hence entire organs of interest. One such technique is called IDEAL (Iterative Decomposition with Echo Asymmetry and Least squares estimation). This article prospectively compares three‐dimensional (3D) IDEAL‐MRI and single‐voxel MRS in the assessment of hepatic (HFF) and pancreatic fat fraction (PFF) in 16 healthy subjects. MRS acquisitions took 3–4 min to complete whereas IDEAL acquisitions were completed in 20‐s breath‐holds. In the liver, there was a strong correlation (slope = 0.90, r² = 0.95, P < 0.001) between IDEAL and MRS‐based fat fractions. In the pancreas, a poorer agreement between IDEAL and MRS was observed (slope = 0.32, r² = 0.51, P < 0.02). The discrepancy of PFF is likely explained by MRS signal contamination from surrounding visceral fat, presumably during respiratory motion. We conclude that IDEAL is equally accurate in characterizing hepatic fat content as MRS, and is potentially better suited for fat quantification in smaller organs such as the pancreas.     

Spectrophotometric determination of reaction stoichiometry and equilibrium constants of metallochromic indicators: III. Antipyrylazo III complexing with Ca2+ and acetylcholine receptor protein

Stoichiometries, equilibrium constants and optical extinction coefficients of calcium-antipyrylazo III (An) complexing are determined with the analytical method described in article I of this series. Spcctrophotometric Ca titrations of An at the wavelengths 595 and 710 nm indicate overall dissociation equilibrium constants for the complexes CaAn, CaAn₂ and Ca₂An to be 4.5 × 10^?4 M, 1.1 × 10^?8 M² and 1.5× 10^?6 M², respectively, extrapolated to zero ionic strength. Ca titrations of solutions containing An plus acetylcholine receptor protein give clear evidence that An binds to the protein to a large extent in the presence of Ca²⁺; furthermore, addition of acetylcholine results in release of protein-bound Ca and An. This is the first reported indication that antipyrylazo III binds to biological material and questions the usefulness of this dye as a Ca indicator in biological systems.     

Fast and sensitive delineation of brain tumor with clinically compatible moxifloxacin labeling and confocal microscopy

Delineation of brain tumor margins during surgery is critical to maximize tumor removal while preserving normal brain tissue to obtain optimal clinical outcomes. Although various imaging methods have been developed, they have limitations to be used in clinical practice. We developed a high‐speed cellular imaging method by using clinically compatible moxifloxacin and confocal microscopy for sensitive brain tumor detection and delineation. Moxifloxacin is a Food and Drug Administration (FDA) approved antibiotic and was used as a cell labeling agent through topical administration. Its strong fluorescence at short visible excitation wavelengths allowed video‐rate cellular imaging. Moxifloxacin‐based confocal microscopy (MBCM) was characterized in normal mouse brain specimens and visualized their cytoarchitecture clearly. Then, MBCM was applied to both brain tumor murine models and two malignant human brain tumors of glioblastoma and metastatic cancer. MBCM detected tumors in all the specimens by visualizing dense and irregular cell distributions, and tumor margins were easily delineated based on the cytoarchitecture. An image analysis method was developed for automated detection and delineation. MBCM demonstrated sensitive delineation of brain tumors through cytoarchitecture visualization and would have potentials for human applications, such as a surgery‐guiding method for tumor removal.      

Rat Sertoli and spermatogenic cells express a similar gene, and its product is antigenically related to an outer dense fiber-associated protein.

We have previously reported that a heterodimeric protein secreted by rat Sertoli cells is antigenically related to a protein associated with outer dense fibers of the sperm tail. Therefore, we have explored the possibility that Sertoli and spermatogenic cells express a similar gene encoding a homologous protein. A Sertoli cell heterodimeric protein cDNA probe recognizes specific mRNA in pachytene and round spermatids fractionated by centrifugal elutriation; however, this specific mRNA was less prominent than in cultured Sertoli cells. In agreement with these observations, in situ hybridization experiments show that Sertoli cells are predominantly engaged in active heterodimeric protein mRNA synthesis, while meiotic prophase spermatocytes and spermatids also show significant but less abundant specific mRNA. Immunoblotting experiments demonstrate that, while Sertoli cells synthesize a heterodimeric protein consisting of two disulfide-linked components with molecular masses of 45 and 35 kD, both primary spermatocytes and round spermatids synthesize single 30 kD monomers not associated by disulfide linkage but recognized by antisera to Sertoli cell heterodimeric protein. Immunoblotting and immunogold electron microscopic studies show that antisera to Sertoli cell heterodimeric protein recognize a protein associated with outer dense fibers. This immunoreactivity was abolished by a 5-min pronase treatment, without affecting the integrity of outer dense fibers. Results of this study and previous studies demonstrate that both Sertoli and spermatogenic cells express a similar gene and that an antigenically related product encoded by this gene becomes associated with outer dense fibers during their assembly at spermiogenesis.