Mannosylerythritol lipid, a yeast extracellular glycolipid, shows high binding affinity towards human immunoglobulin G

BACKGROUND: There have been many attempts to develop new materials with stability and high affinity towards immunoglobulins. Some of glycolipids such as gangliosides exhibit a high affinity toward immunoglobulins. However, it is considerably difficult to develop these glycolipids into the practical separation ligand due to their limited amounts. We thus focused our attention on the feasible use of "mannosylerythritol lipid A", a yeast glycolipid biosurfactant, as an alternative ligand for immunoglobulins, and undertook the investigation on the binding between mannosylerythritol lipid A (MEL-A) and human immunoglobulin G (HIgG). RESULTS: In ELISA assay, MEL-A showed nearly the same binding affinity towards HIgG as that of bovine ganglioside GM1. Fab of human IgG was considered to play a more important role than Fc in the binding of HIgG by MEL-A. The bound amount of HIgG increased depending on the attached amount of MEL-A onto poly (2-hydroxyethyl methacrylate) (polyHEMA) beads, whereas the amount of human serum albumin slightly decreased. Binding-amount and -selectivity of HIgG towards MEL-A were influenced by salt species, salt concentration and pH in the buffer solution. The composite of MEL-A and polyHEMA, exhibited a significant binding constant of 1.43 × 10(6) (M(-1)) for HIgG, which is approximately 4-fold greater than that of protein A reported. CONCLUSIONS: MEL-A shows high binding-affinity towards HIgG, and this is considered to be due to "multivalent effect" based on the binding molar ratio. This is the first report on the binding of a natural human antibody towards a yeast glycolipid

The bulk high-Tc superconducting fluxgatemeter for nondestructiveevaluation

A high-Tc superconductive fluxgate magnetic sensor utilizing sintered YBa2Cu3O7-x core is constructed and applied to detect a flaw in an aluminum plate. The magnetic sensor successfully works in an unshielded environment. An electric current was supplied to an aluminum plate directly. A slit (0.2 mm width, 30 mm length), which is considered as a flaw, on an aluminum plate is successfully detected with this sensor, even though the slit is covered with another aluminum plate. The sensor can detect the flaw with its direction perpendicular to the electric current in the sample. It\u27s supposed that the sensor can determine the length of the flaw larger than the diameter of the detection coil. These results suggest that the sensor has a potential for nondestructive evaluation of non-magnetic metals such as aluminum alloys, and also for their multi-layered structures

Non-destructive testing using a HTS SQUID

We have used a high temperature superconductor (HTS) SQUID in an unshielded environment to perform eddy current nondestructive testing measurement of a multi-layer aluminum structure. The sensor consists of an YBCO dc superconducting quantum interference device (SQUID). As a demonstration of the system\u27s capabilities, subsurface defects in a multi-layer aluminum structure have been located and mapped using eddy current with no magnetic shielding around the specimen

Dose Measurements through the Concrete and Iron Shields under the 100 to 400 MeV Quasi-Monoenergetic Neutron Field (at RCNP, Osaka Univ.)

Shielding benchmark experiments are useful to verify the accuracy of calculation methods for the radiation shielding designs of high-energy accelerator facilities. In the present work, the benchmark experiments were carried out for 244- and 387-MeV quasi-monoenergetic neutron field at RCNP of Osaka University. Neutron dose rates through the test shields, 100-300 cm thick concrete and 40-100 cm thick iron, were measured by four kinds of neutron dose equivalent monitors, three kinds of wide-energy range monitors applied to high-energy neutron fields above 20 MeV and a conventional type rem monitor for neutrons up to 20 MeV, placed behind the test shields. Measured dose rates were compared one another. Measured results with the wide-energy range monitors were in agreement one another for both the concrete and the iron shields. For the conventional type rem monitor, measured results are smaller than those with the wide-energy range monitors for the concrete shields, while that are in agreements for the iron shields. The attenuation lengths were obtained from the measurements. The lengths from all the monitors are in agreement on the whole, though some differences are shown. These results are almost same as those from others measured at several hundred MeV neutron fields

Crystal Structure of the Minimal Cas9 from Campylobacter jejuni Reveals the Molecular Diversity in the CRISPR-Cas9 Systems

The RNA-guided endonuclease Cas9 generates a double-strand break at DNA target sites complementary to the guide RNA and has been harnessed for the development of a variety of new technologies, such as genome editing. Here, we report the crystal structures of Campylobacter jejuni Cas9 (CjCas9), one of the smallest Cas9 orthologs, in complex with an sgRNA and its target DNA. The structures provided insights into a minimal Cas9 scaffold and revealed the remarkable mechanistic diversity of the CRISPR-Cas9 systems. The CjCas9 guide RNA contains a triple-helix structure, which is distinct from known RNA triple helices, thereby expanding the natural repertoire of RNA triple helices. Furthermore, unlike the other Cas9 orthologs, CjCas9 contacts the nucleotide sequences in both the target and non-target DNA strands and recognizes the 5′-NNNVRYM-3′ as the protospacer-adjacent motif. Collectively, these findings improve our mechanistic understanding of the CRISPR-Cas9 systems and may facilitate Cas9 engineering. Keywords: CRISPR-Cas system; Cas9; protospacer adjacent motif; RNA triplex; crystal structureUnited States. Department of Energy (Grant DE-FG02-97ER25308)National Institute of Mental Health (U.S.) (Grant 5DP1-MH100706)National Institute of Mental Health (U.S.) (Grant 1R01-MH110049