Flow-based ammonia gas analyzer with an open channel scrubber for indoor environments.

A robust and fully automated indoor ammonia gas monitoring system with an open channel scrubber (OCS) was developed. The sample gas channel dimensions, hydrophilic surface treatment to produce a thin absorbing solution layer, and solution flow rate of the OCS were optimized to connect the OCS as in-line gas collector and avoid sample humidity effects. The OCS effluent containing absorbed ammonia in sample gas was injected into a derivatization solution flow. Derivatization was achieved with o-phthalaldehyde and sulfite in pH 11 buffer solution. The product, 1-sulfonateisoindole, is detected with a home-made fluorescence detector. The limit of detection of the analyzer based on three times the standard deviation of baseline noise was 0.9 ppbv. Sample gas could be analyzed 40 times per hour. Furthermore, relative humidity of up to 90% did not interfere considerably with the analyzer. Interference from amines was not observed. The developed gas analysis system was calibrated using a solution-based method. The system was used to analyze ammonia in an indoor environment along with an off-site method, traditional impinger gas collection followed by ion chromatographic analysis, for comparison. The results obtained using both methods agreed well. Therefore, the developed system can perform on-site monitoring of ammonia in indoor environments with improved time resolution compared with that of other methods.

The usefulness of the collagen and elastin sponge derived from salmon as an artificial dermis and scaffold for tissue engineering.

Collagen sponge is one of the medical materials that are frequently used in clinical medicine. However, the problem of prion disease harmfully affected the usage of mammals-derived medical materials. Since there have been no reports about prion disease occurring in marine products, we produced the collagen and elastin sponge (CES) made from salmon, and investigated whether the CES could be a substitute for mammalian collagen sponge. Fibroblasts were seeded in the CES to examine whether the CES could be used as a scaffold for tissue engineering. The results of the WST-1 assay showed that the fibroblasts were viable and were well proliferated in the CES. To examine whether the CES could be used as an artificial dermis, the CES and TERUDERMIS (traditional collagen sponge) were grafted onto the skin defects on the dorsum of rats. The histological findings of these ulcers showed non-significant difference between the CES and TERUDERMIS. Because of the safety, the abundance of the resources, and the possessing same ability as TERUDERMIS, the biomedical materials derived from marine products may be a substitute for those derived from mammals.

Miniature open channel scrubbers for gas collection.

An open channel scrubber is proposed as a miniature fieldable gas collector. The device is 100mm in length, 26 mm in width and 22 mm in thickness. The channel bottom is rendered hydrophilic and liquid flows as a thin layer on the bottom. Air sample flows atop the appropriately chosen flowing liquid film and analyte molecules are absorbed into the liquid. There is no membrane at the air-liquid interface: they contact directly each other. Analyte species collected over a 10 min interval are determined by fluorometric flow analysis or ion chromatography. A calculation algorithm was developed to estimate the collection efficiency a priori; experimental and simulated results agreed well. The characteristics of the open channel scrubber are discussed in this paper from both theoretical and experimental points of view. In addition to superior collection efficiencies at relatively high sample air flow rates, this geometry is particularly attractive that there is no change in collection performance due to membrane fouling. We demonstrate field use for analysis of ambient SO(2) near an active volcano. This is basic investigation of membraneless miniature scrubber and is expected to lead development of an excellent micro-gas analysis system integrated with a detector for continuous measurements.

Protein O-mannosyltransferase A of Aspergillus awamori is involved in O-mannosylation of glucoamylase I.

Industrially important extracellular enzymes from filamentous fungi are often O-mannosylated. The structure and function of the pmtA (AapmtA) gene encoding the protein O-D-mannosyltransferase of Aspergillus awamori were characterized. The AapmtA disruptant, designated AaPMTA, was constructed by homologous recombination. The strain AaPMTA exhibited fragile cell morphology with respect to hyphal extension, as well as swollen hyphae formation and conidia formation in potato dextrose medium. Moreover, the AapmtA disruptant showed increased sensitivity to high temperature and Congo red. Thus, the AaPmtA protein is involved in the formation of the normal cell wall. The strain AaPMTA could grow well in liquid synthetic medium and secrete glucoamylase I (GAI-AaPMTA) to a similar extent to the wild-type strain (GAI-WT). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of the GAIs revealed that approximately 33 mannose moieties of GAI were absent in strain AaPMTA. This result indicates that the AaPmtA protein is responsible for the transfer of mannose to GAI. Structural analysis of the O-linked oligosaccharides of GAI also demonstrated that the AapmtA disruption resulted in a reduction of the amounts of O-linked oligosaccharides, such as D-mannose and alpha-1,2-mannotriose, in GAI-AaPMTA. However, the amount of alpha-1,2-mannobiose was comparable between GAI-WT and GAI-AaPMTA. The result suggests the presence of a compensatory mechanism in the synthetic pathway of O-mannosylation in A. awamori.