Effect of Dehydration and Urea on Stability of Homosulfamine in Solid States

In the presence of urea in solid states, the stability of unpulverized homosulfamine hydrate (phase I; UHH) is significantly decreased whereas that of unpulverized homosulfamine anhydrate (UHA) is not. The stability of UHH is decreased slightly more by pulverization (PHH). The major objective of this study was to investigate the effects of urea, dehydration, and pulverization on the stability of homosulfamine in solid states. Binary mixtures of UHH and urea, PHH and urea, and UHA and urea in a ratio of 1:1 (wt/wt) were prepared as physical mixtures and were analyzed by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and Fourier transform infrared (FTIR) spectroscopy to study their appearance and structural changes before and after storage. PXRD analysis revealed that physical mixtures comprising UHH and urea and PHH and urea have the same diffraction pattern as that of the mixture of UHA and urea after preparation. The dehydration rate of the crystal water of UHH was accelerated by the presence of urea in addition to pulverization. Moreover, the PXRD patterns of the physical mixtures of UHH/urea and PHH/urea were significantly altered during storage, whereas that of UHA/urea was not, which was consistent with the SEM and FTIR results. The particle shape and appearance of UHH varied significantly as a result of pulverization. The stability of homosulfamine was influenced not only by the presence of urea and dehydration but also by the surface state and particle size of the crystalline form.     

Disruption of the ABC transporter genes PDR5, YOR1, and SNQ2, and their participation in improved fermentative activity of a sake yeast mutant showing pleiotropic drug resistance

Clotrimazole-resistant mutants from sake yeasts show improved fermentative activity in sake mash and pleiotropic drug resistance (PDR). The PDR mechanism is interpreted by overexpression of ATP-binding cassette (ABC) transporters, which extrude various kinds of drugs out of a cell. In a clotrimazole-resistant mutant, CTZ21, isolated from the haploid sake yeast HL69, the levels of mRNA for three major ABC transporter genes, PDR5, SNQ2, and YOR1, markedly increased. These three genes of CTZ21 were disrupted to investigate which participated in the improved fermentative activity of CTZ21. The fermentative activities of deltapdr5 and deltasnq2 strains of CTZ21 were reduced to that of HL69 in the initial and middle stages of fermentation. In the last stage, however, the sake meter [(1/gravity - 1) x 1443] of the deltapdr5 and deltasnq2 strains rose faster than that of HL69. On the other hand, a deltayor1 strain of CTZ21 fermented sake mash in a manner nearly identical to that of CTZ21 until the last stage of fermentation. But in the last stage, fermentation of the deltayor1 slowed down compared with that of CTZ21. A deltayor1 strain of HL69 also exhibited much reduced fermentative activity in the middle and last fermentation stages. The YOR1 gene seems necessary for sake fermentation to be completed efficiently. The ATP content in sake mash brewed with CTZ21 was drastically decreased throughout the whole fermentation period. This low ATP level was restored to a medium level in the cases of both the deltapdr5 and deltasnq2 strains of CTZ21. In contrast, the deltayor1 of CTZ21 exhibited a low ATP level in sake mash in the same manner as CTZ21. These results suggest that the low ATP level of CTZ21 contributes to a certain extent its improved fermentative activity in the initial and middle stages of sake fermentation.     

Observation of the distribution of Zn protoporphyrin IX (ZPP) in Parma ham by using purple LED and image analysis

We investigated the distribution of Zn protoporphyrin IX (ZPP) in Parma ham by using purple LED light and image analysis in order to elucidate the mechanism of ZPP formation. Autofluorescence spectra of Parma ham revealed that ZPP was present in both lean meat and fat, while red emission other than that of ZPP was hardly detected. Although ZPP was found to be distributed widely in Parma ham, it was more abundant in intermuscular fat and subcutaneous fat than in lean meat. The intensity of red emission was weak in muscles that were exposed during the processing. ZPP in both lean meat and subcutaneous fat tended to be more abundant in the inner region than in the outer region. It was thought that ZPP is transferred from lean meat to fat tissue during the processing, resulting in the small amount of ZPP in the lean meat adjacent to subcutaneous fat. Our results led to a completely new hypothesis that ZPP is formed in lean meat and transferred to fat tissue.     

Electrochromic imaging with polymer electrolyte having high-temperature-dependent conductivity

Space-selective electrochromic imaging was successfully performed with a novel polymer electrolyte composed of poly(vinylbutyral) (PVB), poly(ethyleneglycole) (PEG) and tetra-butylammonium perchlorate (TBAP). The spreading of the electrochromic image is a shortcoming when the image is space-selectively formed by electrochemical reaction. This is due to a cell formation between colored and uncolored parts through an ionic conductor. In order to inhibit the spreading, it would be effective to apply a polymer electrolyte with very low ionic conductivity at room temperature to the imaging system. Based on this, we designed the polymer electrolyte to have a large difference in ionic conductivity between high and low temperatures. This polymer electrolyte enables writing and erasing at a high temperature due to high ionic conductivity, and the image is to be preserved without change in ambient temperature due to very low ionic conductivity. In fact, space-selective image was successfully formed on the electrochromic device with the present polymer electrolyte at 100 °C, and was stable without change for more than a week when the device was kept at 20 °C.     

Genetic and nutritional effects on the fatty acid composition of subcutaneous and intramuscular lipids of steers

Genetic and nutritional influences on fatty acid composition of subcutaneous (SNL) and intramuscular neutral lipids (IMNL) and intramuscular phospholipids (IMPL) of steer carcasses were investigated by removing the effect of carcass fat percentage (CFP) or slaughter age (SA) on the fatty acid composition. To investigate the genetic influences, steer progenies from two dam breed-types (Japanese Black (JB) and f(1) between JB bull and Holstein cows) and three different maturing types of JB sires were used. Dam breed-type did not affect any of the fatty acids except 17:0 in SNL and none of those in IMNL. Percentages of 16:0, 16:1, 18:2, SFA, MUFA and PUFA in SNL differed among sires of JB dam breed-type group (p < 0.05) even after removing the effect of CFP. Studies on the effects of two nutritional planes [high(H) and medium-high(MH)] on the fatty acid composition of SNL, IMNL and IMPL were done using JB steers. The SNL and IMNL of the H plane steers contained greater percentages of saturated fatty acids at the same CFP but less at the same SA than the MH plane animals. The reverse was true for the unsaturated fatty acid contents.     

Relationship between degradation of proteoglycans and weakening of the intramuscular connective tissue during post-mortem ageing of beef

Changes in proteoglycans (PGs) during post-mortem ageing of bovine m. semitendinosus were studied. Electron microscopic observations made it clear that there were two types of PGs in bovine m. semitendinosus immediately post-mortem: PGs were arranged regularly in the basement membrane and PGs associated with collagen fibrils in the perimysium. After 28 days ageing at 4 °C, no PG was observed in the basement membrane, and the greater part of PGs in the perimysium had disappeared. The total amount of PGs decreased with time post-mortem. SDS-polyacrylamide gel electrophoresis indicated that PGs with a high molecular weight disappeared within 7 days post mortem. These results suggest that PGs are degraded during post-mortem ageing of beef. The degradation of PGs seems likely to be the main factor in the weakening of intramuscular connective tissues, i.e., separation of collagen fibrils and fibres from the endomysium and the perimysium, which results in the partial tenderization of beef during post-mortem ageing.