Distribution of spermine in bacilli and lactic acid bacteria

Obligate moderately thermophilic bacilli and obligate moderately thermoacidophilic bacilli contained spermine as the major polyamine in addition to putrescine and spermidine. The identity of spermine was confirmed by thin-layer chromatography and high-performance liquid chromatography before and after treatment with putrescine oxidase. Using these methods, thermospermine and spermine can be separated; thermospermine was not present in these organisms. On the other hand, various facultative thermophiles and mesophilic strains of the genus Bacillus, including alkalophiles and halophiles, lack spermine and other tetraamines. No spermine was detected in several strains of mesophilic or facultative slightly thermophilic lactic acid bacteria, Lactobacillus and Streptococcus.     

Synthesis of RNA oligomer using 9-fluorenylmethoxycarbonyl (Fmoc) group for 5'-hydroxyl protection

An approach using a new combination of protecting groups in RNA oligomer synthesis is proposed, in which 5'-hydroxyl group of ribose moiety is temporarily protected with the alkaline labile 9-fluorenylmethoxycarbonyl (Fmoc) group and the 2'-hydroxyl group is protected with the acid labile 1-ethoxyethyl (EE) group. The adoption of this method presented great selectivity in removing the 5'-hydroxyl protecting group and facilitated the RNA oligomer synthesis. A RNA pentamer was synthesized by the phosphotriester method in solution.     

Natural occurrence of guanidinooxypropylamine in Wistaria floribunda and the sword bean Canavalia gladiata

We found a new guanidinooxyamine in Wistaria floribunda seeds and seedlings of the sword bean, Canavalia gladiata. This amine was not only ninhydrin-positive but also gave a positive alkaline nitroprusside-ferricyanide reaction. It was characterized as gamma-guanidinooxypropylamine [H2N (NH=)CNHO (CH2)3NH2] by comparison with the authentic compound on column and thin-layer chromatograms visualized with specific reagents and by reductive cleavage. Evidence for the occurrence of another unusual guanidino amine, homoagmatine in W. floribunda seeds was also presented.     

Interconversion of polyamines in wild-type strains and mutants of yeasts and the effects of polyamines on their growth

Yeasts of wild-type strains, such as Saccharomyces cerevisiae, Schizosaccharomyces pombe and Candida albicans were shown to have the ability to form aminopropylcadaverine and aminopropylhomospermidine from cadaverine and homospermidine, respectively. A polyamine autotroph S. cerevisiae 179-5, which lacks ornithine decarboxylase, produced both aminopropylcadaverine and aminopropylhomospermidine, while another mutant S. cerevisiae Y 260 A, which lacks spermine synthase, formed only aminopropylcadaverine. Naturally-occurring triamines and tetraamines except norspermidine and norspermine stimulated the growth of S. cerevisiae 179-5. All the six aliphatic diamines with carbon chain length ranging from one to six were effective in activating the growth of S. cerevisiae 179-5, though all of them were not converted to either triamines or tetraamines.     

Entrapment of lipase in silica glass by the sol-gel method and its esterification activity in organic media

Summary Silica glass-entrapped lipase was prepared by the sol-gel method using tetramethoxysilane, and its esterification activity in n-hexane was examined for isoamylbutyrate formation. The hydrogel preparation containing a large amount of water exhibited enough activity. Although the activity of xerogel-entrapped lipase drastically decreased probably due to shrinkage of the gel matrix, the lyophilized gel retained much higher activity than the air-dried gel.     

Increased anti-oxidative action compensates for collagen tissue degeneration in vitiligo dermis

Vitiligo is a common depigmentation disorder characterized by the selective loss of melanocytes. In our daily clinic experience, we noticed that the skin tightness of hypopigmented lesions would be more evident in comparison to that of uninvolved perilesional skin in vitiligo patients. Therefore, we hypothesized that collagen homeostasis might be maintained in vitiligo lesions, irrespective of the substantial excessive oxidative stress that occurs in association with the disease. We found that the expression levels of collagen-related genes and anti-oxidative enzymes were upregulated in vitiligo-derived fibroblasts. Abundant collagenous fibers were observed in the papillary dermis of vitiligo lesions in comparison to uninvolved perilesional skin by electron microscopy. The production of matrix metalloproteinases that degraded collagen fibers was suppressed. The deposition of acrolein adduct protein, which is a product of oxidative stress, was significantly reduced in vitiligo dermis and fibroblasts. As part of the mechanism, we found upregulation of the NRF2 signaling pathway activity, which is an important defense system against oxidative stress. Taken together, we demonstrated that the anti-oxidative action and collagen production were upregulated and that the collagen degeneration was attenuated in vitiligo dermis. These new findings may provide important clues for the maintenance of antioxidant ability in vitiligo lesions.     

Selective release of HMG nonhistone proteins during DNase digestion of Tetrahymena chromatin at different stages of the cell cycle.

The possible role of LG-1, a Tetrahymena specific HMG protein found in the macronuclear chromatin (Hamana, K. and Iwai, K. (1979) J. Biochem. 86, 789-794), was examined in relation to the chromatin structure. The chromatin isolated from cells synchronized at different stages of the cell cycle contained about one molecule of LG-1 per nucleosome. Limited digestion of the chromatin with DNase I or micrococcal nuclease selectively released LG-1 with the nucleosomal core histones and H1 remained insoluble, bound to the resistant DNA. Depending on the cell stages several types of chromatin structure were distinguished by their nuclease sensitivity. However, the chromatin at different stages exhibited the similar behavior of the LG-1 release with the nucleases as a function of the degree of chromatin solubilization. The results suggest that LG-1 proteins play a role in the chromatin organization which is rather independent of the cell stages.     

Kinetics of chemical modification of arginine and lysine residues in calf thymus histone H1

The arginine and lysine residues of calf thymus histone H1 were modified with large molar excesses of 2,3-butanedione and O-methylisourea, respectively. Kinetic study of the modification reaction of the arginine residue revealed that the reaction is divided into the two pseudo-first-order processes. About a third (1 Arg) of the total arginine residues of the H1 molecule was rapidly modified without causing any detectable structural change of the molecule, and the slow modification of the remaining arginine residues (2 Arg) led to a loss of the folded structure of H1. In the case of lysine residue modification, 93% (56 Lys) of the total lysine residues of the H1 was modified with the same rate constant, while 7% (4 Lys) of lysine residue remained unmodified. When the reaction was performed in the presence of 6M guanidine-HCl, all of lysine residues were modified. It is concluded that the 2 arginine and 4 lysine residues resistant to modification are buried in interior regions of the H1 molecule and play an important role in the formation of the H1 globular structure, while the other 1 arginine and 56 lysine residues are exposed to solvent.