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81.
Tsuyoshi Fujiwara Shinzo Izumi Patrick J. Brennan 《Bioscience, biotechnology, and biochemistry》2013,77(8):2301-2308
The disaccharide, 2,3-di-O-methyl-4-O-(3,6-di-O-methyl-β-d-glucopyranosyl)-l-rhamno-pyranose, the distal segment of phenolic glycolipid I, that is a specific antigen from Mycobacterium leprae, and some related disaccharides were synthesised as the glycosides of methyl 3-(p-hydroxyphenyl)propionate. The methyl 3-(p-hydroxyphenyl)propionate was coupled with 2,3,4-tri-O-acetyl-l-rhamnosyl bromide, deacetylated, acetonated, coupled with 2,4,6-tri-O-acetyl-3-O-methyl-d-glucosyl bromide, and converted into a variety of p-(2-methoxycarbonylethyl)phenyl 4-O-(3,6-di-O-methyl-d-glucopyranosyl)-containing disaccharides that are amenable to ready conjugation with protein carriers, thereby providing neo-glycoconjugates for the specific serodiagnosis of leprosy. 相似文献
82.
Yoshiki Tani Koichi Ogata Masao Ukita Tsuyoshi Nakamatsu Yoshikazu Izumi 《Bioscience, biotechnology, and biochemistry》2013,77(2):173-197
Escherichia freundii alkaline phosphatase was found in a membrane fraction and was purified by procedures involving spheroplast formation with lysozyme and EDTA, and DEAE-cellulose and Sephadex G-150 column chromatographies. Then this enzyme along with other phosphatases was investigated on the ability to transfer the phosphoryl group from p-nitrophenyl phosphate to pyridoxine. It was found that the ability of the transphosphorylation varied with these phosphatases. The transphosphorylation to hydroxy compounds such as alcohols, sugars and nucleosides was also compared. Escherichia freundii acid phosphatase showed the highest activity of transphosphorylation among phosphatases tested. The mechanism of transphosphorylation was discussed.An enzyme, pyridoxamine 5′-phosphate transaminase, was purified from the cell-free extract of Clostridium kainantoi. The purification procedures involved ammonium sulfate fractionation, protamine sulfate treatment and, DEAE-cellulose, hydroxylapatite, DEAE-Sephadex and Sephadex G-200 column chromatographies. The purified enzyme, which had approximately 2700-fold higher specific activity over the original extract, showed a single schlieren pattern in the ultracentrifuge. From the spectral analysis, it seemed that pyridoxamine 5′-phosphate transaminase did not contain pyridoxal 5′-phosphate as a prosthetic group. It was recognized that the transamination was accelerated by the addition of amino acid and was inhibited by diisopropyl phosphofluoride. Glutamic acid formed in the reaction was identified to be a D-isomer. A study on the substrate specificity showed that the enzyme might be possible to be specific for pyridoxamine 5′-phosphate.The extracellular formation of vitamin B6 was searched in marine and terrestrial microorganisms. Two bacterial strains were selected and were identified as Vibrio and Flavobacterium, respectively. Marine microorganisms showed the considerable formation of vitamin B6 and the presence of vitamin B6 in sea water was also recognized. The cultural and reaction conditions for vitamin B6 formation by these strains were investigated. Glycerol was commonly the most effective compound on vitamin B6 formation among the compounds tested. It was suggested that both bacteria did not have the control system on vitamin B6 biosynthesis by the amount of possible end products. 相似文献
83.
Yoshikazu Izumi Kuninori Sato Yoshiki Tani Koichi Ogata 《Bioscience, biotechnology, and biochemistry》2013,77(6):1335-1340
The 7-keto-8-aminopelargonic acid (KAPA) synthetase activities of cell-free extracts from various bacteria were investigated. The experiments on the substrate specificity of KAPA synthetase, using crude cell-free extracts from bacteria having high enzyme activity, showed that l-serine and pyruvic acid could replace l-alanine, but that, when the enzyme was partially purified, these compounds were not effective. Many kinds of amino acids such as l-cysteine, l-serine, d-alanine, glycine, d-histidine, and l-histidine, inhibited the enzyme activity. This inhibition was found to be competitive with l-alanine. Pyridoxal 5′-phosphate, which is a cofactor of the enzyme, also inhibited the enzyme activity at high concentrations. The repression of KAPA synthetase by biotin occurred in Bacillus subtilis and B. sphaericus but not in Micrococcus roseus and Pseudomonas fluorescens, even at a concentration of 1000 mµg per ml of biotin. 相似文献
84.
Background
The common grey wolf (Canis lupus) is found throughout the entire Northern hemisphere and preys on many kinds of mammals. The urine of the wolf contains a number of volatile constituents that can potentially be used for predator–prey chemosignalling. Although wolf urine is put to practical use to keep rabbits, rodents, deer and so on at bay, we are unaware of any prior behavioural studies or chemical analyses regarding the fear-inducing impact of wolf urine on laboratory mice.Methodology/Principal Findings
Three wolf urine samples harvested at different times were used in this study. All of them induced stereotypical fear-associated behaviors (i.e., avoidance and freezing) in female mice. The levels of certain urinary volatiles varied widely among the samples. To identify the volatiles that provoked avoidance and freezing, behavioural, chemical, and immunohistochemical analyses were performed. One of the urine samples (sample C) had higher levels of 2,6-dimethylpyrazine (DMP), trimethylpyrazine (TMP), and 3-ethyl-2,5-dimethyl pyrazine (EDMP) compared with the other two urine samples (samples A and B). In addition, sample C induced avoidance and freezing behaviours more effectively than samples A and B. Moreover, only sample C led to pronounced expression of Fos-immunoreactive cells in the accessory olfactory bulb (AOB) of female mice. Freezing behaviour and Fos immunoreactivity were markedly enhanced when the mice were confronted with a mixture of purified DMP, TMP, and EDMP vs. any one pyrazine alone.Conclusions/Significance
The current results suggest that wolf urinary volatiles can engender aversive and fear-related responses in mice. Pyrazine analogues were identified as the predominant active components among these volatiles to induce avoidance and freezing behaviours via stimulation of the murine AOB. 相似文献85.
Izumi Uno Takashi Kozaka Daisuke Miwa Yoji Kitamura Mohammad Anwar-ul Azim Kazuma Ogawa Junichi Taki Seigo Kinuya Kazuhiro Shiba 《PloS one》2016,11(1)
Purpose
To develop a superior VAChT imaging probe for SPECT, radiolabeled (-)-OIDV and (+)-OIDV were isolated and investigated for differences in their binding affinity and selectivity to VAChT, as well as their in vivo activities.Procedures
Radioiodinated o-iodo-trans-decalinvesamicol ([125I]OIDV) has a high binding affinity for vesicular acetylcholine transporter (VAChT) both in vitro and in vivo. Racemic [125I]OIDV was separated into its two optical isomers (-)-[125I]OIDV and (+)-[125I]OIDV by HPLC. To investigate VAChT binding affinity (Ki) of two OIDV isomers, in vitro binding assays were performed. In vivo biodistribution study of each [125I]OIDV isomer in blood, brain regions and major organs of rats was performed at 2,30 and 60 min post-injection. In vivo blocking study were performed to reveal the binding selectivity of two [125I]OIDV isomers to VAChT in vivo. Ex vivo autoradiography were performed to reveal the regional brain distribution of two [125I]OIDV isomers and (-)-[123I]OIDV for SPECT at 60 min postinjection.Results
VAChT binding affinity (Ki) of (-)-[125I]OIDV and (+)-[125I]OIDV was 22.1 nM and 79.0 nM, respectively. At 2 min post-injection, accumulation of (-)-[125I]OIDV was the same as that of (+)-[125I]OIDV. However, (+)-[125I]OIDV clearance from the brain was faster than (-)-[125I]OIDV. At 30 min post-injection, accumulation of (-)-[125I]OIDV (0.62 ± 0.10%ID/g) was higher than (+)-[125I]OIDV (0.46 ± 0.07%ID/g) in the cortex. Inhibition of OIDV binding showed that (-)-[125I]OIDV was selectively accumulated in regions known to express VAChT in the rat brain, and ex vivo autoradiography further confirmed these results showing similar accumulation of (-)-[125I]OIDV in these regions. Furthermore, (-)-[123I]OIDV for SPECT showed the same regional brain distribution as (-)-[125I]OIDV.Conclusion
These results suggest that radioiodinated (-)-OIDV may be a potentially useful tool for studying presynaptic cholinergic neurons in the brain. 相似文献86.
87.
Nakaba Satoshi Arakawa Izumi Morimoto Hikaru Nakada Ryogo Bito Nobumasa Imai Takanori Funada Ryo 《Planta》2016,243(5):1225-1236
Planta - The work demonstrates a relationship between the biosynthesis of the secondary metabolite, agatharesinol, and cytological changes that occur in ray parenchyma during cell death in sapwood... 相似文献
88.
89.
Atrophy or hypofunction of the salivary gland because of aging or disease leads to hyposalivation that affects patient quality of life by causing dry mouth, deterioration of mastication/deglutition, and poor oral hygiene status. Current therapy for atrophy or hypofunction of the salivary gland in clinical practice focuses on symptom relief using drugs and artificial saliva; therefore, there is still a need to develop new therapies. To investigate potential novel therapeutic targets, we induced the differentiation of salivary gland cells by co-culturing human adipose-derived stem cells isolated from buccal fat pads (hBFP-ASCs) with human salivary-gland-derived fibroblasts (hSG-fibros). We examined their potential for transplantation and tissue neogenesis. Following the culture of hBFP-ASCs and hSG-fibros, differentiated cells were transplanted into the submandibular glands of SCID mice, and their degree of differentiation in tissues was determined. We also examined their potential for functional tissue reconstitution using a three-dimensional (3D) culture system. Co-cultured cells expressed salivary-glandrelated markers and generated new tissues following transplantation in vivo. Moreover, cell reconstituted glandular structures in the 3D culture system. In conclusion, coculture of hSG-fibros with hBFP-ASCs led to successful differentiation into salivary gland cells that could be transplanted to generate new tissues. 相似文献
90.
Tomoki Kozawa Kenichiro Sugitani Dorothy Z. Oehler Christopher H. House Izumi Saito Takeshi Watanabe Toshiyuki Gotoh 《Geobiology》2019,17(2):113-126
Lenticular, and commonly flanged, microfossils in 3.0–3.4 Ga sedimentary deposits in Western Australia and South Africa are unusually large (20–80 μm across), robust, and widespread in space and time. To gain insight into the ecology of these organisms, we performed simulations of fluid dynamics of virtual cells mimicking lenticular forms of variable sizes, oblateness, flange presence, and flange thickness. Results demonstrate that (a) the flange reduces sedimentation velocity, (b) this flange function works more effectively in larger cells, and (c) modest oblateness lowers sedimentation rate. These observations support interpretations that the lenticular microbes were planktonic—a lifestyle that could have been advantageous in an early Earth harsh environment including violent volcanic activities, repeated asteroid impacts, and relatively high UV‐radiation. Although the robustness of these organisms could have provided additional protection on the early Earth, this architecture may have impeded a planktonic lifestyle by increasing cell density. However, our data suggest that this disadvantage could have been compensated by enlargement of cell volume, which could have enhanced the ability of the flange to slow sedimentation rate, especially if coupled with vacuolation. The results of this simulation study may help to explain the unique morphology and unusually large size of these Archean microfossils. 相似文献