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41.
Deletion mapping and heterogenote analysis of a mutation responsible for osmosis-sensitive growth, spectinomycin resistance, and alteration of cytoplasmic membrane in Escherichia coli 总被引:6,自引:4,他引:2 下载免费PDF全文
Lambda transducing phages carrying Escherichia coli deoxyribonucleic acid of various lengths from the aroE-rpsL region were lysogenized into the F'3 plasmid and were used for heterogenote analysis of YM101, a sucrose-dependent, spectinomycin-resistant mutant of E. coli. Three characteristics of the mutant strain, resistance to spectinomycin, sucrose dependence of growth, and lack of I-19 protein in the cytoplasmic membrane, were shown to be the result of a mutation in a region designated delta 53-spcl. This region extends over 3.6-kilobase pairs and is located within a cluster of ribosomal genes. The mutation is recessive to the wild-type allele. 相似文献
42.
Influence of molecular size and osmolarity of sugars and dextrans on the synthesis of outer membrane proteins O-8 and O-9 of Escherichia coli K-12. 总被引:43,自引:30,他引:13 下载免费PDF全文
Supplementation of the growth medium with high concentrations of sugars or low-molecular-weight dextrans results in a drastic change in the ratio of outer membrane proteins O-8 and O-9, due to induction of O-8 synthesis and suppression of O-9 synthesis. Sugars and dextrans of molecular weights greater than 600 to 700 switched the synthesis of O-9 to that of O-8 more effectively than those of lower molecular weight, although the effect was almost the same within each of the two groups irrespective of the differences in molecular weight within the group. Proteins O-8 or O-9, or both, are responsible for the formation of pores that allow the passive diffusion of hydrophilic molecules whose molecular weights are smaller than about 600 (T. Nakae, Biochem. Biophys. Res. Commun. 71:877-884, 1976). The results indicate that substances that cannot pass through the outer membrane switch the synthesis of O-9 to that of O-8 more effectively than those that can penetrate this membrane with the aid of O-8, O-9, or both. It is suggested that the osmotic pressure exerted on the outer membrane plays an important role in the regulation of synthesis of the two proteins. 相似文献
43.
Five triterpenoid saponins isolated from the flowers, the mature fruits and the leaves of Fatsia japonica were identified as 3-O-[β-d-glucopyranosyl(1→4)-β-d-glucopyranosyl]-hederagenin (1), 3-O-[β-d-glucopyranosyl-(1→4)-α-l-arabinopyranosyl]-oleanolic acid (2), 3-O-[α-l-arabinopyranosyl]-hederagenin (3), 3-O-[β-d-glucopyranosyl]-hederagenin (4) and 3-O-[β-d-glucopyranosyl(1→4)-α-l-arabinopyranosyl]-hederagenin (5). The saponins 1 and 2 are new, naturally occurring, triterpenoid saponins. The distribution of the five saponins in three parts of the plant was investigated. Saponins 2, 3 and 5 were present in the flowers, saponins 1, 3, 4 and 5 were in the mature fruits and saponins 2, 3, 4 and 5 were in the leaves. 相似文献
44.
Yumiko Oshima Etienne Cartier Liron Boyman Nicolas Verhoeven Brian M. Polster Weiliang Huang Maureen Kane W. Jonathan Lederer Mariusz Karbowski 《The Journal of cell biology》2021,220(6)
Here, we report that acute reduction in mitochondrial translation fidelity (MTF) causes ubiquitination of the inner mitochondrial membrane (IMM) proteins, including TRAP1 and CPOX, which occurs selectively in mitochondria with a severed outer mitochondrial membrane (OMM). Ubiquitinated IMM recruits the autophagy machinery. Inhibiting autophagy leads to increased accumulation of mitochondria with severed OMM and ubiquitinated IMM. This process occurs downstream of the accumulation of cytochrome c/CPOX in a subset of mitochondria heterogeneously distributed throughout the cell (“mosaic distribution”). Formation of mosaic mitochondria, OMM severing, and IMM ubiquitination require active mitochondrial translation and mitochondrial fission, but not the proapoptotic proteins Bax and Bak. In contrast, in Parkin-overexpressing cells, MTF reduction does not lead to the severing of the OMM or IMM ubiquitination, but it does induce Drp1-independent ubiquitination of the OMM. Furthermore, high–cytochrome c/CPOX mitochondria are preferentially targeted by Parkin, indicating that in the context of reduced MTF, they are mitophagy intermediates regardless of Parkin expression. In sum, Parkin-deficient cells adapt to mitochondrial proteotoxicity through a Drp1-mediated mechanism that involves the severing of the OMM and autophagy targeting ubiquitinated IMM proteins. 相似文献
45.
Takahashi Yumiko Sarkar Juli Yamada Jumpei Matsunaga Yutaka Nonaka Yudai Banjo Mai Sakaguchi Ryo Shinya Terunaga Hatta Hideo 《Journal of physiology and biochemistry》2021,77(3):469-480
Journal of Physiology and Biochemistry - To identify factors that influence post-exercise muscle glycogen repletion, we compared the glycogen recovery after level running with downhill running, an... 相似文献
46.
Hiroshi Shiragami Yasuhiro Tanaka Yumiko Uchida Hisao Iwagami Kunisuke Izawa Toshihide Yukawa 《Nucleosides, nucleotides & nucleic acids》2013,32(2-4):391-400
Abstract Regioselective 2′-O-deacetylation of 9-(2,5-di-O-acetyl-3-bromo-3-deoxy-β-D-xylofuranosyl)adenine (1) is achieved by treatment of 1 with β-cyclodextrin (β-CyD) / aq. NaHCO3 or N2H4·H2O / EtOH. The 9-(5-O-Acetyl-3-bromo-3-deoxy-β-D-xylo-furanosyl)adenine (2) obtained is a common intermediate for the synthesis of 2′,3′-dideoxy-adenosine (ddA) (7) and 9-(2-fluoro-2,3-dideoxy-β-D-threo-pentofuranosyl)-adenine (F-ddA) (9). 相似文献
47.
Yumiko Kirihara Mayumi Takechi Kaoru Kurosaki Yuta Kobayashi Tsutomu Kurosawa 《Experimental Animals》2013,62(3):173-180
The combination of ketamine and xylazine is a widely used anesthetic for laboratory
animals. However, due to an abuse problem in Japan, ketamine has been specified as a
narcotic since 2007. Instead of using ketamine, Kawai et al. reported an
injectable formula with an equivalent effect to the mixture of ketamine and xylazine
[11]. The mixture of 0.3 mg/kg body weight (b.w.)
medetomidine (Med.), 4.0 mg/kg b.w. midazoram (Mid.), and 5.0 mg/kg b.w. butorphanol
(But.) produced an anesthetic duration of around 40 min in outbred ICR mice. However, the
anesthetic effect of the mixture for inbred mice strains remains unknown. Therefore, we
examined anesthetic effects of the mixture of Med., Mid., and But. in the BALB/c and
C57BL/6J strains. After intraperitoneal injection into mice, right front paw, left hind
paw, and tail pinch reflexes as well as corneal and righting reflexes were observed. Every
5 min, we scored each reflex category as 0 for reaction or 1 for no reaction. As long as
the total score was at least 4 out of 5, we considered the mixture as putting a mouse in a
surgical anesthetic state. The mixture produced an anesthetic duration of more than 45 min
in both strains of mice. These results indicate that the mixture of Med., Mid., and But.
can be a useful and effective anesthesia for the BALB/c and C57BL/6J strains of inbred
mice as well as outbred ICR mice. 相似文献
48.
Michiaki Yamashita Yumiko Yamashita Tamami Suzuki Yoko Kani Nanami Mizusawa Shintaro Imamura Kenji Takemoto Tatsuro Hara Md. Anwar Hossain Takeshi Yabu Ken Touhata 《Marine biotechnology (New York, N.Y.)》2013,15(5):559-570
The selenium (Se)-containing antioxidant selenoneine (2-selenyl-N α,N α,N α-trimethyl-l-histidine) has recently been discovered to be the predominant form of organic Se in tuna blood. Although dietary intake of fish Se has been suggested to reduce methylmercury (MeHg) toxicity, the molecular mechanism of MeHg detoxification by Se has not yet been determined. Here, we report evidence that selenoneine accelerates the excretion and demethylation of MeHg, mediated by a selenoneine-specific transporter, organic cations/carnitine transporter-1 (OCTN1). Selenoneine was incorporated into human embryonic kidney HEK293 cells transiently overexpressing OCTN1 and zebrafish blood cells by OCTN1. The K m for selenoneine uptake was 13.0 μM in OCTN1-overexpressing HEK293 cells and 9.5 μM in zebrafish blood cells, indicating high affinity of OCTN1 for selenoneine in human and zebrafish cells. When such OCTN1-expressing cells and embryos were exposed to MeHg–cysteine (MeHgCys), MeHg accumulation was decreased and the excretion and demethylation of MeHg were enhanced by selenoneine. In addition, exosomal secretion vesicles were detected in the culture water of embryos that had been microinjected with MeHgCys, suggesting that these may be responsible for MeHg excretion and demethylation. In contrast, OCTN1-deficient embryos accumulated MeHg, and MeHg excretion and demethylation were decreased. Furthermore, Hg accumulation was decreased in OCTN1-overexpressing HEK293 cells, but not in mock vector-transfected cells, indicating that selenoneine and OCTN1 can regulate MeHg detoxification in human cells. Thus, the selenoneine-mediated OCTN1 system regulates secretory lysosomal vesicle formation and MeHg demethylation. 相似文献
49.
Amanda P. Woon Abolghasem Tohidpour Hernan Alonso Yumiko Saijo-Hamano Terry Kwok Anna Roujeinikova 《PloS one》2013,8(11)
The CagA protein of Helicobacter pylori is associated with increased virulence and gastric cancer risk. CagA is translocated into the host cell by a H. pylori type IV secretion system via mechanisms that are poorly understood. Translocated CagA interacts with numerous host factors, altering a variety of host signalling pathways. The recently determined crystal structure of C-terminally-truncated CagA indicated the presence of two domains: the smaller, flexible N-terminal domain and the larger, middle domain. In this study, we have investigated the conformation, oligomeric state and stability of the N-terminal, middle and glutamate-proline-isoleucine-tyrosine-alanine (EPIYA)-repeats domains. All three domains are monomeric, suggesting that the multimerisation of CagA observed in infected cells is likely to be mediated not by CagA itself but by its interacting partners. The middle and the C-terminal domains, but not the N-terminal domain, are capable of refolding spontaneously upon heat denaturation, lending support to the hypothesis that unfolded CagA is threaded C-terminus first through the type IV secretion channel with its N-terminal domain, which likely requires interactions with other domains to refold, being threaded last. Our findings also revealed that the C-terminal EPIYA-repeats domain of CagA exists in an intrinsically disordered premolten globule state with regions in PPII conformation - a feature that is shared by many scaffold proteins that bind multiple protein components of signalling pathways. Taken together, these results provide a deeper understanding of the physicochemical properties of CagA that underpin its complex cellular and oncogenic functions. 相似文献
50.
Shinsuke Mikami Ayumu Nakashima Keigo Nakagawa Tatsuya Maruhashi Yumiko Iwamoto Masato Kajikawa Takeshi Matsumoto Yasuki Kihara Kazuaki Chayama Kensuke Noma Mitsuo Ochi Masahiro Nishimura Koichiro Tsuji Yukio Kato Chikara Goto Yukihito Higashi 《PloS one》2013,8(7)