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排序方式: 共有843条查询结果,搜索用时 15 毫秒
1.
Yutaro Yamagata Yukiko Muramoto Sho Miyamoto Keiko Shindo Masahiro Nakano Takeshi Noda 《Microbiology and immunology》2019,63(5):164-171
Defective interfering (DI) influenza viruses carry a large deletion in a gene segment that interferes with the replication of infectious virus; thus, such viruses have potential for antiviral therapy. However, because DI viruses cannot replicate autonomously without the aid of an infectious helper virus, clonal DI virus stocks that are not contaminated with helper virus have not yet been generated. To overcome this problem, we used reverse genetics to generate a clonal DI virus with a PB2 DI gene, amplified the clonal DI virus using a cell line stably expressing the PB2 protein, and confirmed its ability to interfere with infectious virus replication in vitro. Thus, our approach is suitable for obtaining purely clonal DI viruses, will contribute to the understanding of DI virus interference mechanisms and can be used to develop DI virus‐based antivirals. 相似文献
2.
The gallbladder bile acid composition and the activity of the hepatic steroid 12 alpha-hydroxylase were determined in male and female hamsters. Cholic acid, chenodeoxycholic acid, and deoxycholic acid were the major bile acids in both sexes; in addition, 7-ketodeoxycholic acid and lithocholic acid were present. A sex-linked difference in the ratio of cholic acid (plus its metabolites) to chenodeoxycholic acid (plus its metabolite) was observed. The ratio was 1.93 +/- 0.39 in males and 2.74 +/- 0.54 in females. Another sex-linked difference was found in the activity of the 12 alpha-hydroxylase. The extent of the 12 alpha-hydroxylation of 7 alpha-hydroxycholest-4-en-3-one to yield 7 alpha, 12 alpha-dihydroxycholest-4-en-3-one was about two times greater in the microsomal suspension obtained from the liver of female hamsters than in that of male hamsters. A positive correlation between the 12 alpha-hydroxylase activity and the ratio of cholic acid/chenodeoxycholic acid was also observed. These results strongly support the proposal that the activity of the 12 alpha-hydroxylase is the major factor in determining the relative proportion of cholic acid and chenodeoxycholic acid formed from cholesterol in the liver. 相似文献
3.
4.
Mitsuru Iwata Shoko Iwata Mark A. Everett Bryan B. Fuller 《In vitro cellular & developmental biology. Plant》1990,26(6):554-560
Summary A human foreskin organ culture system has been developed to study the response of human skin to hormonal stimulation. Foreskins
are maintained in culture on floating plastic supports which allows the epidermal surface to be exposed to air while the dermis
is bathed in nutrient medium. Both black and white human foreskins can be maintained in organ culture for at least 1 wk with
no change in the tissue structure or cell viability as determined by histochemical staining and by dopa reaction staining.
Tyrosinase activity in both black and white human foreskin cultures decays markedly during the first 2 d of culture to a new
steady state level which remains stable throughout the culture period. Both black and white foreskin cultures consistently
demonstrate 2- to 10-fold increases in tyrosinase activity when treated with theophylline (1 mM). Approximately 90% of all skin cultures examined showed an increase in enzyme activity when treated with this phosphodiesterase
inhibitor. Dibutyryl cAMP (0.1 mM) and [Nle4, D-phe7]-alpha MSH (10−8
M), were also found to markedly stimulate tyrosinase activity in some skin cultures, whereas alpha-MSH and prostaglandin E1 produced only an inconsistent and small increase in the activity of the enzyme. Histamine (1 μM), vitamin D3 (1 μM), and retinoic acid (1μM) failed to stimulate tyrosinase activity in either white or black foreskin cultures. This hormone-responsive organ culture
system can be utilized to characterize the molecular processes responsible for the regulation of tyrosinase and pigmentation
in human skin.
This work was supported by a research contract from the Oklahoma Center for the Advancement of Science and Technology (OCAST)
and by a research grant from the Presbyterian Health Foundation. 相似文献
5.
Shoko Fujiwara Mitsuhiro Sawada Junichiro Someya Nobuhiro Minaka Masanobu Kawachi Isao Inouye 《Journal of phycology》1994,30(5):863-871
The nucleotide sequences of rbcL genes encoding the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) were determined from six species of Prymnesiophyta to clarify their phylogenetic relationships. Molecular phylogenetic trees were constructed using PAUP (Phylogenetic Analysis Using Parsimony). These analyses suggest that the Prymnesiophyta, except for the Pavlovales, area relatively stable monophyletic group. Pleurochrysis carterae, included in the Isochrysidales, is a sister species of a monophyletic group consisting of other members of the Isochrysidales, Gephyrocapsa oceanica and Emiliania huxleyi, members of the Coccosphaerales, Calyptrosphaera sphaeroidea and Umbilicosphaera sibogae var. foliosa, and a member of the Prymnesiales, Chrysochromulina hirta. The nucleotide sequence of rbcL from G. oceanica was identical to that from E. huxleyi within the region examined. Our trees show that G. oceanica and E. huxleyi are more closely related to C. hirta than to U. sibogae, C. sphaeroidea, and P. carterae. These results suggest that orders in the Prymnesiophyceae, including the above-mentioned genera, should be redefined. 相似文献
6.
Kumiko Ui Shoko Nishihara M. Sakuma S. Togashi R. Ueda Y. Miyata T. Miyake 《In vitro cellular & developmental biology. Animal》1994,30(4):209-216
Summary From the central nervous system ofDrosophila melanogaster 3rd instar larvae, eight continuous cell lines have been established (named ML-DmBG1 to 8). Using ML-DmBG2, single colony
isolation was carried out and six colonial clones were obtained. All reacted to the antibody to horseradish peroxidase, which
is a neuronal marker in insects. Acetylcholine, a known neurotransmitter inDrosophila, was detected in three of the colonial clones by high performance liquid chromatography. Therefore, it is concluded that
the established colonial clones are neural cells originating in the larval central nervous system. Among them, some variation
was observed with respect to morphology, acetylcholine content, and reactivity to anti-HRP. The variation may reflect the
heterogeneity of cells composing the central nervous system. 相似文献
7.
8.
H Kawauchi M Tubokawa K Muramoto 《Biochemical and biophysical research communications》1979,88(4):1249-1254
Endorphin has been isolated from an acid acetone extract of the pituitary of the salmon by ion exchange chromatography and gel filtration. Sequence analysis revealed it to be a nonacosapeptide with following primary structure: Ac-Tyr-Gly-Gly-Phe-Met-Lys-Pro-Tyr-Thr-Lys-Gln-Ser-His-Lys-Pro-Leu-Ile-Thr-Leu-Leu-Lys-His- Ile-Thr-Leu-Lys-Asn-Glu-Gln-OH. It appears that the amino terminal segment which is necessary for analgesic activity is conserved through the evolution of vertebrate except for the blocking of the amino terminal of salmon endorphin. 相似文献
9.
10.
Shoko Nakano Yuko Abe Kimiko Nakajima Shigetoshi Sano Osamu Yamamoto Kazumasa Wakamatsu Shosuke Ito Masahiro Hayashi Tamio Suzuki 《Pigment cell & melanoma research》2021,34(1):101-110
Post‐inflammatory hyperpigmentation (PIH) is a common cutaneous condition that can cause a disfigured appearance. However, the pathophysiology of PIH remains poorly understood, at least in part, because an appropriate animal model for research has not been established. In order to analyze the pathomechanism of PIH, we successfully induced PIH in a hairless version of transgenic mice (hk14‐SCF Tg/HRM) that have a human‐type epidermis containing melanin by repeated hapten application of 2,4‐dinitrofluorobenzene. Histopathologic observation showed epidermal hyperplasia, predominant infiltrations of inflammatory cells, and melanin‐containing cells in the dermis just after elicitation of the atopic dermatitis‐like condition. At week 2, the findings were similar to the characteristics of PIH, that is, an increase of melanin without spongiosis or liquid degeneration in the epidermis and an increase in dermal melanophages. Dynamic analysis of melanin showed that the melanin in the dermis remained for a longer duration than in the epidermis. Furthermore, immunohistochemical staining revealed that the majority of cells containing melanin were positive for the anti‐CD68 antibody, but negative for the anti‐F4/80 antibody. These data suggest that novel treatments of PIH should be targeted against macrophages and should eventually lead to the development of new treatment modalities. 相似文献