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941.
Hironori Uehara Yuji Kunitomi Atsushi Ikai Toshiya Osada 《Journal of nanobiotechnology》2007,5(1):7-6
Background
The localization of specific mRNA generates cell polarity by controlling the translation sites of specific proteins. Although most of these events depend on differences in gene expression, no method is available to examine time dependent gene expression of individual living cells. In situ hybridization (ISH) is a powerful and useful method for detecting the localization of mRNAs, but it does not allow a time dependent analysis of mRNA expression in single living cells because the cells have to be fixed for mRNA detection. To overcome these issues, the extraction of biomolecules such as mRNAs, proteins, and lipids from living cells should be performed without severe damage to the cells. In previous studies, we have reported a single cell nanoprobe (SCN) method to examine gene expression of individual living cells using atomic force microscopy (AFM) without killing the cells. 相似文献942.
Kobayashi M Ohashi S Iwamoto K Shiraiwa Y Kato Y Watanabe T 《Biochimica et biophysica acta》2007,1767(6):596-602
Chlorophyll (Chl) d is a major chlorophyll in a novel oxygenic prokaryote Acaryochloris marina. Here we first report the redox potential of Chl d in vitro. The oxidation potential of Chl d was +0.88 V vs. SHE in acetonitrile; the value was higher than that of Chl a (+0.81 V) and lower than that of Chl b (+0.94 V). The oxidation potential order, Chl b>Chl d>Chl a, can be explained by inductive effect of substituent groups on the conjugated pi-electron system on the macrocycle. Corresponding pheophytins showed the same order; Phe b (+1.25 V)>Phe d (+1.21 V)>Phe a (+1.14 V), but the values were significantly higher than those of Chls, which are rationalized in terms of an electron density decrease in the pi-system by the replacement of magnesium with more electronegative hydrogen. Consequently, oxidation potential of Chl a was found to be the lowest among Chls and Phes. The results will help us to broaden our views on photosystems in A. marina. 相似文献
943.
Fuyu Kobirumaki-Shimozawa Togo Shimozawa Kotaro Oyama Shunsuke Baba Jia Li Tomohiro Nakanishi Takako Terui William E. Louch Shinichi Ishiwata Norio Fukuda 《The Journal of general physiology》2021,153(11)
Sarcomeric contraction in cardiomyocytes serves as the basis for the heart’s pump functions. It has generally been considered that in cardiac muscle as well as in skeletal muscle, sarcomeres equally contribute to myofibrillar dynamics in myocytes at varying loads by producing similar levels of active and passive force. In the present study, we expressed α-actinin–AcGFP in Z-disks to analyze dynamic behaviors of sequentially connected individual sarcomeres along a myofibril in a left ventricular (LV) myocyte of the in vivo beating mouse heart. To quantify the magnitude of the contribution of individual sarcomeres to myofibrillar dynamics, we introduced the novel parameter “contribution index” (CI) to measure the synchrony in movements between a sarcomere and a myofibril (from −1 [complete asynchrony] to 1 [complete synchrony]). First, CI varied markedly between sarcomeres, with an average value of ∼0.3 during normal systole. Second, when the movements between adjacent sarcomeres were asynchronous (CI < 0), a sarcomere and the ones next to the adjacent sarcomeres and farther away moved in synchrony (CI > 0) along a myofibril. Third, when difference in LV pressure in diastole and systole (ΔLVP) was lowered to <10 mm Hg, diastolic sarcomere length increased. Under depressed conditions, the movements between adjacent sarcomeres were in marked asynchrony (CI, −0.3 to −0.4), and, as a result, average CI was linearly decreased in association with a decrease in ΔLVP. These findings suggest that in the left ventricle of the in vivo beating mouse heart, (1) sarcomeres heterogeneously contribute to myofibrillar dynamics due to an imbalance of active and passive force between neighboring sarcomeres, (2) the force imbalance is pronounced under depressed conditions coupled with a marked increase in passive force and the ensuing tug-of-war between sarcomeres, and (3) sarcomere synchrony via the distal intersarcomere interaction regulates the heart''s pump function in coordination with myofibrillar contractility. 相似文献
944.
Hiroyuki Uehara Bok Du Choi Enoch Y. Park Mitsuyasu Okabe 《Biotechnology and Bioprocess Engineering》2000,5(1):7-12
The expression of the mouse α-amylase gene in the methylotrophic yeast,P. pastoris was investigated. The mouse α-amylase gene was inserted into the multi-cloning site of a Pichia expression vector, pPIC9,
yielding a new expression vector pME624. The plasmid pME624 was digested withSalI orBglII, and was introduced intoP. pastoris strain GS115 by the PEG1000 method. Fifty-three transformants were obtained by the transplacement of pME624 digested withSalI orBglII into theHIS
4 locus (38 of Mut+ clone) or into theAOX1 locus (45 of Muts clone). Southern blot was carried out in 11 transformants, which showed that the mouse α-amylase gene was integrated into
thePichia chromosome. When the second screening was performed in shaker culture, transformant G2 showed the highest α-amylase activity,
290 units/ml after 3-day culture, among 53 transformants. When this expression level of the mouse α-amylase gene is compared
with that in recombinantSaccharomyces cerevisiae harboring a plasmid encoding the same mouse α-amylase gene, the specific enzyme activity is eight fold higher than that of
the recombinantS. cerevisiae. 相似文献
945.
Keiji Uehara Toshimasa Harumoto Asana Makino Yasuo Koda Junko Iwano Yasuhiro Suzuki Mari Tanigawa Hiroto Iwai Kana Asano Kana Kurihara Akinori Hamaguchi Hiroshi Kodaira Toshiyuki Atsumi Yoji Yamada Kazuma Tomizuka 《Nucleic acids research》2022,50(9):4840
Extrahepatic delivery of small interfering RNAs (siRNAs) may have applications in the development of novel therapeutic approaches. However, reports on such approaches are limited, and the scarcity of reports concerning the systemically targeted delivery of siRNAs with effective gene silencing activity presents a challenge. We herein report for the first time the targeted delivery of CD206-targetable chemically modified mannose–siRNA (CMM–siRNA) conjugates to macrophages and dendritic cells (DCs). CMM–siRNA exhibited a strong binding ability to CD206 and selectively delivered contents to CD206-expressing macrophages and DCs. Furthermore, the conjugates demonstrated strong gene silencing ability with long-lasting effects and protein downregulation in CD206-expressing cells in vivo. These findings could broaden the use of siRNA technology, provide additional therapeutic opportunities, and establish a basis for further innovative approaches for the targeted delivery of siRNAs to not only macrophages and DCs but also other cell types. 相似文献
946.
947.
Abstract : It is well known that caspases are produced as proforms, which are proteolytically cleaved and activated during apoptosis or programmed cell death. We report here that caspases are activated during apoptosis by treatment with NOC18, a nitric oxide (NO) donor. Our present experiments have examined the way in which NO induces neuronal cell death, using a new type of NO donor that spontaneously releases only NO without enzymatic metabolism. NOC18 induced apoptosis in human neuroblastoma SH-SY5Y cells in a concentration-and time-dependent manner as estimated by DNA fragmentation assay, FACScan analysis, and nuclear morphology. Oxyhemoglobin, an NO trapper, suppressed NOC18-triggered DNA fragmentation, indicating that NO from NOC18 is a real activator in this study. Upon the induction of apoptosis, an increase in caspase-3-like protease activity, but not caspase-1, was observed. Procaspase-2 protein, an inactive form of caspase-2, decreased dramatically. In addition, NOC18 also resulted in poly (ADP-ribose) polymerase (PARP) cleavage, yielding an 85-kDa fragment typical of caspase activity. Oxyhemoglobin blocked the decrease of procaspase-2 and the cleavage of PARP by NOC18 in a concentration-dependent manner. Moreover, NO elicited the release of cytochrome c into the cytosol during apoptosis. These results suggest that both stimulation of caspase activity and cytochrome c release are partly involved in NO-induced neuronal apoptosis. 相似文献
948.
Enhancement of the photodynamic antitumor effect by streptococcal preparation OK-432 in the mouse carcinoma 总被引:3,自引:0,他引:3
Uehara M Sano K Wang ZL Sekine J Ikeda H Inokuchi T 《Cancer immunology, immunotherapy : CII》2000,49(8):401-409
Biological response modifier antitumor effects are enhanced by the activation of the host defense mechanisms. We have investigated
the antitumor effect of photodynamic therapy (PDT) and/or local administration of a biological response modifier, the streptococcal
preparation OK-432, on transplanted NR-S1 mouse squamous cell carcinoma. Hematoporphyrin oligomers (20 mg/kg body weight)
were used to photosensitize PDT. A pulsed Nd:YAG dye laser, tuned at 630 nm, was used as the light source. The laser power
was 15 mJ cm−2 pulse−1, and the irradiation time was 40 min. The photosensitizer was injected intraperitoneally 48 h before laser irradiation. Where
used, OK-432 was injected into the tumor either 3 h prior to PDT or immediately afterwards. The antitumor effects were evaluated
48 h after each protocol by (a) estimating the area of tumor necrosis (%) in hematoxylin/eosin-stained specimens, and (b)
bromodeoxyuridine immunohistochemistry. Furthermore, the tumor sizes were evaluated 3, 7 and 10 days after each protocol,
and the survival time after each protocol was evaluated as well. The anti-tumor effect of PDT was enhanced by administration
of OK-432 3 h before PDT, whereas the administration of OK-432 immediately after PDT did not potentiate a PDT antitumor effect.
Treatment with OK-432 alone had little effect on tumors. Photodynamic therapy in combination with local administration of
OK-432 3 h before PDT is considered to be a useful treatment modality.
Received: 23 July 1999 / Accepted: 31 May 2000 相似文献
949.
950.