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81.
Ji-Gweon Park Yong-Ju Park Nozomi Sugama Se-Jae Kim Akihiro Takemura 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2007,193(4):403-411
As the first step in understanding the molecular oscillation of the circa rhythms in the golden rabbitfish Siganus guttatus—a reef fish with a definite lunar-related rhythmicity—we cloned and sequenced a Period gene (rfPer). The rfPer gene contained an open reading frame that encodes a protein consisting of 1,452 amino acids; this protein is highly homologous
to PER proteins of vertebrates including zebrafish. Phylogenetic analyses indicated that the rfPER protein is related to the
zebrafish PER1 and PER4. The expression of rfPer mRNA in the whole brain, retina, and liver under light/dark (LD) conditions increased at 06:00 h and decreased at 18:00 h,
suggesting that its robust circadian rhythm occurs in neural and peripheral tissues. When daily variation in the expression
in rfPer mRNA in the whole brain and cultured pineal gland were examined under LD conditions, similar expression patterns of the gene
were observed with an increase around dawn. Under constant light condition, the increased expression of rfPer mRNA in the whole brain disappeared around dawn. The present results demonstrate that rfPer is related to zPer4 and possibly zPer1. The present study is the first report on the Period gene from a marine fish. 相似文献
82.
Takashima Y Suzuki K Xuan X Nishikawa Y Unno A Kitoh K 《International journal for parasitology》2008,38(5):601-607
Detection of the initial site of Toxoplasma gondii reactivation in brain tissue is difficult because the number of latent cysts is small and reactivation is a transient event. To detect the early stage of reactivation in mouse brain tissue, we constructed a cyst-forming strain of T. gondii in the tachyzoite stage, specifically expressing red fluorescence. The PLK strain of T. gondii was stably transfected with a red fluorescent protein gene, DsRed Express, under the control of a tachyzoite-specific SAG-1 promoter and the resulting parasite was designated as PLK/RED. Tachyzoites of PLK/RED growing in Vero cells showed red fluorescence. When C57BL/6J mice were i.p. infected with tachyzoites of PLK/RED, red fluorescent tachyzoites were detected in their brains at the fourth day p.i. However, red fluorescent tachyzoites were not detected in BALB/c mice latently infected with PLK/RED, although non-fluorescent cysts were detected in their brains. After treatment of latently infected mice with dexamethasone for 1 month, the mice showed neurological symptoms. In mice with symptoms, red fluorescent tachyzoites were again detected in their brains and in other organs. To detect the initial site of reactivation, BALB/c mice latently infected with the strain were treated with dexamethasone for 3 weeks, and brains were excised before any symptoms appeared. Excised brains were examined for red fluorescence-positive sites. By a histological study of red fluorescent-positive sites, we detected a cyst containing red fluorescent zoites, which still had a PAS stain-positive cyst wall. A few red fluorescent zoites breaking away from the cyst were also observed. The stage-specific expression of fluorescent protein facilitates detection of a rare transient event and makes it possible to detect the initial site of reactivation. 相似文献
83.
Combination of hTERT and bmi-1, E6, or E7 induces prolongation of the life span of bone marrow stromal cells from an elderly donor without affecting their neurogenic potential 下载免费PDF全文
Mori T Kiyono T Imabayashi H Takeda Y Tsuchiya K Miyoshi S Makino H Matsumoto K Saito H Ogawa S Sakamoto M Hata J Umezawa A 《Molecular and cellular biology》2005,25(12):5183-5195
Murine bone marrow stromal cells differentiate not only into mesodermal derivatives, such as osteocytes, chondrocytes, adipocytes, skeletal myocytes, and cardiomyocytes, but also into neuroectodermal cells in vitro. Human bone marrow stromal cells are easy to isolate but difficult to study because of their limited life span. To overcome this problem, we attempted to prolong the life span of bone marrow stromal cells and investigated whether bone marrow stromal cells modified with bmi-1, hTERT, E6, and E7 retained their differentiated capability, or multipotency. In this study, we demonstrated that the life span of bone marrow stromal cells derived from a 91-year-old donor could be extended and that the stromal cells with an extended life span differentiated into neuronal cells in vitro. We examined the neuronally differentiated cells morphologically, physiologically, and biologically and compared the gene profiles of undifferentiated and differentiated cells. The neuronally differentiated cells exhibited characteristics similar to those of midbrain neuronal progenitors. Thus, the results of this study support the possible use of autologous-cell graft systems to treat central nervous system diseases in geriatric patients. 相似文献
84.
This study investigated the respiratory properties and the role of the mitochondria isolated from one phosphoenolpyruvate carboxykinase (PCK)-CAM plant, Hoya carnosa, in malate metabolism during CAM phase III. The mitochondria showed high malate dehydrogenase (mMDH) and aspartate amino transferase (mAST), and a significant amount of malic enzyme (mME) activities. H. carnosa readily oxidized malate via mME and mMDH in the presence of some cofactors such as thiamine pyrophosphate (TPP), coenzyme A (CoA) or NAD(+). A high respiration rate of malate oxidation was observed at pH 7.2 with NAD(+) and glutamate (Glu). Providing AST and Glu simultaneously into the respiratory medium strongly increased the rates of malate oxidation, and this oxidation was gradually inhibited by an inhibitor of alpha-ketoglutarate (alpha-KG) carrier, pyridoxal-5'-phosphate (PLP). The mitochondria readily oxidized aspartate (Asp) or alpha-KG individually with low rates, while they oxidized Asp and alpha-KG simultaneously with high rates, and this simultaneous oxidation was also inhibited by PLP. By measuring the capacity of the mitochondrial shuttle, it was found that the OAA produced via mMDH seemed not to be transported outside the mitochondria, but mAST interconverted OAA and Glu to Asp and alpha-KG, respectively, and exported them out via a malate-aspartate (malate-Asp) shuttle. The data in this research suggest that during phase III of PCK-CAM, H. carnosa mitochondria oxidized malate via both mME and the mMDH systems depending on metabolic requirements. However, malate metabolism by the mMDH system did not operate via a malate-OAA shuttle similarly to Ananas comosus mitochondria, but it operated via a malate-Asp shuttle similarly to Kalancho? daigremontiana mitochondria. 相似文献
85.
86.
Akihiro Inagaki Soichiro Yamaguchi Hiromi Takahashi-Iwanaga Toshihiko Iwanaga Toru Ishikawa 《The Journal of membrane biology》2010,235(1):27-41
ClC-2, a member of the voltage-gated Cl− channel family, is expressed in the distal colonic surface epithelial cells of various species, but its functional significance
remains unclear. Here, by means of electrophysiological and molecular biological techniques, we have identified and characterized
a ClC-2-like conductance naturally expressed by surface epithelial cells acutely dissociated from rectal colon of rats fed
a standard diet. Whole-cell patch-clamp experiments showed that the surface cells, whether an amiloride-sensitive Na+ conductance was present or not, displayed a strong hyperpolarization-activated, inwardly rectifying Cl− current. Analysis both by in situ hybridization and immunohistochemistry confirmed the expression of ClC-2 in the rectal
surface epithelium. The native Cl− current shared common electrophysiological properties including voltage-dependent activation, anion selectivity sequence,
and Zn2+ sensitivity with that recorded from HEK293 cells transfected with ClC-2 cloned from rat rectal colon (rClC-2). Cell-attached
patch recordings on the surface cells revealed that native ClC-2-like currents activated only at potentials at least 40 mV
more negative than resting membrane potentials. In Ussing chamber experiments with rat rectal mucosa, either basolateral or
apical application of Zn2+ (0.1 mM), which inhibited both native ClC-2-like currents and recombinant rClC-2 currents, had little, if any, effects on
basal amiloride-sensitive short-circuit current. Collectively, these results not only demonstrate that a functional ClC-2-type
Cl− channel is expressed in rat rectal surface epithelium, but also suggest that the channel activity may be negligible and thus
nonessential for controlling electrogenic Na+ transport in this surface epithelium under basal physiological conditions. 相似文献
87.
Hirokazu Sakan Kimihiko Nakatani Osamu Asai Akihiro Imura Tomohiro Tanaka Shuhei Yoshimoto Noriyuki Iwamoto Norio Kurumatani Masayuki Iwano Yo-ichi Nabeshima Noboru Konishi Yoshihiko Saito 《PloS one》2014,9(1)
Renal α-Klotho (α-KL) plays a fundamental role as a co-receptor for fibroblast growth factor 23 (FGF23), a phosphaturic hormone and regulator of 1,25(OH)2 vitamin D3 (1,25VitD3). Disruption of FGF23-α-KL signaling is thought to be an early hallmark of chronic kidney disease (CKD) involving reduced renal α-KL expression and a reciprocal rise in serum FGF23. It remains unclear, however, whether the rise in FGF23 is related to the loss of renal α-KL. We evaluated α-KL expression in renal biopsy samples and measured levels of several parameters of mineral metabolism, as well as soluble α-KL (sKL), in serum and urinary samples from CKD patients (n = 236). We found that although renal α-KL levels were significantly reduced and serum FGF23 levels were significantly elevated in early and intermediate CKD, serum phosphate levels remained within the normal range. Multiple regression analysis showed that the increases in FGF23 were significantly associated with reduced renal function and elevated serum phosphate, but were not associated with loss of renal α-KL. Moreover, despite falling renal α-KL levels, the increase in FGF23 enhanced urinary fractional excretion of phosphate and reduced serum 1,25VitD3 levels in early and intermediate CKD, though not in advanced CKD. Serum sKL levels also fell significantly over the course of CKD, and renal α-KL was a significant independent determinant of sKL. These results demonstrate that FGF23 levels rise to compensate for renal failure-related phosphate retention in early and intermediate CKD. This enables FGF23-α-KL signaling and a neutral phosphate balance to be maintained despite the reduction in α-KL. In advanced CKD, however, renal α-KL declines further. This disrupts FGF23 signaling, and serum phosphate levels significantly increase, stimulating greater FGF23 secretion. Our results also suggest the serum sKL concentration may be a useful marker of renal α-KL expression levels. 相似文献
88.
89.
The orotidine-5′-phosphate decarboxylase gene of Saccharomyces exiguus Yp74L-3 was cloned as a DNA fragment complementing a ura4 mutation of this yeast. The coding region of the gene is 807 bp in length, and represents 68.7% similarity to the corresponding
gene of S. cerevisiae (URA3). The cloned URA4 gene was shown to be located on the 790-kbp Chromosome (chr) VIII of S. exiguus Yp74L-3. The neighbor-joining phylogenetic tree based on the orotidine-5′-phosphate decarboxylase coding sequences indicates
that S. exiguus Yp74L-3 is closely related to Kluyveromyces yeasts, as well as to a S. cerevisiae laboratory strain.
Received: 4 February 2000 / Accepted: 3 July 2000 相似文献