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11.
Fourier transform infrared difference spectra upon single reduction of the secondary quinone electron acceptor Q(B) in photosystem II (PSII), without a contribution from the electron donor-side signals, were obtained for the first time using Mn-depleted PSII core complexes of the thermophilic cyanobacterium Thermosynechococcus elongatus. The Q(B)(-)/Q(B) difference spectrum exhibited a strong C...O stretching band of the semiquinone anion at 1480 cm(-)(1), the frequency higher by 2 cm(-)(1) than that of the corresponding band of Q(A)(-), in agreement with the previous S(2)Q(B)(-)/S(1)Q(B) spectrum of the PSII membranes of spinach [Zhang, H., Fischer, G., and Wydrzynski, T. (1998) Biochemistry 37, 5511-5517]. Also, several peaks originating from the Fermi resonance of coupled His modes with its strongly H-bonded NH vibration were observed in the 2900-2600 cm(-)(1) region, where the peak frequencies were higher by 7-24 cm(-)(1) compared with those of the Q(A)(-)/Q(A) spectrum. These frequency differences suggest that H-bond interactions of the CO groups, especially with a His side chain, are different between Q(B)(-) and Q(A)(-). Furthermore, a prominent positive peak was observed at 1745 cm(-)(1) in the C=O stretching region of COOH or ester groups in the Q(B)(-)/Q(B) spectrum. The peak frequency was unaffected by D(2)O substitution, indicating that this peak does not arise from a COOH group but probably from the 10a-ester C=O group of the pheophytin molecule adjacent to Q(B). The absence of protonation of carboxylic amino acids upon Q(B)(-) formation in contrast to the previous observation in the purple bacterium Rhodobacter sphaeroides suggests that the protonation mechanism of Q(B) in PSII is different from that of bacterial reaction centers. 相似文献
12.
Masa-aki Ohto Koji Hayashi Minoru Isobe Kenzo Nakamura 《The Plant journal : for cell and molecular biology》1995,7(2):297-307
Genes coding for sporamin and β-amylase of sweet potato are inducible not only by high levels of metabolizable sugars, such as sucrose, but also by a low concentration of polygalacturonic acid (PGA). Calmodulin inhibitors and EGTA inhibited both the PGA-inducible and the sucrose-inducible accumulation of mRNAs for sporamin and β-amylase in sweet potato. Calmodulin inhibitors, EGTA and La3+, also inhibited the sucrose-inducible expression, in leaves of transgenic tobacco, of a fusion gene, β-Amy:GUS, which consists of the promoter of the β-amylase gene and the coding sequence for β-glucuronidase. The sucrose-inducible expression of the β-Amy:GUS fusion gene was also inhibited by two inhibitors of Ca2+ channels, diltiazem and nicardipine. These results suggest that the sugar-inducible expression of genes for sporamin and β-amylase involves, at least in part, Ca2+-mediated signalling, and that the cytosolic free Ca2+ may mediate cross-talk between signals related to carbohydrate metabolism and other stimuli. Treatment of coelenterazine-loaded leaf discs of tobacco expressing a Ca2+-binding photoprotein, aequorin, with 0.2 M sucrose for 24 h significantly reduced the level of luminescence that could be induced by cold shock, as compared to cold shock-induced luminescence in coelenterazine-loaded leaf discs treated with water. Repression of cold shock-induced luminescence was due to the conversion of holoaequorin to apoaequorin during the treatment with sucrose. Treatment of coelenterazine-loaded leaf discs with a 0.2 M solution of glucose or fructose, but not of mannitol or sorbitol, also reduced the cold shock-induced luminescence. It is suggested that non-synchronous increases in cytosolic level of free Ca2+ occur in leaf discs during treatment with high levels of metabolizable sugars. 相似文献
13.
Akihiko Takegawa Masa-aki Murakami Yoshiro Kaneko Jun-ichi Kadokawa 《Carbohydrate polymers》2010,79(1):1408
In this study, we performed preparation and characterizations of the chitin/cellulose composite gels and films using the two ionic liquids, 1-allyl-3-methylimidazolium bromide and 1-butyl-3-methylimidazolium chloride. First, chitin and cellulose were dissolved in each appropriate ionic liquid. Then, the two liquids were mixed in the desired ratios at 100 °C to give the homogeneous mixtures. The gels were obtained by standing the mixtures for 4 days. On the other hand, the films were obtained by casting the mixtures on glass plates, followed by soaking in water and drying. The obtained gels and films were characterized by XRD and TGA measurements. The mechanical properties of the gels and films were evaluated under compressive and tensile modes, respectively. 相似文献
14.
Masa-aki Higuchi Dan D. Topiol Bilal Ahmed Hokuto Morita Samuel Carbunaru Christopher W. Hess Dawn Bowers Herbert E. Ward Lisa R. Warren Meredith M. DeFranco Michelle S. Troche Shankar J. Kulkarni Erin Hastings Kelly D. Foote Michael S. Okun Daniel Martinez-Ramirez 《PloS one》2015,10(12)
Objective
To investigate the relationship of our interdisciplinary screening process on post-operative unintended hospitalizations and quality of life.Background
There are currently no standardized criteria for selection of appropriate Deep Brain Stimulation candidates and little hard data exists to support the use of any singular method.Methods
An Essential Tremor cohort was selected from our institutional Deep Brain Stimulation database. The interdisciplinary model utilized seven specialties who pre-operatively screened all potential Deep Brain Stimulation candidates. Concerns for surgery raised by each specialty were documented and classified as none, minor, or major. Charts were reviewed to identify unintended hospitalizations and quality of life measurements at 1 year post-surgery.Results
Eighty-six percent (44/51) of the potential screened candidates were approved for Deep Brain Stimulation. Eight (18%) patients had an unintended hospitalization during the follow-up period. Patients with minor or major concerns raised by any specialty service had significantly more unintended hospitalizations when compared to patients without concerns (75% vs. 25%, p < 0.005). The rate of hospitalization revealed a direct relationship to the “level of concern”; ranging from 100% if major concerns, 42% if minor concerns, and 7% if no concerns raised, p = 0.001. Quality of life scores significantly worsened in patients with unintended hospitalizations at 6 (p = 0.046) and 12 months (p = 0.027) when compared to baseline scores. No significant differences in tremor scores between unintended and non-unintended hospitalizations were observed.Conclusions
The number and level of concerns raised during interdisciplinary Deep Brain Stimulation screenings were significantly related to unintended hospitalizations and to a reduced quality of life. The interdisciplinary evaluation may help to stratify risk for these complications. However, data should be interpreted with caution due to the limitations of our study. Further prospective comparative and larger studies are required to confirm our results. 相似文献15.
Masa-aki Yoshida Shuichi Shigeno Kazuhiko Tsuneki Hidetaka Furuya 《Evolution & development》2010,12(1):25-33
SUMMARY The highly specialized cephalopod cardiovascular system has long been considered a valuable model for understanding the evolution of circulatory systems. Despite the number of studies devoted to this topic, the developmental regulatory mechanisms remain largely unexplored. Here, we focus on the vascular endothelial growth factor receptor (VEGFR). This factor is known to mediate levels of endothelial growth factor that is involved in hematopoiesis and vasculogenesis including multichambered heart development in vertebrates. We found a squid VEGFR ortholog that is expressed in the developing blood vessels, notably in the sheet-like endothelial cells of the systemic and branchial hearts. The highly restricted localization of VEGFR in the vascular endothelial cells and its shared expression pattern in the developing hearts of cephalopods and vertebrates suggest a shared molecular signature of closed circulatory systems that has been independently elaborated during evolution. 相似文献
16.
Konishi MA Fukuoka T Shimane Y Mori K Nagano Y Ohta Y Kitamoto D Hatada Y 《Biotechnology letters》2011,33(1):139-145
Purpose of work
To explore a novel glycolipid, we performed biochemical reactions using a recombinant α-glucosidase from Geobacillus sp. which shows excellent transglycosylation reaction to hydroxyl groups in a variety of compounds. 相似文献17.
He PJ Hirata M Yamauchi N Hashimoto S Hattori MA 《Molecular and cellular biochemistry》2007,302(1-2):111-118
The circadian clock is responsible for the generation of circadian rhythms in hormonal secretion and metabolism. These peripheral
clocks could be reset by various cues in order to adapt to environmental variations. The ovary can be characterized as having
highly dynamic physiology regulated by gonadotropins. Here, we aimed to address the status of circadian clock in the ovary,
and to explore how gonadotropins could regulate clockwork in granulosa cells (GCs). To this end, we mainly utilized the immunohistochemistry,
RT-PCR, and real-time monitoring of gene expression methods. PER1 protein was constantly abundant across the daily cycle in
the GCs of immature ovaries. In contrast, PER1 protein level was obviously cyclic through the circadian cycle in the luteal
cells of pubertal ovaries. In addition, both FSH and LH induced Per1 expression in cultured immature and mature GCs, respectively. The promoter analysis revealed that the Per1 expression was mediated by the cAMP response element binding protein. In cultured transgenic GCs, both FSH and LH also induced
the circadian oscillation of Per2. However, the Per2 oscillation promoted by FSH quickly dampened within only one cycle, whereas the Per2 oscillation promoted by LH was persistently maintained. Collectively, these findings strongly suggest that both FSH and LH
play an important role in regulating circadian clock in the ovary; however, they might exert differential actions on the clockwork
in vivo due to each specific role within ovarian physiology. 相似文献
18.
Sarker Subodh C.; Ogawa Masahiro; Takahashi Masa-aki; Asada Kozi 《Plant & cell physiology》1986,27(8):1579-1586
The processing of a 57-kDa peptide into 37- and 22-kDa subunitsof glutelin, a major storage protein of rice, was confirmedby the immunological compatibility between the precursor andglutelin subunits. The 57-kDa peptide reacted with the antiseraraised against purified 37-kDa and 22-kDa subunits of glutelin.The processing was further confirmed by alteration of an invivo protein synthesis by monensin, a sodium ionophore whichinhibits the intracellular transport of secretory and membraneproteins. Infusion of monensin into developing rice grains resultedin suppressed formation of mature glutelin subunits with concomitantaccumulation of the 57-kDa peptide. The present results indicatethat both subunits of rice glutelin were produced by post-translationalcleavage of the 57-kDa peptide. (Received July 9, 1986; Accepted October 1, 1986) 相似文献
19.
When intact cells of Chlamydomonas reinhardtii were anaerobicallyincubated in the dark, rapid inactivation of oxygen evolutionwith benzoquinone as the Hill oxidant occurred. Measurementsof electron transport using thylakoids isolated after anaerobictreatment showed that the inactivation occurred at, or before,the secondary electron acceptor of PS II, whereas PS I activitywas largely unaffected. In addition, after anaerobic treatmentfluorescence transients measured with no addition or with dibromomethylisopropylbenzoquinonepresent were virtually the same as those obtained with DCMUpresent. When 10 mM NaHCO3 was added to inactivated cells, partof the oxygen evolution capacity was restored rapidly. However,almost complete recovery (within 20 to 25 min) required theaddition of oxygen as well. This recovery was not light-dependentand was faster in the presence of 1 mM KCN. We suggest thatthe in activation of benzoquinone-dependent oxygen evolutionwas due to both bicarbonate depletion and reduction of the plastoquinonepool.
1Present address: Institute of Molecular Biophysics, FloridaState University, Tallahassee, Florida 32306, U.S.A. (Received January 17, 1984; Accepted February 25, 1984) 相似文献
20.
Placozoans are marine invertebrates found in tropical and subtropical waters. Their body plan is among the simplest of free-living animals. The present study determined the mitochondrial genome sequence of a placozoan collected on the coast of Shirahama, Wakayama, Honshu, Japan, and compared it with those of Trichoplax adhaerens from the Red Sea and of three strains from the Caribbean Sea. The sequences of mitochondrial respiratory chain of the Japanese placozoan genes are very similar to those of the BZ49 strain from the Caribbean Sea. However, there are distinct differences in gene arrangement, such as the location of two open reading frames. This Japanese placozoan is therefore distinguishable from the other strains. Based on current knowledge of placozoan 16S diversity our 'Shirahama' strain most likely represents the H15 lineage, known from the Philippines. In the mitochondrial genome of placozoans, substitution rates are slower than in bilaterians, whereas the rate of rearrangements is faster. 相似文献