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排序方式: 共有3699条查询结果,搜索用时 12 毫秒
921.
Dong-Soo Park Soo-Kwon Park Sang-Ik Han Hoe-Jeong Wang Nam-Soo Jun Norvie L. Manigbas Young-Min Woo Byoung-Ohg Ahn Doh-Won Yun Ung-Han Yoon Yong-Hwan Kim Myung-Chul Lee Doh-Hoon Kim Min-Hee Nam Chang-Deok Han Hang-Won Kang Gihwan Yi 《Molecular breeding : new strategies in plant improvement》2009,24(1):1-15
A gene detection strategy using two-component Ac/Ds construct, with the mobile Ds transposon, has been developed to better understand gene functions in crops. Currently, 115,000 Ds insertion lines have been generated through the Ac/Ds gene trap system in Korea using japonica rice Dongjin as donor. Four hundred and thirty-seven mutants from 12,162 Ds-tagged lines were catalogued, including physiological and agronomic traits. Different traits were identified with distinct
characteristics in terms of tillers, panicles, leaves, flowers, seed, chlorophyll content, and height. Culm and panicle length,
number of panicles, and days to flowering of the Dongjin Ds population revealed high standard deviations compared with the donor cultivar. An evaluation of the Ds distribution on the chromosome revealed that 74.5% of the Ds were reinserted into gene-rich regions, making this Ac/Ds-mediated gene trap system useful in helping to gain an understanding of the function of genes and thus improve the gene-tagging
system in rice. 相似文献
922.
Biomass granulation in an aerobic:anaerobic-enhanced biological phosphorus removal process in a sequencing batch reactor with varying pH 总被引:1,自引:0,他引:1
Johwan Ahn Simon McIlroy Sarah Schroeder Robert Seviour 《Journal of industrial microbiology & biotechnology》2009,36(7):885-893
Long-term influences of different steady-state pH conditions on microbial community composition were determined by fluorescence
in situ hybridization (FISH) in a laboratory scale reactor configured for enhanced biological phosphorus removal (EBPR). Chemical
profiles were consistent with shifts in populations from polyphosphate-accumulating organisms (PAO) to glycogen-accumulating
organisms (GAO) when pH fell from pH 7.5 to 7.0 and then to 6.5. While biomass was both dispersed and flocculated at pH 7.5,
almost complete granulation occurred gradually after pH was dropped to 7.0, and these granules increased in size as the pH
was reduced further to 6.5. Reverting back to pH 7.5 led to granule breakdown and corresponding increases in anaerobic phosphate
release. Granules consisted almost entirely of Accumulibacter PAO cells, while putative GAO populations were always present in small numbers. Results suggest that low pH may contribute
to granulation under these operational conditions. While chemical profiles suggested the PAO:GAO balance was changing as pH
fell, FISH failed to reveal any marked corresponding increase in GAO abundances. Instead, TEM evidence suggested the Accumulibacter PAO phenotype was becoming more like that of a GAO. These data show how metabolically adaptable the Accumulibacter PAO can be under anaerobic:aerobic conditions in being able to cope with marked changes in plant conditions. They suggest
that decreases in EBPR capacity may not necessarily reflect shifts in community composition, but in the existing population
metabolism. 相似文献
923.
Jeong-Eun Kim Dong-Joo You Cheolju Lee Curie Ahn Jae Young Seong Jong-Ik Hwang 《Cellular signalling》2010,22(11):1645-1654
IκB kinase β (IKKβ) plays a crucial role in biological processes, including immune response, stress response, and tumor development by mediating the activation of various signaling molecules such as NF-κB. Extensive studies on the mechanisms underlying IKK activation have led to the identification of new activators and have facilitated an understanding of the cellular responses related to NF-κB and other target molecules. However, the molecular processes that modulate IKK activity are still unknown. In this study, we show that KEAP1 is a new IKK binding partner, which is responsible for the down-regulation of TNFα-stimulated NF-κB activation. The E(T/S)GE motif, which is found only in the IKKβ subunit of the IKK complex, is essential for interaction with the C-terminal Kelch domain of KEAP1. Reduction of KEAP1 expression by small interfering RNA enhanced NF-κB activity, and up-regulated the expression of NF-κB target genes. Ectopic expression of KEAP1 decreased the expression of IKKβ, which was restored by an autophagy inhibitor. IKK phosphorylation stimulated by TNFα was blocked by KEAP1. Our data demonstrate that KEAP1 is involved in the negative regulation of NF-κB signaling through the inhibition of IKKβ phosphorylation and the mediation of autophagy-dependent IKKβ degradation. 相似文献
924.
This work was to investigate the effect of flavonoids from Angelica gigas Nakai on the proliferation and differentiation of PC12 cells. Several solvents including hexane, chloroform, ethyl acetate,
butanol and water consecutively partitioned. We determined the ethanol crude extract of Angelica gigas Nakai. The hexane fraction was shown to contain the highest number of flavonoids as follows; 21.48 mg/g and the composition
of the flavonoids was as follows: 12.24 mg/g of quercetin, 4.39 mg/g of myricetin and 2.58 mg/g of catechin. In addition,
this hexane fraction greatly increased both cell growth and outgrowth of the neurite, and whose effects were three times higher
than those of the other fractions. The length of the neurites was measured as ca. 110 μm in adding 50 μg/mL of the hexane
fraction, which was about the same as the case of adding 50 ng/mL of NGF as a positive control. This result indicates that
the differentiation of PC12 cells by the addition of the hexane fraction was comparable to the case of adding NGF. The hexane
fraction was also determined to prevent apoptosis of PC12 cells by suppressing DNA fragmentation. It is interesting that the
mixture of three major flavonoids, quercetin, myricetin and catechin showed stronger activity on, both PC12 cell growth and
neuritis outgrowth, than when adding each flavonoid alone. We believe this was due to the synergistic effects of the three
flavonoids. The activities of these flavonoids from Angelica gigas Nakai are reported for the first time in this study. 相似文献
925.
Functional response of Neoseiulus californicus (Acari: Phytoseiidae) to Tetranychus urticae (Acari: Tetranychidae) on strawberry leaves 总被引:2,自引:0,他引:2
Neoseiulus californicus (McGregor) is a predatory mite employed for biological control of the agricultural pest Tetranychus urticae (Koch). We explored whether environmental differences, in this case the trichome densities of abaxial leaf surfaces of strawberry cultivars (‘Maehyang’ and ‘Sulhyang’ varieties) affect the functional response of adult female N. californicus preying on immature stages (egg, larva and nymph) of T. urticae. We also evaluated the functional response of N. californicus to eggs of T. urticae at different temperatures (15, 20, 25, 30 and 35°C). We conducted a logistic regression of the proportion of prey consumed as a function of initial prey density to identify functional response types, and used nonlinear least‐squares regression and the random predator equation to estimate attack rates and handling times. The functional response of adult female N. californicus to T. urticae was not influenced by non‐glandular trichomes on abaxial leaves but was affected by temperature. Overall, adult female N. californicus exhibited a type 2 functional response to T. urticae. The handling time of N. californicus was highest (1.9970 h) against T. urticae nymphs. The attack rate did not change much at 15–30°C, but was significantly higher at 35°C. The handling time decreased significantly with increasing temperature at 15–35°C. At 35°C, the attack rate was highest (0.2087) and the handling time was lowest (0.9511 h). 相似文献
926.
Seidel K Ahn CP Lyons D Nee A Ting K Brownell I Cao T Carano RA Curran T Schober M Fuchs E Joyner A Martin GR de Sauvage FJ Klein OD 《Development (Cambridge, England)》2010,137(22):3753-3761
In many organ systems such as the skin, gastrointestinal tract and hematopoietic system, homeostasis is dependent on the continuous generation of differentiated progeny from stem cells. The rodent incisor, unlike human teeth, grows throughout the life of the animal and provides a prime example of an organ that rapidly deteriorates if newly differentiated cells cease to form from adult stem cells. Hedgehog (Hh) signaling has been proposed to regulate self-renewal, survival, proliferation and/or differentiation of stem cells in several systems, but to date there is little evidence supporting a role for Hh signaling in adult stem cells. We used in vivo genetic lineage tracing to identify Hh-responsive stem cells in the mouse incisor and we show that sonic hedgehog (SHH), which is produced by the differentiating progeny of the stem cells, signals to several regions of the incisor. Using a hedgehog pathway inhibitor (HPI), we demonstrate that Hh signaling is not required for stem cell survival but is essential for the generation of ameloblasts, one of the major differentiated cell types in the tooth, from the stem cells. These results therefore reveal the existence of a positive-feedback loop in which differentiating progeny produce the signal that in turn allows them to be generated from stem cells. 相似文献
927.
928.
Ahn Y 《Collegium antropologicum》2010,34(4):1273-1280
Advances in medical technology and the health sciences have lead to a rapid increase in the prevalence and morbidity of high-risk infants with chronic or permanent sequels such as the birth of early preterm infants. A suitable formula is therefore needed for body surface area (BSA) estimation for high-risk infants to more accurately devise therapeutic regimes in clinical practice. A cohort study involving 5014 high-risk infants was conducted to develop a suitable formula for estimating BSA using four of the existing formulas in the literature. BSA of high-risk infants was calculated using the four BSA equations (Boyd-BSA, Dubois-BSA, Meban-BSA, Mosteller-BSA), from which a new calculation, Mean-BSA, was arithmetically derived as a reference BSA measure. Multiple-regression was performed using nonlinear least squares curve fitting corresponding to the trend line and the new equation, Neo-BSA, developed using Excel and SPSS 17.0. The Neo-BSA equation was constructed as follows: Neo-BSA = 5.520 x W(0.5526) x L(0.300). With the assumption of the least square root relation between weight and length, a BSA scale using only weight was fabricated specifically for clinical applications where weight is more available in high-risk infant populations than is length. The validity of Neo-BSA was evaluated against Meban-BSA, the best of the four equations for high-risk infants, as there is a similarity of subjects in the two studies. The other formulas revealed substantial variances in BSA compared to Neo-BSA. This study developed a new surface area equation, Neo-BSA, as the most suitable formula for BSA measurement of high-risk infants in modern-day societies, where an emerging population of newborns with shorten gestational ages are becoming more prevalent as a result of new advances in the health sciences and new development of reproductive technologies. In particular, a scale for 400-7000 g body weight babies derived from the Neo-BSA equation has the clinical advantage of using only weight as a measurement, since length is often not feasible as a measurement due to the newborn's body posture. Further studies are required to confirm our findings for the application of Neo-BSA and the BSA scale (based on weight) for various populations and ethnicities under different clinical conditions. 相似文献
929.
Joon-Chul Kim Krishna P. Subedi Joung Real Ahn 《Progress in biophysics and molecular biology》2010,103(1):59-70
In atrial myocytes lacking t-tubules, action potential triggers junctional Ca2+ releases in the cell periphery, which propagates into the cell interior. The present article describes growing evidence on atrial local Ca2+ signaling and on the functions of inositol 1,4,5-trisphosphate receptors (IP3Rs) in atrial myocytes, and show our new findings on the role of IP3R subtype in the regulation of spontaneous focal Ca2+ releases in the compartmentalized areas of atrial myocytes. The Ca2+ sparks, representing focal Ca2+ releases from the sarcoplasmic reticulum (SR) through the ryanodine receptor (RyR) clusters, occur most frequently at the peripheral junctions in isolated resting atrial cells. The Ca2+ sparks that were darker and longer lasting than peripheral and non-junctional (central) sparks, were found at peri-nuclear sites in rat atrial myocytes. Peri-nuclear sparks occurred more frequently than central sparks. Atrial cells express larger amounts of IP3Rs compared with ventricular cells and possess significant levels of type 1 IP3R (IP3R1) and type 2 IP3R (IP3R2). Over the last decade the roles of atrial IP3R on the enhancement of Ca2+-induced Ca2+ release and arrhythmic Ca2+ releases under hormonal stimulations have been well documented. Using protein knock-down method and confocal Ca2+ imaging in conjunction with immunocytochemistry in the adult atrial cell line HL-1, we could demonstrate a role of IP3R1 in the maintenance of peri-nuclear and non-junctional Ca2+ sparks via stimulating a posttranslational organization of RyR clusters. 相似文献
930.
Sung Young Kim Hong Ju Ahn Hyun Tae Kang 《Biochemical and biophysical research communications》2010,391(1):28-32
One of the characteristic natures of senescent cells is the hypo- or irresponsiveness not only to growth factors but also to apoptotic stress. In the present study, we confirmed the inhibition of nuclear translocation of activated p-ERK1/2 and NF-kB p50 in response to growth stimuli or LPS in the senescent human diploid fibroblasts. In order to elucidate the underlying mechanism for the senescence-associated hypo-responsiveness, we carried out the comparison study for gene expression profiles through microarray analysis. In consequence, we observed the vast reduction in expression of nucleo-cytoplasmic trafficking genes in senescent cells, when compared with those in young cells. Expression levels of several nucleoporins, karyopherin α, karyopherin β, Ran, and Ran-regulating factors were confirmed to be down-regulated in senescent HDFs by using RT-PCR and Western blot methods. Taken together, these data suggest the operation of certain senescence-associated functional nuclear barriers by down-regulation of the nucleo-cytoplasmic trafficking genes in the senescent cells. 相似文献