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71.
Soo Youn Kim Zheng-Yi Xu Kyungyoung Song Dae Heon Kim Hyangju Kang Ilka Reichardt Eun Ju Sohn Ji?í Friml Gerd Juergens Inhwan Hwang 《The Plant cell》2013,25(8):2970-2985
Fertilization in flowering plants requires the temporal and spatial coordination of many developmental processes, including pollen production, anther dehiscence, ovule production, and pollen tube elongation. However, it remains elusive as to how this coordination occurs during reproduction. Here, we present evidence that endocytosis, involving heterotetrameric adaptor protein complex 2 (AP-2), plays a crucial role in fertilization. An Arabidopsis thaliana mutant ap2m displays multiple defects in pollen production and viability, as well as elongation of staminal filaments and pollen tubes, all of which are pivotal processes needed for fertilization. Of these abnormalities, the defects in elongation of staminal filaments and pollen tubes were partially rescued by exogenous auxin. Moreover, DR5rev:GFP (for green fluorescent protein) expression was greatly reduced in filaments and anthers in ap2m mutant plants. At the cellular level, ap2m mutants displayed defects in both endocytosis of N-(3-triethylammonium-propyl)-4-(4-diethylaminophenylhexatrienyl) pyridinium dibromide, a lypophilic dye used as an endocytosis marker, and polar localization of auxin-efflux carrier PIN FORMED2 (PIN2) in the stamen filaments. Moreover, these defects were phenocopied by treatment with Tyrphostin A23, an inhibitor of endocytosis. Based on these results, we propose that AP-2–dependent endocytosis plays a crucial role in coordinating the multiple developmental aspects of male reproductive organs by modulating cellular auxin level through the regulation of the amount and polarity of PINs. 相似文献
72.
Su-Min Lee Sin Young Park Seoung Woo Shin In Sup Kil Eun Sun Yang 《Free radical research》2013,47(2):165-173
Staurosporine induces the production of reactive oxygen species, which play an important causative role in apoptotic cell death. Recently, it was demonstrated that the control of cellular redox balance and the defense against oxidative damage is one of the primary functions of cytosolic NADP+-dependent isocitrate dehydrogenase (IDPc) by supplying NADPH for antioxidant systems. The present report shows that silencing of IDPc expression in HeLa cells greatly enhances apoptosis induced by staurosporine. Transfection of HeLa cells with an IDPc small interfering RNA (siRNA) markedly decreased activity of IDPc, enhancing the susceptibility of staurosporine-induced apoptosis reflected by DNA fragmentation, cellular redox status and the modulation of apoptotic marker proteins. These results indicate that IDPc may play an important role in regulating the apoptosis induced by staurosporine and the sensitizing effect of IDPc siRNA on the apoptotic cell death of HeLa cells offers the possibility of developing a modifier of cancer chemotherapy. 相似文献
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74.
Eun Sil Kang Gil Hyeong Kim Im Sun Woo Hyo Jung Kim So Young Eun Sun Ah Ham 《Free radical research》2013,47(11-12):930-938
Aldose reductase (AR) is abundantly expressed in a variety of cell lineages and has been implicated in the cellular response against oxidative stress. However, the exact functional role of AR against oxidative stress remains relatively unclear. This study investigated the role of AR in acrolein- or hydrogen peroxide-induced apoptosis using the J774.A.1 macrophage cell line. Ablation of AR with a small interference RNA or inhibition of AR activity significantly enhanced the acrolein- or hydrogen peroxide-induced generation of reactive oxygen species and aldehydes, leading to increased apoptotic cell death. Blockade of AR activity in J774A.1 cells markedly augmented the acrolein- or hydrogen peroxide-induced translocation of Bax to mitochondria along with reduced Bcl-2 and increased release of cytochrome c from the mitochodria. Taken together, these findings indicate that AR plays an important role in the cellular response against oxidative stress, by sequestering the reactive molecules generated in cells exposed to toxic substances. 相似文献
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Hye Jung Choi Jeoung-Yoon Seo Su Mi Hwang Yong-Ill Lee Yong Kee Jeong Ja-Young Moon Woo Hong Joo 《Biotechnology and Bioprocess Engineering》2013,18(5):1000-1007
Bacterial strains growing in river sediments were screened to identify an organic solvent-tolerant strain of Pseudomonas. Using this screen, Pseudomonas sp. BCNU 106 was isolated on the basis of its ability to grow on benzene, toluene, ethylbenzene, and three xylene isomers, o-, m- and p-xylene, as its sole carbon source. BCNU 106 was identified as a gram-negative, rod-shaped aerobic and mesophilic bacterium, which grew in liquid media containing high concentrations of organic solvents. 16S rDNA analysis classified BCNU 106 as a new member of the genus Pseudomonas. BCNU 106 was distinguishable from other Pseudomonas strains that are tolerant to organic solvents in that the isolate had the ability to utilize all three xylene isomers as well as benzene, toluene and ethylbenzene. The unique properties of the isolate such as solvent-tolerance and the ability to degrade xylene isomers may have important implications for the efficient treatment of solvent wastes. 相似文献
78.
Jae-Jin Lee Hyun Ji Lee Gi Seon Jang Ja Myoung Yu Ji Yoon Cha Su Jeong Kim Eun Bit Lee Myung Kyum Kim 《Journal of microbiology (Seoul, Korea)》2013,51(3):305-311
Strain DY59T, a Gram-positive non-motile bacterium, was isolated from soil in South Korea, and was characterized to determine its taxonomic position. Phylogenetic analysis based on the 16S rRNA gene sequence of strain DY59T revealed that the strain DY59T belonged to the family Deinococcaceae in the class Deinococci. The highest degree of sequence similarities of strain DY59T were found with Deinococcus radiopugnans KACC 11999T (99.0%), Deinococcus marmoris KACC 12218T (97.9%), Deinococcus saxicola KACC 12240T (97.0%), Deinococcus aerolatus KACC 12745T (96.2%), and Deinococcus frigens KACC 12220T (96.1%). Chemotaxonomic data revealed that the predominant fatty acids were iso-C15:0 (19.0%), C16:1 ω7c (17.7%), C15:1 ω6c (12.6%), iso-C17:0 (10.3%), and iso-C17:1 ω9c (10.3%). A complex polar lipid profile consisted of a major unknown phosphoglycolipid. The predominant respiratory quinone is MK-8. The cell wall peptidoglycan contained D-alanine, L-glutamic acid, glycine, and L-ornithine (di-amino acid). The novel strain showed resistance to gamma radiation, with a D10 value (i.e. the dose required to reduce the bacterial population by 10-fold) in excess of 5 kGy. Based on the phylogenetic, chemotaxonomic, and phenotypic data, strain DY59T (=KCTC 33033T =JCM 18581T) should be classified as a type strain of a novel species, for which the name Deinococcus swuensis sp. nov. is proposed. 相似文献
79.
Ya-Jie Li Rui Mi Nan Meng Zhi-Xin Wen Xue-Jun Li Mo Chen Yan-Qun Liu Shu-Ying Li 《Journal of Asia》2013,16(3):275-279
Sans-fille (SNF) is the Drosophila homologue of mammalian general splicing factors U1A and U2B″, and plays an important role in sex determination in Drosophila melanogaster. In this study, the snf gene from Antheraea pernyi (Lepidoptera: Saturniidae), an economically important insect, was isolated and characterized. The obtained 925 bp cDNA sequence contains an open reading frame of 669 bp encoding a polypeptide of 222 amino acids, showing 78% sequence identity to that from D. melanogaster. A database search revealed that SNF protein homologs are present in many animals, including invertebrates and vertebrates, with more than 70% amino acid sequence identities, suggesting that they were highly conserved during the evolution of animals. Phylogenetic analysis revealed that A. pernyi SNF was closely related to Bombyx mori SNF. Quantitative real-time PCR (qRT-PCR) analysis showed that the A. pernyi snf gene was transcribed during five larval developmental stages, and in six tested tissues (ovaries, testes, silk glands, fat body, integument, and hemolymph), with the most abundance determined in the gonads (ovaries or testes). Investigation of expression changes throughout embryonic development indicated that A. pernyi snf mRNA was expressed at a low level from days 0 to 4, and reached a maximum level at day 10, but decreased to a low level before hatching. These results suggest that the product of the snf gene may play important roles in the development of A. pernyi. 相似文献
80.
The physiological ecology of Prasiola stipitata was examined in situ from two supralittoral sites in the Bay of Fundy (Nova Scotian, Canada) during November 2011, when the population was undergoing major expansion. Photosynthetic parameters (effective quantum yield, ΦPSII, maximum quantum yield, Fv/Fm, and relative electron transport rate, rETR) were evaluated using chlorophyll fluorescence of PSII. A largely shaded and continuously moist population showed no change in ΦPSII from one hour after sunrise to sunset in which natural irradiance varied between 3 and 300 μmol photons m?2 s?1. High irradiance (up to 1800 μmol photons m?2 s?1) had no apparent negative impacts on either quantum yield or rETR, but high desiccation in the field reduced quantum yield to almost zero. When thalli were brought into the laboratory, no change in Fv/Fm was observed up to 60% dehydration; however, there was a steep decline in Fv/Fm between 60% and 85% dehydration. Thalli showed complete recovery of Fv/Fm within one hour of reimmersion in seawater after 2 days of desiccation. After 15 days of desiccation full recovery required 24 h and after 30 days of desiccation thalli showed only partial recovery. These observations confirm the adaptation to photosynthesis in high irradiances and the rapid recovery following extreme desiccation observed in other Prasiola species. 相似文献