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81.
Hyeong Cheol Park Chan Young Park Sung Cheol Koo Mi Sun Cheong Kyung Eun Kim Min Chul Kim Chae Oh Lim Sang Yeol Lee Dae-Jin Yun Woo Sik Chung 《Plant cell reports》2010,29(11):1297-1304
Plants express many calmodulins (CaMs) and calmodulin-like (CML) proteins that sense and transduce different Ca2+ signals. Previously, we reported divergent soybean (Glycine max) CaM isoforms (GmCaM4/5) with differential abilities to activate CaM-dependent enzymes. To elucidate biological functions
of divergent CaM proteins, we isolated a cDNA encoding a CML protein, AtCML8, from Arabidopsis. AtCML8 shows highest identity with GmCaM4 at the protein sequence level. Expression of AtCML8 was high in roots, leaves, and flowers but low in stems. In addition, the expression of AtCML8 was induced by exposure to salicylic acid or NaCl. AtCML8 showed typical characteristics of CaM such as Ca2+-dependent electrophoretic mobility shift and Ca2+ binding ability. In immunoblot analyses, AtCML8 was recognized only by antiserum against GmCaM4 but not by GmCaM1 antibodies.
Interestingly, AtCML8 was able to activate phosphodiesterase (PDE) but did not activate NAD kinase. These results suggest
that AtCML8 acts as a CML protein in Arabidopsis with characteristics similar to soybean divergent GmCaM4 at the biochemical levels. 相似文献
82.
Evaluation of Adult White Sturgeon Swimming Capabilities and Applications to Fishway Design 总被引:1,自引:0,他引:1
Concern over passage of sturgeon barriers, has focused attention on fishway design that accommodates its swimming performance. In order to evaluate swimming performance, regarding fish ladder type partial barriers, wild adult sturgeons, Acipenser transmontanus; 121–76m fork length, were captured in the San Francisco Bay Estuary and Yolo Bypass toe drain. Hydrodynamic forces and kinematic parameters for swimming performance data were collected in a laboratory flume under three flow conditions through barriers and ramp. The experiments were conducted in a 24.4 m long, 2.1 m wide, and 1.62 m deep aluminum channel. Two geometric configurations of the laboratory model were designed based on channel characteristics that have been identified in natural river systems. At a given swimming speed and fish size, the highest guidance efficiencies of successful white sturgeon passage as a function of flow depth, flow velocity, turbulence intensity, Reynolds number, Froude number and shear velocity observed in the steady flow condition, tested with the horizontal ramp structure, occurred at an approach velocity of 0.33 ms-1. The guidance efficiency of successful sturgeon passage increased both with increasing flow velocity and Froude number, and decreased both with the flow depth and the turbulence intensity. This study also provides evidence that tail beat frequency increases significantly with swimming speed, but tail beat frequency decreases with fish total length. Stride length increases both with swimming speed and fish total length. The importance of unsteady forces is expressed by the reduced frequency both with swimming speed and fish total length. Regression analysis indicates that swimming kinematic variables are explained by the swimming speed, the reduced frequency and the fish total length. The results emphasize the importance of fish ladder type patchiness when a fishway is designed for the passage of sturgeon. 相似文献
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84.
Kang YS Do Y Lee HK Park SH Cheong C Lynch RM Loeffler JM Steinman RM Park CG 《Cell》2006,125(1):47-58
The intricate system of serum complement proteins provides resistance to infection. A pivotal step in the complement pathway is the assembly of a C3 convertase, which digests the C3 complement component to form microbial binding C3 fragments recognized by leukocytes. The spleen and C3 provide resistance against blood-borne S. pneumoniae infection. To better understand the mechanisms involved, we studied SIGN-R1, a lectin that captures microbial polysaccharides in spleen. Surprisingly, conditional SIGN-R1 knockout mice developed deficits in C3 catabolism when given S. pneumoniae or its capsular polysaccharide intravenously. There were marked reductions in proteolysis of serum C3, deposition of C3 on organisms within SIGN-R1(+) spleen macrophages, and formation of C3 ligands. We found that SIGN-R1 directly bound the complement C1 subcomponent, C1q, and assembled a C3 convertase, but without the traditional requirement for either antibody or factor B. The transmembrane lectin SIGN-R1 therefore contributes to innate resistance by an unusual C3 activation pathway. 相似文献
85.
Cheong N Madesh M Gonzales LW Zhao M Yu K Ballard PL Shuman H 《The Journal of biological chemistry》2006,281(14):9791-9800
Members of the ATP binding cassette (ABC) protein superfamily actively transport a wide range of substrates across cell and intracellular membranes. Mutations in ABCA3, a member of the ABCA subfamily with unknown function, lead to fatal respiratory distress syndrome (RDS) in the newborn. Using cultured human lung cells, we found that recombinant wild-type hABCA3 localized to membranes of both lysosomes and lamellar bodies, which are the intracellular storage organelles for surfactant. In contrast, hABCA3 with mutations linked to RDS failed to target to lysosomes and remained in the endoplasmic reticulum as unprocessed forms. Treatment of those cells with the chemical chaperone sodium 4-phenylbutyrate could partially restore trafficking of mutant ABCA3 to lamellar body-like structures. Expression of recombinant ABCA3 in non-lung human embryonic kidney 293 cells induced formation of lamellar body-like vesicles that contained lipids. Small interfering RNA knockdown of endogenous hABCA3 in differentiating human fetal lung alveolar type II cells resulted in abnormal, lamellar bodies comparable with those observed in vivo with mutant ABCA3. Silencing of ABCA3 expression also reduced vesicular uptake of surfactant lipids phosphatidylcholine, sphingomyelin, and cholesterol but not phosphatidylethanolamine. We conclude that ABCA3 is required for lysosomal loading of phosphatidylcholine and conversion of lysosomes to lamellar body-like structures. 相似文献
86.
Cheong JY Cho SW Chung SG Lee JA Yeo M Wang HJ Lee JE Hahm KB Kim JH 《Biochemical genetics》2006,44(5-6):246-255
The natural history of hepatitis B virus (HBV) infection is probably related to host immune factors. Interferon-γ (IFN-γ) plays significant roles in immune defense. This study was undertaken to investigate the association between HBV infection and single nucleotide polymorphisms (SNPs) of IFN-γ, IFN-γ receptor (IFNGR)-1 and 2, and interferon regulatory factor (IRF)-1 genes. Between March 2002 and December 2002, 614 Korean patients were enrolled in two different groups: an HBV clearance group (n = 201), who were hepatitis B surface antigen (HBsAg) negative with antibodies to HBsAg and hepatitis B core antigen, and an HBV persistence group (n = 413), who were repeatedly HBsAg positive. We assessed polymorphisms in the IFN-γ gene at position +874, in the IFNGR-1 gene at positions −56 and +95, in the IFNGR-2 gene at the second position of codon 64 (Gln64Arg), and in the IRF-1 gene promoter (−410, −388), and the genotype distributions of the HBV clearance and persistence groups were compared. On the basis of unconditional logistic regression analysis with adjustment for age and sex, no statistically significant association with susceptibility to persistent HBV infection was observed with the IFN-γ, IFNGR-1 and 2, and IRF-1 gene polymorphisms under the codominant, dominant, and recessive models. 相似文献
87.
Kim MH Park SC Kim JY Lee SY Lim HT Cheong H Hahm KS Park Y 《Biochemical and biophysical research communications》2006,346(3):681-686
Potide-G, a small (5578.9 Da) antimicrobial peptide, was isolated from potato tubers (Solanum tuberosum L. cv. Golden Valley) through extraction of the water-soluble fraction, dialysis, ultrafiltration and DEAE-cellulose and C18 reverse-phase high performance liquid chromatography. This antimicrobial peptide was heat-stable and almost completely suppressed the proteolytic activity of trypsin, chymotrypsin and papain, with no hemolytic activity. In addition, potide-G potently inhibited growth of a variety of bacterial (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Clavibacter michiganense subsp. michiganinse) and fungal (Candida albicans and Rhizoctonia solani) strains. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry revealed that the N-terminal sequence (residues from 1 to 11) of the protein is identical to that of potato proteinase inhibitor, a member of the Kunitz superfamily. And like other members of this class of protease inhibitor, potide-G may have a number of beneficial and therapeutic uses. 相似文献
88.
89.
Justin Perry Linda A. Rymarquis Monica Accerbi Pamela J. Green Simon Prochnik Erika Lindquist Cheong Xin Chan Charles Yarish Senjie Lin Yunyun Zhuang Nicolas A. Blouin Susan H. Brawley 《Journal of phycology》2012,48(4):883-896
Little is known about the genetic and biochemical mechanisms that underlie red algal development, for example, why the group failed to evolve complex parenchyma and tissue differentiation. Here we examined expressed sequence tag (EST) data from two closely related species, Porphyra umbilicalis (L.) J. Agardh and P. purpurea (Roth) C. Agardh, for conserved developmental regulators known from model eukaryotes, and their expression levels in several developmental stages. Genes for most major developmental families were present, including MADS‐box and homeodomain (HD) proteins, SNF2 chromatin‐remodelers, and proteins involved in sRNA biogenesis. Some of these genes displayed altered expression correlating with different life history stages or cell types. Notably, two ESTs encoding HD proteins showed eightfold higher expression in the P. purpurea sporophyte (conchocelis) than in the gametophyte (blade), whereas two MADS domain‐containing paralogs showed significantly different patterns of expression in the conchocelis and blade respectively. These developmental gene families do not appear to have undergone the kinds of dramatic expansions in copy number found in multicellular land plants and animals, which are important for regulating developmental processes in those groups. Analyses of small RNAs did not validate the presence of miRNAs, but homologs of Argonaute were present. In general, it appears that red algae began with a similar molecular toolkit for directing development as did other multicellular eukaryotes, but probably evolved altered roles for many key proteins, as well as novel mechanisms yet to be discovered. 相似文献
90.