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81.
Biological Trace Element Research - We measured serum concentrations of trace elements and evaluated their clinical significance in relation to treatment outcomes of critically ill patients. A...  相似文献   
82.
1. Harvestmen are predators, although they suspected of being partly omnivorous by including fruits in their diet. 2. In the present study, the right-angled mixture triangle (RMT) was used to analyse the macronutritional niche of the harvestman Opilio canestrinii, an invasive species in northern Europe. The study design followed a double-test procedure in which the animals were subjected to two self-selection tests: the first one immediately after being caught in the field and the second after 1 week of ad libitum feeding during which the animals became satiated and nutritionally balanced. A comparison of results from the two tests indicates whether the animals were food limited in the field, and whether they were limited by a particular macronutrient. 3. Females were found to be food limited in the field, whereas males were not. Opilio canestrinii had a target intake of 28% lipid : 52% protein : 20% carbohydrate [i.e. with a considerable proportion of carbohydrate (sugar) in the diet]. Both sexes were non-protein limited in the field, with sugar being more limiting than lipid. 4. The results indicate considerable inclusion of plant-derived sugar in the natural diet. This conclusion was supported by a separate experiment showing enhanced performance (survival, gain in mass) in animals whose only energy supply was fresh fruit. 5. It is concluded that the harvestman is best characterized as an omnivorous predator.  相似文献   
83.
We investigated the molecular mechanism of the glucose effect on the regulation of chondrogenesis. Exposure of chick wing bud mesenchymal cells to high concentrations of glucose stimulated chondrogenesis 2–fold to 2.5-fold without affecting cell proliferation. Glucose increased protein levels and the membrane translocation of protein kinase C alpha (PKC), leading to a reduction of extracellular signal-regulated kinase (ERK) phosphorylation. Phosphorylation of p38 was also increased in a PKC-independent manner by glucose treatment. Glucose also increased cell adhesion molecules such as fibronectin, integrin 1, and N-cadherin at early stages and then decreased these adhesion molecules at later stages of chondrogenesis. These alterations in protein level of adhesion molecules and in the phosphorylation of mitogen-activated protein kinases by glucose were blocked by inhibition of PKC or p38 but were synergistically increased by the inhibition of ERK. Therefore, high doses of glucose induce the down-regulation of ERK activity via PKC and the up-regulation of p38 and result in the stimulation of chondrogenesis of chick mesenchymal cells through modulating the expression of adhesion molecules.This work was supported by the Korea Research Foundation (KRF-2000-DP0352)  相似文献   
84.
Kim HB  Lee H  Oh CJ  Lee NH  An CS 《Molecules and cells》2007,23(1):115-121
Root nodule formation is controlled by plant hormones such as auxin. Auxin-repressed protein (ARP) genes have been identified in various plant species but their functions are not clear. We have isolated a full-length cDNA clone (EuNOD-ARP1) showing high sequence homology to previously identified ARP genes from root nodules of Elaeagnus umbellata. Genomic Southern hybridization showed that there are at least four ARP-related genes in the genome of E. umbellata. The cDNA clone encodes a polypeptide of 120 amino acid residues with no signal peptide or organelle-targeting signals, indicating that it is a cytosolic protein. Its cytosolic location was confirmed using Arabidopsis protoplasts expressing a EuNOD-ARP1:smGFP fusion protein. Northern hybridization showed that EuNOD-ARP1 expression was higher in root nodules than in leaves or uninoculated roots. Unlike the ARP genes of strawberry and black locust, which are negatively regulated by exogenous auxin, EuNOD-ARP1 expression is induced by auxin in leaf tissue of E. umbellata. In situ hybridization revealed that EuNOD-ARP1 is mainly expressed in the fixation zone of root nodules.  相似文献   
85.
86.
After gas chromatography-mass spectrometry (GC-MS) analysis, data processing, including retention time correction, spectral deconvolution, peak alignment, and normalization prior to statistical analysis, is an important step in metabolomics. Several commercial or free software packages have been introduced for data processing, but most of them are vendor dependent. To design a simple method for Agilent GC/MS data processing, we developed an in-house program, "CompExtractor", using Microsoft Visual Basic. We tailored the macro modules of an Agilent Chemstation and implanted them in the program. To verify the performance of CompExtractor processing, 30 samples from the three species of the genus Papaver were analyzed with Agilent 5973 MSD GC-MS. The results of CompExtractor processing were compared with those of AMDIS-SpectConnect processing by hierarchical cluster analysis (HCA) and principal component analysis (PCA). The two methods showed good classification according to their species in HCA. The PC1+PC2 scores were 54.32-63.62% for AMDIS-SpectConnect and 56.65-85.92% for CompExtractor in PCA. Although the CompExtractor processing method is an Agilent GC-MS-specific application and the target compounds must be selected first, it can extract the target compounds more precisely in the raw data file with batch mode and simultaneously assemble the matrix text file.  相似文献   
87.
This study examines the hypothesis that the stopping rule - a traditional postnatal sex selection method where couples decide to cease childbearing once they bear a son - plays a role in high sex ratio of last births (SRLB). The study develops a theoretical framework to demonstrate the operation of the stopping rule in a context of son preference. This framework was used to demonstrate the impact of the stopping rule on the SRLB in Vietnam, using data from the Population Change Survey 2006. The SRLB of Vietnam was high at the level of 130 in the period 1970-2006, and particularly in the period 1986-1995, when sex-selective abortion was not available. Women were 21% more likely to stop childbearing after a male birth compared with a female birth. The SRLB was highest at parity 2 (138.7), particularly in rural areas (153.5), and extremely high (181.9) when the previous birth was female. Given the declining fertility, the stopping rule has a potential synergistic effect with sex-selective abortion to accentuate a trend of one-son families in the population.  相似文献   
88.
The Spo0B-associated GTP-binding protein (Obg) GTPase, essential for bacterial viability, is also conserved in eukaryotes, but its primary role in eukaryotes remains unknown. Here, our functional characterization of Arabidopsis and rice obgc mutants strongly underlines the evolutionarily conserved role of eukaryotic Obgs in organellar ribosome biogenesis. The mutants exhibited a chlorotic phenotype, caused by retarded chloroplast development. A plastid DNA macroarray revealed a plastid-encoded RNA polymerase (PEP) deficiency in an obgc mutant, caused by incompleteness of the PEP complex, as its western blot exhibited reduced levels of RpoA protein, a component of PEP. Plastid rRNA profiling indicated that plastid rRNA processing is defective in obgc mutants, probably resulting in impaired ribosome biogenesis and, in turn, in reduced levels of RpoA protein. RNA co-immunoprecipitation revealed that ObgC specifically co-precipitates with 23S rRNA in vivo. These findings indicate that ObgC functions primarily in plastid ribosome biogenesis during chloroplast development. Furthermore, complementation analysis can provide new insights into the functional modes of three ObgC domains, including the Obg fold, G domain and OCT.  相似文献   
89.
Plant pathogens employ effectors as molecular weapons to manipulate host immunity and facilitate colonization. Fusarium oxysporum f. sp. cubense is the agent of wilt disease in banana plantlets and four races of the pathogen have been identified based on the cultivar specificity. A total of 9 SIX genes have been detected in the genome of Foc TR4 and 6 genes detected in Foc1. Among these SIX genes, SIX2 and SIX8 are only detected in Foc TR4, not identified in Foc1. Expression profiles analysis revealed that SIX genes of Foc TR4 are highly induced after inoculation to Cavendish banana plantlets. Virulence analysis of the SIX2 and SIX8 knock-out mutants showed that SIX8 is required for the virulence of Foc TR4 while SIX2 has no obvious functions. Over expression of SIX8-FLAG proteins in the SIX8 knock-out mutant partly restored the virulence. Western blot analysis suggested that SIX8 could be secreted into the extracellular space and a signal peptide resided the N-terminal polypeptide sequence. This study provides some clues for further research on mechanism of SIX8 in regulating virulence of Foc TR4.  相似文献   
90.
Novel 3,4-dihydroquinazoline-2(1H)-thiones (QNTs) 1 were found to be potent inhibitors of α-MSH-induced melanin production. The effect of QNTs to inhibit melanin formation in B16 melanoma cells was screened in the presence of α-MSH. In defining the mechanism of activity, the effects on tyrosinase activity, on tyrosinase synthesis and on the depigmentation of melanin were evaluated. QNTs did not affect the catalytic activity of tyrosinase, but rather acted as an inhibitor of tyrosinase synthesis.  相似文献   
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