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941.
Vi Khanh Truong Stuart Rundell Rimma Lapovok Yuri Estrin James Y. Wang Christopher C. Berndt David G. Barnes Christopher J. Fluke Russell J. Crawford Elena P. Ivanova 《Applied microbiology and biotechnology》2009,83(5):925-937
The influence of the ultrafine crystallinity of commercial purity grade 2 (as-received) titanium and titanium modified by
equal channel angular pressing (modified titanium) on bacterial attachment was studied. A topographic profile analysis of
the surface of the modified titanium revealed a complex morphology of the surface. Its prominent micro- and nano-scale features
were 100–200-nm-scale undulations with 10–15 μm spacing. The undulating surfaces were nano-smooth, with height variations
not exceeding 5–10 nm. These surface topography characteristics were distinctly different from those of the as-received samples,
where broad valleys (up to 40–60 μm) were detected, whose inner surfaces exhibited asperities approximately 100 nm in height
spaced at 1–2 μm. It was found that each of the three bacteria strains used in this study as adsorbates, viz. Staphylococcus aureus CIP 68.5, Pseudomonas aeruginosa ATCC 9025 and Escherichia coli K12, responded differently to the two types of titanium surfaces. Extreme grain refinement by ECAP resulted in substantially
increased numbers of cells attached to the surface compared to as-received titanium. This enhanced degree of attachment was
accompanied with an increased level of extracellular polymeric substances (EPS) production by the bacteria.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
942.
Johnson RJ Sautin YY Oliver WJ Roncal C Mu W Gabriela Sanchez-Lozada L Rodriguez-Iturbe B Nakagawa T Benner SA 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2009,179(1):67-76
Uric acid has historically been viewed as a purine metabolic waste product excreted by the kidney and gut that is relatively
unimportant other than its penchant to crystallize in joints to cause the disease gout. In recent years, however, there has
been the realization that uric acid is not biologically inert but may have a wide range of actions, including being both a
pro- and anti-oxidant, a neurostimulant, and an inducer of inflammation and activator of the innate immune response. In this
paper, we present the hypothesis that uric acid has a key role in the foraging response associated with starvation and fasting.
We further suggest that there is a complex interplay between fructose, uric acid and vitamin C, with fructose and uric acid
stimulating the foraging response and vitamin C countering this response. Finally, we suggest that the mutations in ascorbate
synthesis and uricase that characterized early primate evolution were likely in response to the need to stimulate the foraging
“survival” response and might have inadvertently had a role in accelerating the development of bipedal locomotion and intellectual
development. Unfortunately, due to marked changes in the diet, resulting in dramatic increases in fructose- and purine-rich
foods, these identical genotypic changes may be largely responsible for the epidemic of obesity, diabetes and cardiovascular
disease in today’s society.
Disclaimers Dr Johnson is listed as an inventor on several patent applications related to the role of uric acid in hypertension and metabolic
syndrome; Dr Johnson is also an author for a book on fructose and uric acid (The Sugar Fix) that was published by Rodale in
2008. 相似文献
943.
Akiko Yanagiya Yuri V. Svitkin Shoichiro Shibata Satoshi Mikami Hiroaki Imataka Nahum Sonenberg 《Molecular and cellular biology》2009,29(6):1661-1669
Eukaryotic mRNAs possess a 5′-terminal cap structure (cap), m7GpppN, which facilitates ribosome binding. The cap is bound by eukaryotic translation initiation factor 4F (eIF4F), which is composed of eIF4E, eIF4G, and eIF4A. eIF4E is the cap-binding subunit, eIF4A is an RNA helicase, and eIF4G is a scaffolding protein that bridges between the mRNA and ribosome. eIF4G contains an RNA-binding domain, which was suggested to stimulate eIF4E interaction with the cap in mammals. In Saccharomyces cerevisiae, however, such an effect was not observed. Here, we used recombinant proteins to reconstitute the cap binding of the mammalian eIF4E-eIF4GI complex to investigate the importance of the RNA-binding region of eIF4GI for cap interaction with eIF4E. We demonstrate that chemical cross-linking of eIF4E to the cap structure is dramatically enhanced by eIF4GI fragments possessing RNA-binding activity. Furthermore, the fusion of RNA recognition motif 1 (RRM1) of the La autoantigen to the N terminus of eIF4GI confers enhanced association between the cap structure and eIF4E. These results demonstrate that eIF4GI serves to anchor eIF4E to the mRNA and enhance its interaction with the cap structure.The cap structure, m7GpppN, is present at the 5′ terminus of all nuclear transcribed eukaryotic mRNAs. Cap-dependent binding of the ribosome to mRNA is mediated by the cap-binding protein eukaryotic translation initiation factor 4E (eIF4E), which forms a complex termed eIF4F together with eIF4G and eIF4A. Mammalian eIF4G, which has two isoforms, eIF4GI and eIF4GII, is a modular, multifunctional protein that binds to poly(A)-binding protein (PABP) (14) and eIF4E (18, 20) via the N-terminal third region. Mammalian eIF4G binds to eIF4A and eIF3 (15) via the middle third region and to eIF4A and Mnk protein kinase at the C-terminal region. eIF4GI also possesses an RNA-binding sequence (2, 9, 33) in the middle region. There are two RNA-binding sites on eIF4GI; one is located amino terminal to the first HEAT domain, and the other is located within the first HEAT domain (23). Mammalian and Saccharomyces cerevisiae eIF4E are similar in size (24 kDa), but mammalian eIF4GI (220 kDa) is larger than its yeast counterpart (150 kDa), as the latter lacks a C-terminal domain corresponding to mammalian eIF4GI (38).The affinity of eIF4E for the cap structure has been a matter of dispute for some time. The earlier works of Carberry et al. (4) and Ueda et al. (39) estimated the equilibrium dissociation constant (Kd) of the eIF4E-cap complex by fluorescence titration to be 2 × 10−6 to 5 × 10−6 M depending on the nature of the cap analog. Later on, development of a new methodology for the fluorescence titration experiments yielded Kd values of 10−7 to 10−8 (29, 41). The source of the difference with the previous reports was thoroughly analyzed (29, 30). The interaction between the cap structure and eIF4E is dramatically enhanced by eIF4GI. This was first reported by showing that cross-linking of mammalian eIF4E to the cap structure is more efficient when it is a subunit of the eIF4F complex (19) or when it is complexed to eIF4GI (11). A similar enhancement of the binding of eIF4E to the cap structure was observed in yeast (40). However, two very different mechanisms were proposed to explain these observations. For the mammalian system, it was postulated that the middle segment of eIF4GI, which binds RNA, stabilizes the eIF4E interaction with the cap structure (11). This model was based primarily on the finding that in poliovirus-infected cells, eIF4GI is cleaved between its N-terminal third and the middle third, and consequently, eIF4E remains attached to the N-terminal eIF4GI fragment lacking the RNA-binding region. Under these conditions, cross-linking of eIF4E to the cap structure was poor (19, 31). In contrast, in yeast, a strong interaction between the cap structure and eIF4E was achieved using an eIF4G fragment containing the eIF4E-binding site that lacks the RNA-binding region (34, 40). Also, the yeast eIF4G fragment from amino acids 393 to 490 (fragment 393-490), which does not contain the RNA-binding site, forms a right-handed helical ring that wraps around the N terminus of eIF4E. This conformational change was suggested in turn to engender an allosteric enhancement of the association of eIF4E with the cap structure (10). Such an interaction between mammalian eIF4GI and eIF4E has not been reported.To understand the mechanism by which eIF4GI stimulates the interaction of eIF4E with the cap structure in mammals, we reconstituted the eIF4E-cap recognition activity in vitro with purified eIF4E and eIF4GI recombinant proteins. Using a chemical cross-linking assay, we demonstrate that only mammalian eIF4GI fragments possessing RNA-binding activity enhance the cross-linking of eIF4E to the cap structure. Our data provide new insight into the mechanism of cap recognition by the eIF4E-eIF4GI complex. 相似文献
944.
Elena Kaparullina Nina DoroninaTatyana Chistyakova Yuri Trotsenko 《Systematic and applied microbiology》2009
A new ethylenediaminetetraacetic acid (EDTA)-utilizing gammaproteobacterial strain LPM-5T was isolated from municipal sewage sludge. Aerobic, gram-negative, motile rods multiply by binary fission. Neutrophilic and mesophilic, these are unable to grow in the presence of 3% NaCl (w/v), and unable to reduce nitrate to nitrite, and are oxidase and catalase positive, but lipase negative. The major cellular fatty acids are Ci15:0, Ca15:0 and C16:1w7c. The dominant phospholipids are phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol (cardiolipin). The DNA G+C content is 68.3 mol% (Tm). The 16S rRNA gene sequence analysis showed a high similarity of strain LPM-5T to the species members of genus Stenotrophomonas: S. maltophilia LMG 958T (98.6%), S. rhizophila CCUG 47042T (98.3%), S. koreensis TR6-01T (97.6%) and S. acidaminiphila CIP 106456T (97.0%). Based on these results and modest DNA–DNA hybridization levels with S. maltophilia VKM B-591T (=LMG 958T) (51%) and S. rhizophila CCUG 47042T (52%), the isolate was classified as a novel species, Stenotrophomonas chelatiphaga sp. nov. (type strain LPM-5T=VKM B-2486=DSM-21508=CCUG 57178). 相似文献
945.
946.
Mizuho Tamura Reiko Aizawa Masatoshi Hori Hiroshi Ozaki 《Histochemistry and cell biology》2009,131(4):483-490
Adenine phosphoribosyltransferase deficiency in mice or an excessive oral intake of adenine leads to the accumulation of 2,8-dihydroxyadenine
(DHA) in renal tubules and that causes progressive renal dysfunction accompanied by interstitial fibrosis. However, the precise
mechanism responsible for DHA-induced progressive fibrosis is not fully understood. The present study investigates the possible
involvement of monocytes/macrophages in the progressive fibrosis induced by feeding adenine to mice. Urinary calculi were
deposited in tubules on day 7 after the initiation of adenine feeding. Elevation of the serum creatinine level and loss of
body weight were observed in a time-dependent manner, suggesting the development of typical renal dysfunction induced by the
adenine feeding. In renal tissue, mRNA expression of MCP-1, MIP-1α, RANTES, IL-1β, CCR2, TGF-β, α-smooth muscle actin (α-SMA)
and collagen 1a1 was increased in parallel. Along with the increased expression of these genes, a remarkable infiltration
of macrophages into the tubulointerstitial area was observed in a time-dependent manner. In addition, in the tubulointerstitial
area, α-SMA positive fibroblasts were increased in parallel with collagen deposition. These results suggest that the excessive
consumption of adenine leads to progressive renal dysfunction in mice. We speculate that the accumulation of DHA in tubules
might stimulate epithelium to produce MCP-1 and that profibrogenic TGF-β produced by infiltrated macrophages might stimulate
interstitial fibroblasts to produce collagen. These results indicate that macrophage infiltration is one of the triggers that
initiates interstitial fibroblast activation and collagen deposition followed by renal dysfunction. 相似文献
947.
M. Hori 《Journal of Applied Entomology》2009,133(6):438-443
The olfactory response of the sorghum plant bug, Stenotus rubrovittatus (Matsumura) (Het., Miridae), to rice, Oryza sativa L., and paddy weed, Scirpus juncoides Roxb. var. ohwianus T. Koyama, was investigated with an olfactometer to clarify the mechanism of the invasion of the bugs in paddy fields. Both adult females and males were significantly attracted to panicles of rice in the flowering and full‐ripe stages. Whole plants (aboveground parts) of rice in the panicle‐formation stage, and stems and leaves of rice in the flowering stage significantly attracted only adult females. Other rice structures tested did not attract males or females. Both males and females were attracted to the flowering spikelets of S. juncoides. Although females showed no olfactory response to stems of S. juncoides in the flowering stage, males were repelled by them. Only females were attracted to whole plants of flowering S. juncoides. Whole plants of S. juncoides in the spikelet‐formation stage significantly attracted only females. The findings suggest that the invasions of S. rubrovittatus into paddy fields are caused by their olfactory responses to the volatiles emitted from rice and some paddy weeds such as S. juncoides. 相似文献
948.
Yuri Shibasaki Michiko Hayasaka Makoto Kakitani Kazuma Tomizuka 《Biochemical and biophysical research communications》2009,381(4):482-486
NaPi-IIb encodes a Na+-dependent Pi co-transporter, which is expressed in various adult tissues and mediates transport of extracellular Pi ions coupling with Na+ ion. To define the role of NaPi-IIbin vivo, NaPi-IIb gene deficient mice were generated utilizing targeted mutagenesis, yielding viable, heterozygous NaPi-IIb mice. In contrast, homozygous NaPi-IIb mice died in utero soon after implantation, indicating that NaPi-IIb was essential for early embryonic development. In situ hybridization revealed NaPi-IIb mRNA expression in the parietal endoderm, followed by the visceral endoderm, at a time point prior to establishment of a functioning chorio-allantoic placenta. At the time point of functional placenta development, the main site of NaPi-IIb production resided in the labyrinthine zone, where embryonic and maternal circulations were in closest contact. Expression patterns of NaPi-IIb suggest that NaPi-IIb plays an important role in Pi absorption from maternal circulation. 相似文献
949.
We attempted to evaluate the affinity of the anionic phospholipids to cytochrome c by means of surface plasmon resonance (SPR) technique and to correlate it with the cytochrome c active site alterations and peroxidase activity. Our experiments showed a strong interdependence between the phospholipid fatty acid saturation degree, the active site structure alterations and peroxidase activity of the cytochrome c phospholipid complex. Cytochrome c peroxidase activity and Trp59 fluorescence increase in the sequence of phosphatidyl choline (PC) → phosphatidylserine (PS) → cardiolipin (CL) → phosphatidic acid (PA). The association constant (Ka) increased in the sequence PC → PA → PS → CL. The SPR spectroscopy data shows that Ka is independent of lipid saturation degree, but correlates with phospholipid negative charge value. 相似文献
950.
Kenji Komatsu Yuri Nishikawa Tomohito Ohtsuka Teruaki Taji Ralph S. Quatrano Shigeo Tanaka Yoichi Sakata 《Plant molecular biology》2009,70(3):327-340
We employed a comparative genomic approach to understand protein phosphatase 2C (PP2C)-mediated abscisic acid (ABA) signaling
in the moss Physcomitrella patens. Ectopic expression of Arabidopsis (Arabidopsis thaliana) abi1-1, a dominant mutant allele of ABI1 encoding a PP2C involved in the negative regulation of ABA signaling, caused ABA insensitivity of P. patens both in gene expression of late embryogenesis abundant (LEA) genes and in ABA-induced protonemal growth inhibition. The transgenic
abi1-1 plants showed decreased ABA-induced freezing tolerance, and decreased tolerance to osmotic stress. Analyses of the P. patens genome revealed that only two (PpABI1A and PpABI1B) PP2C genes were related to ABI1. In the ppabi1a null mutants, ABA-induced expression of LEA genes was elevated, and protonemal growth was inhibited with lower ABA concentration compared to the wild type. Moreover,
ABA-induced freezing tolerance of the ppabi1a mutants was markedly enhanced. We provide the genetic evidence that PP2C-mediated ABA signaling is evolutionarily conserved
between Arabidopsis and P. patens.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Accession Numbers: PpABI1A-AB369256, PpABI1B-AB369255, pphn39k21-AB369257. 相似文献