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971.
Yan Z. Voloshin Oleg A. Varzatskii Ivan I. Vorontsov Ekaterina G. Lebed 《Inorganica chimica acta》2005,358(1):131-146
The template condensation of three methylchloroglyoximate molecules with phenylboronic acid and with BF3 · O(C2H5)2 on an iron(II) ion afforded reactive trichloride phenylboron- and fluoroboron-capped precursors, respectively. The monochloride FeBd2(CH3ClGm)(BF)2 precursor (where Bd2− and CH3ClGm2− are α-benzyldioxime and methylchloroglyoxime dianions) was synthesized by condensation of macrocyclic iron(II) α-benzyldioximate FeBd2(BF2)2(CH3CN)2 with CH3ClGmH2. Mono- and trifunctionalized amine, alkylsulfide, and arylsulfide clathrochelate iron(II) tris-dioximates were prepared starting from these precursors by nucleophilic substitution reactions. The complexes obtained were characterized using elemental analysis, PD mass, IR, UV-Vis, 1H, 13C NMR, and 57Fe Mössbauer spectra, and X-ray crystallography. An encapsulated low-spin iron(II) ion was found to have distorted trigonal-prismatic coordination N6-environment in all clathrochelates synthesized. 相似文献
972.
Reichenbach B Delalande JM Kolmogorova E Prier A Nguyen T Smith CM Holzschuh J Shepherd IT 《Developmental biology》2008,318(1):52-64
The zebrafish enteric nervous system (ENS), like those of all other vertebrate species, is principally derived from the vagal neural crest cells (NCC). The developmental controls that govern the migration, proliferation and patterning of the ENS precursors are not well understood. We have investigated the roles of endoderm and Sonic hedgehog (SHH) in the development of the ENS. We show that endoderm is required for the migration of ENS NCC from the vagal region to the anterior end of the intestine. We show that the expression of shh and its receptor ptc-1 correlate with the development of the ENS and demonstrate that hedgehog (HH) signaling is required in two phases, a pre-enteric and an enteric phase, for normal ENS development. We show that HH signaling regulates the proliferation of vagal NCC and ENS precursors in vivo. We also show the zebrafish hand2 is required for the normal development of the intestinal smooth muscle and the ENS. Furthermore we show that endoderm and HH signaling, but not hand2, regulate gdnf expression in the intestine, highlighting a central role of endoderm and SHH in patterning the intestine and the ENS. 相似文献
973.
Pamplona R Naudí A Gavín R Pastrana MA Sajnani G Ilieva EV Del Río JA Portero-Otín M Ferrer I Requena JR 《Free radical biology & medicine》2008,45(8):1159-1166
The basic molecular underpinnings of the pathological changes that unfold in prion disease remain elusive. A key role of increased oxidative stress has been hypothesized. Given the transient nature of most intermediate molecules implicated, increased oxidative stress is better assessed by quantitating the damage it causes to macromolecules. We used mass spectrometry-based methods to measure specific products of protein oxidation, glycoxidation, and lipoxidation in brains from patients suffering from Creutzfeldt-Jakob disease and Syrian hamsters affected by scrapie. In both cases, increased amounts of glutamic and aminoadipic semialdehydes, products of metal-catalyzed oxidation, malondialdehydelysine (a product of lipoxidation), N-epsilon-carboxyethyllysine (a product of glycoxidation), and N-epsilon-carboxymethyllysine (generated by lipoxidation and glycoxidation) were measured. PrP(Sc), the infectious isoform of the prion protein that accumulates in prion disease, was itself shown to be a target of increased oxidative modification. These changes were accompanied by alterations in fatty acid composition and increased phosphorylation of ERK(1/2) and p38, protein kinases known to respond to increased flows of ROS. These data support an important role of oxidative damage in the pathology of prion disease. 相似文献
974.
Shkoporov AN Khokhlova EV Kulagina EV Smeianov VV Kafarskaia LI Efimov BA 《Bioscience, biotechnology, and biochemistry》2008,72(3):742-748
Bifidobacteria and Bacteroides-like bacteria are strictly anaerobic nonpathogenic members of human intestinal microflora. Here we describe an analysis of the species and subspecies composition of these bacterial populations in healthy children using a combination of culture and molecular methods at two different time points. It was found that B. bifidum and B. longum are the most common dominant taxons in infants aged between 8 and 16 months. The majority of the infants carried several dominant Bifidobacterium strains belonging to different species. Examination of the dominant bifidoflora in some of these children after a 5-year period showed major shifts in both species and strain composition, but the dominant strains remained unchanged in two children. The majority of dominant Bacteroides-like isolates belonged to species B. vulgatus and B. uniformis, but members of genera Alistipes and Barnesiella were common too. In addition, a novel approach to species identification of Bacteroidales order bacteria using amplified ribosomal DNA restriction analysis (ARDRA) is described. 相似文献
975.
976.
Serdin1/Lrrc10 is dispensable for mouse development 总被引:1,自引:0,他引:1
We have previously identified Serdin1/Lrrc10 as a cardiac-specific message that is expressed early in murine heart development and encodes a novel leucine-rich protein. A high degree of evolutionary conservation with respect to protein sequence, cardiac-specific expression, and cis-regulatory elements suggested that LRRC10 has an important and conserved function in cardiac development. Recently, the zebrafish lrrc10 knockdown models were described with a dramatic early defect in heart looping which supported the notion that Serdin1/Lrrc10 is likely to be essential for heart development in all vertebrates. To determine Lrrc10 function in mammalian cardiac development, we have disrupted the Lrrc10 gene in mice. We report here that, in striking contrast to the zebrafish lrrc10 knockdown, Lrrc10-null mice develop normally and exhibit no discernable phenotype. 相似文献
977.
Shenkarev ZO Nadezhdin KD Lyukmanova EN Sobol VA Skjeldal L Arseniev AS 《Journal of inorganic biochemistry》2008,102(5-6):1246-1256
The cyclotides are the family of hydrophobic bioactive plant peptides, characterized by a circular protein backbone and three knot forming disulfide bonds. It is believed that membrane activity of the cyclotides underlines their antimicrobial, cytotoxic and hemolytic properties, but the specific interactions with divalent cations can be also involved. To assess the mode of membrane interaction and divalent cation coordination in cyclotides, the spatial structure of the Möbius cyclotide Kalata B7 from the African perennial plant Oldenlandia affinis was determined in the presence of anisotropic membrane mimetic (dodecylphosphocholine micelles). The model of peptide/cation/micelle complex was built using 5-doxylstearate and Mn2+ relaxation probes. Results show that the peptide binds to the micelle surface with relatively high affinity by two hydrophobic loops (loop 2 – Thr6-Leu7 and loop 5 – Trp19-Ile21). The partially hydrated divalent cation is coordinated by charged side-chain of Glu3, aromatic side chain of Tyr11 and free carbonyls of Thr4 and Thr9, and is located in direct contact with the polar head-groups of detergent. The comparison with data about other cyclotides indicates that divalent cation coordination is the invariant property of all cyclotides, but the mode of peptide/membrane interactions is varied. Probably, the specific cation/peptide interactions play a major, but yet not known, role in the biological activity of the cyclotides. 相似文献
978.
Patricia Torres-Cañabate Eric A. Davidson Ekaterina Bulygina Roberto García-Ruiz Jose A. Carreira 《Biogeochemistry》2008,91(1):1-11
Evidence for abiotic immobilization of nitrogen (N) in soil is accumulating, but remains controversial. Identifying the fate
of N from atmospheric deposition is important for understanding the N cycle of forest ecosystems. We studied soils of two
Abies pinsapo fir forests under Mediterranean climate seasonality in southern Spain—one with low N availability and the other with symptoms
of N saturation. We hypothesized that biotic and abiotic immobilization of nitrate (NO3
−) would be lower in soils under these forests compared to more mesic temperate forests, and that the N saturated stand would
have the lowest rates of NO3
− immobilization. Live and autoclaved soils were incubated with added 15NO3
− (10 μg N g−1 dry soil; 99% enriched) for 24 h, and the label was recovered as total dissolved-N, NO3
−, ammonium (NH4
+), or dissolved organic-N (DON). To evaluate concerns about possible iron interference in analysis of NO3
− concentrations, both flow injection analysis (FIA) and ion chromatography (IC) were applied to water extracts, soluble iron
was measured in both water and salt extracts, and standard additions of NO3
− to salt extracts were analyzed. Good agreement between FIA and IC analysis, low concentrations of soluble Fe, and 100% (±3%)
recovery of NO3
− standard additions all pointed to absence of an interference problem for NO3
− quantification. On average, 85% of the added 15NO3
− label was recovered as 15NO3
−, which supports our hypothesis that rates of immobilization were generally low in these soils. A small amount (mean = 0.06 μg N g−1 dry soil) was recovered as 15NH4
+ in live soils and none in sterilized soils. Mean recovery as DO15N ranged from 0.6 to 1.5 μg N g−1 dry soil, with no statistically significant effect of sterilization or soil type, indicating that this was an abiotic process
that occurred at similar rates in both soils. These results demonstrate a detectable, but modest rate of abiotic immobilization
of NO3
− to DON, supporting our first hypothesis. These mineral soils may not have adequate carbon availability to support the regeneration
of reducing microsites needed for high rates of NO3
− reduction. Our second hypothesis regarding lower expected abiotic immobilization in soils from the N-saturated site was not
supported. The rates of N deposition in this region may not be high enough to have swamped the capacity for soil NO3
− immobilization, even in the stand showing some symptoms of N saturation. A growing body of evidence suggests that soil abiotic
NO3
− immobilization is common, but that rates are influenced by a combination of factors, including the presence of plentiful
available carbon, reduced minerals in anaerobic microsites and adequate NO3
− supply. 相似文献
979.
Microtubule-associated proteins (MAPs) ensure the fidelity of chromosome segregation by controlling microtubule (MT) dynamics and mitotic spindle stability. However, many aspects of MAP function and regulation are poorly understood in a developmental context. We show that mars, which encodes a Drosophila melanogaster member of the hepatoma up-regulated protein family of MAPs, is essential for MT stabilization during early embryogenesis. As well as associating with spindle MTs in vivo, Mars binds directly to protein phosphatase 1 (PP1) and coimmunoprecipitates from embryo extracts with minispindles and Drosophila transforming acidic coiled-coil (dTACC), two MAPs that function as spindle assembly factors. Disruption of binding to PP1 or loss of mars function results in elevated levels of phosphorylated dTACC on spindles. A nonphosphorylatable form of dTACC is capable of rescuing the lethality of mars mutants. We propose that Mars mediates spatially controlled dephosphorylation of dTACC, which is critical for spindle stabilization. 相似文献
980.
Shebzukhov YV Lavrik IN Karbach J Khlgatian SV Koroleva EP Belousov PV Kashkin KN Knuth A Jager E Chi NW Kuprash DV Nedospasov SA 《Cancer immunology, immunotherapy : CII》2008,57(6):871-881
Purpose Tankyrases 1 and 2 are telomere-associated poly(ADP-ribose) polymerases (PARP) that can positively regulate telomere elongation
and interact with multiple cellular proteins. Recent reports implicated tankyrases as tumor antigens and potential targets
of anticancer treatment. We examined expression of tankyrases in colon tumors and immune response to these enzymes in patients
with different types of cancer.
Methods mRNA and protein expression was evaluated by quantitative real-time RT-PCR and Western blotting, respectively. Humoral immune
response to recombinant tankyrases was investigated by modified enzyme-linked immunoassays. Cellular immune response was analysed
by ELISPOT and 51Cr release assays.
Results We found that both mRNA and protein levels of tankyrase 2 (TNKL) are upregulated in colon tumors. In contrast, protein level
of tankyrase 1 (TNKS) is downregulated, while mRNA level shows variable changes. More than a quarter of colon cancer patients
develop humoral immune response to at least one of the two tankyrases. In this study we mapped common and unique B-cell epitopes
located in different domains of the two proteins. Additionally, we present evidence for T-cell responses both to epitopes
that are unique for TNKL and to those shared between TNKL and TNKS.
Conclusion Our study favors a biomarker usage of antibody response to tankyrases. Spontaneous CD8+ T-cell responses to these enzymes are rare and further investigation is needed to evaluate tankyrases as potential targets
for cancer immunotherapy. 相似文献