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31.
Massimiliano Arca Francesco Demartin Lluis Escriche Francesco Isaia Vito Lippolis Vicent Muns Mojtaba Shamsipur Abdollah Yari 《Inorganica chimica acta》2005,358(7):2403-2412
The macrocycles L1-L3 having N2S2O-, N2S2-, and N2S3-donor sets, respectively, and incorporating the 1,10-phenanthroline unit interact in EtOH and MeCN solutions with CuII to give 1:1 [M(L)]2+ complex species. The compounds [Cu(L1)(ClO4)]ClO4 (1), [Cu(L2)(ClO4)]ClO4 · (2) and [Cu(L3)](ClO4)2 (3) were isolated at the solid state and the first two also characterised by X-ray diffraction studies. The conformation adopted by L1 and L2 in the cation complexes reveals the aliphatic portion of the rings folded over the plane containing the heteroaromatic moiety with the ligands encapsulating the metal centre within their cavity by imposing, respectively, a square-based pyramidal and a square planar geometry. In both complexes, the metal ion completes its coordination sphere by interacting with a ClO4− ligand. The compound [Cu(L3)2](PF6)2 (4) containing a 1:2 cation complex was also isolated at the solid state: EPR spectroscopy measurements suggest the presence of a CuN4 chromophore in this complex. The EPR and electronic spectral features of 1-4 have been studied and their redox properties examined in comparison with those observed for Type-1 blue copper proteins.The reactivity of L1-L3 has also been tested toward stoichiometric amounts of the CuI salt [CuCl(PPh3)3]. 相似文献
32.
Ruiz MA Escriche M Lluis C Franco R Martín M Andrés A Ros M 《Journal of neurochemistry》2000,75(2):656-664
Adenosine A(1) receptors (A(1)Rs) have been characterized in primary cultures of neurons from cerebral cortex. The specific adenosine A(1) antagonist 8-cyclopentyl-1,3-[(3)H]dipropylxanthine bound to both membranes and intact cells. When saturation experiments were performed in membranes, a K(D) value of 0.76 nM and a B(max) of 57 fmol/mg of protein were obtained. Competition assays revealed a pharmacological profile characteristic of A(1)Rs. The presence of this receptor was further confirmed by RT-PCR analysis. The expression of the receptor showed no significant changes during the period of culture studied, up to 12 days in vitro. A(1)R agonist inhibited forskolin-stimulated adenylyl cyclase, showing the functional coupling of these receptors with the effector. alphaG(i1, 2) protein level, detected by immunoblot, presented an increase during the period of culture. This increase correlated with an increase in the mRNA level of alphaG(i1) but not alphaG(i2). By immunochemical assays, it is shown that these receptors are expressed in both the neuronal cell body and the proximal dendrites. Colocalization of A(1)Rs with microtubule-associated protein 2 and cell surface adenosine deaminase was shown by confocal microscopy. The high degree of colocalization observed between A(1)Rs and ectoadenosine deaminase in neurons could suggest an important role of the enzyme in adenosine-mediated neuromodulation. 相似文献
33.
Quintela I Vizoso F Serra C González LO Fernandez R Merino AM Baltasar A 《The International journal of biological markers》2001,16(4):240-244
BACKGROUND: The aim of this study was to evaluate the pepsinogen C expression in malignant cutaneous melanomas and analyze its possible relationship to clinical and pathological parameters. Pepsinogen C is an aspartyl proteinase primarily involved in the digestion of proteins in the stomach and represents one of the main androgen-inducible proteins in breast cancer cells. METHOD: Tumoral pepsinogen C expression was retrospectively analyzed in 35 paraffin-embedded tissues from patients with primary malignant cutaneous melanoma and in 10 samples from 10 benign lesions (4 dermal melanocytic nevi, 4 compound melanocytic nevi and 2 dysplastic melanocytic nevi), using immunohistochemical methods. RESULTS: The benign lesions were consistently negative for pepsinogen C, whereas 20 of the 35 malignant melanomas (57%) showed positive immunostaining for pepsinogen C. The percentage of pepsinogen C-positive tumors was significantly higher in men than in women (p=0.01) and in epithelioid melanomas than in fusocellular or mixed type melanomas (p=0.003). In addition, the percentage of pepsinogen-C positive tumors was positively and significantly correlated with lesion thickness (p=0.003), Clark's level of invasion (p=0.028) and tumor stage (p<0.001). CONCLUSION: Pepsinogen C could be a new prognosticator of unfavorable outcome in cutaneous malignant melanoma. 相似文献
34.
González-Cabrera J Herrero S Sayyed AH Escriche B Liu YB Meyer SK Wright DJ Tabashnik BE Ferré J 《Applied and environmental microbiology》2001,67(10):4610-4613
So far, the only insect that has evolved resistance in the field to Bacillus thuringiensis toxins is the diamondback moth (Plutella xylostella). Documentation and analysis of resistant strains rely on comparisons with laboratory strains that have not been exposed to B. thuringiensis toxins. Previously published reports show considerable variation among laboratories in responses of unselected laboratory strains to B. thuringiensis toxins. Because different laboratories have used different unselected strains, such variation could be caused by differences in bioassay methods among laboratories, genetic differences among unselected strains, or both. Here we tested three unselected strains against five B. thuringiensis toxins (Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ca, and Cry1Da) using two bioassay methods. Tests of the LAB-V strain from The Netherlands in different laboratories using different bioassay methods yielded only minor differences in results. In contrast, side-by-side comparisons revealed major genetic differences in susceptibility between strains. Compared with the LAB-V strain, the ROTH strain from England was 17- to 170-fold more susceptible to Cry1Aa and Cry1Ac, respectively, whereas the LAB-PS strain from Hawaii was 8-fold more susceptible to Cry1Ab and 13-fold more susceptible to Cry1Da and did not differ significantly from the LAB-V strain in response to Cry1Aa, Cry1Ac, or Cry1Ca. The relative potencies of toxins were similar among LAB-V, ROTH, and LAB-PS, with Cry1Ab and Cry1Ac being most toxic and Cry1Da being least toxic. Therefore, before choosing a standard reference strain upon which to base comparisons, it is highly advisable to perform an analysis of variation in susceptibility among field and laboratory populations. 相似文献
35.
Development and Characterization of Diamondback Moth Resistance to Transgenic Broccoli Expressing High Levels of Cry1C 总被引:7,自引:5,他引:2 下载免费PDF全文
Jian-Zhou Zhao Hilda L. Collins Juliet D. Tang Jun Cao Elizabeth D. Earle Richard T. Roush Salvador Herrero Baltasar Escriche Juan Ferr Anthony M. Shelton 《Applied microbiology》2000,66(9):3784-3789
A field-collected colony of the diamondback moth, Plutella xylostella, had 31-fold resistance to Cry1C protoxin of Bacillus thuringiensis. After 24 generations of selection with Cry1C protoxin and transgenic broccoli expressing a Cry1C protein, the resistance that developed was high enough that neonates of the resistant strain could complete their entire life cycle on transgenic broccoli expressing high levels of Cry1C. After 26 generations of selection, the resistance ratios of this strain to Cry1C protoxin were 12,400- and 63,100-fold, respectively, for the neonates and second instars by a leaf dip assay. The resistance remained stable until generation 38 (G38) under continuous selection but decreased to 235-fold at G38 when selection ceased at G28. The Cry1C resistance in this strain was seen to be inherited as an autosomal and incompletely recessive factor or factors when evaluated using a leaf dip assay and recessive when evaluated using Cry1C transgenic broccoli. Saturable binding of 125I-Cry1C was found with brush border membrane vesicles (BBMV) from both susceptible and Cry1C-resistant strains. Significant differences in Cry1C binding to BBMV from the two strains were detected. BBMV from the resistant strain had about sevenfold-lower affinity for Cry1C and threefold-higher binding site concentration than BBMV from the susceptible strain. The overall Cry1C binding affinity was just 2.5-fold higher for BBMV from the susceptible strain than it was for BBMV from the resistant strain. These results suggest that reduced binding is not the major mechanism of resistance to Cry1C. 相似文献
36.
37.
Medine CN Lucendo-Villarin B Zhou W West CC Hay DC 《Journal of visualized experiments : JoVE》2011,(56):e2969
Despite progress in modelling human drug toxicity, many compounds fail during clinical trials due to unpredicted side effects. The cost of clinical studies are substantial, therefore it is essential that more predictive toxicology screens are developed and deployed early on in drug development (Greenhough et al 2010). Human hepatocytes represent the current gold standard model for evaluating drug toxicity, but are a limited resource that exhibit variable function. Therefore, the use of immortalised cell lines and animal tissue models are routinely employed due to their abundance. While both sources are informative, they are limited by poor function, species variability and/or instability in culture (Dalgetty et al 2009). Pluripotent stem cells (PSCs) are an attractive alternative source of human hepatocyte like cells (HLCs) (Medine et al 2010). PSCs are capable of self renewal and differentiation to all somatic cell types found in the adult and thereby represent a potentially inexhaustible source of differentiated cells. We have developed a procedure that is simple, highly efficient, amenable to automation and yields functional human HLCs (Hay et al 2008 ; Fletcher et al 2008 ; Hannoun et al 2010 ; Payne et al 2011 and Hay et al 2011). We believe our technology will lead to the scalable production of HLCs for drug discovery, disease modeling, the construction of extra-corporeal devices and possibly cell based transplantation therapies. 相似文献
38.
Alvarez-Martín P O'Connell-Motherway M van Sinderen D Mayo B 《Applied microbiology and biotechnology》2007,76(6):1395-1402
To determine the minimal replicon of pBC1 (a 2.5-kb cryptic plasmid of Bifidobacterium catenulatum L48) and to check the functionality of its identified open reading frames (ORFs) and surrounding sequences, different segments
of pBC1 were amplified by polymerase chain reaction (PCR) and cloned into pBif, a replication probe vector for bifidobacteria.
The largest fragment tested in this manner encompassed most of the pBC1 sequence, while the shortest just included the repB gene and its immediate upstream sequences. Derivatives were all shown to allow replication in bifidobacteria. Surprisingly,
both the transformation frequency and segregational stability in the absence of antibiotic selection decreased with reducing
plasmid length. The relative copy number of the constructs (ranging from around 3 to 23 copies per chromosome equivalent,
as compared to 30 copies for the original pBC1) was shown to be strain dependent and to decrease with reducing plasmid length.
These results suggest that, although not essential, the copG-like and orfX-like genes of pBC1 play important roles in pBC1 replication. Interruption of repB produced a construct incapable of replicating in bifidobacteria. The analysis of pBC1 will allow its use in the construction
of general and specific cloning vectors. 相似文献
39.
Screening of Exopolysaccharide-Producing Lactobacillus and Bifidobacterium Strains Isolated from the Human Intestinal Microbiota 下载免费PDF全文
Patricia Ruas-Madiedo Jos Antonio Moreno Nuria Salazar Susana Delgado Baltasar Mayo Abelardo Margolles Clara G. de los Reyes-Gaviln 《Applied microbiology》2007,73(13):4385-4388
Using phenotypic approaches, we have detected that 17% of human intestinal Lactobacillus and Bifidobacterium strains could be exopolysaccharide (EPS) producers. However, PCR techniques showed that only 7% harbored genes related to the synthesis of heteropolysaccharides. This is the first work to screen the human intestinal ecosystem for the detection of EPS-producing strains. 相似文献
40.
Ostrinia nubilalis Hübner (Lepidoptera: Crambidae), a major pest of corn in temperate climates, can feed on other crops due to its polyphagous behaviour. In particular, this species became a serious problem in some sweet pepper commercial glasshouses in south‐eastern Spain repeatedly sprayed with Bacillus thuringiensis (Bt) products to control Spodoptera exigua Hübner (Lepidoptera: Noctuidae). The susceptibility of an O. nubilalis colony established from individuals collected in these Bt‐sprayed glasshouses was compared with a reference laboratory colony. Differences in susceptibility between the two colonies to Cry1Aa, Cry1Ab, Cry1Ac and Cry2Aa proteins were found. However, our results indicate that the O. nubilalis control failure in the glasshouse was not due to selection for resistance. Intraspecific variation probably accounts for differences between the glasshouse‐derived population and the laboratory strain. This conclusion is based on several lines of evidence: the glasshouse‐derived population retained its susceptibility to a Bt standard product and to most of its individual components (both in the form of protoxins and in the form of activated toxins), and it did not respond to laboratory selection with high doses of Cry1Ab. 相似文献