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931.
This article describes the use of a cationized starch-based material as new ion-exchanger adsorbent for the removal of C.I. Acid Blue 25 (AB 25) from aqueous solutions. Batch adsorption studies concerning the effects of contact time, pH and temperature are presented and discussed. Adsorption experimental data showed that: (i) the process was uniform and rapid: adsorption of dye reached equilibrium in 50 min in the wide pH range of dye solutions; (ii) adsorption kinetics followed the pseudo-second order model; (iii) the Langmuir model yielded a much better fit than the Freundlich model for the dye concentration range under study; (iv) this adsorbent exhibited interesting adsorption capacities: on the basis of the Langmuir analysis, the maximum adsorption capacity was determined to be 322 mg of dye per gram of material at 25 degrees C; (v) the adsorption capacity decreased with increasing temperature; and (vi) the negative value of free energy change indicated the spontaneous nature of adsorption. 相似文献
932.
Bézière N Goossens L Pommery J Vezin H Touati N Hénichart JP Pommery N 《Bioorganic & medicinal chemistry letters》2008,18(16):4655-4657
The design of profen hybrids containing a NO donor moiety connected to an aliphatic spacer led to compounds with a similar cyclooxygenase inhibition compared to their parent profen and with significant antiproliferative activities on PC3 cells. However, inhibition of COX-2 pathway alone did not seem sufficient to inhibit cancer cell proliferation, and NO-release in a time-dependent manner strongly contributes to this activity. 相似文献
933.
do Nascimento C Santos Barbosa RE Mardegan Issa JP Watanabe E Yoko Ito I Monesi N Albuquerque Junior RF 《Microbiological research》2008,163(4):403-407
Molecular methods that permit the simultaneous detection and quantification of a large number of microbial species are currently employed in the evaluation of complex ecosystems. The checkerboard DNA-DNA hybridization technique enables the simultaneous identification of distinct bacterial species in a large number of dental samples. The original technique employed digoxigenin-labeled whole genomic DNA probes which were detected by chemiluminescence. In this study, we present an alternative protocol for labeling and detecting whole genomic DNA probes in the Checkerboard DNA-DNA hybridization method. Whole genomic DNA was extracted from five bacterial species and labeled with fluorescein. The fluorescein labeled whole genomic DNA probes were hybridized against whole genomic DNA or subgingival plaque samples in a checkerboard hybridization format, followed by chemiluminescent detection. Our results reveal that fluorescein is a viable and adequate alternative labeling reagent to be employed in the checkerboard DNA-DNA hybridization technique. 相似文献
934.
Rebecca S LaRue Stefán R Jónsson Kevin AT Silverstein Mathieu Lajoie Denis Bertrand Nadia El-Mabrouk Isidro Hötzel Valgerdur Andrésdóttir Timothy PL Smith Reuben S Harris 《BMC molecular biology》2008,9(1):104
Background
APOBEC3 (A3) proteins deaminate DNA cytosines and block the replication of retroviruses and retrotransposons. Each A3 gene encodes a protein with one or two conserved zinc-coordinating motifs (Z1, Z2 or Z3). The presence of one A3 gene in mice (Z2–Z3) and seven in humans, A3A-H (Z1a, Z2a-Z1b, Z2b, Z2c-Z2d, Z2e-Z2f, Z2g-Z1c, Z3), suggests extraordinary evolutionary flexibility. To gain insights into the mechanism and timing of A3 gene expansion and into the functional modularity of these genes, we analyzed the genomic sequences, expressed cDNAs and activities of the full A3 repertoire of three artiodactyl lineages: sheep, cattle and pigs. 相似文献935.
Sexually transmitted diseases (STDs) are a major public-health problem and also a significant financial burden on the economy. Past and ongoing attempts to create vaccines against sexually transmitted pathogens have met with varying success. This article highlights some of the public-health and social problems that are associated with STDs and the technical and ethical challenges in treating them, and raises several questions that need to be addressed if STDs are to be conquered. 相似文献
936.
Cavalieri F Chiessi E Villa R Viganò L Zaffaroni N Telling MF Paradossi G 《Biomacromolecules》2008,9(7):1967-1973
Micro- and nanoparticles are considered suitable drug delivery systems for their unique features, such as a large surface to volume ratio, and for the possibility to tune their size and hydrophobicity. A polymer/polymer/water emulsion method was used for producing a chemically cross-linked hydrogel made of poly(vinyl alcohol) and of poly(methacrylate) moieties. Mesoscopic investigation of the microparticles was accomplished by laser scanning confocal microscopy. Dynamics of confined water within the gel meshes was studied by quasi-elastic incoherent neutron scattering. Succinoylation of these particles allowed an efficient loading with a maximum doxorubicin payload of about 50% (w/w) of dry microparticles. To evaluate the potentials of such a microdevice for drug delivery, LoVo colon cancer cells have been exposed to doxorubicin loaded microparticles to study the in vitro efficiency of the payload release and the consequent cytotoxic effect. 相似文献
937.
We introduce a method for sequencing peptides by mass spectrometry using a metalloendopeptidase that cleaves proteins at the amino side of lysine (Lys-N). When analyzed by electron transfer dissociation (ETD)-based mass spectrometric sequencing, Lys-N-digested peptides that contain a single lysine residue produce spectra dominated by c-type fragment ions, providing simple ladders for sequence determination. This method should be a valuable strategy for de novo sequencing and the analysis of post-translational modifications. 相似文献
938.
Kempka AP Lipke NL da Luz Fontoura Pinheiro T Menoncin S Treichel H Freire DM Di Luccio M de Oliveira D 《Bioprocess and biosystems engineering》2008,31(2):119-125
Current studies about lipase production by solid-state fermentation involve the use of agro-industrial residues towards developing
cost-effective systems directed to large-scale commercialization of enzyme-catalyzed processes. In this work, lipase production
and partial characterization of the crude enzymatic extracts obtained by Penicillium verrucosum using soybean bran as substrate was investigated. Different inductors were evaluated and the results showed that there is
no influence of this variable on the lipase production, while temperature and initial moisture were the main factors that
affected enzyme production. The optimized cultivation temperature (27.5 °C) and initial moisture of substrate (55%) were determined
using the response surface methodology. Kinetics of lipase production was followed at the optimized growth conditions. Optimum
lipase yield was 40 U/g of dry bran. The crude enzymatic extract showed optimal activity in the range from 30 to 45 °C and
in pH 7.0. 相似文献
939.
Acar M Jafar-Nejad H Takeuchi H Rajan A Ibrani D Rana NA Pan H Haltiwanger RS Bellen HJ 《Cell》2008,132(2):247-258
Notch signaling is broadly used to regulate cell-fate decisions. We have identified a gene, rumi, with a temperature-sensitive Notch phenotype. At 28 degrees C-30 degrees C, rumi clones exhibit a full-blown loss of Notch signaling in all tissues tested. However, at 18 degrees C only a mild Notch phenotype is evident. In vivo analyses reveal that the target of Rumi is the extracellular domain of Notch. Notch accumulates intracellularly and at the cell membrane of rumi cells but fails to be properly cleaved, despite normal binding to Delta. Rumi is an endoplasmic reticulum-retained protein with a highly conserved CAP10 domain. Our studies show that Rumi is a protein O-glucosyltransferase, capable of adding glucose to serine residues in Notch EGF repeats with the consensus C1-X-S-X-P-C2 sequence. These data indicate that by O-glucosylating Notch in the ER, Rumi regulates its folding and/or trafficking and allows signaling at the cell membrane. 相似文献
940.
The photosystem II activity and energy dissipation was investigated when algal Chlamydomonas reinhardtii genotypes were exposed to dichromate toxicity effect. The exposure during 24 h to dichromate effect of two C. reinhardtii mutants having non-functional xanthophylls cycle, as npq1 zeaxanthin deficient and npq2 zeaxanthin accumulating, induced inhibition of PSII electron transport. After dichromate-induced toxicity, PSII functions
of C. reinhardtii mutants were investigated under different light intensities. To determine dichromate toxicity and light intensity effect
on PSII functional properties we investigated the change of energy dissipation via PSII electron transport, non-photochemical
regulated and non-regulated energy dissipation according to Kramer et al. (Photosynth Res 79:209–218, 2004). We showed the dependency between dichromate toxicity and light-induced photoinhibition in algae deficient in xanthophyll
cycle. When algal mutants missing xanthophylls cycle were exposed to dichromate toxicity and to high light intensity energy
dissipation via non-regulated mechanism takes the most important pathway reaching the value of 80%. Therefore, the mutants
npq1 and npq2 having non-functional xanthophylls cycle were more sensitive to dichromate toxic effects. 相似文献