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101.
Laudani CG Habulin M Primozic M Knez Z Della Porta G Reverchon E 《Bioprocess and biosystems engineering》2006,29(2):119-127
Octyl oleate is a useful organic compound with several applications in cosmetic, lubricant and pharmaceutical industry. At first, the enzymatic synthesis of n-octyl oleate by direct lipase-catalysed esterification of oleic acid and 1-octanol was investigated in a stirred batch reactor in solvent-free system. A systematic screening and optimisation of the reaction parameters were performed to gain insight into the kinetics mechanism. Particularly, enzyme concentration, reaction temperature, stirrer speed, water content, substrates concentration and molar ratio were optimised with respect to the final product concentration and reaction rate. The kinetics mechanism of the reaction was investigated. Finally, a comparison of the experimental results obtained in a solvent free-system with those using two different solvents, supercritical carbon dioxide (SC-CO2) and n-hexane, was proposed. It resulted that in SC-CO2 higher concentration of the desired product was attained, requiring lower enzyme concentrations to achieve comparable conversion of free fatty acid into fatty acid ester. 相似文献
102.
Green fluorescent protein (GFP) is an excellent biosensor as a result of its ability to be easily monitored in a wide variety of applications. Enzymes and proteins have been used as biological indicators to evaluate the immediate efficacy of industrial procedures, such as blanching, pasteurization, and disinfection treatments, as well as to monitor the satisfactory preservation of a product subjected to disinfection or sterilization. The purpose of this work was to study GFP stability in chlorinated water for injection (WFI) and chlorinated buffered solutions at various pH ranges, with and without agitation, to evaluate the exposure time required for chlorine to decrease 90% of its fluorescence intensity (decimal reduction time, D-value, min, 25 degrees C). Fluorescence intensity (Ex/Emmax = 394/509 nm) was measured immediately after the addition of GFP (8.0-9.0 microg/mL) into buffered or unbuffered chlorine solutions with or without constant stirring. With solutions constantly stirred, GFP fluorescence decreased abruptly on contact with chlorine in concentrations greater than 150 ppm, with D-values between 1.3 min (147 ppm chlorine) and 1.7 min (183 ppm chlorine). In phosphate buffered chlorine solutions (pH = 7.15 +/- 0.08), GFP retained its structure between 52 and 94 ppm, but protein stability decreased 10-fold when exposed to 110 ppm chlorine. The recovery of GFP fluorescence intensity due to renaturation was observed between 30 and 100 ppm chlorine in WFI (final pH = 11.01 +/- 0.23) without stirring. Stirring enhanced the contact between GFP and chlorine throughout the assay and provided a more accurate D-value evaluation. GFP performed as a suitable fluorescent marker for monitoring disinfection effectiveness. 相似文献
103.
Antonio Porro Michelle Haber Daniel Diolaiti Nunzio Iraci Michelle Henderson Samuele Gherardi Emanuele Valli Marcia A. Munoz Chengyuan Xue Claudia Flemming Manfred Schwab Jason H. Wong Glenn M. Marshall Giuliano Della Valle Murray D. Norris Giovanni Perini 《The Journal of biological chemistry》2010,285(25):19532-19543
104.
Bacci L Picanço MC Moura MF Della Lucia TM Semeão AA 《Journal of economic entomology》2006,99(6):2177-2184
The objective of this work was to determine the best technique, sampling unit, and the number of samples to compose a conventional sampling plan for the cucurbit borers, Diaphania spp. (Lepidoptera: Pyralidae), and for hymenopteran parasitoids on cucumber. This research was carried out in 10 commercial cucumber crops fields from July to December 2000 in Tocantins, Minas Gerais State, Brazil (21 degrees 11' 15" S; 42 degrees 03' 45" W; altitude 363 m). The sampling methods studied were beating on a tray, direct counting of insects on the lower leaf surface, and whole leaf collection. Three sampling units also were studied: leaves from a branch located in the apical, median, or basal third of the canopy. The best sampling systems, which included the best technique and sampling unit, were determined based on the relative variance and the economic precision of the sampling. Once the best sampling systems were established, the numbers of samples to compose the conventional sampling plans were determined. The more suitable sampling system for the larvae of Diaphania spp. in cucumber plants was beating a leaf of the median third of the canopy on a plastic tray. One leaf must be sampled for every 50 plants in a crop. The more suitable sampling system for hymenopteran parasitoids in cucumber plants was to directly count the adults on one leaf of the median third of the canopy. One leaf must be sampled for every 74 plants in a crop. 相似文献
105.
This study showed the impact on germination, mycelial growth and aflatoxin B1 accumulation when interacting Aspergillus aflatoxigenic strains with Kluyveromyces isolates and the effect of water activity on this relationship. Isolates Y14 and Y16 reduced the percentage of germination of all Aspergillus strains and decrease germ tube elongation rate at majority of water activity assayed. Similarly they produced an increase
of germination lag phase and lag phase of growth beside decreased growth rate of all Aspergillus strains. At water activities 0.994, 0.982, 0.955 and 0.937, no aflatoxins were produced in paired cultures with isolates
Y25, Y22, Y16, and Y14, and Kluyveromyces isolates Y14 and Y16 impact both growth and aflatoxin accumulation at wide range of water activity. 相似文献
106.
107.
Molecular dynamics computer simulations were performed for the 25-residue N-terminal tail of the H3 histone protein in the proximity of a DNA segment of 10 base pairs (bp), representing a model for the linker DNA in chromatin. Several least biased configurations were used as initial configurations. The secondary structure content of the protein was increased by the presence of DNA close to it, but the locations of the secondary motifs were different for different initial orientations of the DNA grooves with respect to the protein. As a common feature to all simulations, the electrostatic attraction between negatively charged DNA and positively charged protein was screened by the water solvent and counterbalanced by the intrinsic compaction of the protein due to hydrophobic effects. The protein secondary structure limited the covering of DNA by the protein to 4-5 bp. The degree of compaction and charge density of the bound protein suggests a possible role of H3 tail in a nonspecific bending and plasticity of the linker DNA when the protein is located in the crowded dense chromatin. 相似文献
108.
Bennati AM Castelli M Della Fazia MA Beccari T Caruso D Servillo G Roberti R 《Biochimica et biophysica acta》2006,1761(7):677-685
3Beta-hydroxysterol Delta(14)-reductase operates during the conversion of lanosterol to cholesterol in mammalian cells. Besides the endoplasmic reticulum 3beta-hydroxysterol Delta(14)-reductase (C14SR) encoded by TM7SF2 gene, the lamin B receptor (LBR) of the inner nuclear membrane possesses 3beta-hydroxysterol Delta(14)-reductase activity, based on its ability to complement C14SR-defective yeast strains. LBR was indicated as the primary 3beta-hydroxysterol Delta(14)-reductase in human cholesterol biosynthesis, since mutations in LBR gene were found in Greenberg skeletal dysplasia, characterized by accumulation of Delta(14)-unsaturated sterols. This study addresses the issue of C14SR and LBR role in cholesterol biosynthesis. Both human C14SR and LBR expressed in COS-1 cells exhibit 3beta-hydroxysterol Delta(14)-reductase activity in vitro. TM7SF2 mRNA and C14SR protein expression in HepG2 cells grown in delipidated serum (LPDS) plus lovastatin (sterol starvation) were 4- and 8-fold higher, respectively, than in LPDS plus 25-hydroxycholesterol (sterol feeding), resulting in 4-fold higher 3beta-hydroxysterol Delta(14)-reductase activity. No variations in LBR mRNA and protein levels were detected in the same conditions. The induction of TM7SF2 gene expression is turned-on by promoter activation in response to low cell sterol levels and is mediated by SREBP-2. The results suggest a primary role of C14SR in human cholesterol biosynthesis, whereas LBR role in the pathway remains unclear. 相似文献
109.
M. Leonardi F. Azzaro M. Galletta M. G. Giacobbe M. Masò A. Penna 《Hydrobiologia》2006,555(1):299-305
In the framework of the EU Project STRATEGY, a short-term study was carried out in the Marinello ecosystem, a small brackish
area located on the Tyrrhenian coast of Sicily (Italy). The investigation was aimed at understanding the dynamics of phytoplankton
toxic blooms in relation to other planktonic species and environmental conditions. The study started on 10 March 2003, in
coincidence with the first detection of Alexandrium minutum, a dinoflagellate known as a producer of Paralyzing Shellfish Toxins (PST) and lasted until 4 June 2003, when the bloom collapsed.
The specific identity of A. minutum was confirmed on field mixed samples, through the use of species-specific PCR-primers targeting the 5.8S rDNA-ITS regions.
Water samples and phytoplankton net hauls were taken approximately at 10 days intervals in the Verde Pond, one of the five
basins of the Marinello ecosystem, in order to evaluate the incidence of toxic and non-toxic dinoflagellate species over the
whole planktonic community. The evolution of the main environmental and trophic parameters (temperature, salinity, dissolved
oxygen, POC, C/N, DIN, PO4–P) was simultaneously investigated. Alexandrium blooms were mostly characterized by A. minutum (max. 6 × 105 cells l−1 on April 11) and Alexandrium tamarense as an associated species (max. 2.5 × 104 cells l−1 on March 25). During the bloom, dinoflagellates or small flagellates dominated over the other taxa, with a minimum incidence
of diatoms. The load of dissolved inorganic nitrogen was maximum in the pre-bloom phase (29 μM on March 19), after which it
decreased sharply. An oxygen supersaturation event was registered in coincidence with the A. minutum bloom. The amounts of POC ranged between 266 and 658 μg l−1 showing a discontinuous temporal trend. A recent introduction of A. minutum into the Verde Pond is suggested on the basis of the absence of this species in past years. 相似文献
110.
Novel vasopressin type 2 (AVPR2) gene mutations in Brazilian nephrogenic diabetes insipidus patients
Boson WL Della Manna T Damiani D Miranda DM Gadelha MR Liberman B Correa H Romano-Silva MA Friedman E Silva FF Ribeiro PA De Marco L 《Genetic testing》2006,10(3):157-162
Nephrogenic diabetes insipidus (NDI) is an inherited disorder characterized by renal resistance to the antidiuretic effect of arginine vasopressin (AVP), resulting in polyuria, polydipsia, and hypoosmolar urine. In the vast majority of cases, NDI is associated with germ-line mutations in the vasopressin receptor type 2 gene (AVPR2) and in about 8% of the cases with the water channel aquaporin-2 gene (AQP-2) mutations. To date, approximately 277 families with 185 germ-line mutations in the AVPR2 gene have been described worldwide. In the present study, the AVPR2 gene was genotyped in eight unrelated Brazilian kindred with NDI. In five of these NDI families, novel mutations were noted (S54R, I130L, S187R, 219delT, and R230P), whereas three seemingly unrelated probands were found to harbor previously described AVPR2 gene mutations (R106C, R137H, R337X). Additionally a novel polymorphism (V281V) was detected. In conclusion, although NDI is a rare disease, the findings of mutations scattered over the entire coding region of the AVPR2 gene are a valuable model to determine structure function relationship in G-protein-coupled receptor related diseases. Furthermore, our data indicate that in Brazil the spectrum of AVPR2 gene mutations is "family specific". 相似文献