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971.
Ozaki S Imai H Iwakiri T Sato T Shimoda K Nakayama T Hamada H 《Biotechnology letters》2012,34(3):475-481
A glucosyltransferase (GT) of Phytolacca americana (PaGT3) was expressed in Escherichia coli and purified for the synthesis of two O-β-glucoside products of trans-resveratrol. The reaction was moderately regioselective with a ratio of 4′-O-β-glucoside: 3-O-β-glucoside at 10:3. We used not only the purified enzyme but also the E. coli cells containing the PaGT3 gene for the synthesis of glycoconjugates. E. coli cell cultures also have other advantages, such as a shorter incubation time compared with cultured plant cells, no need for
the addition of exogenous glucosyl donor compounds such as UDP-glucose, and almost complete conversion of the aglycone to
the glucoside products. Furthermore, a homology model of PaGT3 and mutagenesis studies suggested that His-20 would be a catalytically
important residue. 相似文献
972.
Ozu M Dorr RA Teresa Politi M Parisi M Toriano R 《European biophysics journal : EBJ》2011,40(6):737-746
This work studies water permeability properties of human aquaporin 1 (hAQP1) expressed in Xenopus laevis oocyte membranes, applying a technique where cellular content is replaced with a known medium, with the possibility of measuring
intracellular pressure. Consequences on water transport—produced by well-known anisotonic gradients and by the intracellular
effect of probable aquaporin inhibitors—were tested. In this way, the specific intracellular inhibition of hAQP1 by the diuretic
drug furosemide was demonstrated. In addition, experiments imposing anisotonic mannitol gradients with a constant ionic strength
showed that the relationship between water flux and the applied mannitol gradient deflects from a perfect osmometer response
when the gradient is higher than 150 mosmol kgW−1. These results would indicate that the passage of water molecules through hAQP1 may have a maximum rate. As a whole, this
work demonstrates the technical advantage of controlling both intracellular pressure and medium composition in order to study
biophysical properties of hAQP1, and contributes information on water channel behavior under osmotic challenges and the discovery
of new inhibitors. 相似文献
973.
María Belén Hapon Carlos Gamarra-Luques Graciela A Jahn 《Reproductive biology and endocrinology : RB&E》2010,8(1):14
Background
Rats made hypothyroid with propilthyouracil start showing abnormal cycling on the second cycle after the start of the treatment, with a high proportion of spontaneous pseudopregnancies and reduced fertility. 相似文献974.
Cyclodextrin glucanotransferase (CGTase) from Bacillus circulans (ATCC 21783) was immobilised on a silica-based support: purified seasand. Although adsorption of 98% was achieved, considerable
desorption was encountered. This problem was minimised by crosslinking the adsorbed enzyme with glutaraldehyde. The immobilised
enzyme after crosslinking could be used repeatedly for cyclodextrin (CD) production in a batch process. The activity retention
was 80% at the end of the eighth cycle. The immobilised enzyme showed a shift in the pH optimum towards the alkaline side
and also an improvement in the pH stability compared to the free enzyme. It catalysed the formation of β-CD as a major product.
A significant amount of α-CD production was also observed on prolonged incubation.
Electronic Publication 相似文献
975.
Bisetto E Picotti P Giorgio V Alverdi V Mavelli I Lippe G 《Journal of bioenergetics and biomembranes》2008,40(4):257-267
The role of the integral inner membrane subunit e in self-association of F0F1ATP synthase from bovine heart mitochondria was analyzed by in situ limited proteolysis, blue native PAGE/iterative SDS-PAGE, and LC-MS/MS. Selective degradation of subunit e, without disrupting
membrane integrity or ATPase capacity, altered the oligomeric distribution of F0F1ATP synthase, by eliminating oligomers and reducing dimers in favor of monomers. The stoichiometry of subunit e was determined
by a quantitative MS-based proteomics approach, using synthetic isotope-labelled reference peptides IAQL*EEVK, VYGVGSL*ALYEK,
and ELAEAQEDTIL*K to quantify the b, γ and e subunits, respectively. Accuracy of the method was demonstrated by confirming
the 1:1 stoichiometry of subunits γ and b. Altogether, the results indicate that the integrity of a unique copy of subunit
e is essential for self-association of mammalian F0F1ATP synthase.
Elena Bisetto and Paola Picotti contributed equally to this work. 相似文献
976.
Manjula Senthilkumaran Michaela E. Johnson Larisa Bobrovskaya 《Neurochemical research》2016,41(7):1612-1624
In this study we investigated the effects of insulin-induced hypoglycaemia on tyrosine hydroxylase (TH) protein and TH phosphorylation in the adrenal gland, C1 cell group, locus coeruleus (LC) and midbrain dopaminergic cell groups that are thought to play a role in response to hypoglycaemia and compared the effects of different concentrations of insulin in rats. Insulin (1 and 10 U/kg) treatment caused similar reductions in blood glucose concentration (from 7.5–9 to 2–3 mmol/L); however, plasma adrenaline concentration was increased 20–30 fold in response to 10 U/kg insulin and only 14 fold following 1 U/kg. Time course studies (at 10 U/kg insulin) revealed that in the adrenal gland, Ser31 phosphorylation was increased between 30 and 90 min (4–5 fold), implying that TH was activated to increase catecholamine synthesis in adrenal medulla to replenish the stores. In the brain, Ser19 phosphorylation was limited to certain dopaminergic groups in the midbrain, while Ser31 phosphorylation was increased in most catecholaminergic regions at 60 min (1.3–2 fold), suggesting that Ser31 phosphorylation may be an important mechanism to maintain catecholamine synthesis in the brain. Comparing the effects of 1 and 10 U/kg insulin revealed that Ser31 phosphorylation was increased to similar extent in the adrenal gland and C1 cell group in response to both doses whereas Ser31 and Ser19 phosphorylation were only increased in response to 1 U/kg insulin in LC and in response to 10 U/kg insulin in most midbrain regions. Thus, the adrenal gland and some catecholaminergic brain regions become activated in response to insulin administration and brain catecholamines may be important for initiation of physiological defences against insulin-induced hypoglycaemia. 相似文献
977.
978.
Görel Nyman Stina Marntell Anna Edner Pia Funkquist Karin Morgan Göran Hedenstierna 《Acta veterinaria Scandinavica》2009,51(1):22
Background
Sedation with α2-agonists in the horse is reported to be accompanied by impairment of arterial oxygenation. The present study was undertaken to investigate pulmonary gas exchange using the Multiple Inert Gas Elimination Technique (MIGET), during sedation with the α2-agonist detomidine alone and in combination with the opioid butorphanol. 相似文献979.
Milena Lima de Moraes Renata de Faria Barbosa Raquel Espírito Santo Flávia da Silva Santos Edgar Francisco Oliveira de Jesus Fátima Lúcia de Carvalho Sardinha Maria das Graças Tavares do Carmo 《Biological trace element research》2011,139(2):126-136
Adolescence is marked by intensive growth and development. When pregnancy occurs during this period of the mother’s growth,
there is an increase in her nutritional needs. The aim of this study was to determine the levels of calcium, iron, copper,
and zinc in maternal plasma, the placenta, and in the cord plasma of pregnant teenagers and adults. A total of 80 sets of
maternal plasma, placentas, and cord plasma (40 from teenagers and 40 from adults) were analyzed using synchrotron radiation
total reflection X-ray fluorescence. The levels of calcium, copper, and zinc in the maternal and cord plasma from teenagers
were not significantly different than those from adults. Iron levels in the teenagers maternal and cord plasma were higher
than in the adults. All of the minerals analyzed were present at higher levels in the placentas from adults than those from
teenagers. However, the low quantities of placental calcium, iron, copper, and zinc in the teenagers do not compromise the
levels of these minerals in the cord plasma. Future research regarding the placental transport of these minerals is recommended
to investigate the efficiency of mechanisms of transfer of these minerals in pregnant teenagers. 相似文献
980.
Twum-Danso NA 《Filaria journal》2003,2(Z1):S3
This paper presents a summary of reported cases of Serious Adverse Events (SAEs) following treatment with Mectizan® (ivermectin, Merck, Sharpe &; Dohme) in onchocerciasis mass treatment programs from January 1, 1989 to December 31, 2001 through a passive surveillance system. A total of 207 SAE cases were reported out of approximately 165 million reported treatments delivered during the period under review, giving rise to a cumulative incidence of 1 reported SAE per 800,000 reported treatments. The mean age was 40 years and 70% of the cases were males. The mean time between ivermectin intake and onset of illness was 1 day. For 57% of the cases (n = 118), that was their first exposure to ivermectin. The majority of cases were reported from Cameroon (n = 176; 85%) with peaks in the incidence of SAE reporting in 1989–1991 and 1994–1995 when the program expanded to ivermectin-naïve populations. Fifty-five percent of the cases from Cameroon (i.e. 97 out of 176 cases) were encephalopathic and were reported from the central-southern region of the country; two-thirds of these cases were 'probable' or 'possible' cases of Loa loa encephalopathy temporally related to ivermectin treatment. Reporting bias may explain some but not all of the differences in SAE reporting between the 34 onchocerciasis-endemic countries that have, or have had, mass treatment programs. Further research is needed to understand the apparent clustering of encephalopathy cases in central-southern Cameroon since L. loa infection alone probably does not explain the increased incidence of this type of SAE from this region. 相似文献