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61.
62.
Edson L da Silva Mariusz K Piskula Norio Yamamoto Jae-Hak Moon Junji Terao 《FEBS letters》1998,430(3):903
The oxidative susceptibility of plasma obtained from rats after intragastric administration of quercetin was studied to know whether or not quercetin acts as an in vivo antioxidant after metabolic conversion. Quercetin was raised in the rat blood plasma essentially as glucuronide and/or sulfate conjugates. The plasma obtained from rats after quercetin administration was more resistant against copper sulfate-induced lipid peroxidation than the control plasma on the basis of the accumulation of cholesteryl ester hydroperoxides and the consumption of α-tocopherol. The results strongly suggest that some conjugated metabolites of quercetin act as effective antioxidants when plasma is subject to metal ion-induced lipid peroxidation. 相似文献
63.
Anders ?stin Mariusz Kowalyczk Rishikesh P. Bhalerao G?ran Sandberg 《Plant physiology》1998,118(1):285-296
The metabolism of indole-3-acetic
acid (IAA) was investigated in 14-d-old Arabidopsis plants grown in
liquid culture. After ruling out metabolites formed as an effect of
nonsterile conditions, high-level feeding, and spontaneous
interconversions, a simple metabolic pattern emerged. Oxindole-3-acetic
acid (OxIAA), OxIAA conjugated to a hexose moiety via the carboxyl
group, and the conjugates indole-3-acetyl aspartic acid (IAAsp) and
indole-3-acetyl glutamate (IAGlu) were identified by mass spectrometry
as primary products of IAA fed to the plants. Refeeding experiments
demonstrated that none of these conjugates could be hydrolyzed back to
IAA to any measurable extent at this developmental stage. IAAsp was
further oxidized, especially when high levels of IAA were fed into the
system, yielding OxIAAsp and OH-IAAsp. This contrasted with the
metabolic fate of IAGlu, since that conjugate was not further
metabolized. At IAA concentrations below 0.5 μm, most of
the supplied IAA was metabolized via the OxIAA pathway, whereas only a
minor portion was conjugated. However, increasing the IAA
concentrations to 5 μm drastically altered the metabolic
pattern, with marked induction of conjugation to IAAsp and IAGlu. This
investigation used concentrations for feeding experiments that were
near endogenous levels, showing that the metabolic pathways controlling
the IAA pool size in Arabidopsis are limited and, therefore, make good
targets for mutant screens provided that precautions are taken to avoid
inducing artificial metabolism.The plant hormone IAA is an important signal molecule in the
regulation of plant development. Its central role as a growth regulator
makes it necessary for the plant to have mechanisms that strictly
control its concentration. The hormone is believed to be active
primarily as the free acid, and endogenous levels are controlled in
vivo by processes such as synthesis, oxidation, and conjugation. IAA
has been shown to form conjugates with sugars, amino acids, and small
peptides. Conjugates are believed to be involved in IAA transport, in
the storage of IAA for subsequent use, in the homeostatic control of
the pool of the free hormone, and as a first step in the catabolic
pathways (Cohen and Bandurski, 1978; Nowacki and Bandurski, 1980;
Tuominen et al., 1994; Östin et al., 1995; Normanly, 1997). It is
generally accepted that in some species conjugated IAA is the major
source of free IAA during the initial stages of seed germination (Ueda
and Bandurski, 1969; Sandberg et al., 1987; Bialek and Cohen, 1989),
and there is also evidence that in some plants (but not all; see Bialek
et al., 1992), the young seedling is entirely dependent on the release
of free IAA from conjugated pools until the plant itself is capable of
de novo synthesis (Epstein et al., 1980; Sandberg et al., 1987).The function of conjugated IAA during vegetative growth is somewhat
less clear. It has been shown that conjugated IAA constitutes as much
as 90% of the total IAA in the plant during vegetative growth
(Normanly, 1997). However, the role of the IAA conjugates at this stage
of the plant''s life cycle remains unknown. Analysis of endogenous IAA
conjugates in vegetative tissues has revealed the presence of a variety
of different compounds, including indole-3-acetyl-inositol,
indole-3-acetyl-Ala, IAAsp, and IAGlu (Anderson and Sandberg, 1982;
Cohen and Baldi, 1983; Chisnell, 1984; Cohen and Ernstsen, 1991;
Östin et al., 1992). Studies of vegetative tissues have indicated
that IAAsp, one of the major conjugates in many plants, is the first
intermediate in an irreversible deactivation pathway (Tsurumi and Wada,
1986; Tuominen et al., 1994; Östin, 1995). Another mechanism that
is believed to be involved in the homeostatic control of the IAA pool
is catabolism by direct oxidation of IAA to OxIAA, which has been shown
to occur in several plant species (Reinecke and Bandurski, 1983;
Ernstsen et al., 1987).One area in the study of IAA metabolism in which our knowledge is
increasing is the analysis of the homeostatic controls of IAA levels in
plants. It has been possible, for instance, to increase the levels of
IAA in transgenic plants expressing iaaM and iaaH
genes from Agrobacterium tumefaciens. Analysis of these
transgenic plants has indicated that plants have several pathways that
can compensate for the increased production of IAA (Klee et al., 1987;
Sitbon, 1992). It is expected that future studies using now-available
genes will provide further insight into IAA metabolism. For example, a
gene in maize encoding IAA-Glc synthetase has been identified, and
several genes (including ILR1, which may be involved
in hydrolysis of the indole-3-acetyl-Leu conjugate) have been cloned
from Arabidopsis (Szerszen et al., 1994; Bartel and Fink,
1995). Furthermore, Chou et al. (1996) identified a gene that
hydrolyzes the conjugate IAAsp to free IAA in the bacterium
Enterobacter aggloremans.Because of its small genome size, rapid life cycle, and the ease of
obtaining mutants, Arabidopsis is increasingly used as a
genetic model system to investigate various aspects of plant growth and
development. IAA signal transduction is also being investigated
intensively in Arabidopsis in many laboratories (Leyser, 1997). Mutants
with altered responses to externally added auxins or IAA conjugates
have been identified in Arabidopsis. The identified mutants are either
signal transduction mutants such as axr1-4 (Lincoln et al.,
1990), or have mutations in genes involved in auxin uptake or
transport, such as aux1 and pin1 (Okada et al.,
1991; Bennett et al., 1996). A few mutants that are unable to regulate
IAA levels or are unable to hydrolyze IAA conjugates, sur1-2
and ilr1, respectively, have also been identified (Bartel
and Fink, 1995; Boerjan et al., 1995). To our knowledge, no mutant that
is auxotrophic for IAA has been identified to date, which may
reflect the redundancy in IAA biosynthetic pathways or the lethality of
such mutants.In spite of the work reported thus far, many aspects of the metabolism
of IAA in Arabidopsis require further investigation, because few
details of the processes involved in IAA regulation are known. This
lack of knowledge puts severe constraints on genetic analysis of IAA
metabolism in Arabidopsis. For example, it is essential to have prior
knowledge of IAA metabolism to devise novel and relevant screens with
which to identify mutants of IAA metabolism. We have sought to address
this issue by identifying the metabolic pathways involved in catabolism
and conjugation under conditions that minimally perturb physiological
processes. In this investigation we studied the conjugation and
catabolic pattern of IAA by supplying relatively low levels of labeled
IAA and identifying the catabolites and conjugates by MS. Different
feeding systems were tested to optimize the application of IAA and to
avoid irregularities in metabolism attributable to culturing, feeding
conditions, or microbial activity. It is well documented that IAA
metabolism is altered according to the amount of exogenous auxin
applied; therefore, we placed special emphasis on distinguishing
between catabolic routes that occur at near-physiological
concentrations and those that occur at the high auxin concentrations
commonly used in mutant screens. 相似文献
64.
65.
Zuzanna Setkowicz Agata Ga?dzińska Joanna J. Osoba Karolina Karwowska Piotr Majka Jaros?aw Orze? Bartosz Kossowski Piotr Bogorodzki Krzysztof Janeczko Mariusz Wyle?o? Stefan P. Gazdzinski 《PloS one》2015,10(10)
BackgroundObesity is a worldwide epidemic with more than 600 million affected individuals. Human studies have demonstrated some alterations in brains of otherwise healthy obese individuals and elevated risk of neurodegenerative disease of old age; these studies have also pointed to slightly diminished memory and executive functions among healthy obese individuals. Similar findings were obtained in animal models of obesity induced by high fat diet. On the other hand, low carbohydrate high fat diets are currently promoted for losing weight (e.g., Atkin’s style diets). However, the long-term effects of such diets are not known. Additionally, high fat diets leading to (mild) ketonemia were shown to improve brain function in elderly humans and in some animal models.AimTo evaluate the hypothesis that long-term use of a high fat diet was associated with decreases in spatial memory, smaller hippocampi and hippocampi metabolite concentrations in Wistar rats.MethodsTwenty five male Wistar rats were put on high fat diet (HFD; 60% calories from fat, 30% from carbohydrates) on their 55th day of life, while 25 control male rats (CONs) remained on chow. Adequate levels of essential nutrients were provided. Both groups underwent memory tests in 8-arm radial maze at 3rd, 6th, 9th, and 12th month. 1H magnetic resonance spectroscopy was employed to measure concentrations of tNAA (marker of neuronal integrity) at one month and one year, whereas MRI was used to evaluate hippocampal volumes.ResultsObese rats (OBRs) consumed similar amount of calories as CONs, but less proteins. However, their protein intake was within recommended amounts. Throughout the experiment OBRs had statistically higher concentrations of blood ketone bodies than CONs, but still within normal values. At post-mortem assessment, OBRs had 38% larger fat deposits than CONs (p<0.05), as evaluated by volume of epididymis fat, an acknowledged marker of fat deposits in rats. Contrary to our expectations, OBRs had better scores of memory behavioral tasks than CONs throughout the experiment. At one year, their hippocampi were by 2.6% larger than in CONs (p = 0.05), whereas concentration of tNAA was 9.8% higher (p = 0.014).ConclusionLong-term HFD in our study resulted in better memory, larger hippocampal volumes, as well as higher hippocampal metabolite concentrations, possibly due to increased levels of blood ketone bodies. The results should be interpreted with caution, as results from animal models do not necessarily directly translate in human condition. 相似文献
66.
It has been interesting that nearly all of the ion activities that have been analysed thus far have exhibited oscillations that are tightly coupled to growth. Here, we present discrete Fourier transform (DFT) spectra with a finite sampling of tip-growing cells and organs that were obtained from voltage measurements of the elongating coleoptiles of maize in situ. The electromotive force (EMF) oscillations (~ 0.1 μV) were measured in a simple but highly sensitive resistor–inductor circuit (RL circuit), in which the solenoid was initially placed at the tip of the specimen and then was moved thus changing its position in relation to growth (EMF can be measured first at the tip, then at the sub-apical part and finally at the shank). The influx- and efflux-induced oscillations of Ca2+, along with H+, K+ and Cl- were densely sampled (preserving the Nyquist theorem in order to ‘grasp the structure’ of the pulse), the logarithmic amplitude of pulse spectrum was calculated, and the detected frequencies, which displayed a periodic sequence of pulses, were compared with the literature data. A band of life vital individual pulses was obtained in a single run of the experiment, which not only allowed the fundamental frequencies (and intensities of the processes) to be determined but also permitted the phase relations of the various transport processes in the plasma membrane and tonoplast to be established. A discrete (quantised) frequency spectrum was achieved for a growing plant for the first time, while all of the metabolic and enzymatic functions of the life cell cycle were preserved using this totally non-invasive treatment. 相似文献
67.
Given the emerging evidence of an association between periodontal infections and systemic conditions, the search for specific methods to detect the presence of P. gingivalis, a principal etiologic agent in chronic periodontitis, is of high importance. The aim of this study was to characterize antibodies raised against purified P. gingivalis HmuY protein and selected epitopes of the HmuY molecule. Since other periodontopathogens produce homologs of HmuY, we also aimed to characterize responses of antibodies raised against the HmuY protein or its epitopes to the closest homologous proteins from Prevotella intermedia and Tannerella forsythia. Rabbits were immunized with purified HmuY protein or three synthetic, KLH-conjugated peptides, derived from the P. gingivalis HmuY protein. The reactivity of anti-HmuY antibodies with purified proteins or bacteria was determined using Western blotting and ELISA assay. First, we found homologs of P. gingivalis HmuY in P. intermedia (PinO and PinA proteins) and T. forsythia (Tfo protein) and identified corrected nucleotide and amino acid sequences of Tfo. All proteins were overexpressed in E. coli and purified using ion-exchange chromatography, hydrophobic chromatography and gel filtration. We demonstrated that antibodies raised against P. gingivalis HmuY are highly specific to purified HmuY protein and HmuY attached to P. gingivalis cells. No reactivity between P. intermedia and T. forsythia or between purified HmuY homologs from these bacteria and anti-HmuY antibodies was detected. The results obtained in this study demonstrate that P. gingivalis HmuY protein may serve as an antigen for specific determination of serum antibodies raised against this bacterium. 相似文献
68.
Barbara U. Metzler-Zebeli Eva Ebersp?cher Dietmar Grüll Lidia Kowalczyk Timea Molnar Qendrim Zebeli 《PloS one》2015,10(6)
Developing host digestion-resistant starches to promote human health is of great research interest. Chemically modified starches (CMS) are widely used in processed foods and although the modification of the starch molecule allows specific reduction in digestibility, the metabolic effects of CMS have been less well described. This short-term study evaluated the impact of enzymatically modified starch (EMS) on fasting and postprandial profiles of blood glucose, insulin and lipids, and serum metabolome in growing pigs. Eight jugular-vein catheterized pigs (initial body weight, 37.4 kg; 4 months of age) were fed 2 diets containing 72% purified starch (EMS or waxy corn starch (control)) in a cross-over design for 7 days. On day 8, an 8-hour meal tolerance test (MTT) was performed with serial blood samplings. Besides biochemical analysis, serum was analysed for 201 metabolites through targeted mass spectrometry-based metabolomic approaches. Pigs fed the EMS diet showed increased (P<0.05) immediate serum insulin and plasma glucose response compared to pigs fed the control diet; however, area-under-the-curves for insulin and glucose were not different among diets. Results from MTT indicated reduced postprandial serum triglycerides with EMS versus control diet (P<0.05). Likewise, serum metabolome profiling identified characteristic changes in glycerophospholipid, lysophospholipids, sphingomyelins and amino acid metabolome profiles with EMS diet compared to control diet. Results showed rapid adaptations of blood metabolites to dietary starch shifts within 7 days. In conclusion, EMS ingestion showed potential to attenuate postprandial raise in serum lipids and suggested constant alteration in the synthesis or breakdown of sphingolipids and phospholipids which might be a health benefit of EMS consumption. Because serum insulin was not lowered, more research is warranted to reveal possible underlying mechanisms behind the observed changes in the profile of serum lipid metabolome in response to EMS consumption. 相似文献
69.
Fluorescence methods (VistaCam iX proof and DIAGNODent pen) for the detection of occlusal carious lesions in teeth recovered from archaeological context 下载免费PDF全文
Jacek Tomczyk Julian Komarnitki Marta Zalewska Tomasz Lekszycki Dorota Olczak‐Kowalczyk 《American journal of physical anthropology》2014,154(4):525-534
Diagnosis of occlusal enamel caries in archaeologically derived collections remains a controversial problem because the accumulation of contaminants in fissures can interfere with diagnosis. Certain novel light‐induced fluorescence methods, such as the DIAGNODent pen 2190 (DD) and VistaCam iX Proof (VC), have been used to detect dental caries in clinical settings. In this study, the abilities of DD and VC to detect initial enamel caries in archaeologically derived material is determined and compared with those of other methods (visual inspection, X‐ray, histology, and micro‐CT). Dental material encompassing the remains of 58 individuals, including a total of 380 teeth from each of three historical periods: modern Islamic (AD 1850–1950), Islamic (AD 600–1200) and late Roman (AD 200–400), obtained from two archaeological sites (Terqa and Tell Masaikh) located in the Middle Euphrates valley (Syria), were analyzed. VC was found to have excellent sensitivity (98), while DD obtained lower sensitivity (76) in detecting dental caries in its early stages. The results obtained by VC and micro‐CT, considered the most reliable imaging technique, were not statistically significant (P = 0.3068). By contrast, results obtained by DD and micro‐CT results, and DD and VC results were statistically significant (P < 0.0001, P = 0.0015, respectively). However the presence of dirt, stain, calculus, and plaque in the pits and fissures of the occlusal surface compromise correct diagnosis of caries by VC and DD. Consequently, for teeth recovered from archaeological contexts where staining, calculus and plaque are present, the best solution remains micro‐CT. Am J Phys Anthropol 154:525–534, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
70.
A C Frantz A D McDevitt L C Pope J Kochan J Davison C F Clements M Elmeros G Molina-Vacas A Ruiz-Gonzalez A Balestrieri K Van Den Berge P Breyne E Do Linh San E O ?gren F Suchentrunk L Schley R Kowalczyk B I Kostka D ?irovi? N ?prem M Colyn M Ghirardi V Racheva C Braun R Oliveira J Lanszki A Stubbe M Stubbe N Stier T Burke 《Heredity》2014,113(5):443-453
Although the phylogeography of European mammals has been extensively investigated
since the 1990s, many studies were limited in terms of sampling distribution, the
number of molecular markers used and the analytical techniques employed, frequently
leading to incomplete postglacial recolonisation scenarios. The broad-scale genetic
structure of the European badger (Meles meles) is of interest as it may
result from historic restriction to glacial refugia and/or recent anthropogenic
impact. However, previous studies were based mostly on samples from western Europe,
making it difficult to draw robust conclusions about the location of refugia,
patterns of postglacial expansion and recent demography. In the present study,
continent-wide sampling and analyses with multiple markers provided evidence for two
glacial refugia (Iberia and southeast Europe) that contributed to the genetic
variation observed in badgers in Europe today. Approximate Bayesian computation
provided support for a colonisation of Scandinavia from both Iberian and southeastern
refugia. In the whole of Europe, we observed a decline in genetic diversity with
increasing latitude, suggesting that the reduced diversity in the peripheral
populations resulted from a postglacial expansion processes. Although MSVAR v.1.3
also provided evidence for recent genetic bottlenecks in some of these peripheral
populations, the simulations performed to estimate the method''s power to
correctly infer the past demography of our empirical populations suggested that the
timing and severity of bottlenecks could not be established with certainty. We urge
caution against trying to relate demographic declines inferred using MSVAR with
particular historic or climatological events. 相似文献