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1.
Astrocytic excitatory amino acid transporters (EAATs) regulate excitatory transmission and limit excitotoxicity. Evidence for a functional interface between EAATs and glial fibrillary acidic protein (GFAP) relevant to astrocytic morphology led to investigations of actions of transportable (d-Aspartate (d-Asp) and (2S,3S,4R)-2-(carboxycyclopropyl)glycine (l-CCG-III)) and non-transportable (dl-threo-β-benzyloxyaspartate (dl-TBOA)) inhibitors of Glu uptake in murine astrocytes. d-Asp (1 mM), l-CCG-III (0.5 mM) and dl-TBOA (0.5 mM) produced time-dependent (24–72 h) reductions in 3[H]d-Asp uptake (approximately 30–70%) with little or no gliotoxicity. All drugs induced a profound change in phenotype from cobblestone to stellate morphology and image analysis revealed increases in the intensity of GFAP immunolabelling for l-CCG-III and dl-TBOA. Cytochemistry indicated localized changes in F-actin distribution. Cell surface expression of EAAT2, but not EAAT1, was elevated at 72 h. Blockade of Glu uptake by both types of EAAT inhibitor exerts longer-term effects on astrocytic morphology and a compensatory homeostatic rise in EAAT2 abundance. 相似文献
2.
Antonov A. S. Kalinovskii A. I. Dmitrenok P. S. Stonik V. A. 《Russian Journal of Bioorganic Chemistry》2002,28(3):183-188
New triterpene glycosides, ulososides C, (20S,22S,23R,24S)-3,22,23-trihydroxy-3-O-(-D-glucopyranosyl)-32-nor-24-methyllanost-8(9)-ene-30-oic acid, D, (20S,22S,23R,24S)-3,22,23-trihydroxy-3-O-(-D-N-acetylglucosaminopyranosyl)-32-nor-24-methyllanost-8(9)-ene-30-oic acid, and E, (20S,22S,23R,24S)-3,22,23-trihydroxy-3-O-(-D-glucuronopyranosyl-(1 2)--D-arabinopyranosyl-32-nor-24-methyllanost-8(9)-ene-30-oic acid, were isolated from an Ulosa sp. sponge. Their structures were determined by spectral methods and chemical transformations. Specific features of their structures are discussed. 相似文献
3.
Elena Negroni Vanna Chigorno Guido Tettamanti Sandro Sonnino 《Glycoconjugate journal》1996,13(3):347-352
An efficiency assessment of a ganglioside assay procedure was carried out on human serum gangliosides from healthy subjects of different sex and age. The analysis of the gangliosides, extracted with chloroform/methanol and purified by lipid partitioning, ion exchange column chromatographic separation and desalting procedures as described by Sennet al. (1989)Eur J Biochem
181: 657–62, was performed by HPTLC followed by densitometric quantification. The yield of the procedure, expressed as radioactivity recovery, was determined by adding GM3 ganglioside, tritium labelled at the sialic acid acetyl group and at the C3 position of sphingosine, to the lyophilized serum or by associating it with the serum lipoproteins. In spite of the fact that the extraction and purification procedures were performed exactly as described we found the radioactivity recovery to be variable (25–50%) and much lower than that proposed. Much of the radioactivity was found in the organic phase after lipid partitioning, whilst all the ganglioside purification steps led to some further loss. After the introduction of some modifications to the procedure the recovery improved, reaching 67–79%.The analyses on 33 samples of 5 ml showed a human serum ganglioside content of about 10 nmol ml–1 (as corrected for the recovery), and confirmed that GM3 ganglioside is the main component of the total serum ganglioside mixture.
Abbreviations: Ganglioside nomenclature is in accordance with Svennerholm (1980) [37] and the IUPAC-IUB Recommendations (1977, 1982) [38]. GM3, II3Neu5AcLacCer, -Neu5Ac-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer; Cer, ceramide; Neu5Ac,N-acetyl-neuraminic acid;erythro-GM3, GM3 containingerythro-sphingosine;threo-GM3, GM3 containingthreo-sphingosine;erythro-C18 sphingosine, (2s,3R,4E)-2-amino-1,3-dihydroxy-octadecene;erythro-C20 sphingosine, (2S,3R,4E)-2-amino-1,3-dihydroxy-eicosene;threo-C18 sphingosine, (2S,3S,4E)-2-amino-1,3-dihydroxy-octadecene;threo-C20 sphingosine, (2S,3S,4E)-2-amino-1,3-dihydroxy-eicosene; DDQ, dichlorodicyano-benzoquinone. 相似文献
4.
《Bioscience, biotechnology, and biochemistry》2013,77(9):1526-1529
2-Deoxy-2-[(2R,3S)-2-fluoro-3-hydroxytetradecanamido]-3-O-[(3R)-3-hydroxytetradecanoyl]-4-O-phosphono-D-glucopyranose and its (2S,3R)-isomer were respectively synthesized from allyl 2-[(2R,3S)-3-(benzyloxycarbonyloxy)-2-fluorotetradecanamido]-2-deoxy-4,6-O-isopropylidene-β-D-glucopyranoside and its corresponding (2S,3R)-isomer. Both target compounds did not activate macrophage, but the (2S,3R)-analogue strongly inhibited the binding of LPS to macrophage. 相似文献
5.
A plant glycosphingolipid, O-(β-d-mannopyranosyl)-(l → 4)-O-(β-d-glucopyranosyl)-(l → l)-(2S,3S,4R)-4-hydroxy-N-tetracosanoylsphinganine 1, and the stereoisomer, O-(α-d-mannopyranosyl)-(1 → 4)-O-(β-d-glucopyranosyl)-(l → l)-(2S,3S,4R)-4-hydroxy-N-tetracosanoylsphinganine 6, were synthesized in a stereo- and regio-controlled way. 相似文献
6.
A. I. Kalinovskii E. V. Levina V. A. Stonik P. S. Dmitrenok P. V. Andriyashchenko 《Russian Journal of Bioorganic Chemistry》2004,30(2):191-195
Two new asterosaponins, (20R)-3-O--D-(2-O-methylxylopyranosyl)-24-propylcholest-4-ene-3,6,8,15,16,29-hexaol (sanguinoside A) and (20R,24S)-3-O--D-(2,3,4-tri-O-methylxylopyranosyl)-5-cholestane-3,4,6,8,15,24-hexaol (sanguinoside B), were isolated from two species of Pacific Far Eastern Starfish Henricia
sanguinolenta and H. leviuscula
leviuscula, collected in the Sea of Okhotsk. Both glycosides contain aglycones with pentahydroxysteroid nuclei of similar structures, which are substituted at the 3-hydroxy group with differently methylated -D-xylosyl residues. Sanguinoside A has an unusual structure of its aglycone side chain, whereas sanguinoside B has a unique permethylated carbohydrate chain. In addition, laevisculoside G, a known glycoside, was identified in the H. leviuscula starfish. The structures of the isolated glycosides were established by interpreting their spectral data and by comparing their spectral characteristics with those of known compounds. 相似文献
7.
Tatsuji Chuman Masahiro Kohno Kunio Kato Masao Noguchi Hiroko Nomi Kenji Mori 《Bioscience, biotechnology, and biochemistry》2013,77(9):2019-2023
A stereoselective synthesis of erythro-serricornin [(4RS,6R,7S)-4,6-dimethyl-7-hydroxynonan-3-one] was completed starting from l-(+)-tartaric acid. The relative configuration of C(6)-methyl and C(7)-hydroxyl groups in naturally occurring serricornin was threo. 相似文献
8.
Kikue Kubota Akio Kobayashi Tei Yamanishi 《Bioscience, biotechnology, and biochemistry》2013,77(11):2753-2754
Quinoxaline and benzimidazole derivatives obtained from L-rhamnose and L-fucose under deoxygenated, weakly acidic, heated conditions were studied using GLC, HPLC, and NMR.Four quinoxalines and one benzimidazole were obtained from L-rhamnose (RHA-I, II, III, III′, and IV) and L-fucose (FUA-I, II, III, IV, and V) in an acidic solution (MeOH-AcOH-H2I = 8 : 1 : 2) at 80°C. The total yield of the products as sugar was about 80% from either rhamnose or fucose.The structure of RHA-I was (2′S)-2-methyl-3-(2′-hydroxypropyl)quinoxaline; RHA-II, (2′R,3′S)-2-(2′,3′-dihydroxybutyl)quinoxaline; RHA-III, (1′S,2′S,3′S)-2-(1′2′3′-trihydroxybutyl)quinoxaline[2-(L-arabino-1′,2′,3′-trihydroxybutyl)quinoxaline]; RHA-III′, 2-(L-ribo-1′,2′,3′-trihydroxybutyl)quinoxaline; and RHA-IV, 2-(L-manno-1′,2′,3′,4′-tetrahydroxypentyl)-benzimidazole, and the structure of FUA-I was the same as RHA-I; FUA-II, (2′S, 3′S)-2-(2′, 3′-dihydroxybutyl)quinoxaline; FUA-III, (1′R, 2′R, 3′S)-2-(1′,2′,3′-trihydroxybutyl)quinoxaline [2-(L-xylo-1′,2′,3′-trihydroxybutyl)quinoxaline; FUA-IV, 2-(L-lyxo-1′,2′,3′-trihydroxybutyl)-quinoxaline; and FUA-V, 2-(L-galacto-1′,2′,3′,4′-tetrahydroxypentyl)benzimidazole. These results suggest no significant difference for the pathways of quinoxaline and benzimidazole formation between L-rhamnose and L-fucose. Possible pathways are proposed for each sugar. 相似文献
9.
Kosei Shioji Takafumi Ueyama Nobuaki Ueda Emiko Mutoh Tsutomu Kurisaki Hisanobu Wakita Kentaro Okuma 《Journal of Molecular Catalysis .B, Enzymatic》2008,55(3-4):146-151
The lipase-catalyzed optical resolution of 2-, 3-, and 5-hydroxyalkyl phosphorus compounds 1 provided the corresponding optically pure diastereomers in good yields. (SP, R)- and (RP, S)-1 were acylated faster than (SP, S)- and (RP, R)-1. The stereoselectivity at the phosphorus atom changed with the flexibility of the active sites in the lipases. The stereoselectivity at the phosphorus atom was higher in the reaction of 1a than in the reaction of 1b,c. The reaction rate of -hydroxyalkylphosphine oxide 1c was faster than that of 1a, although less enantioselectivity was observed at the phosphorus atom. 相似文献
10.
Bearne SL White RL MacDonnell JE Bahrami S Grønlund J 《Molecular and cellular biochemistry》2001,221(1-2):117-126
Methylaspartase (EC 4.3.1.2) was purified 20fold in 35% yield from Fusobacterium varium, an obligate anaerobe. The purification steps included heat treatment, fractional precipitation with ammonium sulfate and ethanol, gel filtration, and ion exchange chromatography on DEAESepharose. The enzyme is dimeric, consisting of two identical 46 kDa subunits, and requires Mg2+ (Km = 0.27 ± 0.01 mM) and K+ (Km = 3.3 ± 0.8 mM) for maximum activity. Methylaspartasecatalyzed addition of ammonia to mesaconate yielded two diastereomeric amino acids, identified by HPLC as (2S,3S)3methylaspartate (major product) and (2S,3R)3methylaspartate (minor product). Optimal activity for the deamination of (2S,3S)3methylaspartate (Km = 0.51 ± 0.04 mM) was observed at pH 9.7. The Nterminal protein sequence (30 residues) of the F. varium enzyme is 83% identical to the corresponding sequence of the clostridial enzyme. 相似文献
11.
All stereoisomers of xanthoxin (XAN) and abscisic aldehyde (ABA-aldehyde) were prepared from (R) and (S)-4-hydroxy--cyclogeraniol via asymmetric epoxidation. Their stomatal closure activities were measured on epidermal strips of Commelina communis L. Natural (S)-ABA-aldehyde showed strong activity comparable to that of (S)-abscisic acid (ABA). Natural (1S, 2R, 4S)XAN and (1S, 2R, 4R)-epi-XAN also induced stomatal closure at high concentrations. On the other hand, unnatural (1R)-enantiomers of XAN, epi-XAN, and ABA-aldehyde were not effective. To further examine the Stereoselectivity on the biosynthetic pathway to ABA, deuterium-labeled substrates were prepared and fed to Lycopersicon esculentum Mill, under non-stressed or water-stressed conditions. Substantial incorporations into ABA were observed in the cases of natural (1S, 2R, 4S)-XAN, (1S, 2R, 4R)-epi-XAN and both enantiomers of ABA-aldehyde, leading to the following conclusions. The negligible effect of unnatural (1R)-enantiomers of XAN, epi-XAN and ABA-aldehyde can be explained by their own biological inactivity and/or their conversion to inactive (R)-ABA. Even in the isolated epidermal strips, putative aldehyde oxidase activity is apparently sufficient to convert ABA-aldehyde to ABA while the activity of XAN dehydrogenase seems very weak. The stereochemistry of the 1, 2-epoxide is very important for the XAN-dehydrogenase while this enzyme is less selective regarding the 4-hydrdxyl group of XAN and converts both (1S, 2R, 4S)-XAN and (1S, 2R, 4R)-epi-XAN to (S)-ABA-aldehyde. Abscisic aldehyde oxidase can nonstereoselectively convert both (S) and (R)-ABA-aldehyde to biologically active (S) and inactive (R)-ABA, respectively.Abbreviations ABA
abscisic acid
- ABA-aldehyde
abscisic aldehyde
- DET
diethyl tartrate
-
epi-XAN
xanthoxin epimer
- FCC
flash column chromatography
- GC-EI-MS
gas chromatography-electron impact-mass spectrometry
- MeABA
abscisic acid methyl ester
- IR
infrared
- NMR
nuclear magnetic resonance
- PCC
pyridinium chlorochromate
- THF
tetrahydrofuran
- XAN
xanthoxin
The authors are very grateful to Mr J.K. Heald (Department of Biological Sciences, University of Wales, Aberystwyth, UK) and Dr. R. Horgan for carrying out GC-EI-MS analyses and advice, respectively.This work was supported by the Japan Society for the Promotion of Science (Fellowship for Young Japanese Researcher No. 0040672). 相似文献
12.
Mengli Cai Ying Huang Jianhua Liu Ramaswamy Krishnamoorthi 《Journal of biomolecular NMR》1995,6(2):123-128
Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of 1H-1H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -3, 3-3, 2-2, 2-2, and 3-3 (2.3 Å) are shorter than those in the pairs -2, 2-3, 3-2, 2-3, and 3-2 (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the 3-2 and 2-3 spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -2, 2-3, and 3-2 vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined. 相似文献
13.
P. E. Cheshev E. A. Khatuntseva Yu. E. Tsvetkov A. S. Shashkov N. E. Nifantiev 《Russian Journal of Bioorganic Chemistry》2004,30(1):60-70
4-O-Glycosylation of 2-azidoethyl 2,3,6-tri-O-benzyl-4-O-(2,3-di-O-benzyl-6-O-benzoyl--D-galactopyranosyl)--D-glucopyranoside with a disaccharide donor, 4-trichloroacetamidophenyl 4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-1-thio-2-trichloroacetamido--D-galactopyranoside, in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid resulted in a tetrasaccharide, 2-azidoethyl (2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-(1 3)-(4,6-di-O-acetyl-2-deoxy-2-trichloroacetamido--D-galactopyranosyl)-(1 4)-(2,3-di-O-benzyl-6-O-benzoyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside, in 69% yield. The complete removal of O-protecting groups in the tetrasaccharide, the replacement of N-trichloroacetyl by N-acetyl group, and the reduction of the aglycone azide group to amine led to the target aminoethyl glycoside of -D-Gal-(1 3)--D-GalNAc-(1 4)--D-Gal-(1 4)--D-Glc-OCH2CH2NH2 containing the oligosaccharide chain of asialo-GM1 ganglioside in 72% overall yield. Selective 3-O-glycosylation of 2-azidoethyl 2,3,6-tri-O-benzyl-4-O-(2,6-di-O-benzyl--D-galactopyranosyl)--D-glucopyranoside with thioglycoside methyl (ethyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero--D-galacto-2-nonulopyranosyl)oate in acetonitrile in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid afforded 2-azidoethyl [methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero--D-galacto-2-nonulopyranosyl)oate]-(2 3)-(2,6-di-O-benzyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside, the selectively protected derivative of the oligosaccharide chain of GM3 ganglioside, in 79% yield. Its 4-O-glycosylation with a disaccharide glycosyl donor, (4-trichloroacetophenyl-4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl--D-galactopyranosyl) 1-thio-2-trichloroacetamido--D-galactopyranoside in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid gave 2-azidoethyl (2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-(1 3)-(4,6-di-O-acetyl-2-deoxy-2-trichloroacetamido--D-galactopyranosyl)-(1 4)-{[methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero--D-galacto-2-nonulopyranosyl)onate]-(2 3)}-(2,6-di-O-benzyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside in 85% yield. The resulting pentasaccharide was O-deprotected, its N-trichloroacetyl group was replaced by N-acetyl group, and the aglycone azide group was reduced to afford in 85% overall yield aminoethyl glycoside of -D-Gal-(1 3)--D-GalNAc-(1 4)-[-D-Neu5Ac-(2 3)]--D-Gal-(1 4)--D-Glc-OCH2CH2NH2 containing the oligosaccharide chain of GM1 ganglioside. 相似文献
14.
Jeong EJ Cho JH Sung SH Kim SY Kim YC 《Bioorganic & medicinal chemistry letters》2011,21(8):2283-2286
The 80% methanolic extract of Euonymus alatus leaves and twigs afforded three new lignans, (−)-threo-4,9,4′,9′-tetrahydroxy-3,7,3′,5′-tetramethoxy-8-O-8′-neolignan (1), (−)-threo-4,9,4′,9′-tetrahydroxy-3,5,7,3′-tetramethoxy-8-O-8′-neolignan (2), (7R,8R,7′R)-(+)-lyoniresinol (3), together with seventeen known lignans (4-20). The structures of 1-20 were elucidated by extensive 1D and 2D spectroscopic methods including 1H NMR, 13C NMR, 1H-1H COSY, HMQC, HMBC and NOESY. All the isolated compounds except for dilignans (19 and 20) significantly inhibited nitric oxide production in lipopolysaccharide-stimulated RAW264.7 cells. 相似文献
15.
《Bioscience, biotechnology, and biochemistry》2013,77(9):1671-1674
(2S,2’R,3R,4E,8E)-N-2’-Hydroxyoctadecanoyl-1-O-(β-d-glucopyranosyl)-9-methyl-4,8-sphingadienine (Pen III), a cerebroside isolated from Penicillium funiculosum A-1 as the fruiting inducer against Basidiomycete Schizophyllum commune, was synthesized by starting from d-glucose, l-serine, homoprenyl acetate and stearic acid. 相似文献
16.
Joo Hwan Cha Ae Nim Pae Kyung Il Choi Yong Seo Cho Wook Hyun Kim Ye Sun Han Hong-Chul Yun Jongsoo Lee Hun Yeong Koh Eun Lee 《Biotechnology letters》2002,24(20):1695-1698
An NADPH-dependent carbonyl reductase that shows (3R)-selective reducing activity for -substituted--ketoesters was purified from Kluyveromyces marxianus and racemic alkyl 2-substituted-3-oxobutanoates were reduced to the corresponding (2S,3R)- or (2R,3R)-2-substituted-3-hydroxybutanoates with enantiomeric purity (> 99%) and diastereoselectivity (24 98%). 相似文献
17.
Gwon-Soo Kim Si-Hyung Park Yung-Jin Chang Yoong-Ho Lim Soo-Un Kim 《Biotechnology letters》2002,24(19):1553-1556
(+)-Isopiperitenone (100 mg l–1) was converted into (4S,6R)-6-hydroxy- and (4S,8R)-8,9-epoxyisopiperitenone, aside from the already known (+)-7-hydroxyisopiperitenone, by suspension cell culture of Mentha piperita. As (–)-isopiperitenone was hydroxylated similarly, this implies that the hydroxylating enzyme(s) have a broad substrate stereospecificity in regards to the stereochemistry at C4. (–)-(4R)-Carvone was reduced by the Mentha cells both at carbonyl and C1-C6 double bond to give (1R,2S,4R)-neodihydrocarveol and (1R,2R,4R)-dihydrocarveol with the former being the major product. (+)-(4S)-Carvone had a similar reduction pattern, producing (1S,2R,4S)-neodihydrocarveol and (1S,4S)-dihydrocarvone. Formation of these compounds indicates that the peppermint cell culture cannot only hydroxylate the allylic position but also reduce the ,-unsaturated carbonyl system. 相似文献
18.
In this paper we give an analytical reformulation of Holling's (1966) simulation model for invertebrate predatory behaviour. To this end we represent a population of predators as a frequency distribution over a space of (physiological) states. The functional response of a predator is calculated from the (stable) equilibrium distribution of its state as a function of prey density.Starting from the general model various other models are obtained by limit processes, some of them new and some of them old. The more interesting of which will be studied in further papers in this series.List of Notation
a
rate constant of digestion
-
b
maximum of rate constant of prey encounter in the mantid
-
b
maximum pursuit duration in the mantid (p(0))
-
c
satiation threshold for search
-
c
satiation threshold for pursuit in the mantid: c=c(b-Ds/v)/b
-
D
m
maximum sighting distance
-
D
p
pursuit distance
-
D
s
strike distance
-
expectation operator
-
f, f
0
rate of change of satiation during search
-
f
1
rate of change of satiation during prey handling
-
F
functional response: number of prey eaten per unit of time by one predator
-
g
rate constant of effective prey encounter in the gobbler and sucker
- g0
rate constant of prey encounter
- g1
probability of no prey loss from pursuit
- g2
probability of no prey escaping during pursuit
-
H
Holling secretary correction factor in the sucker: fraction of the time spent searching
-
k
R
density of R
- kT
probability density of maximum prey handling time
-
K
probability that maximum prey handling time is
e, i.e. pursuit duration is zero
-
K
R
distribution function of R
-
N
number of prey caught
-
p
(marginal) density of S
- p0
density of S in search
- p1
simultaneous density of S and T
- P
probability
-
p
1
marginal density of S in handling prey
-
q
probability of strike success
-
R
ratio of realized to maximum sighting distance
-
s, S
satiation
-
satiation axis
-
t
time
-
handling time axis
-
u
eating speed
-
U
homogeneous(0,1) random variable
-
v
pursuit speed
-
V
exponential(1) random variable
-
w
prey weight
-
W
exponential(m) random variable
-
x
prey density
-
ratio of maximum successful pursuit duration to meal duration (pm/e)
-
pm
-
relative duration of successful pursuit (p/pm)
-
ratio of shortest to largest sighting distance
-
xe
-
time already spent handling a prey item
-
rate of prey loss during prey handling
-
prey escape rate during pursuit
-
prey biomass density (xw)
-
, T
maximum time still to be spent handling a prey item
-
e
meal duration
-
m
maximum handling time (
e+
p)
-
p
duration of successful pursuit
-
pm
maximum duration of successful pursuit (p(0))
-
hazard rate
-
m
maximum of hazard rate
-
scaled functional response (wF)
-
minimal i-state space 相似文献
19.
An abnormal, structurally modified, kinetically stable S2-state has been reported to be induced when Photosystem II was treated with NaCl-EGTA (or EDTA) in the light or with pH in darkness, both are assumed to release functional Ca2+. In order to compare the mechanism of induction of modified S2-state between the two treatments, effects of illumination during or before low pH-treatment on formation of the abnormal S2-state were investigated by means of thermoluminescence measurements and low temperature EPR spectroscopy. Following results have been obtained: Flash illumination during low pH-treatment did not practically induce the abnormal S2-state, whereas preflash illumination given immediately before low pH-treatment efficiently induced the abnormal S2-state, and its amplitude showed a period-four oscillation on varying the preflash number with maxima at the second and sixth flashes. The abnormal S2-state thus induced by preflashes was identical with the modified S2-state that could be induced in dark-low pH-treated Photosystem II by excitation at 0°C after neutralization to pH 6.5. It was inferred that in low pH-treatment, modified S2-state can be formed from both S2- and S3-states, but its yield from the latter is much higher than from the former, consistent with the early results by Boussac et al. obtained for NaCl-EGTA-light or NaCl-citrate-light treatment.Abbreviations DCMU
3-(3,4-dichlorophenyl)-1,1-dimethylurea
- EDTA
ethylenediaminetetraactate
- EGTA
ethylene glycol bis(-aminoethylether)-N,N,N,N-tetraacetic acid
- Mes
2-(N-morpholino)ethanesulfonic acid
- PS II
Photosystem II 相似文献
20.
S. P. O. Werbrouck P. Redig H. A. Van Onckelen P. C. Debergh 《Journal of Plant Growth Regulation》1996,15(2):87-93
Imidazole fungicides such as imazalil, prochloraz, and triflurnizole and the triazole growth retardant paclobutrazol promote the shoot-inducing effect of exogenous cytokinins in Araceae, such as Spathiphyllum floribundum Schott and Anthurium andreanum Schott. The mechanism of their action could partially be based on the inhibition of gibberellic acid (GA) biosynthesis, because administration of GA3 inhibits the phenomenon completely in S. floribundum. Not only is the suppression of GA biosynthesis involved, but also the metabolism of endogenous cytokinins is significantly altered. Although the balance between isopentenyladenine, zeatin, dihydrozeatin, and their derivatives was shifted to distinguished directions by administration of BA and/or imazalil and/or GA3, no correlation between these changes in metabolic pathways and the number of shoots could be found. The metabolism of BA was not significantly altered by adding imazalil to the micropropagation medium of S. floribundum.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- [9R-5P]DHZ
9--d-ribofuranosyl-dihydrozeatin-monophosphate
- [9R-5P]iP
6-isopentenyl-9--d-ribofuranosyladenine-monophosphate
- [9R-5P]Z
9--d-ribofuranosyl-zeatin-monophosphate
- [9G]BA
6-benzyl-9--d-glucopyranosyladenine
- [9G]DHZ
9--d-glucopyranosyl-dihydrozeatin
- [9G]iP
6-isopentenyl-9--d-glucopyranosyladenine
- [9G]Z
9--d-glucopyranosyl-zeatin
- [9R]BA
6-benzyl-9--d-ribofuranosyladenine
- [9R]DHZ
9--d-ribofuranosyl-dihydrozeatin
- [9R]iP
6-isopentenyl-9--d-ribofuranosyladenine
- [9R]Z
9--d-ribofuranosyl-zeatin
- BA
6-benzyladenine
- DHZ
dihydrozeatin
- ES+ LC-MS/MS
HPLC coupled Electrospray Tandem Mass Spectrometry
- f.m.
fresh mass
- mT
6-(3-hydroxybenzyl)adenine
- IMA
imazalil
- iP
isopentenyladenine
- NAA
1-naphthalene acetic acid
- NFT
Nutrient Film Technique
- (OG)[9R]DHZ
O--glucopyranosyl-9--d-ribofuranosyl-dihydrozeatin
- (OG)[9R]Z
O--d-glucopyranosyl-9--d-ribofuranosyl-zeatin
- (OG)DHZ
O--d-glucopyranosyl-dihydrozeatin
- (OG)Z
O--d-glucopyranosyl-zeatin
- PAR
Photosynthetic Active Radiation
- PBZ
paclobutrazol
- PRO
prochloraz
- TDZ
thidiazuron
- TRI
triflurnizole
- Z
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