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11.
Administration of drugs such as fenfluramine, 20-40 mg/kg, and m-chlorophenylpiperazine (m-CPP), 2.5-5 mg/kg, which release serotonin or activate postsynaptic serotonin receptors, respectively, induced a dramatic decrease in the duodenal content of immunoreactive dynorphin (ir-DYN). The effect was antagonized by cyproheptadine, 1 mg/kg. Similarly, acute administration of the specific serotonin reuptake blockers fluvoxamine, 15 mg/kg, or femoxetine, 10 mg/kg, and 5-hydroxytryptophan (5-HTP), 40-160 mg/kg, evoked a marked decrease in the duodenal content of ir-DYN. A combined administration of fluvoxamine or femoxetine and 5-HTP failed to potentiate the effect of individual treatment. Only a higher dose of fenfluramine, 40 mg/kg, increased the ir-DYN content in the hypothalamus. These results suggest that the brain and gut ir-DYN is independently regulated by the serotonin system and that a serotonin mechanism might stimulate release of the gut dynorphin content. 相似文献
12.
Summary Using the monotone dependence function (mdf) together with correlation coefficient it was found that the Ma-DNA content as well as total protein content are regularly, linearly, positively and strongly dependent in sister cells (proter-opisthe) ofChilodonella steini. Additionally it was shown that proter-opisthe ordering is irrelevant to Ma-DNA and protein contents.Analysis of sister cell generation times (TG) confirmed the existence of regular, linear, positive and strong codependence.The relations between Ma-DNA and total protein contents, between protein content and TG, and between Ma-DNA content and TG were also described. There is a weak, linear dependence between Ma-DNA and total protein contents. Relations of TG and Ma-DNA content or TG and total protein content are non-linear and not even monotone. Low and high levels of DNA or proteins are connected with long generation times. 相似文献
13.
A comparative description of mitochondrial DNA differentiation in selected avian and other vertebrate genera 总被引:14,自引:1,他引:13
Levels of mitochondrial DNA (mtDNA) sequence divergence between species
within each of several avian (Anas, Aythya, Dendroica, Melospiza, and
Zonotrichia) and nonavian (Lepomis and Hyla) vertebrate genera were
compared. An analysis of digestion profiles generated by 13-18 restriction
endonucleases indicates little overlap in magnitude of mtDNA divergence for
the avian versus nonavian taxa examined. In 55 interspecific comparisons
among the avian congeners, the fraction of identical fragment lengths (F)
ranged from 0.26 to 0.96 (F = 0.46), and, given certain assumptions, these
translate into estimates of nucleotide sequence divergence (p) ranging from
0.007 to 0.088; in 46 comparisons among the fish and amphibian congeners, F
values ranged from 0.00 to 0.36 (F = 0.09), yielding estimates of P greater
than 0.070. The small mtDNA distances among avian congeners are associated
with protein-electrophoretic distances (D values) less than approximately
0.2, while the mtDNA distances among assayed fish and amphibian congeners
are associated with D values usually greater than 0.4. Since the
conservative pattern of protein differentiation previously reported for
many avian versus nonavian taxa now appears to be paralleled by a
conservative pattern of mtDNA divergence, it seems increasingly likely that
many avian species have shared more recent common ancestors than have their
nonavian taxonomic counterparts. However, estimates of avian divergence
times derived from mtDNA- and protein-calibrated clocks cannot readily be
reconciled with some published dates based on limited fossil remains. If
the earlier paleontological interpretations are valid, then protein and
mtDNA evolution must be somewhat decelerated in birds. The empirical and
conceptual issues raised by these findings are highly analogous to those in
the long-standing debate about rates of molecular evolution and times of
separation of ancestral hominids from African apes.
相似文献
14.
Methods for computing the standard errors of branching points in an evolutionary tree and their application to molecular data from humans and apes 总被引:23,自引:2,他引:21
Statistical methods for computing the standard errors of the branching
points of an evolutionary tree are developed. These methods are for the
unweighted pair-group method-determined (UPGMA) trees reconstructed from
molecular data such as amino acid sequences, nucleotide sequences,
restriction-sites data, and electrophoretic distances. They were applied to
data for the human, chimpanzee, gorilla, orangutan, and gibbon species.
Among the four different sets of data used, DNA sequences for an
895-nucleotide segment of mitochondrial DNA (Brown et al. 1982) gave the
most reliable tree, whereas electrophoretic data (Bruce and Ayala 1979)
gave the least reliable one. The DNA sequence data suggested that the
chimpanzee is the closest and that the gorilla is the next closest to the
human species. The orangutan and gibbon are more distantly related to man
than is the gorilla. This topology of the tree is in agreement with that
for the tree obtained from chromosomal studies and DNA-hybridization
experiments. However, the difference between the branching point for the
human and the chimpanzee species and that for the gorilla species and the
human-chimpanzee group is not statistically significant. In addition to
this analysis, various factors that affect the accuracy of an estimated
tree are discussed.
相似文献
15.
T. Cichocki D. Heck L. Jarczyk E. Rokita A. Strzałkowski M. Sych 《Histochemistry and cell biology》1985,83(1):87-92
Summary The elemental composition of the human atheroselerotic popliteal artery was examined using the proton-induced X-ray-emission (PIXE) method. The application of a narrow proton beam (3×10 m2) enabled us to determine not only the concentrations of Cl, K, Ca, Fe, Cu, Zn, Br and Pb, but also their localization in different artery-wall regions. The highest mean concentrations of Cl, K, Zn and Br were found in the tunica media. In the investigated sections the distribution of Ca and Fe varied: sometimes, these elements were prevalent in the tunica intima, whereas in other cases, the highest concentrations were observed in the tunica media or tunica adventitia. The concentration profiles of each element were characterized by many sharp, narrow peaks. The highest concentrations of Ca and Fe showed such high levels that only one explanation is possible, i.e. the presence of crystals. The correlation of Ca peaks with those of Zn and Fe is discussed. The usefulness of the micro-PIXE method for the investigation of biomedical materials is also considered. 相似文献
16.
Reinhard Bolli Katarzyna A. Nałecz Angelo Azzi 《Journal of bioenergetics and biomembranes》1986,18(4):277-284
Cytochromec oxidase fromParacoccus denitrificans was homogenously dispersed in Triton X-100. Using gel exclusion chromatography and sucrose gradient centrifugation analysis a molecular weight of the detergent-protein complex of 155,000 was determined. After subtraction of the bound detergent (111 mol/mol hemeaa
3) a molecular weight of 85,000 resulted, which agreed well with the model of a monomer containing two subunits. This monomer showed high cytochromec oxidase activity when measured spectrophotometrically in the presence of Triton X-100 (V
max=85 s–1). The molecular activity, plotted according to Eadie-Hofstee, was monophasic as a function of the cytochromec concentration. AK
m of 3.6×10–6 M was evaluated, similar to theK
m observed in the presence of dodecyl maltoside [Naeczet al. (1985).Biochim. Biophys. Acta
808, 259–272]. 相似文献
17.
Zbigniew Szot Małgorzata Rochalska Maria Wojewódzka Andrzej Chimiak Witold Przychodzen 《Radiation and environmental biophysics》1986,25(1):31-35
Summary Male mice SAS/4 were injected i.v. with239Pu citr(IV) 0.27 µCikg–1–9.99 kBqkg–1. After 1 h 30 µmol kg–1 of 3,4,3 LICAM(C), N, N, N, N-tetra-(2,3-dihydroxybenzoyl)-spermine or Na3CaDTPA as a reference compound was given intraperitoneally. After 4 days the animals were sacrified and the Pu content in livers, kidneys, femurs and carcasses was determined by the liquid scintillation method. It was found that, as compared with the control, 3,4,3 LICAM(C) removed 83% of the Pu activity deposited in the liver, 71% of that in the femur and 79% of the Pu in the whole body. The Pu content in the kidneys exceeded the control value by about 50%. Na3CaDTPA removed 96, 86, 40 and 72% of plutonium from the liver, kidneys, femurs and carcasses respectively.Tetra-DHB-spermine caused the excretion of 50, 57 and 39% of Pu from liver, bone and whole body respectively. The retention of Pu in the kidneys was increased to 400% of the control value. 相似文献
18.
19.
For three types of self-sucking impellers (fourand six-pipe and disk impellers) mixing power, initial point, amount of gas leaving the impeller and mass transfer coefficient were determined experimentally. Investigations were performed for two systems: water and biomass solution.From the point of view of a minimum mixing power and maximum mass transfer coefficient the best impeller has been chosen. Fuzzy multiobjective optimization for determination of optimum operating conditions is proposed.List of Symbols
c
concentration of oxygen
-
D
tank diameter
-
d
impeller diameter
-
g
acceleration of gravity
-
H
height of liquid in the tank
-
H
height of liquid above impeller, H=H-y
-
k
consistency coefficient
-
k
L
a
volumetric mass transfer coefficient
-
N
rotational speed of impeller
-
n
flow behaviour index
-
P
mixing power for pure liquid
-
P
G
mixing power for aerated liquid
-
V
G
volumetric air flow rate
-
y
distance of impeller from the tank bottom
-
v
a
apparent kinematic viscosity of liquid
-
density of liquid
-
time
-
gas hold-up
- Eu=P/N
3
d
5
or EuG=P
G
/N
3
d
5
Euler Number for non-gassed or aerated liquid
- Fr=N
2
d/g
Froude Number
- Fr*=N
2
d
2
/g(H -y)
modified Froude Number
- KG=V
G
/N d
3
gas flow number
- Re=N d
2
/v
a
Reynolds Number
- Sh=k
K
a/(g
2
/v
a
)1/3
Sherwood Number 相似文献
20.
Seasonal changes of the photosynthetic capacity of the Antarctic macroalga Adenocystis utricularis (Bory) Skottsberg 总被引:1,自引:1,他引:0
Summary Photosynthetic oxygen evolution from Antarctic macroalgaAdenocystis utricularis, collected from littoral zone of Admiralty Bay of King George Island (South Shetland), was measured under standard laboratory conditions during a 9-month study period. During autumn and winter the photosynthetic apparatus of the alga revealed an increased capacity to use low irradiance. This coincided with increasing concentrations of chlorophyll a+c. In parallel respiration rates measured at the average monthly water temperature were lower in winter than in summer. 相似文献