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1.
Dr. H. H. Boer L. P. C. Schot H. W. M. Steinbusch Cora Montagne Dagmar Reichelt 《Cell and tissue research》1984,238(2):411-412
Summary Consecutive sections of certain neurons in the central ganglia of the pond snail Lymnaea stagnalis appear to be immunoreactive to anti-dopamine and anti-serotonin. The Cerebral Giant Neurons stain in addition with antivasotocin. The observations indicate the presence of two biogenic amines within the same neuron and in addition their co-existence with a biologically active peptide. 相似文献
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Gas exchange and contents of photosynthetic intermediates of leaves of Arbutus unedo L. were determined with the aim of recognizing the mechanisms of inhibition that were responsible for the midday depression of photosynthesis following exposure to dry air, and the decline in photosynthetic capacity following application of abscisic acid (ABA). Rapidly killed (<0.1 s) leaf samples were taken when gas analysis showed reduced CO2 assimilation. Determination of the contents of 3-phosphoglyceric acid (PGA), ribulose 1,5-bisphosphate (RuBP), triose phosphates, fructose 1,6-bisphosphate and hexose phosphates in the samples showed that significant variation occurred only in the level of PGA. As a result, the ratio PGA/RuBP decreased with increasing inhibition of photosynthesis, particularly when application of ABA had been the cause. A comparison of metabolite patterns did not bring out qualitative differences that would have indicated that effects of ABA and of dry air had been caused by separate mechanisms. Depression of photosynthesis occurred in the presence of sufficient RuBP which indicated that the carboxylation reaction of the carbon-reduction-cycle was inhibited after application of ABA or exposure to dry air.Abbreviations and symbols ABA
abscisic acid
-
C
a
partial pressure of CO2 in the ambient air
-
C
i
partial pressure of CO2 in the intercellular spaces
- I
quantum flux
- PGA
3-phosphoglyceric acid
- RuBP
ribulose 1,5-bisphosphate
-
I
L
leaf temperature
- w
water-vapor pressure difference between leaf and air 相似文献
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Summary Confined placental chorionic mosaicism is reported in 2% of viable pregnancies cytogenetically analyzed on chorionic villi samplings (CVS) at 9–12 weeks of gestation. In follow-up studies this mosaicism has been shown to be associated with increased frequency of second and third trimester pregnancy loss or intrauterine fetal growth retardation. We have studied 54 spontaneous abortions (SA) for the detection of confined placental mosaicism and found 11 of them to be mosaic. All mosaic cases were identified among first trimester spontaneous abortions, and the mosaicism was confined to specific placental or embryonic/fetal cell lineages. These results indicate that the previously reported mosaicism in SA represents both confined and generalized types of mosaicism and that its accepted frequency of 5%–10% in SA will likely be higher. Over the whole gestational period, the confined placental mosaicism is more common than the reported rate of 1%–2% seen in viable pregnancies at CVS, and a higher proportion of pregnancy complications than previously suspected may be associated with confined placental mosaicism. 相似文献
7.
Reinhard Piechocki Dagmar Kupper Ariel Quiñones Renate Langhammer 《Molecular & general genetics : MGG》1986,202(1):162-168
Summary The dnaQ (mutD) gene product which encodes the -subunit of the DNA polymerase III holoenzyme has a central role in controlling the fidelity of DNA replication because both mutD5 and dnaQ49 mutations severely decrease the 3–5 exonucleolytic editing capacity.It is shown in this paper that more than 95% of all anaQ49-induced base pair substitutions are transversions of the types G:C-T:A and A:T-T:A. Not only is this unusual mutational specificity precisely that observed recently for a number of potent carcinogens such as benzo(a) pyrene diolepoxide (BPDE) and aflatoxin B1 (AFB1), which are dependent on the SOS system to mutagenize bacteria, but it is also seen for the constitutively expressed SOS mutator activity in E. coli tif-1 strains as well as for the SOS mutator activity mediated gap filling of apurinic sites. Because the G:C-T:A and A:T-T:A transversions can either result from the insertion of an adenine across from apurinic sites or arise due to the incorporation of syn-adenine opposite a purine base, we postulate that the DNA polymerase III holoenzyme also has a reduced discrimination ability in a dnaQ49 background.The introduction of a lexA (Ind-) allele, which prevents the expression of SOS functions, led to a significant reduction in the dnaQ49-caused mutator effect.Both, the mutational specificity observed and the partial lexA
+ dependence of the mutator effect provoke a reanalysis of the hypothesis that the DNA polymerase III holoenzyme can be converted into the postulated but until now unidentified SOS polymerase. 相似文献
8.
Effects of 2,3,5-triiodobenzoic acid (TIBA) and age of etiolated pea epicotyl segments on the indol-3-ylacetic acid (IAA)
stimulated transport of14C-abscisic acid (ABA) was studied. In spite of a slight decrease of IAA transport after the application of TIBA, the IAA stimulation
of14C-ABA transport did not change. In segments excised from epicotyls of different age,3H-IAA transport was identical and the induction of prolongation growth by IAA in segments from the upper part of the epicotyl
was observed. The IAA ap{ie226-01}ation to the growing segments was connected with intensive attraction of14C-ABA to the site {ie226-02}AA application, while the application of IAA to the older segments was growth ineffective ana
no stimulation of14C-ABA transport by IAA was observed. 相似文献
9.
M Hejzlar V Sedmidubsky A Procházková V Dvorsky L Stastná M Paroubek M Kotasová M Puchmayerová J Silarová L Gleichová 《Journal of hygiene, epidemiology, microbiology, and immunology》1984,29(3):311-315
As a part of preclinical trials of 2,996 clinical isolates from three larger hospitals in Prague were qualitatively and quantitatively assayed for in vitro sensitivity to ceftazidime. In gramnegative bacteria the incidence of resistance to ceftazidime in strain of Enterobacter, Serratia Proteus and Pseudomonas species ranged from 4% to 6% of strains. In grampositive bacteria only strains of enterococci, listeriae and anaerobic bacteria are excluded from the action of this broad-spectrum antibiotic. According to present experiences the antipseudomonal activity of ceftazidime is approximately the same as that of cefsulodine and cefoperazone. Alarmingly, one of the Pseudomonas aeruginosa isolates was found to show a distinct multiresistance to all available lactam, aminoglycoside and broad-spectrum antimicrobials, including ceftazidime. 相似文献
10.