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21.
Information on the distribution of 59 dicranophorid rotifers from diverse habitats in south and central Sweden was analyzed to reveal their relationships to their substrate. They were mainly frequenting macrophytic vegetation. Even some species which have previously been regarded as psammobionts were mostly or only found on periphytic substrates. Like other raptorial predators, dicranophorids have a very broad ecological range. 相似文献
22.
Sarah A. Osmani Author VitaeAuthor Vitae Birger Lindberg Møller Author Vitae 《Phytochemistry》2009,70(3):325-1473
Plant family 1 UDP-dependent glycosyltransferases (UGTs) catalyze the glycosylation of a plethora of bioactive natural products. In Arabidopsis thaliana, 120 UGT encoding genes have been identified. The crystal-based 3D structures of four plant UGTs have recently been published. Despite low sequence conservation, the UGTs show a highly conserved secondary and tertiary structure. The sugar acceptor and sugar donor substrates of UGTs are accommodated in the cleft formed between the N- and C-terminal domains. Several regions of the primary sequence contribute to the formation of the substrate binding pocket including structurally conserved domains as well as loop regions differing both with respect to their amino acid sequence and sequence length. In this review we provide a detailed analysis of the available plant UGT crystal structures to reveal structural features determining substrate specificity. The high 3D structural conservation of the plant UGTs render homology modeling an attractive tool for structure elucidation. The accuracy and utility of UGT structures obtained by homology modeling are discussed and quantitative assessments of model quality are performed by modeling of a plant UGT for which the 3D crystal structure is known. We conclude that homology modeling offers a high degree of accuracy. Shortcomings in homology modeling are also apparent with modeling of loop regions remaining as a particularly difficult task. 相似文献
23.
NDRG1 is necessary for p53-dependent apoptosis 总被引:11,自引:0,他引:11
Stein S Thomas EK Herzog B Westfall MD Rocheleau JV Jackson RS Wang M Liang P 《The Journal of biological chemistry》2004,279(47):48930-48940
24.
The influence of maternal antibodies on clinical and serological response after experimental inoculation with Babesia divergens of newborn calves was studied. Five calves, born to dams seropositive for B.divergens, (Group 1) had specific maternal antibodies when tested 12 h after their first feeding of colostrum. At that point they were inoculated i.v. with B.divergens infected erythrocytes. Five other calves, born to dams seronegative for B.divergens, (Group 2) had no Babesia specific maternal antibodies when inoculated at the same age. Babesia divergens organisms were demonstrated in blood smears from calves in both groups at some point 5 to 10 days p.i. All calves in both groups had B.divergens specific IgM antibodies at 7 to 17 days p.i. as shown by a modified IF-test. Specific IgG antibodies, transferred by colostrum, were found in all calves of Group 1 before inoculation of B.divergens. The IgG titre of these animals increased by a doubling dilution step at 11–25 days p.i. Among calves of Group 2 specific IgG antibodies were found at first between day 9 and 15 p.i. Both IgM and IgG antibody titres had to be investigated since demonstrated IgG antibodies can originate both from maternally transferred antibodies and from actively produced antibodies after an infection. There was no difference in clinical parameters; parasitaemia, PCV, Hb, and rectal temperature between the groups. This experiment gives evidence that there can be a resistance to bovine babesiosis in newborn calves independent of maternal antibodies. 相似文献
25.
Several observations suggest an increased RNA synthesis in livers of protein-deprived rats, though the RNA/DNA ratio is decreased. A number of hormones may be involved in these changes. Therefore, we studied in RNA metabolism in isolated perfused livers taken from protein-fed and protein-deprived rats. (3H)-orotic acid was given to the rats 2 h before liver explantation, and (14C)-orotic acid was added to the perfusate. Other rats, called controls in vivo, whose livers were not transplanted were also given (3H)-orotic acid followed by (14C)-orotic acid. The livers of these rats, which were not hormone supplemented, were labelled for the same length of times as the livers in vitro. The ratio specific RNA radioactivity/specific nucleotide radioactivity x RNA/DNA was determined and taken as a measure of the RNA synthesis per liver cell. In the controls in vivo, this ratio was significantly higher for protein-deprived than for protein-fed rats. In livers from the protein-fed rats, labelling in vitro increased significantly when growth hormone, hydrocortisone, insulin and tri-iodothyronine were added to the perfusate. Labelling was also significantly higher in these livers than in the controls in vivo. In livers from protein-deprived rats, the ratio in question was the same whether the hormones were added to the perfusate or not, and was significantly lower than in the controls in vivo. Differences in RNA labelling are thus obtained in our in vitro system. Gel electrophoresis of RNA demonstrated normal RNA labelling, showing that the system is suitable for studying liver RNA synthesis. Further refinement can be made by studying the labelling of UTP and CTP. The results might suggest that the liver from a protein-fed rat, explanted in vitro, may increase its RNA synthesis under the influence of the four hormones in question, and that the RNA synthesis of the liver of a protein-deprived rat is high in-vivo and that it might decrease, when it is explanted to in vitro conditions. 相似文献
26.
Mika Zagrobelny Mohammed Saddik Motawia Carl Erik Olsen Søren Bak Birger Lindberg Møller 《Insect biochemistry and molecular biology》2013,43(11):1037-1044
Zygaena filipendulae accumulates the cyanogenic glucosides linamarin and lotaustralin by larval sequestration from the food plant or de novo biosynthesis. We have previously demonstrated that the Z. filipendulae male transfers linamarin and lotaustralin to the female in the course of mating. In this study we report the additional transfer of 5-hydroxytryptophan glucoside (5-(β-d-glucopyranosyloxy)-l-Tryptophan) from the Z. filipendulae male internal genitalia to the female spermatophore around 5 h into the mating process. 5-Hydroxytryptophan glucoside is present in the virgin male internal genitalia, and production continues during the early phase of mating. Following initiation of 5-hydroxytryptophan glucoside transfer to the female, the amount in male internal genitalia is drastically reduced until after mating where it is slowly replenished. For unambiguous structural identification, 5-hydroxytryptophan glucoside was chemically synthesized and used as an authentic standard. The biological function of 5-hydroxytryptophan glucoside remains to be established, although we have indications that it may be involved in inducing the female to stay in copula and delay egg-laying to prevent re-mating of the female. To our knowledge 5-hydroxytryptophan glucoside has not previously been reported present in animal tissues. 相似文献
27.
Oligotrophication as a result of planktivorous fish removal with rotenone in the small,eutrophic, Lake Mosvatn,Norway 总被引:2,自引:1,他引:2
In September 1987 the shallow, eutrophic, Lake Mosvatn was treated with rotenone to eliminate planktivorous fish (mainly whitefish,Coregonus lavaretus, L.), and the effects were studied. The first summer after treatment the zooplankton community changed markedly from rotifer
dominance and few grazers, to a community with few rotifers and many grazers. Accordingly there was a fivefold increase in
the biomass ofDaphnia galeata. Adult females ofD. galeata approximately doubled in weight. The decrease in rotifer biomass was probably mainly due to a loss of food by competition
with the daphnids. The phytoplankton community was also markedly affected. Prior to treatment Secchi depth was 1.7 m and Chl-a 23μg l−1 in the summer. After treatment there was an increase in the proportion of small and gelatinous algae and the mean chlorophyll
concentration fell to 7μg Chl-a l−1. Secchi depth increased to>2.3 m (bottom-sight most of the season). After the treatment there were also fewer cyanobacterial
blooms. This seems to be related to oligotrophication caused indirectly by increased grazing by the zooplankton. Total nutrient
concentrations were affected. Prior to treatment the mean summer concentration of total phosphate was 44μg P l−1. This decreased to 29μg P l−1 in the first summer and 23μg P l−1 the second summer after the treatment. Total nitrogen decreased from 0.68 mg N l−1 before treatment to 0.32 mg N l−1 the first summer after the treatment. The phosphate loading was not reduced, therefor it can be concluded that the fish removal
provided a biomanipulation which caused the more oligotrophic conditions. 相似文献
28.
Christian Rosenberg Antje Kickhefel Birger Mensel Tilman Pickartz Ralf Puls Joerg Roland Norbert Hosten 《PloS one》2013,8(10)
Objective
To compare the accuracy of a semi-quantitative proton resonance frequency shift (PRFS) thermal mapping interface and an alternative qualitative T1 thermometry model in predicting tissue necrosis in an established routine setting of MRI-guided laser ablation in the human liver.Materials and Methods
34 cases of PRFS-guided (GRE) laser ablation were retrospectively matched with 34 cases from an earlier patient population of 73 individuals being monitored through T1 magnitude image evaluation (FLASH 2D). The model-specific real-time estimation of necrotizing thermal impact (above 54 °C zone and T1 signal loss, respectively) was correlated in size with the resulting necrosis as shown by lack of enhancement on the first-day contrast exam (T1). Matched groups were compared using the Mann-Whitney test.Results
Online PRFS guidance was available in 33 of 34 cases. Positive size correlation between calculated impact zone and contrast defect at first day was evident in both groups (p < 0.0004). The predictive error estimating necrosis was median 21 % (range 1 % - 52 %) in the PRFS group and 61 % (range 22 - 84 %) in the T1 magnitude group. Differences in estimating lethal impact were significant (p = 0.004), whereas the real extent of therapy-induced necrosis showed no significant difference (p > 0.28) between the two groups.Conclusion
PRFS thermometry is feasible in a clinical setting of thermal hepatic tumor ablation. As an interference-free MR-tool for online therapy monitoring its accuracy to predict tissue necrosis is superior to a competing model of thermally induced alteration of the T1 magnitude signal. 相似文献29.
30.
Patrik Svensson-F?rbom Peter Almgren Bo Hedblad Gunnar Engstr?m Margaretha Persson Anders Christensson Olle Melander 《PloS one》2015,10(6)