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1.
Steffen Harzsch Carsten H. G. Müller Verena Rieger Yvan Perez Silvia Sintoni Christian Sardet Bill Hansson 《Zoomorphology》2009,128(1):53-73
The enigmatic arrow worms (Chaetognatha) are marine carnivores and among the most abundant planktonic organisms. Their phylogenetic
position has been heavily debated for a long time. Most recent molecular studies still provide a diverging picture and suggest
arrow worms to be some kind of basal protostomes. In an effort to understand the organization of the nervous system in this
clade for a broad comparison with other Metazoa we analysed the ultrastructure of the ventral nerve centre in Spadella cephaloptera by transmission electron microscopy. We were able to identify six different types of neurons in the bilateral somata clusters
by means of the cytoplasmic composition (regarding the structure of the neurite and soma including the shape and eu-/heterochromatin
ratio within the nucleus) as well as the size and position of these neurons. Furthermore, our study provides new insights
into the neuropil composition of the ventral nerve centre and several other fine structural features. Our second goal was
to examine if individually identifiable neurons are present in the ventral nerve centres of four chaetognath species, Sagitta setosa, Sagitta enflata, Pterosagitta draco, and Spadella cephaloptera. For that purpose, we processed whole mount specimens of these species for immunolocalization of RFamide-related neuropeptides
and analysed them with confocal laser-scanning microscopy. Our experiments provide evidence for the interspecific homology
of individual neurons in the ventral nerve centres of these four chaetognath species suggesting that the potential to generate
serially arranged neurons with individual identities is part of their ground pattern. 相似文献
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目的:探讨利用分子量阵列平台进行特定序列甲基化分析的方法。方法:通过对不同扩增条件和扩增效率及不同条件处理的质谱分析比较了MassArray平台进行甲基化分析的特点。结果:本研究通过与重亚硫酸盐测序结果比较证实,MassArray分子量阵列技术平台能够反映甲基化修饰的真实水平;通过不同条件下PCR扩增效率与甲基化分析的结果,发现扩增效率是制约MassArray分子量阵列技术平台甲基化分析的关键因素,而产物的放置时间和不同的处理没有明显影响甲基化分析。结论:Mas-sArray甲基化分析平台是高效快速检测甲基化修饰的平台,在使用过程中应该根据实际的实验条件,进行合理的质控。 相似文献
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The circadian movement of the lamina of primary leaves ofPhaseolus coccineus L. depends on circadian changes of the K+, Cl- and (depending on the Cl- availability) malate content in the swelling and shrinking motor cells of the laminar pulvinus. After sowing in soil, the
laminar pulvinus develops within about 26 days. When the leaves emerge from the soil (about 6 days after sowing) and the pulvinus
starts with the diurnal movement (about 9 days after sowing) the pulvinar dimensions are about half of those of the mature
pulvinus. The anatomical structure, however, is basically the same as in the developed pulvinus. In soil-grown plants, the
K+, Cl- and malate content as well as the period length of the circadian leaf movement rhythm change in the developing pulvinus.
In the embryo of the dry seed, the Cl- content is low (0.03 mmol g-1 DW), the K+ content, however, 22-fold higher than the Cl- content. When the leaves emerge from the soil, the pulvinar K+ and Cl- content is the same as in the whole embryo of the dry seed. In the developing pulvinus the K+ content increases by a factor of 2 and the Cl- content by a factor of 41 in the mature pulvinus. The pulvinar malate content increases between the 6th and 10th day from
about 40 to 180Μmol g-1 DW, then decreases until the 17th day and remains thereafter on a low level (around 80 Μmol g-1 DW). These results indicate that the Cl- availability increases in the developing pulvinus with age. It explains furthermore why in young leaves malate was found
as counterion to K+ in the osmotic leaf movement motor, in older ones, however, Cl-. The circadian leaf movement starts 9 days after sowing. The period length decreases during the development of the pulvinus
from 31.3 to 28.6 h in leaves of intact soil-grown plants. In leaves which were cut from the plants and immersed with their
petioles in distilled water, the age dependent decrease of the period length is also found. However, the period lengths are
shorter by more than 1 h than in the leaves of intact plants. The increasing Cl- availability in the developing pulvinus does not seem to be the cause for the age dependent shortening of the period length,
because the period length in 22 days old Cl- deprived pulvini is the same as in 22 days old pulvini with a high Cl- content. 相似文献
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Bettina Buerle Tatyana Sandalova Gunter Schneider Paul‐Gerhard Rieger 《Acta Crystallographica. Section F, Structural Biology Communications》2006,62(8):746-749
The initial degradation of all stereoisomers of the complexing agent iminodisuccinate (IDS) is enabled by an epimerase in the bacterial strain Agrobacterium tumefaciens BY6. This protein was produced in Escherichia coli, purified and crystallized by the hanging‐drop vapour‐diffusion method. Crystals of IDS‐epimerase were obtained under several conditions. The best diffracting crystals were grown in 22% PEG 3350, 0.2 M (NH4)2SO4 and 0.1 M bis‐Tris propane pH 7.2 at 293 K. These crystals belong to the monoclinic space group P21, with unit‐cell parameters a = 55.4, b = 104.2, c = 78.6 Å, β = 103.3°, and diffracted to 1.7 Å resolution. They contain two protein molecules per asymmetric unit. In order to solve the structure using the MAD phasing method, crystals of the l ‐selenomethionine‐substituted epimerase were grown in the presence of 20% PEG 3350, 0.2 M Na2SO4 and 0.1 M bis‐Tris propane pH 8.5. 相似文献
10.
ZHILONG MA GUODONG SONG DONGBO ZHAO DALU LIU XIAOLEI LIU YUXIANG DAI ZHIGANG HE DAOHAI QIAN JIAN GONG HONGBO MENG BO ZHOU TINGSONG YANG ZHENSHUN SONG 《Cytotherapy》2019,21(2):162-174