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71.
环鸟苷酸对卵巢细胞功能的调控   总被引:4,自引:0,他引:4  
环鸟苷酸(cGMP)是一种具有广泛生物学活性的环核苷酸。尽管cGMP作为第二信使,在调控卵巢细胞功能中发挥着广泛而重要的作用早有报道,但直至近年,cGMP在生殖活动中的重要作用才受到人们的关注,而成为生殖科学研究领域的热点之一。卵巢是雌性动物的重要器官,而cGMP在卵巢细胞中起着多方面的调节作用。现对卵巢内cGMP的来源,cGMP在卵巢内抑制雌激素(E2)的合成、LH受体表达、卵泡闭锁的作用,以及cGMP的作用机制等方面的研究进展进行综述。  相似文献   
72.
Dill (Anethum graveolens L.) has been used in traditional Uighur medicine for its various pharmacological activities. Previous studies have suggested that dill seed essential oil (DSEO) has anti-Candida potential and the mechanism of its action also has been studied. Our study examined whether DSEO induces apoptosis in the human pathogen Candida albicans ATCC 64550. Our results indicate that C. albicans ATCC 64550 cells treated with DSEO show some typical apoptosis characters, such as decrease in adenosine triphosphatase (ATPase) activity, chromatin condensation, nuclear fragmentation, and phosphatidylserine (PS) exposure. The DSEO promoted cytochrome c (cyt c) release and metacaspase activation, which resulted in C. albicans ATCC 64550 apoptosis. l-cysteine prevented the DSEO-induced nuclear fragmentation, PS externalization, and metacaspase activation, thus indicating that the reactive oxygen species (ROS) is an important mediator of DSEO-induced apoptosis. To our knowledge, this study is the first to report the induction of apoptosis of this pathogen with concomitant metacaspase activation by DSEO.  相似文献   
73.
系统描述湖北宜昌和秭归新滩晚奥陶世庙坡组三叶虫动物群中的3科6属6种。根据化石保存状态,挤压变形以及个体发育特征,对前人所报道的产于同一层位的有并三叶虫的研究成果作了重新厘定。  相似文献   
74.
<正>Dear Editor,Cumulative evidence supports the role of early-life viral infections,especially respiratory syncytial virus(RSV)and human rhinovirus(HRV),as major antecedents of childhood asthma(Lemanske,2002;Jackson et al.,2008).In this study,the x TAG respiratory viral panel FAST(RVP FAST)assay,a multiplex polymerase chain reaction(PCR)-based method(Arens et al.,2010;BaladaLlasat et al.,2011;Gharabaghi et al.,2011;Selvaraju,2012),was used to investigate the association of infec-  相似文献   
75.
宁夏枸杞的大、小孢子发生和雌、雄配子体发育   总被引:1,自引:0,他引:1  
在幼小花药横切面上,每个角隅处可见一层拱形孢原细胞,其经过平周分裂形成初生造孢细胞、次生造孢细胞,发育为小孢子母细胞。减数分裂过程中胞质分裂为同时型。四分体为四面体型。成熟花粉粒含二细胞,具三孔沟型萌发孔。花药绒毡层由二部分组成:药壁区的绒毡层由初生壁细胞所产生,药隔区的由药隔细胞直接转化成,为双重起源,呈二型性,属分泌型。雌蕊由二个心皮构成二室子房,中轴胎座。倒生胚珠具单珠被、薄珠心,珠被绒毡层。胚囊发育为蓼型。在胚囊细胞分化后,组成胚囊的四种细胞继续发育,表现出各自的形态学变化。  相似文献   
76.
Ensifer meliloti WSM1022 is an aerobic, motile, Gram-negative, non-spore-forming rod that can exist as a soil saprophyte or as a legume microsymbiont of Medicago. WSM1022 was isolated in 1987 from a nodule recovered from the roots of the annual Medicago orbicularis growing on the Cyclades Island of Naxos in Greece. WSM1022 is highly effective at fixing nitrogen with M. truncatula and other annual species such as M. tornata and M. littoralis and is also highly effective with the perennial M. sativa (alfalfa or lucerne). In common with other characterized E. meliloti strains, WSM1022 will nodulate but fixes poorly with M. polymorpha and M. sphaerocarpos and does not nodulate M. murex. Here we describe the features of E. meliloti WSM1022, together with genome sequence information and its annotation. The 6,649,661 bp high-quality-draft genome is arranged into 121 scaffolds of 125 contigs containing 6,323 protein-coding genes and 75 RNA-only encoding genes, and is one of 100 rhizobial genomes sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) project.  相似文献   
77.

Background

In the past twenty years, codeine-containing cough syrups (CCS) was recognized as a new type of addictive drugs. However, the exact neurobiologic mechanisms underlying CCS-dependence are still ill-defined. The aims of this study are to identify CCS-related modulations of neural activity during the resting-state in CCS-dependent individuals and to investigate whether these changes of neural activity can be related to duration of CCS use, the first age of CCS use and impulse control deficits in CCS-dependent individuals. We also want to observe the impact of gray matter deficits on these functional results.

Methodology/Principal Findings

Thirty CCS-dependent individuals and 30 control subjects participated. Resting-state functional MRI was performed by using gradient-echo echo-planar imaging sequence. Regional homogeneity (ReHo) was calculated by using REST software. Voxel-based analysis of the ReHo maps between controls and CCS-dependent groups was performed using two-sample t tests (p<0.05, corrected for multiple comparisons). The Barratt Impulsiveness Scale 11 (BIS.11) was surveyed to assess participants'' impulsivity trait soon after MR examination. Abnormal clusters revealed by group comparison were extracted and correlated with impulsivity, duration of CCS use, and age of first CCS use. ReHo was diminished in the bilateral medial orbitofrontal cortex (mOFC) and left dorsal striatum in CCS-dependent individuals. There were negative correlations between mean ReHo in the bilateral medial OFC, left dorsal striatum and duration of CCS use, BIS.11 total scores, and the subscale of attentional impulsivity in CCS-dependent individuals. There was a significantly positive correlation between mean ReHo in the left dorsal striatum and age of first CCS use in CCS-dependent individuals. Importantly, these results still remain significant after statistically controlling for the regional gray matter deficits.

Conclusion

Resting-state abnormalities in CCS-dependent individuals revealed in the present study may further improve our understanding about the neural substrates of impulse control dysfunction in CCS-dependent individuals.  相似文献   
78.
The interfacial instability between a thiophosphate solid electrolyte and oxide cathodes results in rapid capacity fade and has driven the need for cathode coatings. In this work, the stability, evolution, and performance of uncoated, Li2ZrO3‐coated, and Li3B11O18‐coated LiNi0.5Co0.2Mn0.3O2 cathodes are compared using first‐principles computations and electron microscopy characterization. Li3B11O18 is identified as a superior coating that exhibits excellent oxidation/chemical stability, leading to substantially improved performance over cells with Li2ZrO3‐coated or uncoated cathodes. The chemical and structural origin of the different performance is interpreted using different microscopy techniques which enable the direct observation of the phase decomposition of the Li2ZrO3 coating. It is observed that Li is already extracted from the Li2ZrO3 in the first charge, leading to the formation of ZrO2 nanocrystallites with loss of protection of the cathode. After 50 cycles separated (Co, Ni)‐sulfides and Mn‐sulfides can be observed within the Li2ZrO3‐coated material. This work illustrates the severity of the interfacial reactions between a thiophosphate electrolyte and oxide cathode and shows the importance of using coating materials that are absolutely stable at high voltage.  相似文献   
79.
80.
Long-distance mobile mRNAs play key roles in gene regulatory networks that control plant development and stress tolerance. However, the mechanisms underlying species-specific delivery of mRNA still need to be elucidated. Here, the use of grafts involving highly heterozygous apple (Malus) genotypes allowed us to demonstrate that apple (Malus domestica) oligopeptide transporter3 (MdOPT3) mRNA can be transported over a long distance, from the leaf to the root, to regulate iron uptake; however, the mRNA of Arabidopsis (Arabidopsis thaliana) oligopeptide transporter 3 (AtOPT3), the MdOPT3 homolog from A. thaliana, does not move from shoot to root. Reciprocal heterologous expression of the two types of mRNAs showed that the immobile AtOPT3 became mobile and moved from the shoot to the root in two woody species, Malus and Populus, while the mobile MdOPT3 became immobile in two herbaceous species, A. thaliana and tomato (Solanum lycopersicum). Furthermore, we demonstrated that the different transmissibility of OPT3 in A. thaliana and Malus might be caused by divergence in RNA-binding proteins between herbaceous and woody plants. This study provides insights into mechanisms underlying differences in mRNA mobility and validates the important physiological functions associated with this process.

The long-distance movement of OPT3 is selective between herbaceous and woody plants as shown using Malus and Arabidopsis thaliana plants.  相似文献   
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