Female cuckoo calls elicit anti-predatory behavior in birds

Journal of Ethology - Imperfect Batesian mimicry is common in nature. Female common cuckoos (Cuculus canorus), for instance, seem to be imperfect mimics of hawks (Accipiter spp.) in both appearance...     

Decreased expression of the DBC2 gene and its clinicopathological significance in breast cancer: correlation with aberrant DNA methylation

Loss of DBC2 (deleted in breast cancer 2) gene expression is frequent in breast cancer tissues. This can be explained by homozygous deletions or other mutations in a minority of cases but alternative mechanisms need to be investigated. Here, DBC2 expression was significantly suppressed compared with normal breast tissues in breast cancer tissues when analyzed by RT-PCR. Furthermore, DNA methylation on DBC2 was more prevalent in breast tumors than in normal tissues. DBC2 mRNA levels correlated with the degree of DBC2 methylation in breast cancer tissues and in a breast cancer cell line (T47D). Clinico-pathological correlation analysis showed that DBC2 promoter methylation was associated with tumor-node-metastasis stages II and III/IV, lymph node metastasis, p53 mutation, and HER2-positive status. Thus loss of DBC2 expression is caused by abnormal methylation of DBC2 and might have a role in breast cancer development.     

Two-signal electrochemical method for evaluation suppression and proliferation of MCF-7 cells based on intracellular purine

Two electrochemical signals ascribed to xanthine/guanine and hypanthine/adenine in MCF-7 cells were detected at 0.726 and 1.053 V, respectively. Based on the intensity of signals, the genistein-induced proliferation and suppression of MCF-7 cells could be evaluated. The results showed that with the increase of genistein dose at the range of 10⁻⁹ to 10⁻⁶ M, the two electrochemical signals of MCF-7 cell suspension increased due to the proliferation, whereas the tendency at the high dosage range of more than 10⁻⁵ M was decreased. The proliferation and cytotoxicity obtained by the electrochemical method were in agreement with those obtained by cell counting and the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium] method. Thus, the two-signal electrochemical method is an effective way to evaluate the effect of drugs on cell activity based on purine metabolism.     

两种激活处理促进小鼠孤雌胚胎原核形成

不同人工处理方法激活哺乳动物卵母细胞的机理相似,但其激活效率存在差异。本研究以昆明(KM)、129/Sv×KM F1和C3H×KM F1雌鼠来源的卵母细胞为对象,利用氯化锶(SrCl2,Sr2+)联合细胞松弛素B(cytochalasin B,CB)(Sr2++CB)和离子霉素(ionomycin,Ion)联合6-二甲胺基嘌呤(6-dimethylaminopurine,6-DMAP)(Ion+6-DMAP)两种激活方法处理下对比分析不同品系小鼠卵母细胞的激活效率,并以卵母细胞原核形成率、原核数量和孤雌胚胎体外发育来评价两种激活剂的激活效率。研究结果表明,Ion+6-DMAP激活卵的1原核比率显著高于2原核(p0.05),Sr2++CB激活卵的2原核比率显著高于1原核(p0.05);KM、129/Sv×KM F1和C3H×KM F1各组孤雌胚胎卵裂率和激活率没有显著差异(P0.05),但129/Sv×KM F1和C3H×KM F1囊胚发育率显著高于KM组(p0.05)。3种小鼠品系的卵母细胞用Sr2++CB处理的孤雌胚胎发育率显著高于Ion+6-DMAP。结果证明,Sr2++CB处理小鼠卵母细胞的激活效率明显优于Ion+6-DMAP;129/Sv×KM F1和C3H×KM F1的孤雌胚胎体外发育率显著高于KM小鼠,为研究小鼠遗传背景影响孤雌胚胎发育的机理提供参考。     

Isoproterenol increases sorting of parotid gland cargo proteins to the basolateral pathway

Exocrine cells have an essential function of sorting secreted proteins into the correct secretory pathway. A clear understanding of sorting in salivary glands would contribute to the correct targeting of therapeutic transgenes. The present work investigated whether there is a change in the relative proportions of basic proline-rich protein (PRP) and acidic PRPs in secretory granules in response to chronic isoproterenol treatment, and whether this alters the sorting of endogenous cargo proteins. Immunoblot analysis of secretory granules from rat parotids found a large increase of basic PRP over acidic PRPs in response to chronic isoproterenol treatment. Pulse chase experiments demonstrated that isoproterenol also decreased regulated secretion of newly synthesized secretory proteins, including PRPs, amylase and parotid secretory protein. This decreased efficiency of the apical regulated pathway may be mediated by alkalization of the secretory granules since it was reversed by treatment with mild acid. We also investigated changes in secretion through the basolateral (endocrine) pathways. A significant increase in parotid secretory protein and salivary amylase was detected in sera of isoproterenol-treated animals, suggesting increased routing of the regulated secretory proteins to the basolateral pathway. These studies demonstrate that shifts of endogenous proteins can modulate regulated secretion and sorting of cargo proteins. amylase; parotid secretory protein; polarized secretion     

GSK3 inhibitor-BIO regulates proliferation of immortalized pancreatic mesenchymal stem cells (iPMSCs)

Background

The small molecule 6-bromoindirubin-30-oxime (BIO), a glycogen synthase kinase 3 (GSK3) inhibitor, is a pharmacological agent known to maintain self-renewal in human and mouse embryonic stem cells (ESCs). However, the precise role of GSK3 in immortalized pancreatic mesenchymal stem cells (iPMSCs) growth and survival is not completely understood at present.

Results

To determine whether this molecule is involved in controlling the proliferation of iPMSCs, we examined the effect of BIO on iPMSCs. We found that the inactivation of GSK3 by BIO can robustly stimulate iPMSCs proliferation and mass formation as shown by QRT-PCR, western blotting, 5-Bromo-2-deoxyuridine (BrdU) immunostaining assay and tunel assay. However, we did not find the related roles of BIO on β cell differentiation by immunostaining, QRT-PCR assay, glucose-stimulated insulin release and C-peptide content analysis.

Conclusions

These results suggest that BIO plays a key role in the regulation of cell mass proliferation and maintenance of the undifferentiated state of iPMSCs.     

Stable isotope resolved metabolomics analysis of ribonucleotide and RNA metabolism in human lung cancer cells

We have developed a simple NMR-based method to determine the turnover of nucleotides and incorporation into RNA by stable isotope resolved metabolomics (SIRM) in A549 lung cancer cells. This method requires no chemical degradation of the nucleotides or chromatography. During cell growth, the free ribonucleotide pool is rapidly replaced by de novo synthesized nucleotides. Using [U-¹³C]-glucose and [U-¹³C,¹⁵N]-glutamine as tracers, we showed that virtually all of the carbons in the nucleotide riboses were derived from glucose, whereas glutamine was preferentially utilized over glucose for pyrimidine ring biosynthesis, via the synthesis of Asp through the Krebs cycle. Incorporation of the glutamine amido nitrogen into the N3 and N9 positions of the purine rings was also demonstrated by proton-detected ¹⁵N NMR. The incorporation of ¹³C from glucose into total RNA was measured and shown to be a major sink for the nucleotides during cell proliferation. This method was applied to determine the metabolic action of an anti-cancer selenium agent (methylseleninic acid or MSA) on A549 cells. We found that MSA inhibited nucleotide turnover and incorporation into RNA, implicating an important role of nucleotide metabolism in the toxic action of MSA on cancer cells.     

影响牛胚胎干细胞分离克隆因素的研究

采用与同源胎儿成纤维细胞共同培养及传统饲养层培养方式,以高糖DMEM,添加0.1mM2-巯基乙醇,犊牛血清,细胞因子为培养基,以4-13周龄屠宰牛胎儿为实验材料,探讨影响牛原始生殖细胞分离克隆胚胎干细胞的相关因素,结果发现：当犊牛血清为15%时效果最好;细胞因子添加与否对胚胎干细胞的分离及同源牛胎儿成纤维细胞的贴壁与生长影响并不显著,而在传代过程中中有一定影响;以0.2%胰酶 0.04?TA为细胞消化液效果最佳;以同源胎儿成纤维细胞共培养的方式分离克隆牛胚胎干细胞,本研究观察到效果最好。