Chemical Recycling of PET by Glycolysis: Polymerization and Characterization of the Dimethacrylated Glycolysate

Summary: In the framework of chemical recycling of polymers, leading to the generation of secondary value‐added products, PET flakes taken from post‐consumer soft drink bottles, were glycolyzed with DEG. The oligomers obtained were analyzed for their molecular weight and characterized by FT‐IR and POM. Subsequently, dimethacrylated oligoesters of PET glycolysate (PET‐GLY‐DMA) were synthesized by methacrylation of the glycolyzed PET product. The resulted monomer PET‐GLY‐DMA was studied by FT‐IR, POM and DSC. Thermal polymerization of this monomer was carried out at 80 °C in the presence of benzoyl peroxide as initiator. A UV‐curable formulation was also prepared on the basis of neat PET‐GLY‐DMA, as well as by mixing PET‐GLY‐DMA with styrene, using DMPA as photoinitiator. Nanoparticles of SiO₂ were dispersed into PET‐GLY‐DMA/styrene copolymers as reinforcing agents and the mechanical properties of resins formed were studied.

Preparation of methacrylated PET glycolysate.     

Ions,transport, and energetics in normal and diseased skeletal muscle

Magnetic resonance spectroscopy (MRS) has highlighted the relationship between intracellular ionic homeostasis and the control of muscle energetics. In skeletal muscle, the oxidative rate of ATP synthesis is largely controlled by ADP, the concentration of which is determined by the creatine kinase equilibrium that includes the concentration of H⁺. At the onset of aerobic dynamic exercise, ATP is maintained largely by glycolysis, producing lactic acid and PCr breakdown. Vasodilation follows and ATP synthesis becomes predominantly oxidative. During recovery, PCr resynthesis gives a measure of mitochondrial function, and pH recovery reflects the Na⁺:H⁺ antiport activity. Dynamic³¹P MRS measurements can be used to derive quantitative information about the processes (fluxes and concentrations) described above. In diseased muscle (e.g., mitochondrial myopathy, dystrophy, hypertension) specific changes are observed in some of the control functions, ionic fluxes, or mitochondrial oxidative rates.     

氨纶废丝醇解工艺探讨

以一缩二乙二醇为醇解剂,二月桂酸二丁基锡为催化剂对氨纶废丝进行了醇解。重点分析了醇解时间、催化剂用量、氨纶废丝与醇解剂质量比等工艺条件对回收聚四氢呋喃二元醇(回收PTHF)性能和结构的影响。结果表明,当温度不变时,增加醇解时间、催化剂用量、醇解剂与氨纶废丝比例仅可以在一定程度上提高回收PTHF的收率和纯度。     

Inhibition of Cancer Cell Migration by Gold Nanorods: Molecular Mechanisms and Implications for Cancer Therapy

Gold nanorods have received much attention because of their distinct physicochemical properties and promising applications in bioimaging, biosensing, drug delivery, photothermal therapy, and optoelectronic devices. However, little is known regarding their effect on tumor metastasis. In the present investigation, serum protein‐coated gold nanorods (AuNRs) at low concentrations is shown to exhibit no apparent effects on the viability and proliferation of three different metastatic cancer cell lines, that is, MDA‐MB‐231 human breast cancer cells, PC3 human prostate cancer cells, and B16F10 mouse melanoma cells, but effectively inhibit their migration and invasion in vitro. Quantitative proteomics and real‐time PCR array analyses indicate that exposure of cells to AuNRs can down‐regulate the expression of diverse energy generation‐related genes, which accounts for their inhibition of mitochondrial oxidative phosphorylation (OXPHOS) and glycolysis. The impairment of OXPHOS and glycolysis results in a distinctive reduction of ATP production and subsequent inhibition of F‐actin cytoskeletal assembly, which is crucial for the migration and invasion of cancer cells. The inhibitory effect of AuNRs on cancer cell migration is also confirmed in vivo. Taken together, the unique mechanism in inhibiting cancer cell migration by AuNRs might provide a new approach to specific cancer therapeutic treatment.     

Isolation of GCR1, a major transcription factor of glycolytic genes in Saccharomyces cerevisiae, from Kluyveromyces lactis

To study the function of GCR1, a gene involved in the expression of glycolytic genes in Saccharomyces cerevisiae, a Kluyveromyces lactis gene that complements the growth defect of a S. cerevisiae Deltagcr1 mutant was isolated. Introduction of this gene into the Deltagcr1 mutant also restored the activities of glycolytic enzymes. DNA sequencing of KlGCR1 predicted an open reading frame of a 767 amino acid protein with an overall identity of 33% and similarity of 48% to Gcr1p from S. cerevisiae. Its DDBJ/EMBL/GenBank Accession No. is AB046391.     

不同月龄和部位乌珠穆沁羊AMPK活性与肉品质的关系

为研究乌珠穆沁羊不同生长阶段、不同骨骼肌一磷酸腺苷激活蛋白激酶（adenosine monophosphate-activated proteinkinase,AMPK）活性、糖酵解相关指标和肉质相关指标的内在变化规律,选取3、6、9月龄乌珠穆沁羊背最长肌、股二头肌和腰大肌,分别测定其AMPK活性、肌糖原含量、乳酸含量、己糖激酶（hexokinase,HK）活性、pH值、剪切力和色泽等指标。结果表明：AMPK活性升高时pH24 h值、红度值（a*）明显下降,并呈显著负相关（P<0.05）;剪切力随着月龄增大而降低（P<0.05）,腰大肌黄度值（b*）最大,背最长肌b*最小,腰大肌a*变化规律与b*相同,股二头肌与背最长肌a*变化规律与b*相反;同一部位肌糖原含量与月龄呈显著正相关（P<0.05）,背最长肌最大,股二头肌最小（P<0.05）,乳酸含量变化规律与肌糖原含量总体相同;HK活性与月龄呈正相关（P<0.05）,腰大肌最大,股二头肌最小（P<0.05）,AMPK活性随着b*、肌糖原总体含量、6月龄与9月龄乳酸和HK活性升高呈现显著上升趋势（P&l...     

飞燕草素对三阴性乳腺癌MDA-MB-231细胞糖酵解的影响

目的:探讨飞燕草素对乳腺癌MDA-MB-231细胞糖代谢的影响。方法:以不同浓度的飞燕草素作用MDA-MB-231细胞,CCK-8检测细胞活性,免疫组化染色检测Ki67表达,划痕试验检测细胞的迁移能力;葡萄糖摄取、乳糖和三磷酸腺苷(ATP)测定试剂盒检测MDA-MB-231细胞葡萄糖摄取、乳糖和ATP的生成,己糖激酶(HK)活性试剂盒检测HK活性;蛋白质印迹法检测HK、丙酮酸激酶(PK)、乳酸脱氢酶A(LDHA)和M2-型丙酮酸激酶 2(PKM2)表达。结果:飞燕草素能明显抑制MDA-MB-231细胞增殖,20和40 μmol/L飞燕草素能分别降低细胞存活率至75%和72%(P<0.05);20、40 μmol/L飞燕草素能降低乳腺癌MDA-MB-231细胞Ki67表达阳性的细胞数量,差异有统计学意义(P<0.01);飞燕草素能降低乳腺癌细胞葡萄糖的摄取,降低细胞乳糖和ATP的生成,抑制PKM2、HK和LDHA蛋白的表达,降低p-Akt和p-mTOR蛋白表达。结论:飞燕草素能抑制乳腺癌MDA-MB-231细胞糖代谢,抑制Akt/mTOR通路活性可能是飞燕草素抑制乳腺癌细胞糖酵解的机制。     

糖酵解途径相关基因与植物乳杆菌生理行为的相关性

研究pgm、fba、gap过表达对植物乳杆菌（Lactobacillus plantarum）LR-1的抗逆性、黏附和生物被膜形成的影响。结果表明,pgm、fba基因的过表达可提高植物乳杆菌LR-1的耐热性、耐酸性和抗胆盐性,这两个基因的过表达促进了该菌株生物被膜的形成和黏附。gap基因的转录水平对植物乳杆菌LR-1的抗逆性、生物被膜形成和黏附没有显著影响。pgm、fba、gap的上调提高了该菌株tuf、luxS的转录水平。这种增加在过表达pgm、fba的重组菌株中比在过表达gap的重组菌株中高。此外,生物信息学分析表明,pgm、fba可与多条途径相关的基因相关联。本研究揭示糖酵解途径相关基因在调节植物乳杆菌的抗逆性、黏附和生物被膜形成中的新作用。     

XVI. Yeast sequencing reports. A new essential gene GCR4 located in the upstream region of GCR1

A new essential gene of Saccharomyces cerevisiae was found upstream of GCR1. Its cloning and sequencing predict a 280 amino acid protein (32 577 Da). The predicted protein is fairly hydrophobic, and a search of the database did not identify any homologous proteins. A LEU2 disruption at codon 104 was lethal, but disruption at codon 221 showed a temperature-sensitive conditional growth phenotype. Abnormalities were observed in some glycolytic enzyme levels. The sequence has been submitted to GenBank-EMBL-DDBJ under Accession Number D29645.