The decomposition of α-aminophosphine oxides to phosphonic acid derivatives (P<Superscript>III</Superscript>)

Aminophosphine oxides and aminophosphonates are, in general, very stable compounds. However, following phosphorus–carbon bond cleavage in aqueous acidic media these compounds sometimes decompose to phosphonic acids derivatives (P^III). Despite some controversy in the literature, careful analysis supported by theoretical studies leads to the conclusion that decomposition to P^III derivatives proceeds via an elimination reaction. Figure The decomposition of α-aminophosphine oxides to phosphonic acid derivatives (P^III)     

生物乙烯研究进展

介绍了生物乙烯的背景和发展概况,总结了乙醇脱水反应的机理和所用的各类催化剂,分析了生物乙烯产业化中需要解决的关键技术问题,并指出发展生物乙烯有着光明的前景,对石油路线代替战略有着重要的意义.     

Effects of special brain area regional cerebral blood flow abnormal perfusion on learning and memory function and its molecular mechanism in rats

To study the effect of special brain area regional cerebral blood flow (rCBF) abnormal perfusion on learning and memory function and its molecular mechanism, 64 adult male healthy Sprague-Dawley (SD) rats were randomly divided into two groups, the false operation group (control group) and the operation group (model group). After surgical operation, the operation group undertook bilateral common carotid artery permanent ligation, while the other group did not. Learning and memory function were measured by Y-maze at 4 h, 8 h, 24 h and 3 d after surgical operation, respectively. The rCBF of the right frontal lobe and hippocampus was also detected by the PerifluxPF model laser Doppler flowmetry, and the expressions of c-fos or c-jun or Bcl-2 and Bax were also measured by immune histochemistry S-P method accordingly. Results showed that the rCBF of the right frontal lobe and hippocampus in the operation group was significantly lower than that in the false operation group (P < 0.05). The learning indexes, error number (EN), day of reach standard and total reaction time (TRT) in the operation group, were significantly higher than that in the false operation group (P < 0.05). However, the initiative evasion rate in the operation group was significantly lower than that in the false operation group. The study also found that the rCBF was relatively more, the indexes (EN, the day of reach standard and TRT) relatively fewer, but the initiative evasion rate and the memory keeping rate were relatively more. The positive expression and the average absorbency of Fos and Jun in the operation group were significantly higher than that in the false operation group (P < 0.05). Furthermore, Bax and Bcl-2 positive cells were all increased over time in the operation group, and the expression ratio of Bax/Bcl-2 in the operation group was significantly higher than that in the false operation group (P < 0.01). In conclusion, rCBF decrease can impair the learning and memory function in rats, which may be related to the increase of the expression ratio of c-fos or c-jun or Bcl-2 or Bax in the frontal cortex and hippocampus.     

共情脑机制的研究现状与展望

作为社会交往中的重要因素,共情是指理解并体验他人的情感和知觉感受的能力。目前的研究认为共情依赖于直接的投射机制而非逻辑推理。即观察到他人的情绪状态会涉及一部分处理自我情感的大脑结构的激活,该过程同时还会受到社会认知因素的调节。由于理解和间接体验他人痛觉的能力是维系社会纽带必不可少的,目前研究者越来越多地通过对痛觉共情的研究来揭示关于共情的普遍的神经机制。此外共情的动物模型、镜像神经元系统与共情的产生以及共情的调节等方向也将是研究的重点。     

Schistosoma mansoni: lack of correlation between praziquantel-induced intra-worm calcium influx and parasite death

The schistosomicidal activity of praziquantel (PZQ) is accompanied by a large influx of calcium into the worms, suggesting that this phenomenon could be the source of the observed muscular contraction, surface disruption and eventual death of the parasite. We have incubated live adult schistosomes in a medium containing radioactive calcium and we were able to confirm that PZQ does indeed stimulate calcium entry into the parasite. An even higher calcium uptake, however, occurred in schistosomes exposed to PZQ after pre-incubation with cytochalasin D, a condition that suppresses PZQ schistosomicidal effects and allows the complete survival of the parasites. The calcium blockers nicardipine and nifedipine also failed to prevent the calcium influx induced by PZQ. Similarly, a large calcium influx occurred in 28-day-old worms exposed to PZQ, in spite of the fact that these immature worms are largely insensitive to the schistosomicidal effects of the drug. Schistosomes incubated overnight with radioactive calcium and PZQ and then returned to normal medium, retained a calcium content higher than worms pre-incubated with cytochalasin D, but the difference could be a consequence—rather than a cause—of schistosomicidal effects. These results suggest that calcium accumulation by itself, at least as measured in whole parasites maintained in vitro, may not represent an exhaustive explanation for the schistosomicidal effects of PZQ.     

Involvement of Sema4A in the progression of experimental autoimmune myocarditis

Dilated cardiomyopathy often results from autoimmunity triggered by microbial infections during myocarditis. However, it remains unclear how immunological disorders are implicated in pathogenesis of autoimmune myocarditis. Here, we demonstrated that Sema4A, a class IV semaphorin, plays key roles in experimental autoimmune myocarditis (EAM). Dendritic cells pulsed with myosin heavy chain-α peptides induced severe myocarditis in wild-type mice, but not in Sema4A-deficient mice. In adoptive transfer experiments, CD4⁺ T-cells from wild-type mice induced severe myocarditis, while CD4⁺ T-cells from Sema4A-deficient mice exhibited considerably attenuated myocarditis. Our results indicated that Sema4A is critically involved in EAM by regulating differentiation of T-cells.