Effects of progesterone and estradiol benzoate on superoxide dismutase activity in the brain of male rats

The activities of mitochondrial, manganese-containing superoxide dismutase (MnSOD) and cytoplasmic, copper-zinc-containing superoxide dismutase (CuZnSOD) were measured in subcellular fractions of whole brain homogenates prepared from intact and gonadectomized (GDX) male rats, untreated or treated subcutaneously (sc) with a single dose of 2 mg progesterone (P) and/or 5 g estradiol benzoate (EB). Neither MnSOD nor CuZnSOD was affected by the removal of the testes. Similarly, CuZnSOD activity was steady following systemic administration of P and/or EB to intact and GDX animals 2 h or 24 h prior to sacrifice. On the other hand, both P and EB suppressed MnSOD in the brain of either intact or GDX rats. These results suggest involvement of P and EB in the control of MnSOD activity in the brain of male rats.     

科研院所转制上市的问题及对策

分析了目前我国科研院所转制上市中存在的突出问题,指出了解决问题的根本出路是加速建立我国新型的资本市场体系和风险投资体系,用现代科学的管理方法来加强技术创新和对研发工作的支持力度,并利用产权改革来营造人才成长的宽松环境。     

大豆磷脂对小鼠红细胞膜和脑组织中脂肪酸含量的影响

采用高效液相色谱法研究了小鼠灌胃大豆磷脂乳液(剂量为w(大豆磷脂/体质量)=2.5、5.0、10.0 g/kg)30 d对小鼠红细胞膜和脑组织中脂肪酸含量的影响.结果表明:(1)w(大豆磷脂/体质量)=10.0 g/kg剂量组小鼠红细胞膜和脑组织中亚油酸、亚麻酸的含量及多不饱和脂肪酸(PUFA)占总脂肪酸(TFA)的比例显著增加(P＜0.05),红细胞膜中油酸的含量显著下降(P＜0.05);(2)w(大豆磷脂/体质量)=5.0 g/kg剂量组小鼠红细胞膜中亚油酸、亚麻酸的含量和w(PUFA/TFA),以及脑组织中亚油酸的含量显著提高(P＜0.05);(3)w(大豆磷脂/体质量)=2.5 g/kg剂量组小鼠红细胞膜和脑组织中各所测脂肪酸的含量无显著差异.说明大豆磷脂可增加小鼠红细胞膜和脑组织中亚油酸、亚麻酸等的含量,改善两者的脂肪酸组成,但两者的变化存在差异.     

Analysis with NMR localized spectroscopy of rat brainin vivo andex vivo

The volume-selected MRS of rat brain was performed on a 200 MHz broad horizontal-bore nuclear magnetic resonance imaging spectromete;. The localized proton spectroscopy of rat brain was acquired using the double spin-echo pulse sequence (PRESS) to select the position and size of the volume. Water signal was suppressed by CHESS sequence which was composed of chemical shift selective rf pulses and dephasing gradients. The parameterTE was taken as 40 ms and 135 ms in the experiment. The localized MRS of the rat brain with the status of live and death was obtained in variousTE values. Results showed that volume-selected proton MRS of the rat brainin vivo with longerTE consisted mainly of signals produced by N-acetylaspartate (NAA), creatine (Cre), choline (Cho) and the lactate spectral peak occurred in the MRS of the rat brainex vivo. On the other hand, the MRS of the rat brain with shorterTE contained glutamine/glutamate and lipid signals besides those signals mentioned previously. Although the information abstracted from the MRS of the rat brain with shorterTE may be more than that with longerTE, the spectral resolution of the MRS with shorterTE was slightly worse. In addition, it might indicate that the absolute concentration of NAA was decreased in dead rat brain because the SNR of NAA peak in the MRSex vivo got lower.     

Identification of organ-specific glycosylation of a membrane protein in two tissues using lectins

Since glycosylation of proteins is performed by the host cell, and variable sugar groupings can confer heterogeneity on the same polypeptide, we wished to see whether membrane proteins, in particular the ubiquitous transmembrane Na, K-ATPase, could be glycosylated differently in different organs. Using a highly sensitive enzyme-linked antibody detection system of bound digoxigenin-labelled lectins on nitrocellulose sheets containing electroblotted and subunits of kidney and brain Na,K-ATPase, isolated from various rat strains, in combination with isoform-specific immunoblots, we discovered that brain Na,K-ATPase was highly mannosylated in contrast to renal Na,K-ATPase. Thus, we describe the existence of organ-related glycoforms of an integral ubiquitous membrane protein, i.e. diversification of the same polypeptide by organ-typical sugars. At the same time, the presence of the same glycosylation pattern can make distinct protein isoforms occurring in a same organ more homogeneous. Such organ-related glycoforms may serve for tissue identification and as tissue-specific receptors.     

诱发脑电的ARX参数模型辩识

本文分析了诱发脑电的ARX模型(带外输入的自回归模型),指出其参数的最小二乘估计(LS)的有偏性。提出分步辩识方法,充分利用刺激前脑电信号,可得到参数的无偏、一致有效估计。用计算机仿真检验了理论分析。然而,在ARX模型下,模型参数的无偏估计并不保证诱发脑电波形估计的无偏性,我们推荐一个新的模型,可以得到诱发脑电波形的无偏估计。     

Photoperiodic regulation of mating behaviour in the linden bug,Pyrrhocoris apterus,is mediated by a brain inhibitory factor

Active inhibition of mating behaviour in a male insect is reported here for the first time. InPyrrhocoris apterus L. (Heteroptera), the most important inhibitory pathway runs from the pars intercerebralis (PI) of the brain and does not pass through the corpora allata. The inhibitory activity of the PI is promoted by short day conditions and suppressed by long days. As the effect of photoperiod is delayed, transfer procedures enabled us to record daily rhythms in mating behaviour during short days. While the extirpation of the PI results in a discrete phase shift of the long day rhythm, there is a much less significant phase shift after this operation during short days. Thus the PI has been shown to mediate the effect of photoperiod on both the inhibition and the rhythm of mating behaviour.     

Participation of ACTH1–10 and ACTH4–10 on the melatonin modulation of benzodiazepine receptors in rat cerebral cortex

In this study, we examined the effect of intracerebroventricular (i.c.v) injection of melatonin and/or ACTH_1–10 and ACTH_4–10 on [³H]flunitrazepam binding sites in the cerebral cortex of hypophysectomized rats. Hypophysectomy increased the B_max (maximum number of binding sites) of benzodiazepine (BNZ) receptors for at least 7 days after surgery, without changing K_D (dissociation constant). The i.c.v. injection of melatonin to hypophysectomized rats significantly increased B_max, whereas the same doses of melatonin were ineffective in sham-operated animals. In both cases, K_D values were unchanged. The i.c.v injection of ACTH_1–10 to hypophysectomized animals significantly increased B_max, an effect that was enhanced by simultaneous i.c.v. injection of ACTH_1–10+melatonin, reaching higher values of B_max than the i.c.v. injection of these hormones individually. No significant changes in K_D values were found after ACTH_1–10 and/or melatonin administration. However, the i.c.v. injection of ACTH_4–10 to hypophysectomized rats did not change B_max, although it significantly increased K_D values, indicating a decrease in the BNZ binding affinity. Melatonin injection counteracted this effect of ACTH_4–10, returning K_D to the control value. Moreover, although the lower dose of i.c.v. melatonin used, 10 ng, was unable to modify B_max of BNZ binding in the ACTH_4–10-injected group, the higher dose, 20 ng, significantly increased B_max. The results suggest that these ACTH-derived peptides can modulate the effect of melatonin on brain benzodiazepine receptors.