Does an inhibitor of mitochondrial adenylate kinase also affect oxidative phosphorylation?

Summary Adenylate kinase activity of intact mitochondria is strongly inhibited by Ap₅A, i.e.p ¹,p ⁵-Di (adenosine-5-) pentaphosphate, whereas oxidative phosphorylation is not affected. Therefore, Ap₅A is a useful tool to distinguish between oxidative and non oxidative ATP generating reactions.Acknowledgment. The generous support of Prof. Dr.Walther Lamprecht is gratefully acknowledged. J. L. thanks the Stipendienfonds des Verbandes der Chemische Industrie for a scholarship.     

Blood plasma investigations by resonance raman spectroscopy: Detection of carotenoid pigments

Summary Using Raman spectroscopy, we demonstrate that low levels of -carotene, lycopene, and xanthophyll give rise to resonance enhanced bands in blood plasma. These results explain the significance of previously unidentified spectral maxima which have been related to the state of health of the blood donor.     

Sur l'inversion de l'action hypertensive de la prostaglandine F2α, chez le rat

Summary In normal rats, prostaglandin F₂ is a potent vasoconstrictor. The corresponding systemic hypertension is progressively attenuated by tachyphylaxis, revealing a longlasting fall of blood pressure. Tachyphylaxis is accelerated by previous injection of arachidonic acid and bradykinin. The vasodepressive activity of PGF₂ is inhibited by indomethacin.

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Nous remercions vivement le docteurPike (Upjohn, Kalamazoo) qui nous a fourni gracieusement ces prostaglandines.     

Influence of cyclic nucleotides on protein synthesis in vascular smooth muscle

Summary The incorporation of leucice-¹⁴C into protein in bovine mesenteric arteries was augmented by cyclic GMP (10^–3 M) and decreased by cyclic AMP (10^–3 M). There was no effect of 5 AMP (10^–3 M). The phosphodiesterase inhibiting drugs theophylline (10^–3 M) and papaverine (5×10^–5 g/ml) both decreased the leucine-¹⁴C incorporation.We are indebted to Mrs.Lena Burlin for hear assistance. Finacial support has been provided by the Swedish State Medical Research Council (No. 04X-101X-4498).     

Ecdysone 20-hydroxylase from the midgut of the tobacco hornworm (Manduca sexta L.)

Summary An ecdysone 20-hydroxylase enzyme system that converts -ecdysone to 20-hydroxyecdysone was prepared from the midgut of the tobacco hornworm prepupa. This partially purified enzyme is NADPH dependent and is localized in the mitochondrial fraction of the midgut tissue.     

泰国中-新生代热带植物木化石研究

泰国东北部柯叻府及邻区中-新生代木化石非常丰富并保存有完好的解剖构造,是探究热带植被历史、古气候演化以及古环境变迁等问题的重要实证材料.最近的野外调查和专题研究确认该地区中-新生代木化石11科19属约50个种或种级分类单元,分别隶属于裸子植物和被子植物两大分类群,其中有5科7属20种(包括未定种)为前人在泰国未曾报道的类型.当前木材化石群揭示出在中生代后期,泰国东北部热带针叶树植被以南洋杉科为主;在中新世-更新世时期,该地区主要发育落叶和常绿阔叶树植被,代表热带气候环境.     

水解法制备高吸水腈纶正交实验

对腈纶纤维的水解工艺进行研究．正交实验结果表明，实验范围内，水解时间是影响腈纶纤维吸水率的关键因素，随着时间的延长，吸水率增加；水解温度80℃时吸水率较高；NaOH浓度对水解腈纶的吸水率也产生较大的影响．温度、时间和NaOH浓度都会对纤维白度产生影响．     

BP网络应用于黄河水质的预测研究

利用黄河兰州段水质指标浓度时间序列作为学习样本，选取了DO、COD、氨氮、重金属离子等l0项指标作为输出参数，运用人工神经网络BP模型中的Levenberg—Marguardt优化算法对学习样本优化建模，将优化好的网络的预测结果与实测结果进行了比较，表明BP网络可以很好地用于黄河水质指标值及水质类别的预测。     

A carbon- and oxygen-isotope record of recent environ- mental change from Qinghai Lake, NE Tibetan Plateau

An understanding of natural climatic variability is essential for evaluating anthropogenic impacts on recent and future climate[1—3]. Due to the lack of lengthy instrumental records, such an understanding must be gained from natural archives of climate change. Palaeolimnological indicators of past lake levels may provide a sensitive record of changes in effective precipitation in closed basins. This approach is particularly relevant on the Tibetan Plateau, where instrumental records are very…