Non-invasive detection of respiratory muscles activity during assisted ventilation

The instantaneous pressure applied by the respiratory muscles [Pmus(t)] of a patient under ventilatory support may be continuously assessed with the help of a model of the passive respiratory system updated cycle by cycle. Inspiratory activity (IA) is considered present when Pmus goes below a given threshold. In six patients, we compared IA with (i) inspiratory activity (IAref) obtained from esophageal pressure and diaphragmatic EMG and (ii) that (IAvent) detected by the ventilator. In any case, a ventilator support onset coincides with an IA onset but the opposite is not true. IA onset is always later than IAref beginning ((0.21 +/- 0.10 s) and IA end always precedes IAref end (0.46 +/- 0.16 s). These results clearly deteriorate when the model is not updated.     

Spatial distribution of the copepod Centropages typicus in Ligurian Sea (NW Mediterranean). Role of surface currents estimated by Topex-Poseidon altimetry

A particle-tracking model was used to simulate the dispersion and development of the planktonic copepod Centropages typicus during spring in Ligurian Sea. We show that mesoscale current structure, with a coastal jet and eddies, plays a key role in the transport and dispersion of C. typicus during its life cycle. Although, in the north, offshore Nice, cohorts can be advected southwestward out of Ligurian basin, more to the south others are retained in the central eddy and may give the start to the spring bloom of this species. However, input of individuals from the south through the Corsican Channel and along the west coast of Corsica may also be important in spring. This study shows that the ambit of C. typicus population is larger than the Ligurian Sea.     

Site-specific phosphorylation of neurofilament-L is mediated by calcium/calmodulin-dependent protein kinase II in the apical dendrites during long-term potentiation

Neurofilament-L (NF-L), one subunit of the neuronal intermediate filaments, is a major element of neuronal cytoskeletons. The dynamics of NF-L are regulated by phosphorylation of its head domain. The phosphorylation sites of the NF-L head domain by protein kinase A, protein kinase C, and Rho-associated kinase have been previously identified, and those by calcium/calmodulin-dependent protein kinase II (CaMKII) were identified in this study. A series of site- and phosphorylation state-specific antibodies against NF-L was prepared to investigate NF-L phosphorylation in neuronal systems. Long-term potentiation (LTP) is a cellular model of neuronal plasticity that is thought to involve the phosphorylation of various proteins. NF-L is considered a possible substrate for phosphorylation. During LTP stimulation of mouse hippocampal slices, the series of antibodies demonstrated the increase in the phosphorylation level of Ser(57) in NF-L and the visualization of the localized distribution of Ser(57) phosphorylation in a subpopulation of apical dendrites of the pyramidal neurons. Furthermore, Ser(57) phosphorylation during LTP is suggested to be mediated by CaMKII. Here we show that NF-L is phosphorylated by CaMKII in a subpopulation of apical dendrites during LTP, indicating that Ser(57) is a novel phosphorylation site of NF-L in vivo related to the neuronal signal transduction.     

The role of phosphorylation on the structure and dynamics of phospholamban: a model from molecular simulations

Phospholamban (PLB) is a small membrane protein that regulates the activity of the calcium ATP-ase in the cardiac, slow-twitch, and smooth muscle sarcoplasmic reticulum through the reversible phosphorylation of Ser16. We present here a comparative molecular dynamics study of unmodified and phosphorylated PLB immersed in a phospholipid membrane. The study has been performed under different ionic strength conditions, using the NMR structures of two PLB variants determined in mixed organic solvent and dodecylphosphocholine micelles. The simulations indicate that all PLB forms studied display a highly dynamic behavior of the N-terminal cytoplasmic moiety, with a decrease of its helical content in the phosphorylated forms. The cytoplasmic domain undergoes large collective motions sampling conformations parallel as well as perpendicular to the membrane surface in all the simulations. The transmembrane domain retains a tightly folded helical conformation with a small tilt with respect to the membrane plane probably induced by the presence of Asn30 and Asn34 within the hydrophobic environment. Furthermore, the phosphoric group on Ser16 establishes transient electrostatic interactions with the phospholipid heads. We propose a model in which phosphorylation diminishes the probability of interactions of PLB with residues near Lys400 in the SERCA pump, thus relieving its inhibition.     

Nitrogen Fixation and ATPase of Root Nodules from Sesbania cannabina with Chemical and Physical Treatments

The nitrogenase activity of root nodules from Sesbania cannabina plants treated with Na2S2O4, DTT and trypsin was increased by 108%–114%, 106%–117% and 103%–119%, respectively. EM observation showed that the density of ATP-hydrolase as the marker of lead phosphate particles which were distributed on the peribacteroid membrane was much more significant than that of the control, but the bacteroids in peribacteroid membrane did not have ATP-hydrolase particles present. Dark treatment of the same age plants accelerated the nodule senescence and the ATP-hydrolase particles most densified on the peribacteroid membrane of the nodules, meanwhile, dense ATP-hydrolase particles also appeared in a number of degenerative bacteroids. This again confirms the conformation change of ATP-ase in bacteroids from ATP synthetase to ATP-hydrolase and its relation to nitrogen fixation with the senescence of nodules. The comparison of ATP-hydrolase particle density on the peribacteroid membrane of the nodule cells with different treatmemts are carried out and the role of the ATP-hydrolase on the peribacteroid membrane in substance transportation are discussed.     

Pollen Tetrads in Lilium with a Discussion on the Delimitation Between L.semer vivoideum and Its Ally

In the course of our palynological study on the Chinese Lilium, pollen tetrads are found in two taxa of the genus: L. sempervivoideum and L. amoenum. The latter is distributed in NW. and S. Yunnan Province. It was established by Wilson, but reduced later by himself to a synonym of L. sempervivoideum which occurs from S. Sichuan to C. Yunnan. However, it is regarded as a species distinct from the former by many authors, such as Sealy (1949), Woodcock and Stearn (1950) and S. Y. Liang (1980). Their pollen tetrads are similar in aperture appearance and sexine patterns, but different in the shape, size and arrangement of sculptural elements, as shown by LM and SEM examination. Their leaf shape and flower colour are different, though there are some transitions between them. Based on the facts mentioned above, it is reasonable to regard the two taxa as two subspecies in L. sempervivoideum.     

艾蒿提取物对菜青虫的生物活性

采用微波辅助提取、溶剂浸提 ,以正己烷、乙醇、正己烷 +乙醇 (体积比 1∶1 )为溶剂从艾蒿ArtemisiaargyiL啨ｖｌ.etVant茎叶得到了提取物。另外 ,还用水蒸气蒸馏法获得了精油。生物活性试验表明 ,它们对菜青虫PierisrapaeL .具有较强的拒食活性和一定的触杀活性。其中 ,正己烷为溶剂的微波辅助提取物的拒食活性和触杀活性最强。     

不同产地南方红豆杉枝叶的紫杉醇含量及其指纹图谱的比较分析

采用HPLC法对来源于6个产地(陕西周至和汉中;甘肃天水;安徽胡乐、聂家山和仙寓山)的12份野生南方红豆杉[ Taxus chinensis var.mairei( Lemée et Lévl.) Cheng et L.K.Fu]枝叶中的紫杉醇含量进行了比较分析,并对不同产地南方红豆杉指纹图谱的相似度进行了比较和特征指纹图谱的构建.结果表明:不同产地南方红豆杉枝叶中紫杉醇的含量有明显差异,来源于陕西和甘肃的枝叶样品中紫杉醇含量明显高于来源于安徽的样品,以产自陕西周至的枝叶样品中紫杉醇含量最高(0.019 3 mg·g-1).各样品的指纹图谱均有12个共有峰,其中9号共有峰的保留时间(32.75 min)与紫杉醇标准品一致,被确定为南方红豆杉指纹图谱的参照峰(s).各共有峰相对保留时间的RSD值均低于1％,但相对峰面积的RSD值均高于40％,说明各样品共有峰的保留时间稳定,但相对含量差异较大.除来源于安徽聂家山的2个样品外,其他样品的相似度值均在0.8以上,说明各样品间指纹图谱的相似度较高.根据12个样品的指纹图谱建立了南方红豆杉枝叶的特征指纹图谱,可用于南方红豆杉的鉴定及质量控制.由测定结果推测:不同产地南方红豆杉枝叶中紫杉醇含量的差异可能与生长环境的差异有关.     

Les assemblages de graptolites du llandovery dans le synclinorium du Ménes-Bélair (Massif Armoricain)

Ampelites in the lower member of the Formation 0839 de la Lande-Murée (Silurian of the Ménez-Bélair Syncline) have yielded rich and well-preserved graptolite faunas. This material, and that in older collections, indicates the presence of all or part of the Turriculatus, Crispus and Griestoniensis Zones. Earlier Llandovery graptolite zones are not represented in the Ménez-Bélair Syncline and breaks encompassing the Lower Llandovery and the earliest part of the Upper Llandovery is envisaged.