The human translation initiation multi-factor complex promotes methionyl-tRNAi binding to the 40S ribosomal subunit

The delivery of Met-tRNAi to the 40S ribosomal subunit is thought to occur by way of a ternary complex (TC) comprising eIF2, GTP and Met-tRNAi. We have generated from purified human proteins a stable multifactor complex (MFC) comprising eIF1, eIF2, eIF3 and eIF5, similar to the MFC reported in yeast and plants. A human MFC free of the ribosome also is detected in HeLa cells and rabbit reticulocytes, indicating that it exists in vivo. In vitro, the MFC-GTP binds Met-tRNAi and delivers the tRNA to the ribosome at the same rate as the TC. However, MFC-GDP shows a greatly reduced affinity to Met-tRNAi compared to that for eIF2-GDP, suggesting that MFC components may play a role in the release of eIF2-GDP from the ribosome following AUG recognition. Since an MFC–Met-tRNAi complex is detected in cell lysates, it may be responsible for Met-tRNAi–40S ribosome binding in vivo, possibly together with the TC. However, the MFC protein components also bind individually to 40S ribosomes, creating the possibility that Met-tRNAi might bind directly to such 40S-factor complexes. Thus, three distinct pathways for Met-tRNAi delivery to the 40S ribosomal subunit are identified, but which one predominates in vivo remains to be elucidated

Evidence of relationship between strain and In-incorporation:Growth of N-polar In-rich InAlN buffer layer by OMCVD

International audienc

Substance P induces gastric mucosal protection at supraspinal level via increasing the level of endomorphin-2 in rats.

The aim of the present study was to analyze the potential role of substance P (SP) in gastric mucosal defense and to clarify the receptors and mechanisms that may be involved in it. Gastric ulceration was induced by oral administration of acidified ethanol in male Wistar rats. Mucosal levels of calcitonin gene-related peptide (CGRP) and somatostatin were determined by radioimmunoassay. For analysis of gastric motor activity the rubber balloon method was used. We found that central (intracerebroventricular) injection of SP (9.3-74pmol) dose-dependently inhibited the formation of ethanol-induced ulcers, while intravenously injected SP (0.37-7.4nmol/kg) had no effect. The mucosal protective effect of SP was inhibited by pretreatment with neurokinin 1-, neurokinin 2-, neurokinin 3- and mu-opioid receptor antagonists, while delta- and kappa-opioid receptor antagonists had no effect. Endomorphin-2 antiserum also antagonized the SP-induced mucosal protection. In the gastroprotective dose range SP failed to influence the gastric motor activity. Inhibition of muscarinic cholinergic receptors, or the synthesis of nitric oxide or prostaglandins significantly reduced the effect of SP. In addition, centrally injected SP reversed the ethanol-induced reduction of gastric mucosal CGRP content. It can be concluded, that SP may induce gastric mucosal protection initiated centrally. Its protective effect is likely to be mediated by endomorphin-2, and vagal nerve may convey the centrally initiated protection to the periphery, where both prostaglandins, nitric oxide and CGRP are involved in mediating this effect

River histories : A thematic review

Peer reviewe

Forces in the knee during vertical jumping and weightlifting

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Growth evolution of N-polar indium-rich InAlN layer on c-sapphire via strain relaxation by ultrathin AlON interlayer

International audienceInAlN as a functional inorganic material is a promising alternative to the commonly used InGaN in tunnel diodes and optoelectronic devices, due to its tunable wider range of energy bandgap (0.65-6.2 eV), thus empowering utilization of the whole solar spectrum. Moreover, high electron drift velocity and carrier concentration are considered as the most desirable prerequisite of indium-rich InAlN. N-polar indium-rich InAlN could be more beneficial due to the reverse direction of the polarization compared to Ga-polar. However, unanswered questions persist concerning growth evolution of N-polar indium-rich InAlN grown by organometallic chemical vapor deposition (OMCVD). In this study, energy dispersive X-ray spectroscopy (EDX) and high-angle annular dark-field (HAADF) imaging are used to characterize N-polar layer at nanometer scale in order to determine the evolution of the layer on (0001) sapphire substrate. Long nitridation of sapphire substrate leading to the formation of~2 nm AlON ultrathin interlayer, which relaxes strain at the InAlN/sapphire interface with assistance of a low-temperature AlN interlayer is observed. EDX analysis confirms that after strain relaxation of InAlN layer, the indium-incorporation has only a weak dependence on the polarity of the layer. The incorporation of indium at preferential sites is also discussed at length

Highly disordered two-dimensional electron system in a weak magnetic field

The highly disordered two-dimensional electron gas contained in multi-δ-layers was experimentally investigated by a magnetotransport method to obtain information about the nature of electron states in the range of weak magnetic fields. The data observed have been found to be in conflict with the widely accepted floating of the extended states at vanishing magnetic fields and we have suggested an alternative interpretation of the data as a direct transition from an integral quantum Hall liquid to a two-dimensional disordered conductor with the transport controlled by weakly localized states

Bulbous gold–carbon nanodot hybrid nanoclusters for cancer therapy

Carbon nanodots are used to stabilize gold-nanoclusters. Charge-transfer interactions between carbon nanodots and gold were detected by transient absorption spectroscopy