Search results for "synthesis"

Chaperones Involved in Hepatitis B Virus Morphogenesis

1999

Little is known about host cell factors necessary for hepatitis B virus (HBV) assembly which involves envelopment of cytosolic nucleocapsids by the S, M and L transmembrane viral envelope proteins and subsequent budding into intraluminal cisternae. Central to virogenesis is the L protein that mediates hepatocyte receptor binding and envelopment of capsids. To serve these topologically conflicting roles, L protein exhibits an unusual dual membrane topology, disposing its N-terminal preS domain inside and outside of the virion lipid envelope. The mixed topology is achieved by posttranslational preS translocation of about half of the L protein molecules across a post-endoplasmic reticulum memb…

Mammalian BiP controls posttranslational ER translocation of the hepatitis B virus large envelope protein.

2008

AbstractThe hepatitis B virus L protein forms a dual topology in the endoplasmic reticulum (ER) via a process involving cotranslational membrane integration and subsequent posttranslational translocation of its preS subdomain. Here, we show that preS posttranslocation depends on the action of the ER chaperone BiP. To modulate the in vivo BiP activity, we designed an approach based on overexpressing its positive and negative regulators, ER-localized DnaJ-domain containing protein 4 (ERdj4) and BiP-associated protein (BAP), respectively. The feasibility of this approach was confirmed by demonstrating that BAP, but not ERdj4, destabilizes the L/BiP complex. Overexpressing BAP or ERdj4 inhibits…

Sequences in the 5′ Nontranslated Region of Hepatitis C Virus Required for RNA Replication

2001

ABSTRACT Sequences in the 5′ and 3′ termini of plus-strand RNA viruses harbor cis -acting elements important for efficient translation and replication. In case of the hepatitis C virus (HCV), a plus-strand RNA virus of the family Flaviviridae , a 341-nucleotide-long nontranslated region (NTR) is located at the 5′ end of the genome. This sequence contains an internal ribosome entry site (IRES) that is located downstream of an about 40-nucleotide-long sequence of unknown function. By using our recently developed HCV replicon system, we mapped and characterized the sequences in the 5′ NTR required for RNA replication. We show that deletions introduced into the 5′ terminal 40 nucleotides abolis…

Enantioselective Synthesis of Herbertane Sesquiterpenes. Synthesis of (−)-Herbertene and (−)-α-Herbertenol

2001

Polifunkcionālo kvaternizēto piridina atvasinājumu sintēze un īpašības

2003

Advisor: Duburs, Gunārs ; Tirzītis, Gunārs

SYNTHESIS OF HETEROCYCLES IN NON-CONVENTIONAL MEDIA: THE CASE OF IONIC LIQUIDS

2022

The synthesis of heterocycles is a prominent feature of organic chemistry, due to the enormous importance of such compounds in fields like medicinal or industrial chemistry. In the effort of improving their synthesis, the nature of the solvent plays a pivotal role. In this context, the use on non-conventional solvent like ionic liquids can determine significant improvements reaction outcomes, sustainability of the process, and possibility to be coupled with non-conventional synthetic methodologies, like ultrasounds or microwave irradiation. In this chapter, we present a bird’s-eye view on recent examples of the application of ionic liquids as solvents or catalysts, evidencing, whenever poss…

Circuit Theory and the Employment Issue.

2005

The circuit is a time-honoured concept in economics. It can be traced back to the Physiocrats of eighteenth-century France, who viewed production as a circular process initiated by advances, that is, capital expenditures which are recouped when goods are produced and then sold. Ever since then, however, this conception, without being explicitly discarded, has been left on the sidelines. For instance, Schumpeter, Keynes, Kalecki and J. Robinson, to mention twentieth-century economists only, undoubtedly made allowance for the circuit but did not give it prominence.1 In fact, the idea of making use of this conception as a research tool remained largely dormant until the late 1960s in France an…

Activation of oligodendroglial Fyn kinase enhances translation of mRNAs transported in hnRNP A2-dependent RNA granules.

2008

Central nervous system myelination requires the synthesis of large amounts of myelin basic protein (MBP) at the axon–glia contact site. MBP messenger RNA (mRNA) is transported in RNA granules to oligodendroglial processes in a translationally silenced state. This process is regulated by the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 binding to the cis-acting A2 response element (A2RE). Release of this repression of MBP mRNA translation is thus essential for myelination. Mice deficient in the Src family tyrosine kinase Fyn are hypomyelinated and contain reduced levels of MBP. Here, we identify hnRNP A2 as a target of activated Fyn in oligodendrocytes. We show that…

Heterogeneous nuclear ribonucleoprotein (hnRNP) F is a novel component of oligodendroglial RNA transport granules contributing to regulation of myeli…

2011

Myelin basic protein (MBP) is a major component of central nervous system (CNS) myelin. The absence of MBP results in the loss of almost all compact myelin in the CNS. MBP mRNA is sorted into RNA granules that are transported to the periphery of oligodendrocytes in a translationally inactive state. A central mediator of this transport process is the trans-acting factor heterogeneous nuclear ribonucleoprotein (hnRNP) A2 that binds to the cis-acting A2-response element in the 3′UTR of MBP mRNA. Recently, we found that activation of the Src family nonreceptor tyrosine kinase Fyn in oligodendrocytes leads to phosphorylation of hnRNP A2 and to increased translation of MBP mRNA. Here, we identify…

Nucleosynthesis in magneto-rotational supernovae

2020

Abstract We present the nucleosynthesis of magneto-rotational supernovae (MR-SNe) including neutrino-driven and magneto-rotational-driven ejecta based, for the first time, on two-dimensional simulations with accurate neutrino transport. The models analysed here have different rotation and magnetic fields, allowing us to explore the impact of these two key ingredients. The accurate neutrino transport of the simulations is critical to analyse the slightly neutron rich and proton rich ejecta that are similar to the, also neutrino-driven, ejecta in standard supernovae. In the model with strong magnetic field, the r-process produces heavy elements up to the third r-process peak (A ∼ 195), in agr…