Penicillins

Garcı́a-Estrada, Carlos; Martı́n, Juan-Francisco

doi:10.1007/978-1-4939-1191-2_2

Cited by 6 publications

(4 citation statements)

References 146 publications

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“…DAC thanks support granted by CONACyT (480147). The calculations described in this article have been carried out in the suite xAct for Mathematica-see [26].…”

Section: Acknowledgmentsmentioning

confidence: 99%

Construction of anti-de Sitter-like spacetimes using the metric conformal Einstein field equations: the vacuum case

Carranza

Kroon

2018

Class. Quantum Grav.

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We make use of the metric version of the conformal Einstein field equations to construct anti-de Sitter-like spacetimes by means of a suitably posed initial-boundary value problem. The evolution system associated to this initial-boundary value problem consists of a set of conformal wave equations for a number of conformal fields and the conformal metric. This formulation makes use of generalised wave coordinates and allows the free specification of the Ricci scalar of the conformal metric via a conformal gauge source function. We consider Dirichlet boundary conditions for the evolution equations at the conformal boundary and show that these boundary conditions can, in turn, be constructed from the 3-dimensional Lorentzian metric of the conformal boundary and a linear combination of the incoming and outgoing radiation as measured by certain components of the Weyl tensor. To show that a solution to the conformal evolution equations implies a solution to the Einstein field equations we also provide a discussion of the propagation of the constraints for this initial-boundary value problem. The existence of local solutions to the initial-boundary value problem in a neighbourhood of the corner where the initial hypersurface and the conformal boundary intersect is subject to compatibility conditions between the initial and boundary data. The construction described is amenable to numerical implementation and should allow the systematic exploration of boundary conditions.

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“…DAC thanks support granted by CONACyT (480147). The calculations described in this article have been carried out in the suite xAct for Mathematica-see [26].…”

Section: Acknowledgmentsmentioning

confidence: 99%

Construction of anti-de Sitter-like spacetimes using the metric conformal Einstein field equations: the vacuum case

Carranza

Kroon

2018

Class. Quantum Grav.

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“…For the vector

these are given by

where

denotes the Hodge dual of

. A computation using the package for [ 25 ] readily gives that the only non-zero components of the electric part are given by

while the magnetic part vanishes identically. These expressions are regular at

0

—by disregarding the coordinate singularity due to the use of spherical coordinates.…”

Section: Schwarzschild–de Sitter Spacetimesmentioning

confidence: 99%

Conformal geodesics and the evolution of spacetimes with positive Cosmological constant

Minucci

2024

Phil. Trans. R. Soc. A.

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This article provides a discussion on the construction of conformal Gaussian gauge systems to study the evolution of solutions to the Einstein field equations with positive Cosmological constant. This is done by means of a gauge based on the properties of conformal geodesics. The use of this gauge, combined with the extended conformal Einstein field equations, yields evolution equations in the form of a symmetric hyperbolic system for which standard Cauchy stability results can be employed. This strategy is used to study the global properties of de Sitter-like spacetimes with constant negative scalar curvature. It is then adapted to study the evolution of the Schwarzschild–de Sitter spacetime in the static region near the conformal boundary. This review is based on Minucci et al . 2021 Class. Quantum Grav . 38 , 145026. ( doi:10.1088/1361-6382/ac0356 ) and Minucci et al . 2023 Class. Quantum Grav . 40 , 145005. ( doi:10.1088/1361-6382/acdb3f ). This article is part of a discussion meeting issue ‘At the interface of asymptotics, conformal methods and analysis in general relativity’.

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“…The biosynthesis of benzylpenicillin in P. chrysogenum is an excellent model for studying the transport of precursors and intermediates through different organelles in filamentous fungi [ 16 , 18 , 19 ]. Briefly, in this pathway, the amino acids L-α-aminoadipic acid, L-cysteine and L-valine are condensed to form the tripeptide δ(L-α-aminoadipyl)-L-cysteinyl-D-valine (ACV) by a multidomain ACV synthetase (ACVS) encoded by the pcbAB gene.…”

Section: Numerous Transporters Are Involved In the Translocation Of F...mentioning

confidence: 99%

Vacuolal and Peroxisomal Calcium Ion Transporters in Yeasts and Fungi: Key Role in the Translocation of Intermediates in the Biosynthesis of Fungal Metabolites

Martı́n

2022

Genes

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The intracellular calcium content in fungal cells is influenced by a large number of environmental and nutritional factors. Sharp changes in the cytosolic calcium level act as signals that are decoded by the cell gene expression machinery, resulting in several physiological responses, including differentiation and secondary metabolites biosynthesis. Expression of the three penicillin biosynthetic genes is regulated by calcium ions, but there is still little information on the role of this ion in the translocation of penicillin intermediates between different subcellular compartments. Using advanced information on the transport of calcium in organelles in yeast as a model, this article reviews the recent progress on the transport of calcium in vacuoles and peroxisomes and its relation to the translocation of biosynthetic intermediates in filamentous fungi. The Penicillium chrysogenum PenV vacuole transporter and the Acremonium chrysogenum CefP peroxisomal transporter belong to the transient receptor potential (TRP) class CSC of calcium ion channels. The PenV transporter plays an important role in providing precursors for the biosynthesis of the tripeptide δ-(-α-aminoadipyl-L-cysteinyl-D-valine), the first intermediate of penicillin biosynthesis in P. chrysogenum. Similarly, CefP exerts a key function in the conversion of isopenicillin N to penicillin N in peroxisomes of A. chrysogenum. These TRP transporters are different from other TRP ion channels of Giberella zeae that belong to the Yvc1 class of yeast TRPs. Recent advances in filamentous fungi indicate that the cytosolic calcium concentration signal is connected to the calcitonin/calcineurin signal transduction cascade that controls the expression of genes involved in the subcellular translocation of intermediates during fungal metabolite biosynthesis. These advances open new possibilities to enhance the expression of important biosynthetic genes in fungi.

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Penicillins

Cited by 6 publications

References 146 publications

Construction of anti-de Sitter-like spacetimes using the metric conformal Einstein field equations: the vacuum case

Construction of anti-de Sitter-like spacetimes using the metric conformal Einstein field equations: the vacuum case

Conformal geodesics and the evolution of spacetimes with positive Cosmological constant

Vacuolal and Peroxisomal Calcium Ion Transporters in Yeasts and Fungi: Key Role in the Translocation of Intermediates in the Biosynthesis of Fungal Metabolites

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