scholarly journals Eukaryotic and Prokaryotic Phytochelatin Synthases Differ Less in Functional Terms Than Previously Thought: A Comparative Analysis of Marchantia polymorpha and Geitlerinema sp. PCC 7407

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 914 ◽  
Author(s):  
Erika Bellini ◽  
Claudio Varotto ◽  
Marco Borsò ◽  
Lorenza Rugnini ◽  
Laura Bruno ◽  
...  
Keyword(s):  
Higher Plants ◽  
Cadmium Stress ◽  
Marchantia Polymorpha ◽  
Average Content ◽  
In Vitro Activity ◽  
Phytochelatin Synthase ◽  
Functional Studies ◽  
Control Samples

This paper reports functional studies on the enzyme phytochelatin synthase in the liverwort Marchantia polymorpha and the cyanobacterium Geitlerinema sp. strain PCC 7407. In vitro activity assays in control samples (cadmium-untreated) showed that phytochelatin synthase was constitutively expressed in both organisms. In the presence of 100 µM cadmium, in both the liverwort and the cyanobacterium, the enzyme was promptly activated in vitro, and produced phytochelatins up to the oligomer PC4. Likewise, in vivo exposure to 10–36 µM cadmium for 6-120 h induced in both organisms phytochelatin synthesis up to PC4. Furthermore, the glutathione (GSH) levels in M. polymorpha were constitutively low (compared with the average content in higher plants), but increased considerably under cadmium stress. Conversely, the GSH levels in Geitlerinema sp. PCC 7407 were constitutively high, but were halved under metal treatments. At odds with former papers, our results demonstrate that, as in M. polymorpha and other plants, the cyanobacterial phytochelatin synthase exposed to cadmium possesses manifest transpeptidasic activity, being able to synthesize phytochelatins with a degree of oligomerization higher than PC2. Therefore, prokaryotic and eukaryotic phytochelatin synthases differ less in functional terms than previously thought.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

scholarly journals POLRMT mutations impair mitochondrial transcription causing neurological disease

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Monika Oláhová ◽  
Bradley Peter ◽  
Zsolt Szilagyi ◽  
Hector Diaz-Maldonado ◽  
Meenakshi Singh ◽  
...  
Keyword(s):  
Progressive External Ophthalmoplegia ◽  
Global Developmental Delay ◽  
Disease Mechanism ◽  
Mitochondrial Transcription ◽  
Functional Studies ◽  
Mtdna Deletions ◽  
Molecular Nature ◽  
Important Disease

AbstractWhile >300 disease-causing variants have been identified in the mitochondrial DNA (mtDNA) polymerase γ, no mitochondrial phenotypes have been associated with POLRMT, the RNA polymerase responsible for transcription of the mitochondrial genome. Here, we characterise the clinical and molecular nature of POLRMT variants in eight individuals from seven unrelated families. Patients present with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood; one subject displayed an indolent progressive external ophthalmoplegia phenotype. Massive parallel sequencing of all subjects identifies recessive and dominant variants in the POLRMT gene. Patient fibroblasts have a defect in mitochondrial mRNA synthesis, but no mtDNA deletions or copy number abnormalities. The in vitro characterisation of the recombinant POLRMT mutants reveals variable, but deleterious effects on mitochondrial transcription. Together, our in vivo and in vitro functional studies of POLRMT variants establish defective mitochondrial transcription as an important disease mechanism.

scholarly journals Intracellular localisation of Mycobacterium tuberculosis affects efficacy of the antibiotic pyrazinamide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pierre Santucci ◽  
Daniel J. Greenwood ◽  
Antony Fearns ◽  
Kai Chen ◽  
Haibo Jiang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Host Cell ◽  
Combination Chemotherapy ◽  
In Vitro Activity ◽  
In Vivo Efficacy ◽  
Human Macrophages ◽  
Ion Microscopy ◽  
Intracellular Localisation

AbstractTo be effective, chemotherapy against tuberculosis (TB) must kill the intracellular population of the pathogen, Mycobacterium tuberculosis. However, how host cell microenvironments affect antibiotic accumulation and efficacy remains unclear. Here, we use correlative light, electron, and ion microscopy to investigate how various microenvironments within human macrophages affect the activity of pyrazinamide (PZA), a key antibiotic against TB. We show that PZA accumulates heterogeneously among individual bacteria in multiple host cell environments. Crucially, PZA accumulation and efficacy is maximal within acidified phagosomes. Bedaquiline, another antibiotic commonly used in combined TB therapy, enhances PZA accumulation via a host cell-mediated mechanism. Thus, intracellular localisation and specific microenvironments affect PZA accumulation and efficacy. Our results may explain the potent in vivo efficacy of PZA, compared to its modest in vitro activity, and its critical contribution to TB combination chemotherapy.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

scholarly journals The ER–Golgi intermediate compartment is a key membrane source for the LC3 lipidation step of autophagosome biogenesis

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Liang Ge ◽  
David Melville ◽  
Min Zhang ◽  
Randy Schekman
Keyword(s):  
Autophagosome Formation ◽  
Functional Studies ◽  
A Cell ◽  
Intermediate Compartment ◽  
Membrane Isolation ◽  
Necessary And Sufficient ◽  
Organelle Membrane ◽  
Catabolic Process

Autophagy is a catabolic process for bulk degradation of cytosolic materials mediated by double-membraned autophagosomes. The membrane determinant to initiate the formation of autophagosomes remains elusive. Here, we establish a cell-free assay based on LC3 lipidation to define the organelle membrane supporting early autophagosome formation. In vitro LC3 lipidation requires energy and is subject to regulation by the pathways modulating autophagy in vivo. We developed a systematic membrane isolation scheme to identify the endoplasmic reticulum–Golgi intermediate compartment (ERGIC) as a primary membrane source both necessary and sufficient to trigger LC3 lipidation in vitro. Functional studies demonstrate that the ERGIC is required for autophagosome biogenesis in vivo. Moreover, we find that the ERGIC acts by recruiting the early autophagosome marker ATG14, a critical step for the generation of preautophagosomal membranes.

scholarly journals In Vitro Import of a Nuclearly Encoded tRNA into Mitochondria of Solanum tuberosum

2003 ◽  
Vol 23 (11) ◽  
pp. 4000-4012 ◽  
Author(s):  
Ludovic Delage ◽  
André Dietrich ◽  
Anne Cosset ◽  
Laurence Maréchal-Drouard
Keyword(s):  
Solanum Tuberosum ◽  
Higher Plants ◽  
Plant Mitochondria ◽  
Protein Translation ◽  
Trna Genes ◽  
Vitro Assay ◽  
Trna Import

ABSTRACT Some of the mitochondrial tRNAs of higher plants are nuclearly encoded and imported into mitochondria. The import of tRNAs encoded in the nucleus has been shown to be essential for proper protein translation within mitochondria of a variety of organisms. Here, we report the development of an in vitro assay for import of nuclearly encoded tRNAs into plant mitochondria. This in vitro system utilizes isolated mitochondria from Solanum tuberosum and synthetic tRNAs transcribed from cloned nuclear tRNA genes. Although incubation of radioactively labeled in vitro-transcribed tRNAAla, tRNAPhe, and tRNAMet-e with isolated potato mitochondria resulted in importation, as measured by nuclease protection, the amount of tRNA transcripts protected at saturation was at least five times higher for tRNAAla than for the two other tRNAs. This difference in in vitro saturation levels of import is consistent with the in vivo localization of these tRNAs, since cytosolic tRNAAla is naturally imported into potato mitochondria whereas tRNAPhe and tRNAMet-e are not. Characterization of in vitro tRNA import requirements indicates that mitochondrial tRNA import proceeds in the absence of any added cytosolic protein fraction, involves at least one protein component on the surface of mitochondria, and requires ATP-dependent step(s) and a membrane potential.

Rifampicin inhibition of the plastid rRNA synthesis of Marchantia polymorpha

1975 ◽  
Vol 17 (3) ◽  
pp. 327-335
Author(s):  
S. Loiseaux ◽  
R. Mache ◽  
C. Rozier
Keyword(s):  
Bacterial Contamination ◽  
Higher Plants ◽  
Rrna Synthesis ◽  
Marchantia Polymorpha ◽  
Electrophoretic Mobilities ◽  
Bacterial Rna

The effect of rifampicin on the synthesis of plastid rRNA in Marchantia polymorpha was studied in vivo. As bacterial rRNA and plastid rRNA have the same electrophoretic mobilities, this study was possible only after a method for inhibiting bacterial contamination was developed. It was established that 91–100% of the rRNA synthesized by cultures of bacteria from Marchantia, after a labelling period of 3 and 9 h by 32-P, is inhibited by 10 mug/ml of rifampicin. The same inhibition was observed when Marchantia was labelled for 3 h in the presence of 10 mug/ml of rifampicin, showing that no plastid rRNA was synthesized under out conditions, but only bacterial RNA. However, when labelling was continued for 9 h two important peaks of rRNA (23 and 19 s) were labelled in the presence of 10 or 20 mug/ml of rifampicin. These peaks are of chlorophastic origin as confirmed by the following facts: the labelling is light-activated; plastids isolated from thalli labelled for 12 h also show these two radioactive peaks. Cytoplasmic rRNA is synthesized under certain conditions. The synthesis of plastid rRNA is inhibited by higher concentrations of rifampicin, a concentration of 250 mug/ml producing at least 75% inhibition. Marchantia, a primitive multicellular plant, differs in this respect from higher plants, which seem to be, in most cases, insensitive to rifampicin

scholarly journals A Review of Plants Used in South African Traditional Medicine for the Management and Treatment of Hypertension

Planta Medica ◽  
2018 ◽  
Vol 85 (04) ◽  
pp. 312-334 ◽  
Author(s):  
Fatai Balogun ◽  
Anofi Ashafa
Keyword(s):  
South Africa ◽  
Medicinal Plants ◽  
South African ◽  
Plant Species ◽  
Agricultural Research ◽  
Higher Plants ◽  
In Vivo Studies ◽  
Research Councils

AbstractSouth Africa contains 9% of the worldʼs higher plants, and despite its rich biodiversity, it has one of the highest prevalence of hypertension in Africa. This review provides information on medicinal plants embraced in South Africa for hypertension management, with the aim of reporting pharmacological information on the indigenous use of these plants as antihypertensives. This review not only focuses on the activity of antihypertensive medicinal plants but also reports some of its phytochemical constituents and other ethnopharmacological and therapeutic properties. Information obtained from scientific and or unpublished databases such as Science Direct, PubMed, SciFinder, JSTOR, Google Scholar, Web of Science, and various books revealed 117 documented antihypertensive plant species from 50 families. Interestingly, Asteraceae topped the list with 16 species, followed by Fabaceae with 8 species; however, only 25% of all plant species have demonstrated antihypertensive effects originating from both in vitro and in vivo studies, lending credence to their folkloric use. Only 11 plant species reportedly possess antihypertensive properties in animal models, with very few species subjected to analytical processes to reveal the identity of their bioactive antihypertensive compounds. In this review, we hope to encourage researchers and global research institutions (universities, agricultural research councils, and medical research councils), particularly those showing an interest in natural products, for the need for concerted efforts to undertake more studies aimed at revealing the untapped potential of these plants. These studies are very important for the development of new pharmaceuticals of natural origin useful for the management of hypertension.

Overexpression of a plant cysteine synthase gene and biosynthesis of a plant specific metabolite, β-(pyrazol-1-yl)-L-alanine, in Escherichia coli

1994 ◽  
Vol 72 (1) ◽  
pp. 188-192 ◽  
Author(s):  
Kazuki Saito ◽  
Reiko Kanda ◽  
Makoto Kurosawa ◽  
Isamu Murakoshi
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Control ◽  
Spinacia Oleracea ◽  
Higher Plants ◽  
Total Soluble Protein ◽  
T7 Promoter ◽  
Cysteine Synthase ◽  
Mechanistic Investigation

Cysteine synthase (EC 4.2.99.8) in higher plants is responsible for biosynthesis of not only cysteine but also some nonprotein amino acids such as β-(pyrazol-1-yl)-L-alanine. The cDNA of a cysteine synthase from spinach (Spinacia oleracea) was inserted into pET8c (=pET3d) under the transcriptional control of strong T7 promoter to yield an overexpression vector pCEK1. The amount of the exogenous cysteine synthase was increased up to 40% of the total soluble protein of Escherichia coli transformed with pCEK1. β-(Pyrazol-1-yl)-L-alanine, a specific metabolite in plants of the Cucurbitaceae, was biosynthesized by overexpressed cysteine synthase from pyrazole in the presence of O-acetyl-L-serine and serine, in vitro and in vivo, respectively. The present study provides the system for mechanistic investigation of biosynthesis of cysteine and biogenetically related β-substituted alanines at molecular genetic level.

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