scholarly journals Cellulose biosynthesis in higher plants

2014 ◽  
Vol 65 (1-2) ◽  
pp. 17-24 ◽  
Author(s):  
Krystyna Kudlicka ◽  
R. M. Brown, Jr
Keyword(s):  
Higher Plants ◽  
Regulatory Protein ◽  
Cellulose Synthase ◽  
Cell Disruption ◽  
Cellulose Synthesis ◽  
Higher Plant ◽  
Cellulose Synthase Complex ◽  
Enzyme Complexes

Knowledge of the control and regulation of cellulose synthesis is fundamental to an understanding of plant development since cellulose is the primary structural component of plant cell walls. <em>In vivo</em>, the polymerization step requires a coordinated transport of substrates across membranes and relies on delicate orientations of the membrane-associated synthase complexes. Little is known about the properties of the enzyme complexes, and many questions about the biosynthesis of cell wall components at the cell surface still remain unanswered. Attempts to purify cellulose synthase from higher plants have not been successful because of the liability of enzymes upon isolation and lack of reliable <em>in vitro</em> assays. Membrane preparations from higher plant cells incorporate UDP-glucose into a glucan polymer, but this invariably turns out to be predominantly β -1,3-linked rather than β -1,4-linked glucans. Various hypotheses have been advanced to explain this phenomenon. One idea is that callose and cellulose-synthase systems are the same, but cell disruption activates callose synthesis preferentially. A second concept suggests that a regulatory protein as a part of the cellulose-synthase complex is rapidly degraded upon cell disruption. With new methods of enzyme isolation and analysis of the <em>in vitro</em> product, recent advances have been made in the isolation of an active synthase from the plasma membrane whereby cellulose synthase was separated from callose synthase.

A New Working Hypothesis for the Structure and Function of the Golgi Apparatus in Plant Cell Wall Biogenesis

1973 ◽  
Vol 31 ◽  
pp. 456-457 ◽  
Author(s):  
R. Malcolm Brown
Keyword(s):  
Golgi Apparatus ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Synthetase Activity ◽  
Higher Plant ◽  
General Belief ◽  
Glucan Synthetase ◽  
And Function

It is the general belief of many investigators that the pathway of cellulose biogenesis occurs via soluble pools of hexose phosphate monomers and the plasma membrane which is thought to be the site of polymerization and/or crystalization. Brown and coworkers and Ray (see 1) have proposed to the contrary that the Golgi apparatus is the site of cellulose biogenesis in certain scale-producing algae and higher plants respectively. While it has been fairly well established that cellulose can be biosynthesized by the Golgi apparatus, considerable doubt has been expressed that this type of system could be applicable to cellulose biogenesis in higher plant systems. Conversely, the problems associated with in vitro cellulose biosynthesis in Golgi-enriched homogenates raises questions about the in vivo localization of B-(1,4)-glucan synthetase activity.

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 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.

Production of the CYS3 regulator, a bZIP DNA-binding protein, is sufficient to induce sulfur gene expression in Neurospora crassa

1992 ◽  
Vol 12 (4) ◽  
pp. 1568-1577
Author(s):  
J V Paietta
Keyword(s):  
Gene Expression ◽  
Neurospora Crassa ◽  
Structural Gene ◽  
Control Point ◽  
Regulatory Protein ◽  
Negative Regulator ◽  
Temperature Sensitive ◽  
Cys3 Protein

The cys-3+ gene of Neurospora crassa encodes a bZIP (basic region-leucine zipper) regulatory protein that is essential for sulfur structural gene expression (e.g., ars-1+). Nuclear transcription assays confirmed that cys-3+ was under sulfur-regulated transcriptional control and that cys-3+ transcription was constitutive in sulfur controller (scon)-negative regulator mutants. Given these results, I have tested whether expression of cys-3+ under high-sulfur (repressing) conditions was sufficient to induce sulfur gene expression. The N. crassa beta-tubulin (tub) promoter was fused to the cys-3+ coding segment and used to transform a cys-3 deletion mutant. Function of the tub::cys-3 fusion in homokaryotic transformants grown under high-sulfur conditions was confirmed by Northern (RNA) and Western immunoblot analysis. The tub::cys-3 transformants showed arylsulfatase gene expression under normally repressing high-sulfur conditions. A tub::cys-3ts fusion encoding a temperature-sensitive CYS3 protein was used to confirm that the induced structural gene expression was due to CYS3 protein function. Constitutive CYS3 production did not induce scon-2+ expression under repressing conditions. In addition, a cys-3 promoter fusion to lacZ showed that CYS3 production was sufficient to induce its own expression and provides in vivo evidence for autoregulation. Finally, an apparent inhibitory effect observed with a strain carrying a point mutation at the cys-3 locus was examined by in vitro heterodimerization studies. These results support an interpretation of CYS3 as a transcriptional activator whose regulation is a crucial control point in the signal response pathway triggered by sulfur limitation.

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.

scholarly journals Snail Driving Alternative Splicing of CD44 by ESRP1 Enhances Invasion and Migration in Epithelial Ovarian Cancer

2017 ◽  
Vol 43 (6) ◽  
pp. 2489-2504 ◽  
Author(s):  
Le Chen ◽  
Ying Yao ◽  
Lijuan Sun ◽  
Jiajia Zhou ◽  
Minmin Miao ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Alternative Splicing ◽  
Epithelial Ovarian Cancer ◽  
Epithelial Mesenchymal Transition ◽  
Regulatory Protein ◽  
Cell Counting ◽  
Migration And Invasion ◽  
Mesenchymal Transition

Background/Aims: Our study aims to investigate the role, effect and mechanisms of ESRP1 (epithelial splicing regulatory protein 1) in epithelial-mesenchymal transition (EMT) in epithelial ovarian cancer (EOC). Methods: Microarray and immunohistochemical analysis of ESRP1 expression were performed in EOC cases. The correlations between ESRP1 expression and clinical factors on EOC were assessed. Lentivirus-mediated RNA interference and EGFP vector which contains ESRP1 gene were used to down-regulate and up-regulate ESRP1 expression in human EOC cell lines. Roles of ESRP1 in cell growth, migration and invasion of EOC cells were also measured by Cell Counting Kit-8 and Transwell systems in vitro and by a nude mice intraperitoneal transplantation model in vivo. Results: By the analysis of Gene Expression Omnibus (GEO) (p<0.05) and our own microarray data (p<0.001), ESRP1 expression in EOC was significantly different from normal ovarian tissue. It was abundant in the nuclei of cancer cells and in malignant lesions. However, it was weakly expressed or negative in both normal and benign lesions. High ESRP1 expression in EOC was associated with poor clinical outcomes. Decreased ESRP1 expression significantly increased cell migration and invasion both in vivo and in vitro. Snail strongly repressed ESRP1 transcription through binding to the ESRP1 promoter in EOC cells. Furthermore, ESRP1 regulated the expression of CD44s. Down-regulated ESRP1 resulted in an isoform switching from CD44v to CD44s, which modulated epithelial-mesenchymal transition (EMT) program in EOC. Up-regulatin of ESRP1 was detected in mesenchymal to epithelial transition (MET) in vivo. Conclusions: ESRP1 regulates CD44 alternative splicing during the EMT process which plays an important role in EOC carcinogenesis. In addition, ESRP1 is associated with disease prognosis in EOC.

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.

scholarly journals Recognition of RNA Editing Sites Is Directed by Unique Proteins in Chloroplasts: Biochemical Identification of cis-Acting Elements and trans-Acting Factors Involved in RNA Editing in Tobacco and Pea Chloroplasts

2002 ◽  
Vol 22 (19) ◽  
pp. 6726-6734 ◽  
Author(s):  
Tetsuya Miyamoto ◽  
Junichi Obokata ◽  
Masahiro Sugiura
Keyword(s):  
Rna Editing ◽  
Editing Site ◽  
Mrna Editing ◽  
Higher Plant ◽  
In Vitro System ◽  
Cis Acting ◽  
Biochemical Identification ◽  
Editing Activity

ABSTRACT RNA editing in higher-plant chloroplasts involves C-to-U conversions at specific sites. Although in vivo analyses have been performed, little is known about the biochemical aspects of chloroplast editing reactions. Here we improved our original in vitro system and devised a procedure for preparing active chloroplast extracts not only from tobacco plants but also from pea plants. Using our tobacco in vitro system, cis-acting elements were defined for psbE and petB mRNAs. Distinct proteins were found to bind specifically to each cis-element, a 56-kDa protein to the psbE site and a 70-kDa species to the petB site. Pea chloroplasts lack the corresponding editing site in psbE since T is already present in the DNA. Parallel in vitro analyses with tobacco and pea extracts revealed that the pea plant has no editing activity for psbE mRNAs and lacks the 56-kDa protein, whereas petB mRNAs are edited and the 70-kDa protein is also present. Therefore, coevolution of an editing site and its cognate trans-factor was demonstrated biochemically in psbE mRNA editing between tobacco and pea plants.

scholarly journals Biochemistry of postharvest spoilage of sweet potato (Ipomoea batatas L.). 2. Comparison of cellulolytic enzyme production in cultures and fungi-infected sweet potato tubers

2006 ◽  
pp. 48-57
Author(s):  
R. C. Ray
Keyword(s):  
Sweet Potato ◽  
Enzyme Production ◽  
Ipomoea Batatas ◽  
Rhizopus Oryzae ◽  
Cellulose Synthesis ◽  
Cellulolytic Enzyme ◽  
Optimum Temperature ◽  
Potato Tubers

The study was conducted to determine the production in vitro and in vivo of cellulases by Botrydiplodia theobromae and Rhizopus oryzae. Isolates of these organisms were obtained from the postharvest decay of sweetpotato tubers. Results revealed that B. theobrornae and R. oryzae which were isolated from postharvest spoilage of sweetpotato tubers produced endo-13-1,4-glucanase and exo-V-1 ,4-glucanase in culture and in fungi-infected tissues of sweetpotato tubers. The optimum temperature and pH for cellulose synthesis and activity were 30°C and pH 6.5, respectively.

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