scholarly journals Recreating the synthesis of starch granules in yeast

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Barbara Pfister ◽  
Antoni Sánchez-Ferrer ◽  
Ana Diaz ◽  
Kuanjen Lu ◽  
Caroline Otto ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Starch Granule ◽  
Model System ◽  
Starch Biosynthesis ◽  
Biosynthesis Pathway ◽  
Starch Granules ◽  
Structure And Properties ◽  
The Core ◽  
Holistic Understanding ◽  
Complete Set

Starch, as the major nutritional component of our staple crops and a feedstock for industry, is a vital plant product. It is composed of glucose polymers that form massive semi-crystalline granules. Its precise structure and composition determine its functionality and thus applications; however, there is no versatile model system allowing the relationships between the biosynthetic apparatus, glucan structure and properties to be explored. Here, we expressed the core Arabidopsis starch-biosynthesis pathway in Saccharomyces cerevisiae purged of its endogenous glycogen-metabolic enzymes. Systematic variation of the set of biosynthetic enzymes illustrated how each affects glucan structure and solubility. Expression of the complete set resulted in dense, insoluble granules with a starch-like semi-crystalline organization, demonstrating that this system indeed simulates starch biosynthesis. Thus, the yeast system has the potential to accelerate starch research and help create a holistic understanding of starch granule biosynthesis, providing a basis for the targeted biotechnological improvement of crops.

1Sl(1B) Chromosome substitution in Chinese Spring wheat promotes starch granule development and starch biosynthesis

2015 ◽  
Vol 66 (9) ◽  
pp. 894 ◽  
Author(s):  
Min Cao ◽  
Guanxing Chen ◽  
Chang Wang ◽  
Shoumin Zhen ◽  
Xiaohui Li ◽  
...  
Keyword(s):  
Chinese Spring ◽  
Starch Granule ◽  
Starch Biosynthesis ◽  
Substitution Line ◽  
Wheat Starch ◽  
Starch Granules ◽  
Grain Development ◽  
Chromosome Substitution ◽  
Aegilops Longissima ◽  
Chinese Spring Wheat

The common wheat variety Chinese Spring (CS) chromosome substitution line CS-1Sl(1B) was used in this study, in which the 1B chromosome in CS (Triticum aestivum L., 2n = 6x = 42, AABBDD) was substituted by the 1Sl from Aegilops longissima (2n = 2x = 14, SlSl). The results showed that the substitution of 1B in CS by 1Sl chromosome could significantly increase amylopectin and total starch contents. The dynamic changes in starch granules during grain development in CS and CS-1Sl(1B) demonstrated that the substitution line possessed higher amount of A-type starch granules and greater diameter of both A- and B-granules. qRT-PCR revealed that some key genes involved in starch biosynthesis, such as starch synthases (SSI, SSII and SSIII), starch branching enzymes (SBE IIa and SBE IIb) and granule-bound starch synthase (GBSS I), displayed higher transcript levels of mRNA expressions during grain development in CS-1Sl(1B). Our results indicate that the substituted 1Sl chromosome carries important genes that influence starch granule development and starch biosynthesis, which may be used as potential gene resources for improvement of wheat starch quality.

Production and Characterization of Porous Starch Granule and Poly(butylene adipate-co-terephthalate) Blend as a Bio-Composite

2012 ◽  
Vol 550-553 ◽  
pp. 1513-1521
Author(s):  
Sirirat Thothong ◽  
Klanarong Sriroth ◽  
Rattana Tantatherdtam ◽  
Amnat Jarerat
Keyword(s):  
Starch Granule ◽  
Rice Starch ◽  
Starch Granules ◽  
Screw Extruder ◽  
Elongation At Break ◽  
Single Screw ◽  
Single Screw Extruder ◽  
Scanning Electron ◽  
Granular Starch

To improve the miscibility of native rice starch granules and poly(butylene adipate-co-terephthalate)(PBAT), rice starch was hydrolyzed by a mixture of α-amylase and amyloglucosidase. The obtained porous rice granular starch was then mechanically blended with PBAT by single screw extruder. Many pits and holes on the surface of starch granules were observed by scanning electron microscopy (SEM). The rough surface of the rice starch granules improved the compatibility of the polymers in the blends, which consequently increased the tensile strength and the elongation at break. In addition, SEM also revealed that the porous granules were homogeneously distributed in the polymer matrix with no appearance of gaps.

An examination of quinone toxicity using the yeast Saccharomyces cerevisiae model system

Toxicology ◽  
2004 ◽  
Vol 201 (1-3) ◽  
pp. 185-196 ◽  
Author(s):  
Chester E Rodriguez ◽  
Masaru Shinyashiki ◽  
John Froines ◽  
Rong Chun Yu ◽  
Jon M Fukuto ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Model System ◽  
Yeast Saccharomyces Cerevisiae ◽  
Quinone Toxicity

The chromatin structure of Saccharomyces cerevisiae autonomously replicating sequences changes during the cell division cycle

1991 ◽  
Vol 11 (10) ◽  
pp. 5301-5311
Author(s):  
J A Brown ◽  
S G Holmes ◽  
M M Smith
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Division ◽  
Chromatin Structure ◽  
Dnase I ◽  
S Phase ◽  
Cell Division Cycle ◽  
Characteristic Change ◽  
The Core ◽  
Dnase I Hypersensitive Sites ◽  
Hypersensitive Sites

The chromatin structures of two well-characterized autonomously replicating sequence (ARS) elements were examined at their chromosomal sites during the cell division cycle in Saccharomyces cerevisiae. The H4 ARS is located near one of the duplicate nonallelic histone H4 genes, while ARS1 is present near the TRP1 gene. Cells blocked in G1 either by alpha-factor arrest or by nitrogen starvation had two DNase I-hypersensitive sites of about equal intensity in the ARS element. This pattern of DNase I-hypersensitive sites was altered in synchronous cultures allowed to proceed into S phase. In addition to a general increase in DNase I sensitivity around the core consensus sequence, the DNase I-hypersensitive site closest to the core consensus became more nuclease sensitive than the distal site. This change in chromatin structure was restricted to the ARS region and depended on replication since cdc7 cells blocked near the time of replication initiation did not undergo the transition. Subsequent release of arrested cdc7 cells restored entry into S phase and was accompanied by the characteristic change in ARS chromatin structure.

scholarly journals Bornyl Diphosphate Synthase From Cinnamomum burmanni and Its Application for (+)-Borneol Biosynthesis in Yeast

2021 ◽  
Vol 9 ◽  
Author(s):  
Rui Ma ◽  
Ping Su ◽  
Juan Guo ◽  
Baolong Jin ◽  
Qing Ma ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Biosynthetic Pathway ◽  
Main Product ◽  
Microbial Fermentation ◽  
Biosynthesis Pathway ◽  
Analgesic Effects ◽  
Pathway Reconstruction ◽  
Key Enzyme ◽  
Shake Flasks

(+)-Borneol is a desirable monoterpenoid with effective anti-inflammatory and analgesic effects that is known as soft gold. (+)-bornyl diphosphate synthase is the key enzyme in the (+)-borneol biosynthesis pathway. Despite several reported (+)-bornyl diphosphate synthase genes, relatively low (+)-borneol production hinders the attempts to synthesize it using microbial fermentation. Here, we identified the highly specific (+)-bornyl diphosphate synthase CbTPS1 from Cinnamomum burmanni. An in vitro assay showed that (+)-borneol was the main product of CbTPS1 (88.70% of the total products), and the Km value was 5.11 ± 1.70 μM with a kcat value of 0.01 s–1. Further, we reconstituted the (+)-borneol biosynthetic pathway in Saccharomyces cerevisiae. After tailored truncation and adding Kozak sequences, the (+)-borneol yield was improved by 96.33-fold to 2.89 mg⋅L–1 compared with the initial strain in shake flasks. This work is the first reported attempt to produce (+)-borneol by microbial fermentation. It lays a foundation for further pathway reconstruction and metabolic engineering production of this valuable natural monoterpenoid.

scholarly journals Starch Granule Size and Morphology of Arabidopsis thaliana Starch-Related Mutants Analyzed during Diurnal Rhythm and Development

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5859
Author(s):  
Qingting Liu ◽  
Yuan Zhou ◽  
Joerg Fettke
Keyword(s):  
Arabidopsis Thaliana ◽  
Starch Granule ◽  
Granule Size ◽  
High Temporal Resolution ◽  
Starch Granules ◽  
Transitory Starch ◽  
Young Leaves ◽  
Size And Morphology ◽  
Safranin O

Transitory starch plays a central role in the life cycle of plants. Many aspects of this important metabolism remain unknown; however, starch granules provide insight into this persistent metabolic process. Therefore, monitoring alterations in starch granules with high temporal resolution provides one significant avenue to improve understanding. Here, a previously established method that combines LCSM and safranin-O staining for in vivo imaging of transitory starch granules in leaves of Arabidopsis thaliana was employed to demonstrate, for the first time, the alterations in starch granule size and morphology that occur both throughout the day and during leaf aging. Several starch-related mutants were included, which revealed differences among the generated granules. In ptst2 and sex1-8, the starch granules in old leaves were much larger than those in young leaves; however, the typical flattened discoid morphology was maintained. In ss4 and dpe2/phs1/ss4, the morphology of starch granules in young leaves was altered, with a more rounded shape observed. With leaf development, the starch granules became spherical exclusively in dpe2/phs1/ss4. Thus, the presented data provide new insights to contribute to the understanding of starch granule morphogenesis.

scholarly journals Telomerase biogenesis requires a novel Mex67 function and a cytoplasmic association with the Sm7 complex

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Yulia Vasianovich ◽  
Emmanuel Bajon ◽  
Raymund J Wellinger
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Life Cycle ◽  
Reverse Transcriptase ◽  
Nuclear Export ◽  
Complex Life Cycle ◽  
Telomerase Reverse Transcriptase ◽  
Telomerase Rna ◽  
The Core ◽  
Nuclear Stability

The templating RNA is the core of the telomerase reverse transcriptase. In Saccharomyces cerevisiae, the complex life cycle and maturation of telomerase includes a cytoplasmic stage. However, timing and reason for this cytoplasmic passage are poorly understood. Here, we use inducible RNA tagging experiments to show that immediately after transcription, newly synthesized telomerase RNAs undergo one round of nucleo-cytoplasmic shuttling. Their export depends entirely on Crm1/Xpo1, whereas re-import is mediated by Kap122 plus redundant, kinetically less efficient import pathways. Strikingly, Mex67 is essential to stabilize newly transcribed RNA before Xpo1-mediated nuclear export. The results further show that the Sm7 complex associates with and stabilizes the telomerase RNA in the cytoplasm and promotes its nuclear re-import. Remarkably, after this cytoplasmic passage, the nuclear stability of telomerase RNA no longer depends on Mex67. These results underscore the utility of inducible RNA tagging and challenge current models of telomerase maturation.

scholarly journals A Millennial Myosin Census

2001 ◽  
Vol 12 (4) ◽  
pp. 780-794 ◽  
Author(s):  
Jonathan S. Berg ◽  
Bradford C. Powell ◽  
Richard E. Cheney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Phylogenetic Analysis ◽  
Molecular Basis ◽  
General Interest ◽  
Class Iii ◽  
New Class ◽  
The Past ◽  
Human Genes ◽  
Complete Set ◽  
Myosin Superfamily

The past decade has seen a remarkable explosion in our knowledge of the size and diversity of the myosin superfamily. Since these actin-based motors are candidates to provide the molecular basis for many cellular movements, it is essential that motility researchers be aware of the complete set of myosins in a given organism. The availability of cDNA and/or draft genomic sequences from humans,Drosophila melanogaster, Caenorhabditis elegans, Arabidopsis thaliana,Saccharomyces cerevisiae, Schizosaccharomyces pombe, andDictyostelium discoideum has allowed us to tentatively define and compare the sets of myosin genes in these organisms. This analysis has also led to the identification of several putative myosin genes that may be of general interest. In humans, for example, we find a total of 40 known or predicted myosin genes including two new myosins-I, three new class II (conventional) myosins, a second member of the class III/ninaC myosins, a gene similar to the class XV deafness myosin, and a novel myosin sharing at most 33% identity with other members of the superfamily. These myosins are in addition to the recently discovered class XVI myosin with N-terminal ankyrin repeats and two human genes with similarity to the class XVIII PDZ-myosin from mouse. We briefly describe these newly recognized myosins and extend our previous phylogenetic analysis of the myosin superfamily to include a comparison of the complete or nearly complete inventories of myosin genes from several experimentally important organisms.

LEU3 of Saccharomyces cerevisiae activates multiple genes for branched-chain amino acid biosynthesis by binding to a common decanucleotide core sequence

1988 ◽  
Vol 8 (7) ◽  
pp. 2690-2697
Author(s):  
P Friden ◽  
P Schimmel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Upstream Region ◽  
Promoter Regions ◽  
Sequence Element ◽  
The Core ◽  
Core Sequence ◽  
Flanking Sequences ◽  
Branched Chain

LEU3 of Saccharomyces cerevisiae encodes an 886-amino-acid polypeptide that regulates transcription of a group of genes involved in leucine biosynthesis and has been shown to bind specifically to a 114-base-pair DNA fragment of the LEU2 upstream region (P. Friden and P. Schimmel, Mol. Cell. Biol. 7:2707-2717, 1987). We show here that, in addition to LEU2, LEU3 binds in vitro to sequences in the promoter regions of LEU1, LEU4, ILV2, and, by inference, ILV5. The largely conserved decanucleotide core sequence shared by the binding sites in these genes is CCGGNNCCGG. Methylation interference footprinting experiments show that LEU3 makes symmetrical contacts with the conserved bases that lie in the major groove. Synthetic oligonucleotides (19 to 29 base pairs) which contain the core decanucleotide and flanking sequences of LEU1, LEU2, LEU4, and ILV2 have individually been placed upstream of a LEU3-insensitive test promoter. The expression of each construction is activated by LEU3, although the degree of activation varies considerably according to the specific oligonucleotide which is introduced. A promoter construction with substitutions in the core sequence remains LEU3 insensitive, however. One of the oligonucleotides (based on a LEU2 sequence) was also tested and shown to confer leucine-sensitive expression on the test promoter. The results demonstrate that only a short sequence element is necessary for LEU3-dependent promoter binding and activation and provide direct evidence for an expanded repertoire of genes that are activated by LEU3.

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