scholarly journals Emission and biosynthesis of volatile terpenoids from the plasmodial slime mold Physarum polycephalum

2019 ◽  
Vol 15 ◽  
pp. 2872-2880
Author(s):  
Xinlu Chen ◽  
Tobias G Köllner ◽  
Wangdan Xiong ◽  
Guo Wei ◽  
Feng Chen
Keyword(s):  
Physarum Polycephalum ◽  
Slime Mold ◽  
Terpene Biosynthesis ◽  
Terpene Synthases ◽  
Slime Molds ◽  
Geranyl Diphosphate ◽  
Monoterpene Synthase ◽  
Cellular Slime ◽  
Volatile Terpenoids

Terpene synthases (TPSs) are pivotal enzymes for the production of diverse terpenes, including monoterpenes, sesquiterpenes, and diterpenes. In our recent studies, dictyostelid social amoebae, also known as cellular slime molds, were found to contain TPS genes for making volatile terpenes. For comparison, here we investigated Physarum polycephalum, a plasmodial slime mold also known as acellular amoeba. Plasmodia of P. polycephalum grown on agar plates were found to release a mixture of volatile terpenoids consisting of four major sesquiterpenes (α-muurolene, (E)-β-caryophyllene, two unidentified sesquiterpenoids) and the monoterpene linalool. There were no qualitative differences in terpenoid composition at two stages of young plasmodia. To understand terpene biosynthesis, we analyzed the transcriptome and genome sequences of P. polycephalum and identified four TPS genes designated PpolyTPS1–PpolyTPS4. They share 28–73% of sequence identities. Full-length cDNAs for the four TPS genes were cloned and expressed in Escherichia coli to produce recombinant proteins, which were tested for sesquiterpene synthase and monoterpene synthase activities. While neither PpolyTPS2 nor PpolyTPS3 was active, PpolyTPS1 and PpolyTPS4 were able to produce sesquiterpenes and monoterpenes from the respective substrates farnesyl diphosphate and geranyl diphosphate. By comparing the volatile profile of P. polycephalum plasmodia and the in vitro products of PpolyTPS1 and PpolyTPS4, it was concluded that most sesquiterpenoids emitted from P. polycephalum were attributed to PpolyTPS4. Phylogenetic analysis placed the four PpolyTPSs genes into two groups: PpolyTPS1 and PpolyTPS4 being one group that was clustered with the TPSs from the dictyostelid social amoeba and PpolyTPS2 and PpolyTPS3 being the other group that showed closer relatedness to bacterial TPSs. The biological role of the volatile terpenoids produced by the plasmodia of P. polycephalum is discussed.

Evidence for differential cellular adhesion as the mechanism of sorting-out of various cellular slime mold species

Development ◽  
1979 ◽  
Vol 53 (1) ◽  
pp. 163-178
Author(s):  
John Sternfeld
Keyword(s):  
Cell Surface ◽  
Single Species ◽  
Cellular Adhesion ◽  
Slime Mold ◽  
Cellular Slime Mold ◽  
Adhesive Properties ◽  
Slime Molds ◽  
Species Sorting ◽  
Cellular Slime ◽  
Chemotactic Gradient

Various authors have shown previously that if the amoebae of two species of slime molds are mixed they have the ability to sort themselves out. In the work reported here, the sortingout of cells of several slime mold species was examined in clumps of cells in suspension. Cells of four species, Dictyostelium discoideum (Dd), D. mucoroides (Dm), D. purpureum (Dp), and Polysphondylium violaceum (Pv), were mixed in pairs in suspension and clumps of cells formed. Dd and Pv cells sorted out completely and formed separate clumps, each of single species. Both Dd and Dm, when mixed separately with Dp, formed clumps containing both species. Sorting-out took place in these clumps such that the cells of Dd and Dm partially enveloped the Dp cells. Finally, in the Dd-Dm mixtures, the Dm cells always sorted out such that they surrounded the Dd cells. When mixed in a 1:2 ratio (Dd:Dm) the Dm cells formed a complete shell around a sphere of Dd cells. Sorting-out of cells in clumps in suspension can occur by either of two possible mechanisms: response of cells to a chemotactic gradient or differences in cell surface strengths of adhesion (Steinberg, 1964). Mixing of two species in a clump of cells and observing the process of sorting-out permits one to distinguish between these two mechanisms (Steinberg, 1964). By such an analysis it was found that the sorting-out observed in mixtures of Dd and Dm is consistent with the mechanism of differential cellular adhesion. The major reasons for this are (1) when the adhesive properties of the cells are known to change the Dd cells began to move inside the clumps, (2) the Dd cells coalesced into islands rather than streaming inward independently, and (3) the Dd cells and cell masses did not lie at the center of the clumps but rather lay randomly within the clumps. The partial envelopment observed in the Dd-Dp and Dm-Dp mixtures and the separate clumps formedby the Dd-Pv mixtures are also consistent with differential cellular adhesion. They represent cases in whichthe interspecific strengths of adhesion are low (Dd-Dp and Dm-Dp) and near zero (Dd-Pv).

In vitro nucleation of microtubules from microtubule-organizing center prepared from cellular slime mold

Cell Motility ◽  
1982 ◽  
Vol 2 (3) ◽  
pp. 257-272 ◽  
Author(s):  
Ryoko Kuriyama ◽  
Chikako Sato ◽  
Yoshio Fukui ◽  
Soryu Nishibayashi
Keyword(s):  
Slime Mold ◽  
Cellular Slime Mold ◽  
Microtubule Organizing Center ◽  
Organizing Center ◽  
Cellular Slime

scholarly journals Composition and Biosynthesis of Scent Compounds from Sterile Flowers of an Ornamental Plant Clematis florida cv. ‘Kaiser’

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1711
Author(s):  
Yifan Jiang ◽  
Renjuan Qian ◽  
Wanbo Zhang ◽  
Guo Wei ◽  
Xiaohua Ma ◽  
...  
Keyword(s):  
Floral Scent ◽  
Ornamental Plant ◽  
Terpene Synthase ◽  
Enzyme Assays ◽  
Total Volatile ◽  
Terpene Biosynthesis ◽  
Geranyl Diphosphate ◽  
Multiple Products ◽  
Key Genes

Clematis florida is a popular ornamental vine species known for diverse colors and shapes of its flowers but not for scent. Here we investigated the composition and biosynthesis of floral scent in ‘Kaiser’, a fragrant cultivar of C. florida that has sterile flowers. Volatile profiling revealed that flowers of ‘Kaiser’ emit more than 20 compounds, with monoterpenes being most abundant. Among the three floral organs, namely sepals, transformed-petals, and ovaries, ovaries had the highest rates of total volatile emission. To determine the molecular mechanism underlying floral scent biosynthesis in ‘Kaiser’, we sequenced a flower transcriptome and searched the transcriptome for terpene synthase genes (TPSs), which are key genes for terpene biosynthesis. Among the TPS genes identified, three were putative intact full-length genes and were designated CfTPS1, CfTPS2, and CfTPS3. Phylogenetic analysis placed CfTPS1, CfTPS2, and CfTPS3 to the TPS-g, TPS-b, and TPS-a subfamily, respectively. Through in vitro enzyme assays with Escherichia coli-expressed recombinant proteins, both CfTPS1 and CfTPS2 were demonstrated to catalyze the conversion of geranyl diphosphate to linalool, the most abundant constituent of C. florida floral scent. In addition, CfTPS1 and CfTPS2 produced the sesquiterpene nerolidol from (E,E)-farnesyl diphosphate. CfTPS3 showed sesquiterpene synthase activity and produced multiple products in vitro. All three CfTPS genes showed higher levels of expression in sepals than those in transformed-petals and ovaries. Our results show that despite being sterile, the flowers of ‘Kaiser’ have normal mechanisms for floral scent biosynthesis that make the flowers fragrant.

scholarly journals Biosynthesis of monoterpene scent compounds in roses

Science ◽  
2015 ◽  
Vol 349 (6243) ◽  
pp. 81-83 ◽  
Author(s):  
Jean-Louis Magnard ◽  
Aymeric Roccia ◽  
Jean-Claude Caissard ◽  
Philippe Vergne ◽  
Pulu Sun ◽  
...  
Keyword(s):  
Nudix Hydrolase ◽  
In Planta ◽  
Terpene Synthases ◽  
Geranyl Diphosphate ◽  
Monoterpene Biosynthesis

The scent of roses (Rosaxhybrida) is composed of hundreds of volatile molecules. Monoterpenes represent up to 70% percent of the scent content in some cultivars, such as the Papa Meilland rose. Monoterpene biosynthesis in plants relies on plastid-localized terpene synthases. Combining transcriptomic and genetic approaches, we show that the Nudix hydrolase RhNUDX1, localized in the cytoplasm, is part of a pathway for the biosynthesis of free monoterpene alcohols that contribute to fragrance in roses. The RhNUDX1 protein shows geranyl diphosphate diphosphohydrolase activity in vitro and supports geraniol biosynthesis in planta.

scholarly journals Breakdown of self/nonself recognition in cannibalistic strains of the predatory slime mold, Dictyostelium caveatum.

1986 ◽  
Vol 102 (1) ◽  
pp. 298-305 ◽  
Author(s):  
D R Waddell ◽  
K T Duffy
Keyword(s):  
Giant Cells ◽  
Slime Mold ◽  
Sexual Cycle ◽  
Slime Molds ◽  
Multicellular Development ◽  
Cellular Slime ◽  
Nonself Recognition ◽  
Cellular Slime Molds

Dictyostelium caveatum amebas feed upon both bacteria and the amebas of other cellular slime molds. The capacity to feed extensively upon other cellular slime molds is unique to D. caveatum amebas. They are able to phagocytose amebas larger than themselves by nibbling pieces of the cells until they are small enough to ingest. Here we report the isolation from previously cloned stock cultures of stable, cannibalistic strains of D. caveatum in which self/nonself recognition has broken down. Because of the extensive cannibalism, amebas of these strains do not complete multicellular development, and instead wander about for long periods while feeding upon each other. Although the cannibalistic behavior resembles that exhibited by the presumably diploid giant cells in the sexual cycle of other cellular slime molds, these strains are haploid and do not form macrocysts.

scholarly journals Morphogenesis and dynamics of slime molds in various environments

2019 ◽  
Author(s):  
Fernando Patino-Ramirez ◽  
Aurèle Boussard ◽  
Chloé Arson ◽  
Audrey Dussutour
Keyword(s):  
Image Analysis ◽  
Physarum Polycephalum ◽  
Secondary Growth ◽  
Growth Dynamics ◽  
Critical Distance ◽  
Slime Mold ◽  
Automated Image Analysis ◽  
Slime Molds ◽  
Chemical Substances ◽  
External Stimuli

AbstractCells, including unicellulars, are highly sensitive to external constraints from their environment. Amoeboid cells change their cell shape during locomotion and in response to external stimuli. Physarum polycephalum is a large multinucleated amoeboid cell that extends and develops pseudopods. In this paper, changes in cell behavior and shape were measured during the exploration of homogenous and non-homogenous environments that presented neutral, and nutritive and/or adverse substances. In the first place, we developed a fully automated image analysis method to measure quantitatively changes in both migration and shape. Then we measured various metrics that describe the area covered, the exploration dynamics, the migration rate and the slime mold shape. Our results show that: 1) Not only the nature, but also the spatial distribution of chemical substances affect the exploration behavior of slime molds; 2) Nutritive and adverse substances both slow down the exploration and prevent the formation of pseudopods; and 3) Slime mold placed in an adverse environment preferentially occupies previously explored areas rather than unexplored areas using mucus secretion as a buffer. Our results also show that slime molds migrate at a rate governed by the substrate up until they get within a critical distance to chemical substances.Author summaryPhysarum polycephalum, also called slime mold, is a giant single-celled organism that can grow to cover several square meters, forming search fronts that are connected to a system of intersecting veins. An original experimental protocol allowed tracking the shape of slime mold placed in homogenous substrates containing an attractant (glucose) or a repellent (salt), or inhomogeneous substrates that contained an attractive spot (glucose), an eccentric slime mold and a repulsive spot (salt) in between. For the first time, the rate of exploration of unexplored areas (primary growth) and the rate of extension in previously explored areas (secondary growth) were rigorously measured, by means of a sophisticated image analysis program. This paper shows that the chemical composition of the substrate has more influence on the morphology and growth dynamics of slime mold than that of concentrated spots of chemicals. It was also found that on a repulsive substrate, slime mold exhibits a bias towards secondary growth, which suggests that the mucus produced during slime mold migration acts as a protective shell in adverse environments.

Phosphoinositol diphosphates: non-enzymic formation in vitro and occurrence in vivo in the cellular slime mold Dictyostelium

1992 ◽  
Vol 234 ◽  
pp. 247-262 ◽  
Author(s):  
Georg W. Mayr ◽  
Thomas Radenberg ◽  
Ulrich Thiel ◽  
Günter Vogel ◽  
Leonard R. Stephens
Keyword(s):  
Slime Mold ◽  
Cellular Slime Mold ◽  
Cellular Slime

scholarly journals Transcriptomic and metabolomic analyses provide insight into the volatile compounds of citrus leaves and flowers

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Haipeng Zhang ◽  
Mengjun Chen ◽  
Huan Wen ◽  
Zhenhua Wang ◽  
Jiajing Chen ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Expression Levels ◽  
Monoterpene Synthase ◽  
Terpene Alcohols ◽  
Sweet Smell ◽  
Negative Effect ◽  
Volatile Terpenoids ◽  
Citrus Leaves ◽  
Sabinene Synthase

Abstract Background Previous reports have mainly focused on the volatiles in citrus fruits, and there have been few reports about the volatiles in citrus leaves and flowers. However, citrus leaves and flowers are also rich in volatile compounds with unique aromas. Here, to investigate the volatiles in citrus leaves and flowers, volatile profiling was performed on leaves from 62 germplasms and flowers from 25 germplasms. Results In total, 196 and 82 volatile compounds were identified from leaves of 62 citrus germplasms and flowers of 25 citrus germplasms, respectively. The dominant volatile terpenoids were more diverse in citrus leaves than in peels. A total of 34 volatile terpenoids were commonly detected in the leaves of at least 20 germplasms, among which 31 were overaccumulated in the leaves of wild or semiwild germplasms. This result was consistent with the high expression levels of five genes and one key gene of the mevalonate and 2-C-methyl-D-erythritol-4-phosphate (MEP) biosynthetic pathways, respectively, as well as the low expression levels of geranylgeranyl diphosphate synthase of the MEP pathway, relative to the levels in cultivars. Fully open flowers showed increased levels of four terpene alcohols and a decrease in sabinene content compared with balloon-stage flowers, especially in sweet orange. A monoterpene synthase gene was identified and functionally characterized as a sabinene synthase in vitro. Conclusions Collectively, our results suggest that 31 important terpenoids are abundant in wild or semiwild citrus germplasms, possibly because of a negative effect of domestication on the volatiles in citrus leaves. The sweet smell of fully open flowers may be attributed to increased levels of four terpene alcohols. In addition, a sabinene synthase gene was identified by combined transcriptomic and metabolomic analyses.

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