scholarly journals Guayule (Parthenium argentatum A. Gray), a Renewable Resource for Natural Polyisoprene and Resin: Composition, Processes and Applications

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 664
Author(s):  
Amandine Rousset ◽  
Ali Amor ◽  
Teerasak Punvichai ◽  
Sandrine Perino ◽  
Serge Palu ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Current Knowledge ◽  
Renewable Resource ◽  
Sole Source ◽  
Southern United States ◽  
Parthenium Argentatum ◽  
Northern Mexico ◽  
Botanical Description ◽  
Multiple Product ◽  
Economic Considerations

Natural rubber is an essential material, especially for plane and truck tyres but also for medical gloves. Asia ranks first in the production of natural rubber, of which the Hevea tree is currently the sole source. However, it is anticipated that this source alone will not be able to fulfill the growing demand. Guayule, a shrub native to northern Mexico and southern United States, may also contribute. This plant not only contains polyisoprene, but also resin, a mixture of lipids and terpenoids. This review summarizes various aspects of this plant, from the usage history, botanical description, geographical distribution and cultivation practices, down to polyisoprene and resin biosynthesis including their distribution within the plant and molecular composition. Finally, the main processes yielding dry rubber or latex are depicted, as well as the properties of the various extracts along with economic considerations. The aim is to provide a wide picture of current knowledge available about this promising crop, a good feedstock candidate for a multiple-product biorefinery.

scholarly journals Degradation of non-vulcanized natural rubber renewable resource for fine chemicals used in polymer synthesis

Polímeros ◽  
2013 ◽  
Vol 23 (4) ◽  
pp. 441-450 ◽  
Author(s):  
Alexander FAINLEIB ◽  
Renata V. PIRES ◽  
Elizabete F. LUCAS ◽  
Bluma G. SOARES
Keyword(s):  
Natural Rubber ◽  
Renewable Resource ◽  
Polymer Synthesis ◽  
Fine Chemicals

scholarly journals Biodegradation of Tetralin: Genomics, Gene Function and Regulation

Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 339 ◽  
Author(s):  
Belén Floriano ◽  
Eduardo Santero ◽  
Francisca Reyes-Ramírez
Keyword(s):  
Gene Expression ◽  
Current Knowledge ◽  
Gene Clusters ◽  
Sole Source ◽  
Regulatory Elements ◽  
Catabolic Pathway ◽  
Regulatory Systems ◽  
Biochemical Genetic ◽  
Complex Regulation ◽  
Rhodococcus Sp

Tetralin (1,2,3,4-tetrahydonaphthalene) is a recalcitrant compound that consists of an aromatic and an alicyclic ring. It is found in crude oils, produced industrially from naphthalene or anthracene, and widely used as an organic solvent. Its toxicity is due to the alteration of biological membranes by its hydrophobic character and to the formation of toxic hydroperoxides. Two unrelated bacteria, Sphingopyxis granuli strain TFA and Rhodococcus sp. strain TFB were isolated from the same niche as able to grow on tetralin as the sole source of carbon and energy. In this review, we provide an overview of current knowledge on tetralin catabolism at biochemical, genetic and regulatory levels in both strains. Although they share the same biodegradation strategy and enzymatic activities, no evidences of horizontal gene transfer between both bacteria have been found. Moreover, the regulatory elements that control the expression of the gene clusters are completely different in each strain. A special consideration is given to the complex regulation discovered in TFA since three regulatory systems, one of them involving an unprecedented communication between the catabolic pathway and the regulatory elements, act together at transcriptional and posttranscriptional levels to optimize tetralin biodegradation gene expression to the environmental conditions.

scholarly journals Influence of Filler from a Renewable Resource and Silane Coupling Agent on the Properties of Epoxidized Natural Rubber Vulcanizates

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Wiphawadee Pongdong ◽  
Charoen Nakason ◽  
Claudia Kummerlöwe ◽  
Norbert Vennemann
Keyword(s):  
Mechanical Properties ◽  
Metal Oxide ◽  
Natural Rubber ◽  
Elevated Temperatures ◽  
Polymer Network ◽  
Renewable Resource ◽  
Dynamic Mechanical Properties ◽  
Epoxidized Natural Rubber ◽  
Cure Characteristics ◽  
Temperature Scanning

Rice husk ash (RHA) was used as a reinforcing filler in epoxidized natural rubber (ENR) with various loading levels (0, 10, 20, and 30 phr), and silica filled ENR was also studied for comparison. The effects of RHA content on cure characteristics, mechanical properties, dynamic mechanical properties, and thermoelastic behavior of the filled ENR composites were investigated. It was found that the incorporation of RHA significantly affected the cure characteristics and mechanical properties. That is, the incorporation of RHA caused faster curing reactions and increased Young’s modulus and tensile strength relative to the unfilled compound. This might be attributed to the metal oxide impurities in RHA that enhance the crosslinking reactions, thus increasing the crosslink density. Further improvements in the curing behavior and the mechanical properties of the filled composites were achieved byin situsilanization with bis(triethoxysilylpropyl) tetrasulfide (Si69). It was found that the rubber-filler interactions reinforced the composites. This was indicated by the decreased damping characteristic(tan ⁡δ)and the other changes in the mechanical properties. Furthermore, the ENR composites with Si69 had improved filler dispersion. Temperature scanning stress relaxation (TSSR) results suggest that the metal oxide impurities in RHA promote degradation of the polymer network at elevated temperatures.

scholarly journals Adolescent Metabolic Syndrome Risk Is Increased with Higher Infancy Weight Gain and Decreased with Longer Breast Feeding

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Kim Khuc ◽  
Estela Blanco ◽  
Raquel Burrows ◽  
Marcela Reyes ◽  
Marcela Castillo ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Weight Gain ◽  
Current Knowledge ◽  
Age Groups ◽  
Sole Source ◽  
The Metabolic Syndrome ◽  
Early Infant ◽  
Increased Risk ◽  
Infant Weight Gain

Background. Prevalence of the metabolic syndrome is increasing in pediatric age groups worldwide. Meeting the criteria for the metabolic syndrome puts children at risk for later cardiovascular and metabolic disease.Methods. Using linear regression, we examined the association between infant weight gain from birth to 3 months and risk for the metabolic syndrome among 16- to 17-year-old Chilean adolescents (n=357), accounting for the extent of breastfeeding in infancy and known covariates including gender, birth weight, and socioeconomic status.Results. Participants were approximately half male (51%), born at 40 weeks of gestation weighing 3.5 kg, and 48% were exclusively breastfed for≥90days. Factors independently associated with increased risk of metabolic syndrome in adolescence were faster weight gain in the first 3 months of life (B=0.16,P<0.05) and male gender (B=0.24,P<0.05). Breastfeeding as the sole source of milk for≥90days was associated with significantly decreased risk of metabolic syndrome (B=−0.16).Conclusion. This study adds to current knowledge about early infant growth and breastfeeding and their long-term health effects.

Cytogenetic analyses of intersectional hybrids between Parthenium argentatum and Parthenium confertum

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 134-140 ◽  
Author(s):  
A. Hashemi ◽  
A. Estilai ◽  
J. G. Waines
Keyword(s):  
Natural Rubber ◽  
Growth Habit ◽  
Backcross Progeny ◽  
Woody Species ◽  
Herbaceous Species ◽  
Parthenium Argentatum ◽  
Preferential Pairing ◽  
Homologous Chromosomes ◽  
Multivalent Formation ◽  
Cytogenetic Analyses

Induced tetraploid guayule (Parthenium argentatum Gray, a rubber-producing and woody species of section Parthenicaeta) was crossed to P. confertum var. lyratum Gray, a herbaceous species of section Argyrocheta. Hybrids were obtained when guayule was used as female. Like their diploid progenitors, induced tetraploids were sexual and self-incompatible. At meiosis, they averaged 0.30 I, 29.63 II, 0.12 III, and 3.02 IV. Parthenium confertum had 69 chromosomes and was apomictic. At meiosis, it averaged 1.00 I, 32.98 II, and 0.51 IV. Hybrids received 36 chromosomes from guayule and 34 chromosomes from P. confertum. At meiosis, they averaged 0.52 I, 33.44 II, 0.20 III, and 0.50 IV. F1 plants behaved like an amphidiploid in which homologous chromosomes of guayule genome paired with each other and homologous chromosomes of P. confertum genome also paired preferentially. Chromosome association in the hybrids indicated that P. confertum parent may be a tetraploid with suppressed multivalent formation. Although hybrids were partially fertile and produced backcross progeny, the transfer of desirable traits (rapid growth and herbaceous growth habit) from P. confertum into guayule will depend on elimination of preferential pairing in the hybrids.Key words: guayule, natural rubber, meiosis, chromosome pairing.

scholarly journals Impacts of the Atlantic Multidecadal Variability on North American Summer Climate and Heat Waves

2018 ◽  
Vol 31 (9) ◽  
pp. 3679-3700 ◽  
Author(s):  
Yohan Ruprich-Robert ◽  
Thomas Delworth ◽  
Rym Msadek ◽  
Frederic Castruccio ◽  
Stephen Yeager ◽  
...  
Keyword(s):  
United States ◽  
North Atlantic ◽  
North American ◽  
Heat Waves ◽  
Southern United States ◽  
Atlantic Multidecadal Variability ◽  
Multidecadal Variability ◽  
Northern Mexico ◽  
The North ◽  
North American Climate

The impacts of the Atlantic multidecadal variability (AMV) on summertime North American climate are investigated using three coupled global climate models (CGCMs) in which North Atlantic sea surface temperatures (SSTs) are restored to observed AMV anomalies. Large ensemble simulations are performed to estimate how AMV can modulate the occurrence of extreme weather such as heat waves. It is shown that, in response to an AMV warming, all models simulate a precipitation deficit and a warming over northern Mexico and the southern United States that lead to an increased number of heat wave days by about 30% compared to an AMV cooling. The physical mechanisms associated with these impacts are discussed. The positive tropical Atlantic SST anomalies associated with the warm AMV drive a Matsuno–Gill-like atmospheric response that favors subsidence over northern Mexico and the southern United States. This leads to a warming of the whole tropospheric column, and to a decrease in relative humidity, cloud cover, and precipitation. Soil moisture response to AMV also plays a role in the modulation of heat wave occurrence. An AMV warming favors dry soil conditions over northern Mexico and the southern United States by driving a year-round precipitation deficit through atmospheric teleconnections coming both directly from the North Atlantic SST forcing and indirectly from the Pacific. The indirect AMV teleconnections highlight the importance of using CGCMs to fully assess the AMV impacts on North America. Given the potential predictability of the AMV, the teleconnections discussed here suggest a source of predictability for the North American climate variability and in particular for the occurrence of heat waves at multiyear time scales.

scholarly journals Potential Applications of Guayulins to Improve Feasibility of Guayule Cultivation

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 804 ◽  
Author(s):  
Francisco M. Jara ◽  
Katrina Cornish ◽  
Manuel Carmona
Keyword(s):  
Current Knowledge ◽  
Raw Material ◽  
South East Asia ◽  
Parthenium Argentatum ◽  
Rubber Latex ◽  
The Past ◽  
Potential Applications ◽  
Desert Areas ◽  
High Concentrations ◽  
Interesting Alternative

Guayule (Parthenium argentatum Gray) is an interesting alternative and renewable source of rubber/latex which has been used in the past. Guayule rubber and latex products are not available in the market largely because the raw material cost is higher than the current sources produced in South-East Asia and other tropical countries (Hevea brasiliensis). Guayule contains many other compounds whose joint exploitation could make guayule cultivation profitable, especially in semi-desert areas where cultivation of other crops is difficult or impossible. Guayulins A–D, sesquiterpene esters, appear to have some commercial promise. Despite being accumulated in relatively high concentrations (its majority representative, guayulin A, can account for up to 13.7% of the resin content of this plant, which itself ranges from 6%–12%), guayulins have received little direct attention from scientists. This review presents the current knowledge about the activity of these compounds and, based on known activities of similar compounds from other species, potential uses as fungicides, miticides and insecticides are suggested.

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