Impact of Genetic Background in Fitness Cost Studies: An Example from Glyphosate-Resistant Palmer Amaranth

Weed Science ◽  
2014 ◽  
Vol 62 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Darci Giacomini ◽  
Philip Westra ◽  
Sarah M. Ward
Keyword(s):  
Genetic Background ◽  
Pollen Viability ◽  
Volume Ratio ◽  
Metabolic Cost ◽  
Palmer Amaranth ◽  
Fitness Cost ◽  
Gene Copy ◽  
Georgia Population ◽  
Set Up ◽  
Cost Studies

Since its discovery in 2005, glyphosate-resistant Palmer amaranth has become a major problem for many farmers in the southern United States. One mechanism of resistance found in a Georgia population of glyphosate-resistant Palmer amaranth is amplification of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene throughout the genome, with some resistant plants containing and expressing more than 100EPSPSgenes. Such high numbers ofEPSPSgenes and protein production could result in a fitness cost to resistant plants due to (1) metabolic cost of overproduction of this enzyme and (2) disruption of other genes after insertion of theEPSPSgene. A greenhouse experiment was set up to investigate differences in growth and reproduction between glyphosate-susceptible and -resistant Palmer amaranth plants. Measurements included growth rate, plant height/volume ratio, final biomass, photosynthetic rate, inflorescence length, pollen viability, and seed set. This study found no significant fitness costs for plants with the resistance trait. This study also provided a clear example of how controlling for genetic background is important in fitness cost studies and how potentially misleading results can be obtained if only a few fitness traits are measured. These results indicate that glyphosate-resistant Palmer amaranth plants with highEPSPSgene copy numbers are likely to persist in field populations, even in the absence of glyphosate, potentially leading to long-term loss of glyphosate as a control option for Palmer amaranth.

scholarly journals Using a simple rope-pulley system that mechanically couples the arms, legs, and treadmill reduces the metabolic cost of walking

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Daisey Vega ◽  
Christopher J. Arellano
Keyword(s):  
Metabolic Cost ◽  
Metabolic Energy ◽  
Metabolic Effects ◽  
Whole Body ◽  
Walking Ability ◽  
Arm Swing ◽  
Pulley System ◽  
Young Subjects ◽  
Walking Recovery ◽  
Set Up

Abstract Background Emphasizing the active use of the arms and coordinating them with the stepping motion of the legs may promote walking recovery in patients with impaired lower limb function. Yet, most approaches use seated devices to allow coupled arm and leg movements. To provide an option during treadmill walking, we designed a rope-pulley system that physically links the arms and legs. This arm-leg pulley system was grounded to the floor and made of commercially available slotted square tubing, solid strut channels, and low-friction pulleys that allowed us to use a rope to connect the subject’s wrist to the ipsilateral foot. This set-up was based on our idea that during walking the arm could generate an assistive force during arm swing retraction and, therefore, aid in leg swing. Methods To test this idea, we compared the mechanical, muscular, and metabolic effects between normal walking and walking with the arm-leg pulley system. We measured rope and ground reaction forces, electromyographic signals of key arm and leg muscles, and rates of metabolic energy consumption while healthy, young subjects walked at 1.25 m/s on a dual-belt instrumented treadmill (n = 8). Results With our arm-leg pulley system, we found that an assistive force could be generated, reaching peak values of 7% body weight on average. Contrary to our expectation, the force mainly coincided with the propulsive phase of walking and not leg swing. Our findings suggest that subjects actively used their arms to harness the energy from the moving treadmill belt, which helped to propel the whole body via the arm-leg rope linkage. This effectively decreased the muscular and mechanical demands placed on the legs, reducing the propulsive impulse by 43% (p < 0.001), which led to a 17% net reduction in the metabolic power required for walking (p = 0.001). Conclusions These findings provide the biomechanical and energetic basis for how we might reimagine the use of the arms in gait rehabilitation, opening the opportunity to explore if such a method could help patients regain their walking ability. Trial registration: Study registered on 09/29/2018 in ClinicalTrials.gov (ID—NCT03689647).

scholarly journals Molecular Relationships between Bronchial Asthma and Hypertension as Comorbid Diseases

2018 ◽  
Vol 15 (4) ◽  
Author(s):  
Elena Yu. Bragina ◽  
Irina A. Goncharova ◽  
Anna F. Garaeva ◽  
Evgeniy V. Nemerov ◽  
Anastasija A. Babovskaya ◽  
...  
Keyword(s):  
Bronchial Asthma ◽  
Genetic Background ◽  
Regulation Of Gene Expression ◽  
Common Phenomenon ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Multiple Factors ◽  
Comorbid Diseases ◽  
Set Up ◽  
Molecular Relationships

AbstractComorbidity, a co-incidence of several disorders in an individual, is a common phenomenon. Their development is governed by multiple factors, including genetic variation. The current study was set up to look at associations between isolated and comorbid diseases of bronchial asthma and hypertension, on one hand, and single nucleotide polymorphisms associated with regulation of gene expression (eQTL), on the other hand. A total of 96 eQTL SNPs were genotyped in 587 Russian individuals. Bronchial asthma alone was found to be associated with rs1927914 (TLR4), rs1928298 (intergenic variant), and rs1980616 (SERPINA1); hypertension alone was found to be associated with rs11065987 (intergenic variant); rs2284033 (IL2RB), rs11191582 (NT5C2), and rs11669386 (CARD8); comorbidity between asthma and hypertension was found to be associated with rs1010461 (ANG/RNASE4), rs7038716, rs7026297 (LOC105376244), rs7025144 (intergenic variant), and rs2022318 (intergenic variant). The results suggest that genetic background of comorbidity of asthma and hypertension is different from genetic backgrounds of both diseases manifesting isolated.

Variable Inheritance of AmplifiedEPSPSGene Copies in Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri)

Weed Science ◽  
2018 ◽  
Vol 67 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Darci A. Giacomini ◽  
Philip Westra ◽  
Sarah M. Ward
Keyword(s):  
Copy Number ◽  
Single Gene ◽  
Gene Copy Number ◽  
Transgressive Segregation ◽  
Palmer Amaranth ◽  
Gene Copy ◽  
Amaranthus Palmeri ◽  
Gene Copies ◽  
Central United States ◽  
Free Environment

AbstractGlyphosate-resistant (GR) Palmer amaranth (Amaranthus palmeriS. Watson) is considered one of the most troublesome weeds in the southern and central United States, but results of previous research to determine the mode of inheritance of this trait have been conflicting and inconclusive. In this study, we examined segregation patterns ofEPSPSgene-copy numbers in F1and F2generations ofA. palmeriand found no evidence of a Mendelian single-gene pattern of inheritance. Transgressive segregation for copy number was exhibited by several F1and all of the F2families, most likely the product ofEPSPScopy-number variation within each plant. This variation was confirmed by assaying gene-copy number across clonal generations and among individual shoots on the same plant, demonstrating thatEPSPSamplification levels vary significantly within a single plant. Increases and decreases in copy number occurred in a controlled, stress-free environment in the absence of glyphosate, indicating thatEPSPSgene amplification is a random and variable process within the plant. The ability ofA. palmerito gain or loseEPSPSgene copies is a valuable adaptive trait, allowing this species to respond rapidly to selection pressures and changing environments.

Fitness cost due to herbicide resistance may trigger genetic background evolution

Evolution ◽  
2014 ◽  
Vol 69 (1) ◽  
pp. 271-278 ◽  
Author(s):  
Henri Darmency ◽  
Yosra Menchari ◽  
Valérie Le Corre ◽  
Christophe Délye
Keyword(s):  
Herbicide Resistance ◽  
Genetic Background ◽  
Fitness Cost

Skipping vs. running as the bipedal gait of choice in hypogravity

2015 ◽  
Vol 119 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Gaspare Pavei ◽  
Carlo M. Biancardi ◽  
Alberto E. Minetti
Keyword(s):  
Center Of Pressure ◽  
Metabolic Cost ◽  
Bipedal Locomotion ◽  
Pressure Measurements ◽  
Low Gravity ◽  
Bipedal Gait ◽  
Space Suits ◽  
Functional Analog ◽  
The Difference ◽  
Set Up

Hypogravity challenges bipedal locomotion in its common forms. However, as previously theoretically and empirically suggested, humans can rely on “skipping,” a less common gait available as a functional analog (perhaps a vestigium) of quadrupedal gallop, to confidently move when gravity is much lower than on Earth. We set up a 17-m-tall cavaedium (skylight shaft) with a bungee rubber body-suspension system and a treadmill to investigate the metabolic cost and the biomechanics of low-gravity (Mars, Moon) locomotion. Although skipping is never more metabolically economical than running, the difference becomes marginal at lunar gravities, with both bouncing gaits approaching values of walking on Earth (cost ≈2 J·kg−1·m−1). Nonmetabolic factors may thus be allowed to dominate the choice of skipping on the Moon. On the basis of center of pressure measurements and body segments kinetics, we can speculate that these factors may include a further reduction of mechanical work to move the limbs when wearing space suits and a more effective motor control during the ground (regoliths)-boot interaction.

scholarly journals Deciphering S-RNase Allele Patterns in Cultivated and Wild Accessions of Italian Pear Germplasm

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1228
Author(s):  
Stefania Bennici ◽  
Mario Di Guardo ◽  
Gaetano Distefano ◽  
Giuseppina Las Casas ◽  
Filippo Ferlito ◽  
...  
Keyword(s):  
Wild Species ◽  
Genetic Background ◽  
Heterogeneous Distribution ◽  
Allele Distribution ◽  
S Alleles ◽  
History Of ◽  
Self Fertilization ◽  
S Allele ◽  
Set Up ◽  
Wild Accessions

The genus Pyrus is characterized by an S-RNase-based gametophytic self-incompatibility (GSI) system, a mechanism that promotes outbreeding and prevents self-fertilization. While the S-genotype of the most widely known pear cultivars was already described, little is known on the S-allele variability within local accessions. The study was conducted on 86 accessions encompassing most of the local Sicilian varieties selected for their traits of agronomic interest and complemented with some accessions of related wild species (P. pyrifolia Nakai, P. amygdaliformis Vill.) and some national and international cultivars used as references. The employment of consensus and specific primers enabled the detection of 24 S-alleles combined in 48 S-genotypes. Results shed light on the distribution of the S-alleles among accessions, with wild species and international cultivars characterized by a high diversity and local accessions showing a more heterogeneous distribution of the S-alleles, likely reflecting a more complex history of hybridization. The S-allele distribution was largely in agreement with the genetic structure of the studied collection. In particular, the “wild” genetic background was often characterized by the same S-alleles detected in P. pyrifolia and P. amygdaliformis. The analysis of the S-allele distribution provided novel insight into the contribution of the wild and international cultivars to the genetic background of the local Sicilian or national accessions. Furthermore, these results provide information that can be readily employed by breeders for the set-up of novel mating schemes.

Treatment of Refinery Wastewater with Isolated Biological Aerated Filters: A Pilot-Scale Study

2012 ◽  
Vol 610-613 ◽  
pp. 2332-2341
Author(s):  
Jian Guang Huang ◽  
Li Zhong ◽  
Wen Yu Xie
Keyword(s):  
Waste Water ◽  
Waste Water Treatment ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Pilot Scale ◽  
Mean Value ◽  
Operating Conditions ◽  
Water Volume ◽  
High Concentration ◽  
Set Up

A pilot scale biochemical treatment system containing three isolated biological aerated filters, one oil-separation pool and one secondary sedimentation tank was set up and used for high concentration organic waste water treatment. Effect of different operating conditions on Chemical Oxygen Demand (CODCr), sulphides, hydroxybenzene and oil degradation was investigated. And the ways of sulphides removal were also explored. While CODCr, the concentrations of sulphides, hydroxybenzene and oil in the waste water are no more than 1500 mg/L, 800 mg/L, 15 mg/L and 150mg/L, respectively, the system can run stably and the total removal of these pollutants is 88.8%, 98.8%, 96.8% and 91.0% accordingly though hydraulic retention time (HRT) varies from 7.95 hr to 15.90 hr and the air/water volume ratio (AWVR) varies from 12 to 8. Most of the sulphides are removed by Biodegradation with Isolated Biological Aerated Filters. Most of the pollutants are removed in the 1st BAF and about 96.5% by mean value of sulphides transforme into elemental sulfur and only about 2.7% by mean value of sulphides transforme into sulphates.

scholarly journals FURTHER EVIDENCE FOR SELECTIVE DIFFERENCES BETWEEN ISOALLELES IN DROSOPHILA

Genetics ◽  
1975 ◽  
Vol 79 (1) ◽  
pp. 127-141
Author(s):  
Christopher Wills ◽  
Julia Phelps ◽  
Richard Ferguson
Keyword(s):  
Genetic Background ◽  
Inbred Lines ◽  
Drosophila Pseudoobscura ◽  
Weak Effect ◽  
Mendelian Expectation ◽  
Set Up ◽  
Octanol Dehydrogenase ◽  
Sister Mating

ABSTRACT A number of separate strains of Drosophila pseudoobscura were inbred for 38 generations of brother-sister mating with forced heterozygosity for two alleles of either the octanol dehydrogenase or esterase-5 locus. Crosses were set up within each of these inbred lines such that simple mendelian ratios were expected, and eggs from these crosses were placed on media with additions of simple chemicals likely to interact with alleles of the two loci—octanol and ethanol for the ODH locus and tributyrin and triacetin for the E-5 locus. Similar crosses were set up involving parental flies with normally heterozygous genetic background as a control.—Significant deviations from mendelian expectation were observed in inbred E-5 flies grown on tributyrin, inbred ODH males grown on octanol, and inbred ODH females grown on ethanol. There was also a strong effect of octanol medium on males of one of the inbred E-5 lines, and a weak effect of tributyrin medium on ODH inbred females.—The probability that these results reflect interactions between these loci and the environment is assessed in the light of differences between the present results and those obtained at earlier stages of inbreeding.

scholarly journals Enhancing Percolation in Phosphatic Clay Using Diatoms under Laboratory Conditions

2018 ◽  
Author(s):  
Melba D. Horton ◽  
Dieff Vital ◽  
Paul Defino ◽  
Sarah Spaulding ◽  
Gary Albarelli
Keyword(s):  
Crop Production ◽  
Fine Particles ◽  
Volume Ratio ◽  
Cost Effective ◽  
Organic Content ◽  
Phosphate Mining ◽  
Laboratory Conditions ◽  
Freshwater Habitats ◽  
Sediment Particles ◽  
Set Up

ABSTRACTClay settling areas are large impoundments brought about by phosphate mining with water-holding capacity that renders it very poor for agriculture and crop production. This study aims to enhance water percolation in phosphatic clay using porous diatom frustules under laboratory conditions. Phosphatic clay collected from settling areas was brought to the laboratory for the experiment. Diatom frustules were purchased commercially and dry samples of the diatom, Didymosphenia were provided by the University of Colorado-Boulder. Oven-dried clay was mixed with diatom frustules into 125 mL centrifuge tubes following a 1:1 volume ratio as experimental set-ups while pure phosphatic clay was used as control. Deionized water was poured into each set-up and the percentage of unpercolated water overlying the sediment, water retained in the sediment particles, water that percolated and passed through the hole of the centrifuge tube were monitored for 48 hours. Results showed that the addition of diatom frustules enhances the percolation of water in the sediment mixture especially those with Didymosphenia frustules. However, this mixture also showed higher percentage of water retained in the sediment particles which could be attributed to the high carbon and organic content brought about by the presence of stalks which is a major component of this species morphology. Considering how Didymosphenia disturbs freshwater habitats, proper management may render it useful for the mitigation of clay settling areas in the land environment. The implication of this on crop production remains to be explored and further in situ experimentations need to be conducted.IMPORTANCEClay settling areas abound in places where phosphate mining is conducted. The very fine particles and the chemical property of this phosphatic clay allows it to hold water more than normal clay sediments making the area unstable and less suitable for agricultural use. Studies show that mitigative measures to enhance surface drainage is very costly leaving most areas barren and unused. Diatoms are unicellular algae in various size and shapes with silicified cell walls that are porous and are ubiquitous in aquatic environments. The significance of our research is being able to demonstrate the potential use of diatoms, most especially the genus Didymosphenia which is regarded as an environmental threat to some habitats, in mitigating the drainage problem in clay settling areas by mixing phosphatic clay with diatom frustules. This process is cost-effective and more importantly provides utilization of a resource that is regarded as nuisance in freshwater environments.

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