Seasonal variation of picloram metabolism in broom (Gutierrezia sarothrae) and threadleaf (Gutierrezia microcephala) snakeweed populations in a common garden

Weed Science ◽  
2004 ◽  
Vol 52 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Larissa A. Gibbs ◽  
Tracy M. Sterling
Keyword(s):  
Differential Susceptibility ◽  
Common Garden ◽  
Western United States ◽  
Phenological Stage ◽  
Application Timing ◽  
Tissue Sensitivity ◽  
Gutierrezia Sarothrae ◽  
Two Populations ◽  
Treatment Application

Broom and threadleaf snakeweed are major rangeland weeds in the western United States, and picloram is the major herbicide used for their management. Previous work has shown that these species are most susceptible to picloram applied in autumn or when precipitation is high and that differences in herbicide absorption and tissue sensitivity as measured by picloram-induced ethylene production do not fully explain variation in seasonal response. Therefore, the role of picloram metabolism in seasonal susceptibility to picloram was examined. Because snakeweed is characterized as highly genetically variable, picloram metabolism was evaluated monthly for 3 yr among populations from two species as well. Picloram metabolism was examined monthly for 3 yr among two populations of threadleaf and nine populations of broom snakeweed grown in a common garden. Metabolism ranged from 30 to 70% of picloram applied, and picloram was converted to two metabolites more polar than picloram regardless of species or population. Although metabolism was greatest in the year with the most precipitation, rate of metabolism was unrelated to precipitation received in the 7-d period before treatment. Application timing as defined by a given month or specific phenological stage was not related to the level of metabolism. We conclude that variation in picloram metabolism is not involved in differential susceptibility across season or population.

scholarly journals Susceptibility of Echinochloa populations to cyhalofop-butyl in Southern region of Brazil and impact of the weed phenology on its efficacy of control

2017 ◽  
Vol 47 (4) ◽  
Author(s):  
Augusto Kalsing ◽  
Sérgio Mateus Tronquini ◽  
Carlos Henrique Paim Mariot ◽  
Rogerio da Silva Rubin ◽  
Angela Da Cas Bundt ◽  
...  
Keyword(s):  
Factorial Design ◽  
Regional Scale ◽  
Differential Susceptibility ◽  
Southern Region ◽  
Phenological Stage ◽  
Phenological Stages ◽  
Growth Season ◽  
Application Timing ◽  
Rice Farmers ◽  
Timing Delay

ABSTRACT: Cyhalofop-butyl stands out among the herbicides in the control of imidazolinone-resistant Echinochloa species; but, rice farmers are not always satisfied with the control achieved with this herbicide. The objectives were to evaluate in regional scale the susceptibility of Echinochloa populations to cyhalofop-butyl, and quantify the effect of the weed phenology on its efficacy of control. For this, three trials were carried out under greenhouse conditions with a fully random design, using Echinochloa populations collected in rice fields in the southern region of Brazil. In two trials, the susceptibility level of 156 (2012/13 growth season) and 103 (2013/14 growth season) populations were evaluated with the application of cyhalofop-butyl at 360g ha-1. In other trial, in which treatments were arranged in a bi-factorial design (A = 6 x B = 5), it was evaluated six cyhalofop-butyl rates and five phenological stages of E. crus-galli populations. Echinochloa populations had showed differential susceptibility to cyhalofop-butyl, especially in the 2013/14 growth season, where 20 out of the 103 populations had control lower than 90%. The efficacy of this herbicide was inversely proportional to the phenological stage, and the application timing delay contributed directly to the decrease of susceptibility to the herbicide. Cyhalofop-butyl is an effective alternative to control imidazolinone-resistant Echinochloa populations, as long as the application timing occurs in the early phenological stages (2 to 4 leaves).

Highly sensitive adolescent benefits in positive school transitions: Evidence for vantage sensitivity in Japanese high-schoolers

2020 ◽  
Author(s):  
Shuhei Iimura
Keyword(s):  
High School ◽  
Statistical Power ◽  
Environmental Influences ◽  
Differential Susceptibility ◽  
School Transition ◽  
Well Being ◽  
Crossover Point ◽  
Japanese Adolescents ◽  
Highly Sensitive

Some researchers indicate that the transition to high school deflects adolescent developmental trajectories. Others assert it provides a new possibility for the promotion of adolescents’ socioemotional well-being. One critical view missing in such claims is that individual variabilities interact with environmental influences. We employed the framework of Differential Susceptibility Theory, which postulates that individual susceptibilities moderate external influences for better and for worse. In order to clarify the mechanism of adolescents’ differential adjustments, this paper investigated the role of sensory-processing sensitivity using the Japanese version of Highly Sensitive Child Scale for Adolescence (J-HSCS), and tested whether the diathesis-stress model or the differential susceptibility model best describes students’ socioemotional adjustment across their high school transition. The current paper used the two-wave data collected from Japanese adolescents aged from 14 to 15 years (n = 412, 50% girls). In Study 1, we investigated the replicability of psychometric properties of J-HSCS. The results supported previous findings, indicating its validity for the bifactor model. In Study 2, we utilized confirmatory competitive model testing, which maximizes statistical power by parameterizing the crossover point to allow a direct comparison of alternative models. The results indicated that neither the diathesis-stress nor the differential susceptibility models fitted the data. Rather, a strong vantage sensitivity model was revealed, suggesting that highly susceptible adolescents disproportionately benefitted from a positive school transition over their counterparts. This finding signified the role of adolescents’ sensitivity to environmental influences and the importance of considering its moderation under person x environment interactions.

scholarly journals Microtubule–microtubule sliding by kinesin-1 is essential for normal cytoplasmic streaming in Drosophila oocytes

2016 ◽  
Vol 113 (34) ◽  
pp. E4995-E5004 ◽  
Author(s):  
Wen Lu ◽  
Michael Winding ◽  
Margot Lakonishok ◽  
Jill Wildonger ◽  
Vladimir I. Gelfand
Keyword(s):  
Cytoplasmic Streaming ◽  
Cell Types ◽  
Nurse Cells ◽  
Wild Type ◽  
Actin Cortex ◽  
Microtubule Motor ◽  
Multiple Cell ◽  
Cytoplasmic Microtubules ◽  
Two Populations

Cytoplasmic streaming in Drosophila oocytes is a microtubule-based bulk cytoplasmic movement. Streaming efficiently circulates and localizes mRNAs and proteins deposited by the nurse cells across the oocyte. This movement is driven by kinesin-1, a major microtubule motor. Recently, we have shown that kinesin-1 heavy chain (KHC) can transport one microtubule on another microtubule, thus driving microtubule–microtubule sliding in multiple cell types. To study the role of microtubule sliding in oocyte cytoplasmic streaming, we used a Khc mutant that is deficient in microtubule sliding but able to transport a majority of cargoes. We demonstrated that streaming is reduced by genomic replacement of wild-type Khc with this sliding-deficient mutant. Streaming can be fully rescued by wild-type KHC and partially rescued by a chimeric motor that cannot move organelles but is active in microtubule sliding. Consistent with these data, we identified two populations of microtubules in fast-streaming oocytes: a network of stable microtubules anchored to the actin cortex and free cytoplasmic microtubules that moved in the ooplasm. We further demonstrated that the reduced streaming in sliding-deficient oocytes resulted in posterior determination defects. Together, we propose that kinesin-1 slides free cytoplasmic microtubules against cortically immobilized microtubules, generating forces that contribute to cytoplasmic streaming and are essential for the refinement of posterior determinants.

scholarly journals Springtime high surface ozone events over the western United States: Quantifying the role of stratospheric intrusions

2012 ◽  
Vol 117 (D21) ◽  
pp. n/a-n/a ◽  
Author(s):  
Meiyun Lin ◽  
Arlene M. Fiore ◽  
Owen R. Cooper ◽  
Larry W. Horowitz ◽  
Andrew O. Langford ◽  
...  
Keyword(s):  
United States ◽  
Surface Ozone ◽  
High Surface ◽  
Western United States ◽  
Stratospheric Intrusions

scholarly journals Forces Necessary to Initiate Dispersal for Three Tumbleweeds

2008 ◽  
Vol 1 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Dirk V. Baker ◽  
K. George Beck ◽  
Bogusz J. Bienkiewicz ◽  
Louis B. Bjostad
Keyword(s):  
Water Treatment ◽  
Conversion Factor ◽  
Common Garden ◽  
High Water ◽  
Western United States ◽  
Field Collection ◽  
Stem Strength ◽  
Wind Velocities ◽  
Diffuse Knapweed ◽  
Water Treatments

AbstractAlthough diffuse knapweed, kochia, and Russian thistle are important tumbleweeds of the western United States, environmental factors contributing to their dispersal are not well understood. Bolting rosettes of these species were transplanted to pots and reared in a common garden to determine the affect of postsenescence water on stem strength. There were no differences in stem strength among three water treatments for Russian thistle. Kochia, under moderate water treatment, required more than twice the force to break compared to plants under the zero and high water treatments. In contrast, diffuse knapweed plants under zero water treatment required four to six times greater force to break compared to plants under the moderate and high water treatments. There was a strong difference in diffuse knapweed stem strength between field collection sites that corresponded to observed differences in proportion of plants tumbling. A wind tunnel was used to develop a conversion factor between force and wind velocity. Wind velocities necessary to break diffuse knapweed stems ranged from 16 to 37 m/s (36 to 77 mph).

scholarly journals Private specificities of H-2K and H-2D loci as possible selective targets for effector lymphocytes in cell-mediated immunity.

1975 ◽  
Vol 141 (1) ◽  
pp. 11-26 ◽  
Author(s):  
B D Brondz ◽  
I K Egorov ◽  
G I Drizlikh
Keyword(s):  
T Lymphocytes ◽  
Target Cells ◽  
Cell Mediated Immunity ◽  
Skin Grafts ◽  
Immune Lymphocytes ◽  
Direct Cytotoxicity ◽  
Cross Absorption ◽  
Private Specificity ◽  
Two Populations

Receptors of effector T lymphocytes of congeneic strains of mice do not recognize public H-2 specificities and react to private H-2 specificities only. This has been established with the use of three tests: direct cytotoxicity assay of immune lymphocytes upon target cells, specific absorption of the lymphocytes on the target cells, and rejection of skin grafts at an accelerated fashion. Immunization with two private H-2 specificities in the system C57BL/10ScSn leads to B10.D2 induces formation of two corresponding populations of effector lymphocytes in unequal proportion: a greater part of them is directed against the private specificity H-2.33 (Kb), while the smaller part is towards H-2.2 (Db) private specificity. These two populations of effector lymphocytes do not overlap, as demonstrated by experiments on their cross-absorption on B10.D2 (R107), B10.D2 (R101), B10.A(2R), and B10.A(5R) target cells, as well as on mixtures of R107 and R101 targets. Following removal of lymphocytes reacting with one of the private H-2 specificities, lymphocytes specific to the other specificity are fully maintained. A mixture of target cells, each bearing one of the two immunizing private specificities, absorbs 100% of the immune lymphocytes and is totally destroyed by them. It is suggested that H-2 antigens are natural complexes of hapten-carrier type, in which the role of hapten is played by public H-2 specifities and that of the carrier determinant by either private H-2 specificities or structures closely linked to them. Various models of steric arrangement of MHC determinants recognized by receptors of effector T lymphocytes are discussed.

scholarly journals Estrogen binding by leukocytes during phagocytosis,.

1977 ◽  
Vol 145 (4) ◽  
pp. 983-998 ◽  
Author(s):  
S J Klebanoff
Keyword(s):  
Chronic Granulomatous Disease ◽  
Reaction Mechanisms ◽  
Dehydrogenase Deficiency ◽  
Cell Types ◽  
Neutrophil Function ◽  
Granulomatous Disease ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Estrogen Binding ◽  
Two Populations

Estradiol binds covalently to normal leukocytes during phagocytosis. The binding involves three cell types, neutrophils, eosinophils, and monocytes and at least two reaction mechanisms, one involving the peroxidase of neutrophils and monocytes (myeloperoxidase [MPO]) and possibly the eosinophil peroxidase, and the second involving catalase. Binding is markedly reduced when leukocytes from patients with chronic granulomatous disease (CGD), severe leukocytic glucose 6-phosphate dehydrogenase deficiency, and familial lipochrome histiocytosis are employed and two populations of neutrophils, one which binds estradiol and one which does not, can be demonstrated in the blood of a CGD carrier. Leukocytes from patients with hereditary MPO deficiency also bind estradiol poorly although the defect is not as severe as in CGD. These findings are discussed in relation to the inactivation of estrogens during infection and the possible role of estrogens in neutrophil function.

Role of insulin and branched-chain amino acids in regulating protein metabolism during fasting

1990 ◽  
Vol 258 (6) ◽  
pp. E907-E917 ◽  
Author(s):  
M. Frexes-Steed ◽  
M. L. Warner ◽  
N. Bulus ◽  
P. Flakoll ◽  
N. N. Abumrad
Keyword(s):  
Amino Acids ◽  
Protein Metabolism ◽  
Insulin Dose ◽  
Group Iii ◽  
Group I ◽  
Tissue Sensitivity ◽  
Branched Chain ◽  
Independent Effects ◽  
Dose Dependent

This study examines the independent effects of insulin and amino acids on protein metabolism after a 12-h and 4-day fast in healthy volunteers. Leucine (Leu) kinetics were examined during sequential insulin infusions of 0 (group I) or 0.0125 (groups II and III), 1.2, and 10 mU.kg-1.min-1. Plasma Leu was maintained at 12-h fasted levels in groups I and II and at 84-h fasted levels in group III. Four-day fast (vs. 1 day, P less than 0.01) was associated with a 79% drop in plasma insulin and elevations in plasma Leu (122%), Leu rates of appearance (Ra) (21%), and Leu oxidation (56%), and no change in nonoxidative rates of disappearance (Rd). Insulin resulted in a dose-dependent suppression of endogenous Leu Ra with group III = I greater than II. Leu oxidation rose 1.7-fold in group III at the highest insulin dose but remained stable in the two other groups. In conclusion, 4-day fasting is associated with enhanced proteolysis and Leu oxidation with no change in nonoxidative Rd (protein synthesis). Elevated branched-chain (and other) amino acids were required to restore tissue sensitivity and specificity to the effects of insulin on protein metabolism after 4 days of fasting.

The role of waterlogging and sand accretion in modulating the morphology of the dune slack plant Scirpus americanus

1990 ◽  
Vol 68 (8) ◽  
pp. 1780-1787 ◽  
Author(s):  
Denise M. Seliskar
Keyword(s):  
Sand Dune ◽  
Plant Morphology ◽  
Common Garden ◽  
Stem Growth ◽  
Reciprocal Transplant ◽  
Dune Slack ◽  
Coastal Sand Dune ◽  
Scirpus Americanus ◽  
Common Garden Experiments

Scirpus americanus Pers., a major dune slack plant in coastal sand dune ecosystems, differs in height along transects ranging between the lowest and highest elevational areas of slacks located along the coast of Delaware, U.S.A. Using reciprocal transplant and common garden experiments, results suggest that environmental factors rather than hereditary traits are more important in accounting for the differences in plant morphology expressed in the field. Dune slack plants are exposed to stresses of waterlogging and sand accretion in their natural environment. In controlled greenhouse experiments waterlogging was shown to inhibit stem growth and cause an increase in aerenchymatous tissue, whereas periodic sand deposition caused an increase in the plant height of Scirpus.

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