Using Leaf Fluorescence for Evaluating Atrazine Tolerance of Three Perennial Warm-season Grasses

Atrazine [6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4-diamine] blocks photosymthetic electron transport in susceptible plants. The energy from the interrupted electron transport is fluoresced from the leaves of atrazine-treated plants. The purpose of this study was to evaluate leaf fluorescence as a nondestructive bioassay of the relative atrazine tolerance of 3 perennnial, warm-season grasses. Leaf section of switchgrass [Panicum virgatum L.] (high tolerance), indiangrass [Sorghastrum nutans (L.) Nash] (intermediate tolerance), and sideoats grama [Boutelouacurtipendula (Michx.) Torr.] (lower tolerance) were placed in distilled water for 20 minute and then in atrazine solutions. Fluorescence readings were taken prior to and after the atrazine treatment with a portable fluorometer. The difference between the 2 readings provided a reliable measure with low variability of the relative atrazine tolerance of the grasses studied and was effective on greenhouse- and field-grown plants. Optiumum atrazine concentrations and incubation periods were 10-3 M (atrazine in distilled H2O) and 30 min, respectively

ATRAZINE TOLERANCE OF WARM-SEASON GRASS SEEDLINGS (FLUORESCENCE, DELAYED APPLICATION)

Weed control is a necessary component of a grass establishment program. Although atrazine {2-chloro-4-(ethyl amino)-6-(isopropylamino)-s-triazine} can be used with switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardi Vitmann) most warm-season grass seedlings are susceptible to atrazine. A greenhouse screening procedure was used to compare the atrazine tolerance of switchgrass seedlings with indiangrass (Sorghastrum nutans (L.) Nash), sideoats grama (Bouteloua curtipendula (Michx.) Torr.), blue grama (Bouteloua gracilis (H.B.K.) Lag ex Steud), \u27Caucasian\u27 bluestem (Bothriochloa caucasica (Trin.) C. E. Hubbard), \u27Plains\u27 bluestem (Bothriochloa ischaemum var ischaemum (L.) Keng, little bluestem (Schizachyrium scoparium (Michx.) Nash), and prairie sandreed (Calamovilfa longifolia (Hook) Schribn) seedlings. Indiangrass and sideoats grama seedlings from one cycle of field selection for atrazine tolerance were also compared. Switchgrass, Plains and Caucasian bluestem, and prairie sandreed had the most tolerance to atrazine. Little bluestem and indiangrass (unselected and cycle 1) were intermediate, and sideoats grama (unselected and cycle 1) and blue grama had the least tolerance to atrazine. Indiangrass and sideoats grama were used to evaluate leaf fluorescence as a possible screening technique. Concentrations of 10(\u27-2) or 10(\u27-3) M atrazine for sideoats grama or indiangrass respectively and an incubation period of 30 minutes distinguished atrazine treated leaf sections from control. No difference was detected between established and young indiangrass and between greenhouse and field grown plants. Using a 30 minute incubation and 10(\u27-3) M atrazine 33 lines of young indiangrass plants were screened. Thirteen plants had a change in relative fluorescence of less than 1 which was used as the differentiation criterion. A floating leaf disk test did not differentiate among plants of differing atrazine sensitivities. Delaying the application of atrazine 7, 14 or 21 days after planting permitted indiangrass and sideoats grama to be established in the field. In both field and greenhouse studies atrazine reduced actual emergence of the seed for sideoats grama, switchgrass, and indiangrass

Evaluation of immunophenotypic and molecular biomarkers for Sézary syndrome using standard operating procedures: multicenter study of 59 cases

Differentiation between Sezary syndrome and erythrodermic inflammatory dermatoses can be challenging, and a number of studies have attempted to identify characteristic immunophenotypic changes and molecular biomarkers in Sezary cells that could be useful as additional diagnostic criteria. In this European multicenter study, the sensitivity and specificity of these immunophenotypic and recently proposed but unconfirmed molecular biomarkers in Sezary syndrome were investigated. Peripheral blood CD4(+) T cells from 59 patients with Sezary syndrome and 19 patients with erythrodermic inflammatory dermatoses were analyzed for cell surface proteins by flow cytometry and for copy number alterations and differential gene expression using custom-made quantitative PCR plates. Experiments were performed in duplicate in two independent centers using standard operating procedures with almost identical results. Sezary cells showed MYC gain (40%) and MNT loss (66%); up-regulation of DNM3 (75%), TWIST1 (69%), EPHA4 (66%), and PLS3 (66%); and down-regulation of STAT4 (91%). Loss of CD26 (>= 80% CD4(+) T cells) and/or CD7 (>= 40% CD4(+) T cells) and combination of altered expression of STAT4, TWIST1, and DNM3 or PLS3 could distinguish, respectively, 83% and 98% of patients with Sezary syndrome from patients with erythrodermic inflammatory dermatoses with 100% specificity. These additional diagnostic panels will be useful adjuncts in the differential diagnosis of Sezary syndrome versus erythrodermic inflammatory dermatoses.Peer reviewe

Fission Yeast MAP Kinase Sty1 Is Recruited to Stress-induced Genes

The stress-induced expression of many fission yeast genes is dependent upon the Sty1 mitogen-activated protein kinase (MAPK) and Atf1 transcription factor. Atf1 is phosphorylated by Sty1 yet this phosphorylation is not required for stress-induced gene expression, suggesting another mechanism exists whereby Sty1 activates transcription. Here we show that Sty1 associates with Atf1-dependent genes and is recruited to both their promoters and coding regions. This occurs in response to various stress conditions coincident with the kinetics of the activation of Sty1. Association with promoters is not a consequence of increased nuclear accumulation of Sty1 nor does it require the phosphorylation of Atf1. However, recruitment is completely abolished in a mutant lacking Sty1 kinase activity. Both Atf1 and its binding partner Pcr1 are required for association of Sty1 with Atf1-dependent promoters, suggesting that this heterodimer must be intact for optimal recruitment of the MAPK. However, many Atf1-dependent genes are still expressed in a pcr1Δ mutant but with significantly delayed kinetics, thus providing an explanation for the relatively mild stress sensitivity displayed by pcr1Δ. Consistent with this delay, Sty1 and Atf1 cannot be detected at these promoters in this condition, suggesting that their association with chromatin is weak or transient in the absence of Pcr1