Selection of glyphosate resistance in Amaranthus tuberculatus (Mq ex DC) J.D. Sauer and potential for transfer of glyphosate resistance in Conyza

Iowa farmers rely on glyphosate (N-(phosphonomethyl) glycine) resistant crops for weed management in row crops. Inconsistent glyphosate control was reported in common waterhemp (Amaranthus tuberculatus (Mq. ex DC) and horseweed (Conyza canadensis (L.) Cronq.) populations. Therefore, an investigation was undertaken to ascertain the potential for selection of glyphosate resistance in common waterhemp and assess the possibility for transfer of glyphosate resistance in two Conyza species.;Rate responses verified that 0.62 kg acid equivalents (ae) of glyphosate ha-1 were required to reduce biomass by 50% ( GR50) in common waterhemp from Everly, Iowa, compared to 0.24 kg ae ha-1 of a pristine population from Paint Creek, Ohio. Recurrent selection was performed to isolate resistant and susceptible plants within the Everly population. Rate responses suggested that the frequency of resistant individuals increased in the first (S1) and second (S2) recurrent generations and that selection reduced the overall population variability to glyphosate. Interestingly, both the S1 and S2 populations selected for glyphosate resistance demonstrated sex ratios skewed towards maleness. Since variability for glyphosate resistance remained in the S2, a three-level selection strategy was used to isolate asexually propagated plants with a homogenous response to glyphosate. This research suggested that resistance can evolve in common waterhemp with a variable response to glyphosate.;Hybridization between the glyphosate resistant horseweed and dwarf fleabane (Conyza ramosissima Cronq.) ranged from 0% to 9% in assisted crosses and \u3e95% in artificial crosses. The interspecific hybrid ( FH1 ) was phenotypically intermediate to both parents, but shared more homology to the dwarf fleabane parent. Stability, heterosis, and absence of reproductive barriers confirmed that the FH1 was fertile. Inheritance of glyphosate resistance in the FH1 followed the hybrid resistance model and the nuclear encoded, incompletely-dominant single gene (R-allele) model in the hybrid progeny ( FH2 ). We argue that adequate fitness and niche differentiation are prerequisites for successful hybrid adaptation in the environment and that hybridization in Conyza may complicate the containment of glyphosate resistance in current agroecosystems

A BAYESIAN RANDOM COEFFICIENT NONLINEAR REGRESSION MODEL FOR A SPLIT-PLOT EXPERIMENT

In random coefficients regression, we are often interested in the mean of a certain para-meter particular to the experimental unit (EU). When the mean depends on some treatment regimen, we are then interested in comparing the means among the different treatments. When the EUs are repeatedly measured on a variable containing information about the EU parameter, a standard procedure is to estimate each EU parameter and treat the estimates as the response variables. This is especially true when the regression model for an EU is non-linear. Often, for designed experiments with a factorial treatment structure, the estimated EU parameters are then modeled with an appropriate linear (mixed) model. Here, we consider a split-plot experiment conducted to detect differences in the half-life of a compound between different treatment regimens of the compound, namely compound preparation and temperature (whole-plot factors) and initial compound amount (split-plot factor). Initially, we provide a standard (classical) analysis plan, and then present a Bayes random coefficients regression model to address the researcher’s questions of interest. We finally compare the results from the standard and Bayes analyses

Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely

Evaluación de tres sistemas de labranza sobre el comportamiento de plagas y respuestas agronomicas del maíz en monocultivo asociado con el frijol de cobertura Stizolobium deeringianum (L.) Bort.

125 p.En 1992 y 1993 se compararon sistemas labranza convencional (LCO) , labranza tracción animal (LTA) y labranza cero (LCE) , además del frijol terciopelo (Stizolobinn deerinqianum) , con los objetivos de evaluar e l comportamiento de plagas y las respuestas agronómicas del maíz, rentabilidad de los tratamientos y la distribución de microorganismos y propiedades químicas del suelo. El sistema de labranza y la cobertura no han cambiado la Densidad poblacional de bacterias y hongos del suelo. La LCE presentó menor pH del suelo pero el contenido de potasio fue mayor. Sin embargo, las demás propiedades quimicas fueron similares.la mortalidad por Listronotus spp. Fue mayor en LTA y LCE, pero los factores de mortalidad: mala calidad de semilla y semilla no encontrada representaron más del 20% de la mortalidad tota. Las infestaciones de plagas del suelo fueron similares, pero hubo más larvas de lepidópteros en LCO y LTA

Restoration of Hypoglycemia Awareness Alters Brain Activity in Type 1 Diabetes

OBJECTIVE Impaired awareness of hypoglycemia (IAH) in type 1 diabetes (T1D) is a major risk factor for severe hypoglycemia (SH) and is associated with atypical responses to hypoglycemia in brain regions involved in arousal, decision making, and memory. Whether restoration of hypoglycemia awareness alters these responses is unknown. We sought to investigate the impact of awareness restoration on brain responses to hypoglycemia. RESEARCH DESIGN AND METHODS Twelve adults with T1D and IAH underwent pseudocontinuous arterial spin labeling functional MRI during a hypoglycemic clamp (5–2.6 mmol/L) before and after a hypoglycemia avoidance program of structured education (Dose Adjustment for Normal Eating), specialist support, and sensor-augmented pump therapy (Medtronic MiniMed 640G). Hypoglycemic cerebral blood flow (CBF) responses were compared pre- and postintervention using predefined region-of-interest analysis of the thalamus, anterior cingulate cortex (ACC), orbitofrontal cortex (OFC), and hippocampus. RESULTS Postintervention, Gold and Clarke scores fell (6.0 ± 1.0 to 4.0 ± 1.6, P = 0.0002, and 5.7 ± 1.7 to 3.4 ± 1.8, P = 0.0008, respectively), SH rates reduced (1.5 ± 2 to 0.3 ± 0.5 episodes per year, P = 0.03), hypoglycemic symptom scores increased (18.8 ± 6.3 to 27.3 ± 12.7, P = 0.02), and epinephrine responses did not change (P = 0.2). Postintervention, hypoglycemia induced greater increases in ACC CBF (P = 0.01, peak voxel coordinates [6, 40, −2]), while thalamic and OFC activity did not change. CONCLUSIONS Increased blood flow is seen within brain pathways involved in internal self-awareness and decision making (ACC) after restoration of hypoglycemia awareness, suggesting partial recovery of brain responses lost in IAH. Resistance of frontothalamic networks, involved in arousal and emotion processing, may explain why not all individuals with IAH achieve awareness restoration with education and technology alone.</p

Modeling glyphosate resistance management strategies for Palmer Amaranth (Amaranthus palmeri) in cotton

A simulation model is used to explore management options to mitigate risks of glyphosate resistance evolution in Palmer amaranth in glyphosate-resistant cotton in the southern United States. Our first analysis compares risks of glyphosate resistance evolution for seven weed-management strategies in continuous glyphosate-resistant cotton monoculture. In the "worst-case scenario'' with five applications of glyphosate each year and no other herbicides applied, evolution of glyphosate resistance was predicted in 74% of simulated populations. In other strategies, glyphosate was applied with various combinations of preplant, PRE, and POST residual herbicides. The most effective strategy included four glyphosate applications with a preplant fomesafen application, and POST tank mixtures of glyphosate plus S-metolachlor followed by glyphosate plus flumioxazin. This strategy reduced the resistance risk to 12% of populations. A second series of simulations compared strategies where glyphosate-resistant cotton was grown in one-to-one rotations with corn or cotton with other herbicide resistance traits. In general, crop rotation reduced risks of resistance by approximately 50% and delayed the evolution of resistance by 2 to 3 yr. These analyses demonstrate that risks of glyphosate resistance evolution in Palmer amaranth can be reduced by reducing glyphosate use within and among years, controlling populations with diverse herbicide modes of action, and ensuring that population size is kept low. However, no strategy completely eliminated the risk of glyphosate resistance

Altered functional connectivity during hypoglycaemia in type 1 diabetes

Behavioural responses to hypoglycaemia require coordinated recruitment of broadly distributed networks of interacting brain regions. We investigated hypoglycaemia-related changes in brain connectivity in people without diabetes (ND) and with type 1 diabetes with normal (NAH) or impaired (IAH) hypoglycaemia awareness. Two-step hyperinsulinaemic hypoglycaemic clamps were performed in 14 ND, 15 NAH and 22 IAH participants. BOLD timeseries were acquired at euglycaemia (5.0 mmol/L) and hypoglycaemia (2.6 mmol/L), with symptom and counter-regulatory hormone measurements. We investigated hypoglycaemia-related connectivity changes using established seed regions for the default mode (DMN), salience (SN) and central executive (CEN) networks and regions whose activity is modulated by hypoglycaemia: the thalamus and right inferior frontal gyrus (RIFG). Hypoglycaemia-induced changes in the DMN, SN and CEN were evident in NAH (all p < 0.05), with no changes in ND or IAH. However, in IAH there was a reduction in connectivity between regions within the RIFG (p = 0.001), not evident in the ND or NAH groups. We conclude that hypoglycaemia induces coordinated recruitment of the DMN and SN in diabetes with preserved hypoglycaemia awareness which is absent in IAH and ND. Changes in connectivity in the RIFG, a region associated with attentional modulation, may be key in impaired hypoglycaemia awareness

Impaired Awareness of Hypoglycemia Disrupts Blood Flow to Brain Regions Involved in Arousal and Decision Making in Type 1 Diabetes

© 2019 by the American Diabetes Association. OBJECTIVE: Impaired awareness of hypoglycemia (IAH) affects one-quarter of adults with type 1 diabetes and significantly increases the risk of severe hypoglycemia. Differences in regional brain responses to hypoglycemia may contribute to the susceptibility of this group to problematic hypoglycemia. This study investigated brain responses to hypoglycemia in hypoglycemia aware (HA) and IAH adults with type 1 diabetes, using three-dimensional pseudo-continuous arterial spin labeling (3D pCASL) functional MRI to measure changes in regional cerebral blood flow (CBF). RESEARCH DESIGN AND METHODS: Fifteen HA and 19 IAH individuals underwent 3D pCASL functional MRI during a two-step hyperinsulinemic glucose clamp. Symptom, hormone, global, and regional CBF responses to hypoglycemia (47 mg/dL [2.6 mmol/L]) were measured. RESULTS: In response to hypoglycemia, total symptom score did not change in those with IAH (P = 0.25) but rose in HA participants (P < 0.001). Epinephrine, cortisol, and growth hormone responses to hypoglycemia were lower in the IAH group (P < 0.05). Hypoglycemia induced a rise in global CBF (HA P = 0.01, IAH P = 0.04) but was not different between groups (P = 0.99). IAH participants showed reduced regional CBF responses within the thalamus (P = 0.002), right lateral orbitofrontal cortex (OFC) (P = 0.002), and right dorsolateral prefrontal cortex (P = 0.036) and a lesser decrease of CBF in the left hippocampus (P = 0.023) compared with the HA group. Thalamic and right lateral OFC differences survived Bonferroni correction. CONCLUSIONS: Responses to hypoglycemia of brain regions involved in arousal, decision making, and reward are altered in IAH. Changes in these pathways may disrupt IAH individuals' ability to recognize hypoglycemia, impairing their capacity to manage hypoglycemia effectively and benefit fully from conventional therapeutic pathways to restore awareness