Raphanus sativus L. Chinese Radish Jumbo Scarlet has characteristics that make it an excellent plant model for vernalization studies. This study further characterizes flower induction of R. sativus ...Chinese Radish Jumbo Scarlet. Seed were imbibed in distilled water containing 0, 10−5M or 10−3M GA3 for 24 h and were then exposed to 6 ± 0.5°C (vernalized) for 0, 2, 4, 6, or 8 days. Seedlings were then grown under a short‐ (8 h) or long‐day photoperiod (8 h with or without a 4‐h night interruption; 2200–0200 h). Of unvernalized plants grown under long‐ and short‐day conditions, 45 and 3% flowered, respectively. Saturation of the vernalization response occurred after a 4‐ or 8‐day vernalization treatment when plants were placed under long‐ or short‐days, respectively. Basal leaf number and days to anthesis decreased when seeds were cooled for 2 or 4 days and were imbibed with 10−3M GA3 compared to distilled water only. These data indicate that R. sativus Chinese Jumbo Scarlet has principally an obligate vernalization requirement when grown under short‐days. GA3 application only facilitated flowering when the length of the vernalization treatment was marginal. Taken together, these data support the use of this plant as a model plant for identifying vernalization responses under short‐day conditions.
Abstract only
Forty percent of the world population is hypertensive and estimates predict an increase to over 60% in the next 10 years. Exercise has been shown to be effective at reducing ...hypertension more so than a majority of drug interventions. However, exercise in hypertensive patients carries an elevated risk for myocardial ischemia, infarction, cardiac arrest, stroke, and possibly death during physical activity due to accompanying exaggerations in blood pressure (BP). Understanding the mechanisms through which BP management becomes dysregulated during physical activity is critical to identifying strategies for hypertensive patients to safely benefit from exercise. Our laboratory has previously established that the muscle mechanoreflex, a cardiovascular regulating reflex engaged during contraction of skeletal muscle, contributes significantly to the potentiated BP response to exercise in hypertension. However, the mechanisms underlying the pathogenesis of this mechanoreflex dysfunction remain undetermined. Mechanoreflex sensory information is processed within the nucleus tractus solitarii (NTS) of the brainstem. The inhibitory neurotransmitter, gamma‐aminobutyric acid (GABA), is known to contribute to cardiovascular regulation within the NTS. Microinjection of GABA receptor agonists within the NTS has been shown to increase resting BP. It is logical, therefore, to hypothesize that the exaggerated BP response to mechanoreflex activation in hypertension is mediated by abnormal increases in GABA production within the NTS. To test this hypotheses, the role of central GABA on mechanoreflex function was investigated in 21 normotensive Wystar‐Kyoto (WKY) and 21 spontaneously hypertensive (SHR) age matched (12–16 week) male rats. The BP response to activation of the mechanoreflex, via passive stretch of the soleus and gastrocnemius muscles, was assessed before and after the microdialysis of 1) the GABA synthesis inhibitor 3‐mercaptopropionic acid (3‐MP; 850 μM, 10 μg total); 2) the GABA
A
receptor antagonist bicuculline methiodide (BIC; 88 nM, 5 ng total); or 3) the GABA
B
receptor antagonist 2‐hydroxy saclofen (SAC; 885 μM, 30 ng total) into the NTS for 45 minutes at 2.5 μL/min. The mechanoreflex‐induced change in BP from baseline before microdialysis (23 ± 2 mmHg/kg) was significantly attenuated after the administration of 3‐MP (12 ± 2 mmHg/kg) in WKY rats (
p
< 0.05). In contrast, 3‐MP did not affect the pressor response to stretch in SHR. Likewise, the dialysis of BIC and SAC did not significantly affect the BP response to stretch in either WKY or SHR. The results of the studies demonstrate that endogenous GABA synthesis within the NTS modulates the BP response to mechanoreflex activation in normotensive rats. However, it does not appear that abnormal elevations in NTS GABA account for mechanoreflex‐induced exaggerations in BP in hypertensive rats. The data do support the concept that the ability of GABA to modulate mechanoreflex‐mediated changes in BP is compromised in hypertensive animals.
Support or Funding Information
Supported by NIH HL‐088422.
Palomar Gattini-IR Kishalay De; Matthew J. Hankins; Mansi M. Kasliwal ...
Publications of the Astronomical Society of the Pacific,
02/2020, Letnik:
132, Številka:
1008
Journal Article
Recenzirano
Palomar Gattini-IR is a new wide-field, near-infrared (NIR) robotic time domain survey operating at Palomar Observatory. Using a 30 cm telescope mounted with a H2RG detector, Gattini-IR achieves a ...field of view (FOV) of 25 sq. deg. with a pixel scale of 8″.7 in J-band. Here, we describe the system design, survey operations, data processing system and on-sky performance of Palomar Gattini-IR. As a part of the nominal survey, Gattini-IR scans ≈7500 square degrees of the sky every night to a median 5σ depth of 15.7 AB mag outside the Galactic plane. The survey covers ≈15,000 square degrees of the sky visible from Palomar with a median cadence of 2 days. A real-time data processing system produces stacked science images from dithered raw images taken on sky, together with point-spread function (PSF)-fit source catalogs and transient candidates identified from subtractions within a median delay of ≈4 hr from the time of observation. The calibrated data products achieve an astrometric accuracy (rms) of ≈0″.7 with respect to Gaia DR2 for sources with signal-to-noise ratio > 10, and better than ≈0″.35 for sources brighter than ≈12 Vega mag. The photometric accuracy (rms) achieved in the PSF-fit source catalogs is better than ≈3% for sources brighter than ≈12 Vega mag and fainter than the saturation magnitude of ≈8.5 Vega mag, as calibrated against the Two Micron All Sky Survey catalog. The detection efficiency of transient candidates injected into the images is better than 90% for sources brighter than the 5σ limiting magnitude. The photometric recovery precision of injected sources is 3% for sources brighter than 13 mag, and the astrometric recovery rms is ≈0″.9. Reference images generated by stacking several field visits achieve depths of ≳16.5 AB mag over 60% of the sky, while it is limited by confusion in the Galactic plane. With a FOV ≈40× larger than any other existing NIR imaging instrument, Gattini-IR is probing the reddest and dustiest transients in the local universe such as dust obscured supernovae in nearby galaxies, novae behind large columns of extinction within the galaxy, reddened microlensing events in the Galactic plane and variability from cool and dust obscured stars. We present results from transients and variables identified since the start of the commissioning period.
We present a systematic study of the most luminous (MIR Vega magnitudes brighter than −14) infrared (IR) transients discovered by the SPitzer InfraRed Intensive Transients Survey (SPIRITS) between ...2014 and 2018 in nearby galaxies (D < 35 Mpc). The sample consists of nine events that span peak IR luminosities of M4.5,peak between −14 and −18.2, show IR colors between 0.2 < (3.6-4.5) < 3.0, and fade on timescales between 55 days < tfade < 480 days. The two reddest events (AV > 12) show multiple, luminous IR outbursts over several years and have directly detected, massive progenitors in archival imaging. With analyses of extensive, multiwavelength follow-up, we suggest the following possible classifications: five obscured core-collapse supernovae (CCSNe), two erupting massive stars, one luminous red nova, and one intermediate-luminosity red transient. We define a control sample of all optically discovered transients recovered in SPIRITS galaxies and satisfying the same selection criteria. The control sample consists of eight CCSNe and one Type Iax SN. We find that 7 of the 13 CCSNe in the SPIRITS sample have lower bounds on their extinction of 2 < AV < 8. We estimate a nominal fraction of CCSNe in nearby galaxies that are missed by optical surveys as high as (90% confidence). This study suggests that a significant fraction of CCSNe may be heavily obscured by dust and therefore undercounted in the census of nearby CCSNe from optical searches.
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