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Takahashi H, Yamamoto T, Tsuboi A. Molecular mechanisms underlying activity-dependent ischemic tolerance in the brain. Neurosci Res 2023; 186:3-9. [PMID: 36244569 DOI: 10.1016/j.neures.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/05/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022]
Abstract
Ischemic stroke is one of the leading causes of death and disability worldwide. The inhibition of cerebral blood flow triggers intertwined pathological events, resulting in cell death and loss of brain function. Interestingly, animals pre-exposed to short-term ischemia can tolerate subsequent severe ischemia. This phenomenon is called ischemic tolerance and is also triggered by other noxious stimuli. However, whether short-term exposure to non-noxious stimuli can induce ischemic tolerance remains unknown. Recently, we found that pre-exposing mice to an enriched environment for 40 min is sufficient to facilitate cell survival after a subsequent stroke. The neuroprotective process depends on the neuronal activity soon before stroke, of which the activity-dependent transcription factor Npas4 is essential. Excessive Ca2+ influx triggers Npas4 expression in ischemic neurons, leading to the activation of neuroprotective programs. Pre-induction of Npas4 in the normal brain effectively supports cell survival after stroke. Furthermore, our study revealed that Npas4 regulates L-type voltage-gated Ca2+ channels through expression of the small Ras-like GTPase Gem in ischemic neurons. Ischemic tolerance is a good model for understanding how to promote neuroprotective mechanisms in the normal and injured brain. Here, we highlight activity-dependent ischemic tolerance and discuss its role in promoting neuroprotection against stroke.
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Affiliation(s)
- Hiroo Takahashi
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan.
| | - Tohru Yamamoto
- Department of Molecular Neurobiology, Faculty of Medicine, Kagawa University, Kagawa 761-0793, Japan
| | - Akio Tsuboi
- Dynamic Brain Network Laboratory, Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
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Matsuo M, Seo K, Taruno A, Mizoro Y, Yamaguchi Y, Doi M, Nakao R, Kori H, Abe T, Ohmori H, Tominaga K, Okamura H. A light-induced small G-protein gem limits the circadian clock phase-shift magnitude by inhibiting voltage-dependent calcium channels. Cell Rep 2022; 39:110844. [PMID: 35613591 DOI: 10.1016/j.celrep.2022.110844] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/09/2022] [Accepted: 04/28/2022] [Indexed: 11/23/2022] Open
Abstract
Calcium signaling is pivotal to the circadian clockwork in the suprachiasmatic nucleus (SCN), particularly in rhythm entrainment to environmental light-dark cycles. Here, we show that a small G-protein Gem, an endogenous inhibitor of high-voltage-activated voltage-dependent calcium channels (VDCCs), is rapidly induced by light in SCN neurons via the calcium (Ca2+)-mediated CREB/CRE transcriptional pathway. Gem attenuates light-induced calcium signaling through its interaction with VDCCs. The phase-shift magnitude of locomotor activity rhythms by light, at night, increases in Gem-deficient (Gem-/-) mice. Similarly, in SCN slices from Gem-/- mice, depolarizing stimuli induce larger phase shifts of clock gene transcription rhythms that are normalized by the application of an L-type VDCC blocker, nifedipine. Voltage-clamp recordings from SCN neurons reveal that Ca2+ currents through L-type channels increase in Gem-/- mice. Our findings suggest that transcriptionally activated Gem feeds back to suppress excessive light-evoked L-type VDCC activation, adjusting the light-induced phase-shift magnitude to an appropriate level in mammals.
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Contreras GF, Saavedra J, Navarro-Quezada N, Mellado G, Gonzalez C, Neely A. Direct inhibition of Ca V2.3 by Gem is dynamin dependent and does not require a direct alfa/beta interaction. Biochem Biophys Res Commun 2022; 586:107-113. [PMID: 34837834 DOI: 10.1016/j.bbrc.2021.11.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/21/2021] [Accepted: 11/14/2021] [Indexed: 11/17/2022]
Abstract
The Rad, Rem, Rem2, and Gem/Kir (RGK) sub-family of small GTP-binding proteins are crucial in regulating high voltage-activated (HVA) calcium channels. RGK proteins inhibit calcium current by either promoting endocytosis or reducing channel activity. They all can associate directly with Ca2+ channel β subunit (CaVβ), and the binding between CaVα1/CaVβ appears essential for the endocytic promotion of CaV1.X, CaV2.1, and CaV2.2 channels. In this study, we investigated the inhibition of CaV2.3 channels by RGK proteins in the absence of CaVβ. To this end, Xenopus laevis oocytes expressing CaV2.3 channels devoid of auxiliary subunit were injected with purified Gem and Rem and found that only Gem had an effect. Ca currents and charge movements were reduced by injection of Gem, pointing to a reduction in the number of channels in the plasma membrane. Since this reduction was ablated by co-expression of the dominant-negative mutant of dynamin K44A, enhanced endocytosis appears to mediate this reduction in the number of channels. Thus, Gem inhibition of CaV2.3 channels would be the only example of a CaVβ independent promotion of dynamin-dependent endocytosis.
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Affiliation(s)
- Gustavo F Contreras
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaiso, Chile; Centro Interdisciplinario de Neurociencias Valparaíso, Chile
| | - Jonathan Saavedra
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaiso, Chile; Centro Interdisciplinario de Neurociencias Valparaíso, Chile; Doctorado en Ciencias Mención Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Nieves Navarro-Quezada
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaiso, Chile; Centro Interdisciplinario de Neurociencias Valparaíso, Chile
| | - Guido Mellado
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaiso, Chile; Centro Interdisciplinario de Neurociencias Valparaíso, Chile; Doctorado en Ciencias Mención Biofisica y Biología Computacional, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carlos Gonzalez
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaiso, Chile; Centro Interdisciplinario de Neurociencias Valparaíso, Chile; Cardiovascular Research, Lankenau Institute for Medical Research, Wynnewood, Pennsylvania, USA
| | - Alan Neely
- Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaiso, Chile
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Chen M, Jiang Y, Cai X, Lu X, Chao H. Combination of Gemcitabine and Thymosin alpha 1 exhibit a better anti-tumor effect on nasal natural killer/T-cell lymphoma. Int Immunopharmacol 2021; 98:107829. [PMID: 34119916 DOI: 10.1016/j.intimp.2021.107829] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/13/2021] [Accepted: 05/25/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Nasal natural killer/T-cell lymphoma (NNKTL) is an aggressive and poor prognostic malignant tumor along with high-level infection of Epstein-Barr virus (EBV). Gemcitabine (Gem) and Thymosin alpha 1 (Tα1) exert an anti-tumor effect in various cancers. However, the effect of the combination of Gem and Tα1 in NNKTL remains unknown. METHODS SNK6 cells were treated with Gem, Tα1 and Gem plus Tα1 for 48 h. The expression levels of EBV and inflammatory factors were measured by qRT-PCR assay. The effect of Gem and Tα1 on cell viability, proliferation, apoptosis, autophagy was detected by CCK-8, colony formation, flow cytometry, autophagic flux measurement, respectively. Western blot was used to evaluate the expression of proteins related to epithelial-mesenchymal transition (EMT), apoptosis and autophagy. In vivo xenograft models were used to further verify the roles of Gem and Tα1. Tumors were removed for weight measurement, H&E and IHC staining. RESULTS We identified that the half maximal inhibitory concentration (IC50) of Gem and Tα1 was 116.5 μmol/ml and 1.334 μmol/ml. Alone or combined administration of Gem and Tα1 dramatically attenuated the EBV viral load and promoted inflammatory factors expression in SNK6 cells, among which the combination of Gem and Tα1 treatment showed the most significant effect. Besides, combination treatment with Gem and Tα1 markedly inhibited cell growth and EMT progress, and enhanced apoptosis and autophagy. Similarly, Gem combined with Tα1 suppressed tumor growth, promoted apoptosis and autophagy in vivo. Additionally, combination treatment with Gem and Tα1 inhibited PI3K/AKT/mTOR pathway. CONCLUSION In summary, combination administration of Gem and Tα1 suppressed the progression of NNKTL in vivo and in vitro. Our study provided an effective therapeutic strategy potentially for the clinical treatment of NNKTL.
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Affiliation(s)
- Meiyu Chen
- Department of Hematology, Affiliated Changzhou Second Hospital of Nanjing Medical University, Changzhou, Jiangsu 213003, China.
| | - Yu Jiang
- Department of Hematology, Affiliated Changzhou Second Hospital of Nanjing Medical University, Changzhou, Jiangsu 213003, China.
| | - Xiaohui Cai
- Department of Hematology, Affiliated Changzhou Second Hospital of Nanjing Medical University, Changzhou, Jiangsu 213003, China
| | - Xuzhang Lu
- Department of Hematology, Affiliated Changzhou Second Hospital of Nanjing Medical University, Changzhou, Jiangsu 213003, China
| | - Hongying Chao
- Department of Hematology, Affiliated Changzhou Second Hospital of Nanjing Medical University, Changzhou, Jiangsu 213003, China.
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Wang Y, Wang G, Chen H, Sun Y, Sun M, Liu X, Jian W, He Z, Sun J. A facile di-acid mono-amidation strategy to prepare cyclization-activating mono-carboxylate transporter 1-targeting gemcitabine prodrugs for enhanced oral delivery. Int J Pharm 2020; 573:118718. [PMID: 31756441 DOI: 10.1016/j.ijpharm.2019.118718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/14/2019] [Accepted: 09/19/2019] [Indexed: 10/25/2022]
Abstract
Intestinal mono-carboxylate transporter 1 (MCT1) plays an important role in the oral absorption of short-chain fatty acids that were used as oxidative metabolite. However, the prodrug strategy targeting intestinal MCT1 for oral delivery is rarely exploited. The oral bioavailability of Gemcitabine (Gem) is low mainly due to its poor intestinal permeability and rapid metabolism. Herein, a facile di-acid mono-amidation strategy was firstly developed to target MCT1 for oral chemotherapy. The N4-amino group of Gem is mono-amidated with di-acids containing different carbon chain lengths, which could recognize intestinal MCT1 and are bio-activated at physiological pH independent of the hydrolysis enzymes. The adipic acid-Gem shows higher MCT1 affinity, better gastrointestinal tract stability (3-fold), improved oral bioavailability (8.8-fold), and less gastrointestinal toxicity in comparison to Gem. Moreover the bio-activation rate of the prodrugs decreases with the increased fatty acid chain length of the linkage under physiological conditions. In summary, we present the first evidence that MCT1 could act as a new target for oral prodrug delivery, and that the linkage could modify the bio-activation rate for achieving optimal oral bioavailability. Our findings provide novel knowledge to rationally design intestinal transporter-targeting oral carrier prodrug.
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Affiliation(s)
- Yang Wang
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China; School of Pharmacy, Guang Xi University of Chinese Medicine, Wuhe Rode, Nanning 530200, China
| | - Gang Wang
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China; School of Pharmacy, Guang Xi University of Chinese Medicine, Wuhe Rode, Nanning 530200, China
| | - Hongxiang Chen
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China; Center for Drug Evaluation, Jianguo Rode, Beijing 100022, China
| | - Yixin Sun
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China
| | - Mengchi Sun
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China
| | - Xiaohong Liu
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China
| | - Wang Jian
- Key Laboratory of Structure-Based Drug Design and Discovery, Shenyang Pharmaceutical University, Ministry of Education, China
| | - Zhonggui He
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China
| | - Jin Sun
- School of Pharmacy, Shenyang Pharmaceutical University, Wenhua Road, Shenyang 110016, China; Municipal Key Laboratory of Biopharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, China.
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Singh RN, Howell MD, Ottesen EW, Singh NN. Diverse role of survival motor neuron protein. Biochim Biophys Acta Gene Regul Mech 2017; 1860:299-315. [PMID: 28095296 PMCID: PMC5325804 DOI: 10.1016/j.bbagrm.2016.12.008] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 02/07/2023]
Abstract
The multifunctional Survival Motor Neuron (SMN) protein is required for the survival of all organisms of the animal kingdom. SMN impacts various aspects of RNA metabolism through the formation and/or interaction with ribonucleoprotein (RNP) complexes. SMN regulates biogenesis of small nuclear RNPs, small nucleolar RNPs, small Cajal body-associated RNPs, signal recognition particles and telomerase. SMN also plays an important role in DNA repair, transcription, pre-mRNA splicing, histone mRNA processing, translation, selenoprotein synthesis, macromolecular trafficking, stress granule formation, cell signaling and cytoskeleton maintenance. The tissue-specific requirement of SMN is dictated by the variety and the abundance of its interacting partners. Reduced expression of SMN causes spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA displays a broad spectrum ranging from embryonic lethality to an adult onset. Aberrant expression and/or localization of SMN has also been associated with male infertility, inclusion body myositis, amyotrophic lateral sclerosis and osteoarthritis. This review provides a summary of various SMN functions with implications to a better understanding of SMA and other pathological conditions.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States.
| | - Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
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Beqollari D, Bannister RA. Defining the MO's of RGK proteins. Channels (Austin) 2016; 10:333-335. [PMID: 27249780 DOI: 10.1080/19336950.2016.1192845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Donald Beqollari
- a Department of Medicine-Cardiology Division , University of Colorado School of Medicine , Aurora , CO , USA
| | - Roger A Bannister
- a Department of Medicine-Cardiology Division , University of Colorado School of Medicine , Aurora , CO , USA
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Abstract
Rad/Rem/Rem2/Gem (RGK) proteins are Ras-like GTPases that potently inhibit all high-voltage-gated calcium (CaV1/CaV2) channels and are, thus, well-positioned to tune diverse physiological processes. Understanding how RGK proteins inhibit CaV channels is important for perspectives on their (patho)physiological roles and could advance their development and use as genetically-encoded CaV channel blockers. We previously reported that Rem can block surface CaV1.2 channels in 2 independent ways that engage distinct components of the channel complex: (1) by binding auxiliary β subunits (β-binding-dependent inhibition, or BBD); and (2) by binding the pore-forming α1C subunit N-terminus (α1C-binding-dependent inhibition, or ABD). By contrast, Gem uses only the BBD mechanism to block CaV1.2. Rem molecular determinants required for BBD CaV1.2 inhibition are the distal C-terminus and the guanine nucleotide binding G-domain which interact with the plasma membrane and CaVβ, respectively. However, Rem determinants for ABD CaV1.2 inhibition are unknown. Here, combining fluorescence resonance energy transfer, electrophysiology, systematic truncations, and Rem/Gem chimeras we found that the same Rem distal C-terminus and G-domain also mediate ABD CaV1.2 inhibition, but with different interaction partners. Rem distal C-terminus interacts with α1C N-terminus to anchor the G-domain which likely interacts with an as-yet-unidentified site. In contrast to some previous studies, neither the C-terminus of Rem nor Gem was sufficient to inhibit CaV1/CaV2 channels. The results reveal that similar molecular determinants on Rem are repurposed to initiate 2 independent mechanisms of CaV1.2 inhibition.
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Affiliation(s)
- Akil A Puckerin
- a Department of Pharmacology & Molecular Signaling , Columbia University , New York , NY , USA
| | - Donald D Chang
- b Department of Physiology & Cellular Biophysics , Columbia University , New York , NY , USA
| | - Prakash Subramanyam
- b Department of Physiology & Cellular Biophysics , Columbia University , New York , NY , USA
| | - Henry M Colecraft
- a Department of Pharmacology & Molecular Signaling , Columbia University , New York , NY , USA.,b Department of Physiology & Cellular Biophysics , Columbia University , New York , NY , USA
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Kariya S, Sampson JB, Northrop LE, Luccarelli CM, Naini AB, Re DB, Hirano M, Mitsumoto H. Nuclear localization of SMN and FUS is not altered in fibroblasts from patients with sporadic ALS. Amyotroph Lateral Scler Frontotemporal Degener 2014; 15:581-7. [PMID: 24809826 DOI: 10.3109/21678421.2014.907319] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Abstract Sporadic amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with no established biological marker. Recent observation of a reduced number of gems (survival motor neuron protein (SMN)-positive nuclear bodies) in cells from patients with familial ALS and the mouse models suggests an involvement of SMN in ALS pathology. At a molecular level, fused in sarcoma (FUS), one of the familial ALS-linked proteins, has been demonstrated to directly interact with SMN, while impaired nuclear localization of mutated FUS causes defective gem formation. Our objective was to determine whether gems and/or nuclear FUS levels in skin derived fibroblasts from sporadic ALS patients are consistently reduced and thus could constitute a novel and readily available biomarker of the disease. Fibroblasts from 20 patients and 17 age-matched healthy controls were cultured and co-immunostained for SMN and FUS. Results showed that no difference was detected between the two groups in the number of gems and in expression pattern of FUS. The number of gems negatively correlated with the age at biopsy in both ALS and control subjects. In conclusion, the expression pattern of SMN and FUS in fibroblasts cannot serve as a biomarker for sporadic ALS. Donor age-dependent gem reduction is a novel observation that links SMN with cellular senescence.
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Affiliation(s)
- Shingo Kariya
- Department of Pathology and Cell Biology, Center for Motor Neuron Biology and Disease and the Columbia Translational Neuroscience Initiative, Columbia University Medical Center , New York
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Bradley CA, Lamey HA, Endres GJ, Henson RA, Hanson BK, McKay KR, Halvorson M, LeGare DG, Porter PM. Efficacy of Fungicides for Control of Sclerotinia Stem Rot of Canola. Plant Dis 2006; 90:1129-1134. [PMID: 30781091 DOI: 10.1094/pd-90-1129] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Sclerotinia stem rot (SSR), incited by Sclerotinia sclerotiorum, causes yield reductions to canola (Brassica napus) grown in North Dakota and Minnesota. Field trials were conducted in North Dakota and Minnesota from 2000 to 2004 to evaluate the effect of foliar fungicides on SSR and canola yield. Levels of SSR varied among years and location. In general, fungicides that consistently reduced SSR incidence compared with an untreated control were azoxystrobin, benomyl, boscalid, iprodione, prothioconazole, tebuconazole, thiophanate-methyl, trifloxystrobin, and vinclozolin. Significant reductions in SSR incidence with fungicides did not always translate into differences in canola yield, however. Inconsistent results were observed with different timings of applications based on percent bloom. This indicates that application timing should be based on factors in addition to percent bloom.
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Affiliation(s)
- C A Bradley
- Department of Plant Pathology, North Dakota State University, Fargo 58105
| | - H A Lamey
- Department of Plant Pathology, North Dakota State University, Fargo 58105
| | - G J Endres
- Carrington Research Extension Center, North Dakota State University, Carrington, 58421
| | - R A Henson
- Carrington Research Extension Center, North Dakota State University, Carrington, 58421
| | - B K Hanson
- Langdon Research Extension Center, North Dakota State University, Langdon 58249
| | - K R McKay
- North Central Research Extension Center, North Dakota State University, Minot 58701
| | - M Halvorson
- North Central Research Extension Center, North Dakota State University, Minot 58701
| | - D G LeGare
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul 55108
| | - P M Porter
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul 55108
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