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Fletcher K, Martin F, Isakeit T, Cavanaugh K, Magill C, Michelmore R. The genome of the oomycete Peronosclerospora sorghi, a cosmopolitan pathogen of maize and sorghum, is inflated with dispersed pseudogenes. G3 (Bethesda) 2023; 13:jkac340. [PMID: 36592124 PMCID: PMC9997571 DOI: 10.1093/g3journal/jkac340] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/14/2022] [Accepted: 12/05/2022] [Indexed: 01/03/2023]
Abstract
Several species in the oomycete genus Peronosclerospora cause downy mildew on maize and can result in significant yield losses in Asia. Bio-surveillance of these pathogens is a high priority to prevent epidemics on maize in the United States and consequent damage to the US economy. The unresolved taxonomy and dearth of molecular resources for Peronosclerospora spp. hinder these efforts. P. sorghi is a pathogen of sorghum and maize with a global distribution, for which limited diversity has been detected in the southern USA. We characterized the genome, transcriptome, and mitogenome of an isolate, representing the US pathotype 6. The highly homozygous genome was assembled using 10× Genomics linked reads and scaffolded using Hi-C into 13 chromosomes. The total assembled length was 303.2 Mb, larger than any other oomycete previously assembled. The mitogenome was 38 kb, similar in size to other oomycetes, although it had a unique gene order. Nearly 20,000 genes were annotated in the nuclear genome, more than described for other downy mildew causing oomycetes. The 13 chromosomes of P. sorghi were highly syntenic with the 17 chromosomes of Peronospora effusa with conserved centromeric regions and distinct chromosomal fusions. The increased assembly size and gene count of P. sorghi is due to extensive retrotransposition, resulting in putative pseudogenization. Ancestral genes had higher transcript abundance and were enriched for differential expression. This study provides foundational resources for analysis of Peronosclerospora and comparisons to other oomycete genera. Further genomic studies of global Peronosclerospora spp. will determine the suitability of the mitogenome, ancestral genes, and putative pseudogenes for marker development and taxonomic relationships.
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Affiliation(s)
- Kyle Fletcher
- The Genome Center, University of California, Davis, CA 95616, USA
| | - Frank Martin
- U.S. Department of Agriculture–Agriculture Research Service, Salinas, CA, 93905, USA
| | - Thomas Isakeit
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Keri Cavanaugh
- The Genome Center, University of California, Davis, CA 95616, USA
| | - Clint Magill
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Richard Michelmore
- The Genome Center, University of California, Davis, CA 95616, USA
- Departments of Plant Sciences, Molecular & Cellular Biology, Medical Microbiology & Immunology, University of California, Davis, CA 95616, USA
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2
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Palmer W, Jacygrad E, Sagayaradj S, Cavanaugh K, Han R, Bertier L, Beede B, Kafkas S, Golino D, Preece J, Michelmore R. Genome assembly and association tests identify interacting loci associated with vigor, precocity, and sex in interspecific pistachio rootstocks. G3 (Bethesda) 2022; 13:6861913. [PMID: 36454230 PMCID: PMC9911073 DOI: 10.1093/g3journal/jkac317] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/09/2022] [Accepted: 11/11/2022] [Indexed: 12/03/2022]
Abstract
Understanding the basis of hybrid vigor remains a key question in crop breeding and improvement, especially for rootstock development where F1 hybrids are extensively utilized. Full-sibling UCB-1 F1 seedling rootstocks are widely planted in commercial pistachio orchards that are generated by crossing 2 highly heterozygous outbreeding parental trees of Pistacia atlantica (female) and P. integerrima (male). This results in extensive phenotypic variability, prompting costly removal of low-yielding small trees. To identify the genetic basis of this variability, we assembled chromosome-scale genome assemblies of the parental trees of UCB-1. We genotyped 960 UCB-1 trees in an experimental orchard for which we also collected multiyear phenotypes. We genotyped an additional 1,358 rootstocks in 6 commercial pistachio orchards and collected single-year tree-size data. Genome-wide single marker association tests identified loci associated with tree size and shape, sex, and precocity. In the experimental orchard, we identified multiple trait-associated loci and a strong candidate for ZZ/ZW sex chromosomes. We found significant marker associations unique to different traits and to early vs late phenotypic measures of the same trait. We detected 2 loci strongly associated with rootstock size in commercial orchards. Pseudo-testcross classification of markers demonstrated that the trait-associated alleles for each locus were segregating in the gametes of opposite parents. These 2 loci interact epistatically to generate the bimodal distribution of tree size with undesirable small trees observed by growers. We identified candidate genes within these regions. These findings provide a foundational resource for marker development and genetic selection of vigorous pistachio UCB-1 rootstock.
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Affiliation(s)
- William Palmer
- Genome Center, University of California, Davis, One Shields Ave, Davis, CA 95616, USA,Present address: Gencove, 30-02 48th Avenue, Suite 370, Long Island City, NY 11101, USA
| | - Ewelina Jacygrad
- Genome Center, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Sagayamary Sagayaradj
- Genome Center, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Keri Cavanaugh
- Genome Center, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Rongkui Han
- Genome Center, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Lien Bertier
- Genome Center, University of California, Davis, One Shields Ave, Davis, CA 95616, USA,Present address: Ohalo Genetics, 9565 Soquel Dr. Suite 101, Aptos, CA 95003, USA
| | - Bob Beede
- UC Cooperative Extension, 680 North Campus Dr., Hanford, CA 93230, USA
| | - Salih Kafkas
- Department of Horticulture, University of Çukurova, 01330 Adana, Turkey
| | - Deborah Golino
- Foundation Plant Services, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - John Preece
- National Clonal Germplasm Repository, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - Richard Michelmore
- Corresponding author: Departments of Plant Sciences, Molecular & Cellular Biology, Medical Microbiology and Immunology, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA.
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Fletcher K, Zhang L, Gil J, Han R, Cavanaugh K, Michelmore R. AFLAP: assembly-free linkage analysis pipeline using k-mers from genome sequencing data. Genome Biol 2021; 22:115. [PMID: 33883006 PMCID: PMC8061198 DOI: 10.1186/s13059-021-02326-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 03/25/2021] [Indexed: 11/20/2022] Open
Abstract
Our assembly-free linkage analysis pipeline (AFLAP) identifies segregating markers as k-mers in the raw reads without using a reference genome assembly for calling variants and provides genotype tables for the construction of unbiased, high-density genetic maps without a genome assembly. AFLAP is validated and contrasted to a conventional workflow using simulated data. AFLAP is applied to whole genome sequencing and genotype-by-sequencing data of F1, F2, and recombinant inbred populations of two different plant species, producing genetic maps that are concordant with genome assemblies. The AFLAP-based genetic map for Bremia lactucae enables the production of a chromosome-scale genome assembly.
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Affiliation(s)
- Kyle Fletcher
- The Genome Center, University of California, Davis, USA
| | - Lin Zhang
- The Genome Center, University of California, Davis, USA
| | - Juliana Gil
- The Genome Center, University of California, Davis, USA
| | - Rongkui Han
- The Genome Center, University of California, Davis, USA
| | | | - Richard Michelmore
- The Genome Center, University of California, Davis, USA
- Departments of Plant Sciences, Molecular & Cellular Biology, Medical Microbiology & Immunology, University of California, Davis, USA
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Fletcher K, Gil J, Bertier LD, Kenefick A, Wood KJ, Zhang L, Reyes-Chin-Wo S, Cavanaugh K, Tsuchida C, Wong J, Michelmore R. Genomic signatures of heterokaryosis in the oomycete pathogen Bremia lactucae. Nat Commun 2019; 10:2645. [PMID: 31201315 PMCID: PMC6570648 DOI: 10.1038/s41467-019-10550-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 05/14/2019] [Indexed: 12/26/2022] Open
Abstract
Lettuce downy mildew caused by Bremia lactucae is the most important disease of lettuce globally. This oomycete is highly variable and rapidly overcomes resistance genes and fungicides. The use of multiple read types results in a high-quality, near-chromosome-scale, consensus assembly. Flow cytometry plus resequencing of 30 field isolates, 37 sexual offspring, and 19 asexual derivatives from single multinucleate sporangia demonstrates a high incidence of heterokaryosis in B. lactucae. Heterokaryosis has phenotypic consequences on fitness that may include an increased sporulation rate and qualitative differences in virulence. Therefore, selection should be considered as acting on a population of nuclei within coenocytic mycelia. This provides evolutionary flexibility to the pathogen enabling rapid adaptation to different repertoires of host resistance genes and other challenges. The advantages of asexual persistence of heterokaryons may have been one of the drivers of selection that resulted in the loss of uninucleate zoospores in multiple downy mildews.
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Affiliation(s)
- Kyle Fletcher
- Genome Center, University of California, Davis, CA, 95616, USA
| | - Juliana Gil
- Genome Center, University of California, Davis, CA, 95616, USA
- Plant Pathology Graduate Group, University of California, Davis, CA, 95616, USA
| | - Lien D Bertier
- Genome Center, University of California, Davis, CA, 95616, USA
| | - Aubrey Kenefick
- Genome Center, University of California, Davis, CA, 95616, USA
| | - Kelsey J Wood
- Genome Center, University of California, Davis, CA, 95616, USA
- Integrated Genetics and Genomics Graduate Group, University of California, Davis, CA, 95616, USA
| | - Lin Zhang
- Genome Center, University of California, Davis, CA, 95616, USA
| | - Sebastian Reyes-Chin-Wo
- Genome Center, University of California, Davis, CA, 95616, USA
- Integrated Genetics and Genomics Graduate Group, University of California, Davis, CA, 95616, USA
- Bayer Crop Science, 37437 CA-16, Woodland, CA, 95695, USA
| | - Keri Cavanaugh
- Genome Center, University of California, Davis, CA, 95616, USA
| | - Cayla Tsuchida
- Genome Center, University of California, Davis, CA, 95616, USA
- Plant Pathology Graduate Group, University of California, Davis, CA, 95616, USA
- Arcadia Biosciences, Davis, CA, 95616, USA
| | - Joan Wong
- Genome Center, University of California, Davis, CA, 95616, USA
- Plant Biology Graduate Group, University of California, Davis, CA, 95616, USA
- Pacific Biosciences of California, Inc., Menlo Park, CA, 94025, USA
| | - Richard Michelmore
- Genome Center, University of California, Davis, CA, 95616, USA.
- Departments of Plant Sciences, Molecular and Cellular Biology, Medical Microbiology and Immunology, University of California, Davis, CA, 95616, USA.
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Wróblewski T, Spiridon L, Martin EC, Petrescu AJ, Cavanaugh K, Truco MJ, Xu H, Gozdowski D, Pawłowski K, Michelmore RW, Takken FL. Genome-wide functional analyses of plant coiled-coil NLR-type pathogen receptors reveal essential roles of their N-terminal domain in oligomerization, networking, and immunity. PLoS Biol 2018; 16:e2005821. [PMID: 30540748 PMCID: PMC6312357 DOI: 10.1371/journal.pbio.2005821] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 12/31/2018] [Accepted: 11/16/2018] [Indexed: 12/22/2022] Open
Abstract
The ability to induce a defense response after pathogen attack is a critical feature of the immune system of any organism. Nucleotide-binding leucine-rich repeat receptors (NLRs) are key players in this process and perceive the occurrence of nonself-activities or foreign molecules. In plants, coevolution with a variety of pests and pathogens has resulted in repertoires of several hundred diverse NLRs in single individuals and many more in populations as a whole. However, the mechanism by which defense signaling is triggered by these NLRs in plants is poorly understood. Here, we show that upon pathogen perception, NLRs use their N-terminal domains to transactivate other receptors. Their N-terminal domains homo- and heterodimerize, suggesting that plant NLRs oligomerize upon activation, similar to the vertebrate NLRs; however, consistent with their large number in plants, the complexes are highly heterometric. Also, in contrast to metazoan NLRs, the N-terminus, rather than their centrally located nucleotide-binding (NB) domain, can mediate initial partner selection. The highly redundant network of NLR interactions in plants is proposed to provide resilience to perturbation by pathogens.
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Affiliation(s)
- Tadeusz Wróblewski
- The Genome Center, University of California–Davis, Davis, California, United States of America
| | - Laurentiu Spiridon
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Eliza Cristina Martin
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Andrei-Jose Petrescu
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of the Romanian Academy, Bucharest, Romania
| | - Keri Cavanaugh
- The Genome Center, University of California–Davis, Davis, California, United States of America
| | - Maria José Truco
- The Genome Center, University of California–Davis, Davis, California, United States of America
| | - Huaqin Xu
- The Genome Center, University of California–Davis, Davis, California, United States of America
| | - Dariusz Gozdowski
- Department of Experimental Design and Bioinformatics, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Warsaw, Poland
| | - Krzysztof Pawłowski
- Department of Experimental Design and Bioinformatics, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Warsaw, Poland
| | - Richard W. Michelmore
- The Genome Center, University of California–Davis, Davis, California, United States of America
- Departments of Plant Sciences, Molecular & Cellular Biology, and Medical Microbiology & Immunology, University of California–Davis, Davis, California, United States of America
- Department of Medical Microbiology and Immunology, University of California–Davis, Davis, California, United States of America
| | - Frank L.W. Takken
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands
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Nandety RS, Caplan JL, Cavanaugh K, Perroud B, Wroblewski T, Michelmore RW, Meyers BC. The role of TIR-NBS and TIR-X proteins in plant basal defense responses. Plant Physiol 2013; 162:1459-72. [PMID: 23735504 PMCID: PMC3707564 DOI: 10.1104/pp.113.219162] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 06/01/2013] [Indexed: 05/02/2023]
Abstract
Toll/interleukin receptor (TIR) domain-containing proteins encoded in the Arabidopsis (Arabidopsis thaliana) genome include the TIR-nucleotide binding site (TN) and TIR-unknown site/domain (TX) families. We investigated the function of these proteins. Transient overexpression of five TX and TN genes in tobacco (Nicotiana benthamiana) induced chlorosis. This induced chlorosis was dependent on ENHANCED DISEASE RESISTANCE1, a dependency conserved in both tobacco and Arabidopsis. Stable overexpression transgenic lines of TX and TN genes in Arabidopsis produced a variety of phenotypes associated with basal innate immune responses; these were correlated with elevated levels of salicylic acid. The TN protein AtTN10 interacted with the chloroplastic protein phosphoglycerate dehydrogenase in a yeast (Saccharomyces cerevisiae) two-hybrid screen; other TX and TN proteins interacted with nucleotide binding-leucine-rich repeat proteins and effector proteins, suggesting that TN proteins might act in guard complexes monitoring pathogen effectors.
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Affiliation(s)
| | - Jeffery L. Caplan
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Keri Cavanaugh
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Bertrand Perroud
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Tadeusz Wroblewski
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
| | - Richard W. Michelmore
- Department of Plant and Soil Sciences (R.S.N., B.C.M.), and Delaware Biotechnology Institute (R.S.N., J.L.C., B.C.M.), University of Delaware, Newark, Delaware 19711; and
- UC Davis Genome Center, University of California, Davis, California 95616 (K.C., B.P., T.W., R.W.M.)
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Abstract
Cricotracheal resection has been advocated in the management of severe subglottic stenosis. One of the possible complications of this procedure is injury to the recurrent laryngeal nerve (RLN). We describe a new technique in which electrodes are placed directly through the thyroid cartilage to monitor the RLN intraoperatively. Nine cats' left vocal cords were monitored, and 3 cats had unilateral vocal cord injury postoperatively: 1 right cord and 2 left cords. Even though this technique was efficacious, our ability to monitor the RLNs was difficult secondary to difficulty interpreting the nerve monitor's wave morphologies. The future use of RLN nerve monitoring during cricotracheal resection will depend upon the ability to distinguish true stimulation from artifact. Monitoring of the RLN could be beneficial in patients with previous operations for subglottic stenosis.
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Affiliation(s)
- K Cavanaugh
- Department of Otolaryngology-Head and Neck Surgery, Loyola University Medical Center, Maywood, Illinois 60153, USA
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Zeballos JL, Savedoff B, Beeharry G, Flores R, Cavanaugh K. A roundtable discussion on international cooperation in health reform in the Americas. Rev Panam Salud Publica 2000; 8:140-6. [PMID: 11026785 DOI: 10.1590/s1020-49892000000700019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
There is little consensus on the optimal management of postparotidectomy salivary fistulas. Timely treatment is important since fistulas may result in wound dehiscence and infection. Management options include pressure dressings, total parotidectomy, tympanic neurectomy, graft interpositioning, surgical closure of the tract, radiation therapy, and pharmacotherapy. Unfortunately, many therapies require weeks to months for resolution and possess additional risks. The affected patient often suffers social embarrassment from the drainage. Through our work with neurologically impaired children with sialorrhea, we have had success with using glycopyrrolate, an anticholinergic frequently used to decrease salivary secretions. We present a case of a patient with a postparotidectomy fistula which was successfully treated with glycopyrrolate and pressure dressings. The rationale and potential use of glycopyrrolate for the treatment of a salivary fistula are the focus of this presentation.
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Affiliation(s)
- K Cavanaugh
- Department of Otolaryngology-Head and Neck Surgery, Loyola University Medical Center, Maywood, IL 60153, USA
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Bartus RT, Dean RL, Cavanaugh K, Eveleth D, Carriero DL, Lynch G. Time-related neuronal changes following middle cerebral artery occlusion: implications for therapeutic intervention and the role of calpain. J Cereb Blood Flow Metab 1995; 15:969-79. [PMID: 7593358 DOI: 10.1038/jcbfm.1995.123] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Changes in neocortex and striatum were characterized over time following focal ischemia to the brain. Rats were subjected to permanent middle cerebral artery occlusion (MCA-O) and sacrificed 1, 3, 6, 12, or 24 h later. The affected tissue was processed for tetrazolium chloride (TTC) and cresyl violet staining, as well as for Western blots to detect calpain-induced spectrin proteolysis. Significant changes in cell size and spectrin breakdown occurred within the first hour of occlusion, with further, dramatic changes in these two early markers continuing over time. Initial evidence of cell loss was noted at 1 h postocclusion in the striatum and at 3 h in the neocortex. However, even in the center of the most affected portion of the neocortex, the majority of cells appeared to be intact through 6 h. By this time, a significant TTC-defined infarct also emerged. These quantitative data indicate that calpain-induced proteolysis occurs very soon after the ischemic insult, is correlated with earliest changes in cell hypotrophy, and precedes or occurs in tandem with evidence of significant cell loss. They also demonstrate that, while some cell loss occurs earlier than previously believed, the majority of cells remains morphologically intact well beyond what is typically thought to be the window of opportunity for intervention. The results thus raise the question of how long after the ischemic event pharmaceutic intervention might be employed to salvage substantial numbers of neurons.
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Affiliation(s)
- R T Bartus
- Alkermes, Inc., Cambridge, MA 01239, USA
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Cavanaugh K. Automated keratometry. CLAO J 1987; 13:195. [PMID: 3453764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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