Publications by authors named "Kent Chapman"

126 Publications

EARLY RESPONSIVE TO DEHYDRATION 7 Localizes to Lipid Droplets via Its Senescence Domain.

Front Plant Sci 2021 14;12:658961. Epub 2021 Apr 14.

Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada.

Lipid droplets (LDs) are neutral-lipid-containing organelles found in all kingdoms of life and are coated with proteins that carry out a vast array of functions. Compared to mammals and yeast, relatively few LD proteins have been identified in plants, particularly those associated with LDs in vegetative (non-seed) cell types. Thus, to better understand the cellular roles of LDs in plants, a more comprehensive inventory and characterization of LD proteins is required. Here, we performed a proteomics analysis of LDs isolated from drought-stressed leaves and identified EARLY RESPONSIVE TO DEHYDRATION 7 (ERD7) as a putative LD protein. mCherry-tagged ERD7 localized to both LDs and the cytosol when ectopically expressed in plant cells, and the protein's C-terminal senescence domain (SD) was both necessary and sufficient for LD targeting. Phylogenetic analysis revealed that ERD7 belongs to a six-member family in that, along with homologs in other plant species, is separated into two distinct subfamilies. Notably, the SDs of proteins from each subfamily conferred targeting to either LDs or mitochondria. Further, the SD from the ERD7 homolog in humans, spartin, localized to LDs in plant cells, similar to its localization in mammals; although, in mammalian cells, spartin also conditionally localizes to other subcellular compartments, including mitochondria. Disruption of gene expression in revealed no obvious changes in LD numbers or morphology under normal growth conditions, although this does not preclude a role for ERD7 in stress-induced LD dynamics. Consistent with this possibility, a yeast two-hybrid screen using ERD7 as bait identified numerous proteins involved in stress responses, including some that have been identified in other LD proteomes. Collectively, these observations provide new insight to ERD7 and the SD-containing family of proteins in plants and suggest that ERD7 may be involved in functional aspects of plant stress response that also include localization to the LD surface.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2021.658961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8079945PMC
April 2021

Verification of the ACL Top 50 Family (350, 550, and 750) for Harmonization of Routine Coagulation Assays in a Large Network of 60 Laboratories.

Am J Clin Pathol 2021 Apr 23. Epub 2021 Apr 23.

Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, Australia.

Objectives: To verify a single platform of hemostasis instrumentation, the ACL TOP 50 Family, comprising 350, 550, and 750 instruments, across a large network of 60 laboratories.

Methods: Comparative evaluations of instrument classes (350 vs 550 and 750) were performed using a large battery of test samples for routine coagulation tests, comprising prothrombin time/international normalized ratio, activated partial thromboplastin time (APTT), thrombin time, fibrinogen and D-dimer, and using HemosIL reagents. Comparisons were also made against existing equipment (Diagnostica Stago Satellite, Compact, and STA-R Evolution) and existing reagents to satisfy national accreditation standards. Verification of manufacturer normal reference ranges (NRRs) and generation of an APTT heparin therapeutic range were undertaken.

Results: The three instrument types were verified as a single instrument class, which will permit standardization of methods and NRRs across all instruments (n = 75) to be deployed in 60 laboratories. In particular, ACL TOP 350 test result data were similar to ACL TOP 550 and 750 and showed no to limited bias. All manufacturer NRRs were verified with occasional minor variance.

Conclusions: This ACL TOP 50 Family (350, 550, and 750) verification will enable harmonization of routine coagulation across all laboratories in the largest public pathology network in Australia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ajcp/aqab004DOI Listing
April 2021

Analyzing Mass Spectrometry Imaging Data of C-Labeled Phospholipids in and (Pennycress) Embryos.

Metabolites 2021 Mar 4;11(3). Epub 2021 Mar 4.

Department of Biological Sciences & BioDiscovery Institute, University of North Texas, Denton, TX 76203, USA.

The combination of C-isotopic labeling and mass spectrometry imaging (MSI) offers an approach to analyze metabolic flux in situ. However, combining isotopic labeling and MSI presents technical challenges ranging from sample preparation, label incorporation, data collection, and analysis. Isotopic labeling and MSI individually create large, complex data sets, and this is compounded when both methods are combined. Therefore, analyzing isotopically labeled MSI data requires streamlined procedures to support biologically meaningful interpretations. Using currently available software and techniques, here we describe a workflow to analyze C-labeled isotopologues of the membrane lipid and storage oil lipid intermediate-phosphatidylcholine (PC). Our results with embryos of the oilseed crops, and (pennycress), demonstrated greater C-isotopic labeling in the cotyledons of developing embryos compared with the embryonic axis. Greater isotopic enrichment in PC molecular species with more saturated and longer chain fatty acids suggest different flux patterns related to fatty acid desaturation and elongation pathways. The ability to evaluate MSI data of isotopically labeled plant embryos will facilitate the potential to investigate spatial aspects of metabolic flux in situ.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/metabo11030148DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7999836PMC
March 2021

Production of tocotrienols in seeds of cotton (Gossypium hirsutum L.) enhances oxidative stability and offers nutraceutical potential.

Plant Biotechnol J 2021 Jan 25. Epub 2021 Jan 25.

Department of Biological Sciences, BioDiscovery Institute, University of North Texas, Denton, TX, USA.

Upland cotton (Gossypium hirsutum L.) is an economically important multi-purpose crop cultivated globally for fibre, seed oil and protein. Cottonseed oil also is naturally rich in vitamin E components (collectively known as tocochromanols), with α- and γ-tocopherols comprising nearly all of the vitamin E components. By contrast, cottonseeds have little or no tocotrienols, tocochromanols with a wide range of health benefits. Here, we generated transgenic cotton lines expressing the barley (Hordeum vulgare) homogentisate geranylgeranyl transferase coding sequence under the control of the Brassica napus seed-specific promoter, napin. Transgenic cottonseeds had ~twofold to threefold increases in the accumulation of total vitamin E (tocopherols + tocotrienols), with more than 60% γ-tocotrienol. Matrix assisted laser desorption ionization-mass spectrometry imaging showed that γ-tocotrienol was localized throughout the transgenic embryos. In contrast, the native tocopherols were distributed unequally in both transgenic and non-transgenic embryos. α- Tocopherol was restricted mostly to cotyledon tissues and γ-tocopherol was more enriched in the embryonic axis tissues. Production of tocotrienols in cotton embryos had no negative impact on plant performance or yield of other important seed constituents including fibre, oil and protein. Advanced generations of two transgenic events were field grown, and extracts of transgenic seeds showed increased antioxidant activity relative to extracts from non-transgenic seeds. Furthermore, refined cottonseed oil from the two transgenic events showed 30% improvement in oxidative stability relative to the non-transgenic cottonseed oil. Taken together, these materials may provide new opportunities for cottonseed co-products with enhanced vitamin E profile for improved shelf life and nutrition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pbi.13557DOI Listing
January 2021

Lipid Signaling through G Proteins.

Trends Plant Sci 2021 Jan 16. Epub 2021 Jan 16.

BioDiscovery Institute, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA. Electronic address:

N-Acylethanolamine (NAE) signaling has received considerable attention in vertebrates as part of the endocannabinoid signaling system, where anandamide acts as a ligand for G protein-coupled cannabinoid receptors. Recent studies indicate that G proteins also are required for some types of NAE signaling in plants. The genetic ablation of the Gβγ dimer or loss of the full set of extra-large G proteins strongly attenuated NAE-induced chloroplast responses in seedlings. Intriguing parallels and distinct differences have emerged between plants and animals in NAE signaling, despite the conserved use of these lipid mediators to modulate cellular processes. Here we compare similarities and differences and identify open questions in a fundamental lipid signaling pathway in eukaryotes with components that are both conserved and diverged in plants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tplants.2020.12.012DOI Listing
January 2021

2B or not 2B? A diagnosis of von Willebrand disease a lifetime of 86 years in the making.

Blood Coagul Fibrinolysis 2021 Apr;32(3):229-233

NSW Health Pathology West, Institute of Clinical Pathology and Medical Research (ICPMR).

Type 2B von Willebrand disease (2B VWD) is a rare, autosomal dominant bleeding disorder characterized by a hyperadhesive form of von Willebrand factor (VWF). 2B VWD expresses phenotypically as an enhanced ristocetin-induced platelet aggregation and usually also a discordance in VWF activity versus protein level, with loss of high molecular weight VWF and (mild) thrombocytopenia. While all cases of 2B VWD supposedly share these characteristics, there is significant heterogeneity in laboratory findings within this group of patients, which are largely dictated by the underlying genetic defect. We present a case of such a patient, expressing a clearly atypical VWF phenotype, but as still associated with enhanced ristocetin-induced platelet aggregation, thrombocytopenia, and a previously undescribed VWF variant (c.4130C>G; p.Ala1377Gly). The patient was misdiagnosed over his lifetime as idiotypic thrombocytopenia - a (mis)diagnosis that took a lifetime of 86 years to redress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MBC.0000000000000994DOI Listing
April 2021

Chemical Genetics to Uncover Mechanisms Underlying Lipid-Mediated Signaling Events in Plants.

Methods Mol Biol 2021 ;2213:3-16

Noble Research Institute LLC, Ardmore, OK, USA.

Like animals, plants use various lipids as signaling molecules to guide their growth and development. The focus of our work is on the N-acylethanolamine (NAE) group of lipid mediators, which have been shown to play important physiological roles in plants. However, mechanisms by which NAEs modulate plant function remain elusive. Chemical genetics has emerged as a potent tool to elucidate signaling pathways in plants, particularly those orchestrated by plant hormones. Like plant hormones, exogenous application of NAEs elicits distinct plant growth phenotypes that can serve as biological readouts for chemical genetic screens. For example, N-lauroylethanolamide (NAE 12:0) inhibits seedling development in the model plant Arabidopsis thaliana. Thus, a library of small synthetic chemical compounds can be rapidly screened for their ability to reverse the inhibitory effect of NAE 12:0 on seedling development. Chemicals identified through such screens could be potential agonists/antagonists of NAE receptors or signaling pathways and therefore serve as additional tools for understanding NAE function in plants. In this chapter, we describe general protocols for NAE 12:0-based chemical genetic screens in Arabidopsis. Although such screens were designed primarily for NAE 12:0, they could potentially be applied for similar work with other NAE species or plant lipid mediators.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-1-0716-0954-5_1DOI Listing
March 2021

A multicenter laboratory assessment of a new automated chemiluminescent assay for ADAMTS13 activity.

J Thromb Haemost 2021 02 21;19(2):417-428. Epub 2020 Nov 21.

Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia.

Background: Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal disorder caused by ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) deficiency. Prompt identification/exclusion of TTP can thus be facilitated by rapid ADAMTS13 testing. The most commonly utilized (enzyme-linked immunosorbent assay [ELISA]-based) assay takes several hours to perform and so does not generally permit rapid testing.

Objectives: To evaluate the utility of a new automated test for ADAMTS13 activity, the HemosIL AcuStar ADAMTS13 Activity assay, based on chemiluminescence and able to be performed on an ACL AcuStar instrument within 33 minutes.

Patients/methods: This multicenter (n = 8) assessment included testing of more than 700 test samples, with similar numbers of prospective (n = 348) and retrospective (n = 385) samples. The main comparator was the Technozym ADAMTS13 Activity ELISA. We also assessed comparative performance for detection of ADAMTS13 inhibitors using a Bethesda assay.

Results: Overall, the chemiluminescent assay yielded similar results to the comparator ELISA, albeit with slight negative bias. ADAMTS13 inhibitor detection was also comparable, albeit with slight positive bias with the AcuStar assay. Assay precision was similar with both assays, and we also verified assay normal reference ranges.

Conclusions: The HemosIL AcuStar ADAMTS13 Activity assay provided results rapidly, which were largely comparable with the Technozym ADAMTS13 Activity ELISA assay, albeit lower on average. Conversely, inhibitor levels tended to be identified at a higher level on average. Thus, the HemosIL AcuStar ADAMTS13 Activity assay provides a fast and accurate means to quantitate plasma levels of ADAMTS13 for TTP/ADAMTS13 identification/exclusion, and potentially also for other applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jth.15157DOI Listing
February 2021

A multicentre assessment of contemporary laboratory assays for heparin induced thrombocytopenia.

Pathology 2021 Feb 5;53(2):247-256. Epub 2020 Oct 5.

NSW Health Pathology, NSW, Australia; Prince of Wales Hospital, Randwick, NSW, Australia.

Heparin induced thrombocytopenia (HIT) is a rare but potentially fatal complication of heparin therapy. In some patients, HIT causes platelet activation and thrombosis (sometimes abbreviated HITT), which leads to adverse clinical sequalae ('pathological HIT'). The likelihood of HIT is initially assessed clinically, typically using a scoring system, of which the 4T score is that most utilised. Subsequent laboratory testing to confirm or exclude HIT facilitates exclusion or diagnosis and management. The current investigation comprises a multicentre (n=9) assessment of contemporary laboratory testing for HIT, as performed over the past 1-3 years in each site and comprising testing of over 1200 samples. The primary laboratory test used by study participants (n=8) comprised a chemiluminescence procedure (HIT-IgG) performed on an AcuStar instrument. Additional immunological testing performed by study sites included lateral flow (STiC, Stago), enzyme linked immunosorbent assay (ELISA), Asserachrom (HPIA IgG), PaGIA (BioRad), plus functional assays, primarily serotonin release assay (SRA) or platelet aggregation methods. The chemiluminescence procedure yielded a highly sensitive screening method for identifying functional HIT, given high area under the curve (AUC, generally ≥0.9) in a receiver operator characteristic (ROC) analysis against SRA as gold standard. ELISA testing resulted in lower ROC AUC scores (<0.8) and higher levels of false positives. Although there is clear association with the likelihood of HIT, the 4T score had less utility than literature suggests, and was comparable to a previous study reported by some of the authors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pathol.2020.07.012DOI Listing
February 2021

Lipophilic signals lead to organ-specific gene expression changes in seedlings.

Plant Direct 2020 Jul 15;4(7):e00242. Epub 2020 Jul 15.

BioDiscovery Institute and Department of Biological Sciences University of North Texas Denton TX USA.

In plants, -acylethanolamines (NAEs) are most abundant in desiccated seeds and their levels decline during germination and early seedling establishment. However, endogenous NAE levels rise in seedlings when ABA or environmental stress is applied, and this results in an inhibition of further seedling development. When the most abundant, polyunsaturated NAEs of linoleic acid (18:2) and linolenic acid (18:3) were exogenously applied, seedling development was affected in an organ-specific manner. NAE 18:2 primarily affected primary root elongation and NAE 18:3 primarily affected cotyledon greening and expansion and overall seedling growth. The molecular components and signaling mechanisms involved in this pathway are not well understood. In addition, the bifurcating nature of this pathway provides a unique system in which to study the spatial aspects and interaction of these lipid-specific and organ-targeted signaling pathways. Using whole transcriptome sequencing (RNA-seq) and differential expression analysis, we identified early (1-3 hr) transcriptional changes induced by the exogenous treatment of NAE 18:2 and NAE 18:3 in cotyledons, roots, and seedlings. These two treatments led to a significant enrichment in ABA-response and chitin-response genes in organs where the treatments led to changes in development. In seedlings, NAE 18:2 treatment led to the repression of genes involved in cell wall biogenesis and organization in roots and seedlings. In addition, cotyledons, roots, and seedlings treated with NAE 18:3 also showed a decrease in transcripts that encode proteins involved in growth processes. NAE 18:3 also led to changes in the abundance of transcripts involved in the modulation of chlorophyll biosynthesis and catabolism in cotyledons. Overall, NAE 18:2 and NAE 18:3 treatment led to lipid-type and organ-specific gene expression changes that include overlapping and non-overlapping gene sets. These data will provide future, rich opportunities to examine the genetic pathways involved in transducing early signals into downstream physiological changes in seedling growth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/pld3.242DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7403840PMC
July 2020

SEIPIN Isoforms Interact with the Membrane-Tethering Protein VAP27-1 for Lipid Droplet Formation.

Plant Cell 2020 09 20;32(9):2932-2950. Epub 2020 Jul 20.

Department of Biological Sciences, BioDiscovery Institute, University of North Texas, Denton, Texas 76203

SEIPIN proteins are localized to endoplasmic reticulum (ER)-lipid droplet (LD) junctions where they mediate the directional formation of LDs into the cytoplasm in eukaryotic cells. Unlike in animal and yeast cells, which have single SEIPIN genes, plants have three distinct SEIPIN isoforms encoded by separate genes. The mechanism of SEIPIN action remains poorly understood, and here we demonstrate that part of the function of two SEIPIN isoforms in Arabidopsis (), AtSEIPIN2 and AtSEIPIN3, may depend on their interaction with the vesicle-associated membrane protein (VAMP)-associated protein (VAP) family member AtVAP27-1. VAPs have well-established roles in the formation of membrane contact sites and lipid transfer between the ER and other organelles, and here, we used a combination of biochemical, cell biology, and genetics approaches to show that AtVAP27-1 interacts with the N termini of AtSEIPIN2 and AtSEIPIN3 and likely supports the normal formation of LDs. This insight indicates that the ER membrane tethering machinery in plant cells could play a role with select SEIPIN isoforms in LD biogenesis at the ER, and additional experimental evidence in supports the possibility that this interaction may be important in other eukaryotic systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1105/tpc.19.00771DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7474298PMC
September 2020

Seedling Chloroplast Responses Induced by -Linolenoylethanolamine Require Intact G-Protein Complexes.

Plant Physiol 2020 09 14;184(1):459-477. Epub 2020 Jul 14.

Department of Biological Sciences and BioDiscovery Institute, University of North Texas, Denton, Texas 76203

In animals, several long-chain -acylethanolamines (NAEs) have been identified as endocannabinoids and are autocrine signals that operate through cell surface G-protein-coupled cannabinoid receptors. Despite the occurrence of NAEs in land plants, including nonvascular plants, their precise signaling properties and molecular targets are not well defined. Here we show that the activity of -linolenoylethanolamine (NAE 18:3) requires an intact G-protein complex. Specifically, genetic ablation of the Gβγ dimer or loss of the full set of atypical Gα subunits strongly attenuates an NAE-18:3-induced degreening of cotyledons in Arabidopsis () seedlings. This effect involves, at least in part, transcriptional regulation of chlorophyll biosynthesis and catabolism genes. In addition, there is feedforward transcriptional control of G-protein signaling components and G-protein interactors. These results are consistent with NAE 18:3 being a lipid signaling molecule in plants with a requirement for G-proteins to mediate signal transduction, a situation similar, but not identical, to the action of NAE endocannabinoids in animal systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1104/pp.19.01552DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7479873PMC
September 2020

The endocannabinoid system.

Essays Biochem 2020 09;64(3):485-499

BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203, U.S.A.

Thirty years ago, the discovery of a cannabinoid (CB) receptor that interacts with the psychoactive compound in Cannabis led to the identification of anandamide, an endogenous receptor ligand or endocannabinoid. Research on endocannabinoids has since exploded, and additional receptors along with their lipid mediators and signaling pathways continue to be revealed. Specifically, in humans, the release of endocannabinoids from membrane lipids occurs on demand and the signaling process is rapidly attenuated by the breakdown of the ligand suggesting a tight regulation of the endocannabinoid system (ECS). Additionally, the varying distribution of CB receptors between the central nervous system and other tissues allows for the ECS to participate in a wide range of cognitive and physiological processes. Select plant-derived 'phyto'cannabinoids such as Δ-9-tetrahydrocannabinol (Δ9-THC) bind to the CB receptors and trigger the ECS, and in the case of Δ9-THC, while it has therapeutic value, can also produce detrimental effects. Current research is aimed at the identification of additional phytocannabinoids with minimal psychotropic effects with potential for therapeutic development. Although decades of research on the ECS and its components have expanded our understanding of the mechanisms and implications of endocannabinoid signaling in mammals, it continues to evolve. Here, we provide a brief overview of the ECS and its overlap with other related lipid-mediated signaling pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/EBC20190086DOI Listing
September 2020

Genomic investigation of inherited thrombotic microangiopathy-aHUS and TTP.

Int J Lab Hematol 2020 Jun;42 Suppl 1:33-40

NSW Health Pathology North, John Hunter Campus, New Lambton Heights, NSW, Australia.

Thrombotic microangiopathies (TMA) are a heterogeneous group of red cell fragmentation syndromes characterized by a tendency for thrombosis and pathognomonic red cell fragments in peripheral blood, which results in thrombosis in the microvasculature due to endothelial damage. Genomic investigations into inherited TMAs are of diagnostic, prognostic and therapeutic value. Here, we present two cases that capture the importance of performing genomic testing in rare disorders. Treatment options for these conditions, such as plasma exchange and monoclonal antibodies against complement factors, are intensive and expensive health care interventions. The results of genomic investigation into rare TMAs can better inform the clinicians and their patients of prognosis and suitable personalized treatment options.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ijlh.13201DOI Listing
June 2020

Cellular Plasticity in Response to Suppression of Storage Proteins in the Embryo.

Plant Cell 2020 07 30;32(7):2383-2401. Epub 2020 Apr 30.

Leibniz Institute of Plant Genetics and Crop Plant Research OT Gatersleben, D-06466 Seeland, Germany

The tradeoff between protein and oil storage in oilseed crops has been tested here in oilseed rape () by analyzing the effect of suppressing key genes encoding protein storage products (napin and cruciferin). The phenotypic outcomes were assessed using NMR and mass spectrometry imaging, microscopy, transcriptomics, proteomics, metabolomics, lipidomics, immunological assays, and flux balance analysis. Surprisingly, the profile of storage products was only moderately changed in RNA interference transgenics. However, embryonic cells had undergone remarkable architectural rearrangements. The suppression of storage proteins led to the elaboration of membrane stacks enriched with oleosin (sixfold higher protein abundance) and novel endoplasmic reticulum morphology. Protein rebalancing and amino acid metabolism were focal points of the metabolic adjustments to maintain embryonic carbon/nitrogen homeostasis. Flux balance analysis indicated a rather minor additional demand for cofactors (ATP and NADPH). Thus, cellular plasticity in seeds protects against perturbations to its storage capabilities and, hence, contributes materially to homeostasis. This study provides mechanistic insights into the intriguing link between lipid and protein storage, which have implications for biotechnological strategies directed at improving oilseed crops.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1105/tpc.19.00879DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7346569PMC
July 2020

The genome of jojoba (): A taxonomically isolated species that directs wax ester accumulation in its seeds.

Sci Adv 2020 03 11;6(11):eaay3240. Epub 2020 Mar 11.

National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.

Seeds of the desert shrub, jojoba (), are an abundant, renewable source of liquid wax esters, which are valued additives in cosmetic products and industrial lubricants. Jojoba is relegated to its own taxonomic family, and there is little genetic information available to elucidate its phylogeny. Here, we report the high-quality, 887-Mb genome of jojoba assembled into 26 chromosomes with 23,490 protein-coding genes. The jojoba genome has only the whole-genome triplication (γ) shared among eudicots and no recent duplications. These genomic resources coupled with extensive transcriptome, proteome, and lipidome data helped to define heterogeneous pathways and machinery for lipid synthesis and storage, provided missing evolutionary history information for this taxonomically segregated dioecious plant species, and will support efforts to improve the agronomic properties of jojoba.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/sciadv.aay3240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065883PMC
March 2020

Lipid droplets in plants and algae: Distribution, formation, turnover and function.

Semin Cell Dev Biol 2020 12 5;108:82-93. Epub 2020 Mar 5.

University of North Texas, BioDiscovery Institute, Department of Biological Sciences, Denton, TX, 76203, USA.

Plant oils represent an energy-rich and carbon-dense group of hydrophobic compounds. These oils are not only of economic interest, but also play important, fundamental roles in plant and algal growth and development. The subcellular storage compartments of plant lipids, referred to as lipid droplets (LDs), have long been considered relatively inert oil vessels. However, research in the last decade has revealed that LDs play far more dynamic roles in plant biology than previously appreciated, including transient neutral lipid storage, membrane remodeling, lipid signaling, and stress responses. Here we discuss recent developments in the understanding of LD formation, turnover and function in land plants and algae.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.semcdb.2020.02.014DOI Listing
December 2020

Heterogeneous Distribution of Erucic Acid in Seeds.

Front Plant Sci 2019 29;10:1744. Epub 2020 Jan 29.

National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.

() is the world's most widely grown temperate oilseed crop. Although breeding for human consumption has led to removal of erucic acid from refined canola oils, there is renewed interest in the industrial uses of erucic acid derived from , and there is a rich germplasm available for use. Here, low- and high-erucic acid accessions of seeds were examined for the distribution of erucic acid-containing lipids and the gene transcripts encoding the enzymes involved in pathways for its incorporation into triacylglycerols (TAGs) across the major tissues of the seeds. In general, the results indicate that a heterogeneous distribution of erucic acid across seed tissues was contributed by two isoforms (out of six) of ( and a combination of phospholipid:diacylglycerol acyltransferase (PDAT)- and diacylglycerol acyltransferase (DGAT)-mediated incorporation of erucic acid into TAGs in cotyledonary tissues. An absence of the expression of these two isoforms accounted for the absence of erucic acid in the TAGs of the low-erucic accession.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpls.2019.01744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7001127PMC
January 2020

Fatty Acid Amide Hydrolases: An Expanded Capacity for Chemical Communication?

Trends Plant Sci 2020 03 7;25(3):236-249. Epub 2020 Jan 7.

BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA. Electronic address:

Fatty acid amide hydrolase (FAAH) is an enzyme that belongs to the amidase signature (AS) superfamily and is widely distributed in multicellular eukaryotes. FAAH hydrolyzes lipid signaling molecules - namely, N-acylethanolamines (NAEs) - which terminates their actions. Recently, the crystal structure of Arabidopsis thaliana FAAH was solved and key residues were identified for substrate-specific interactions. Here, focusing on residues surrounding the substrate-binding pocket, a comprehensive analysis of FAAH sequences from angiosperms reveals a distinctly different family of FAAH-like enzymes. We hypothesize that FAAH, in addition to its role in seedling development, also acts in an N-acyl amide communication axis to facilitate plant-microbe interactions and that structural diversity provides for the flexible use of a wide range of small lipophilic signaling molecules.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tplants.2019.11.002DOI Listing
March 2020

Nature-Guided Synthesis of Advanced Bio-Lubricants.

Sci Rep 2019 08 12;9(1):11711. Epub 2019 Aug 12.

Department of Materials Science and Engineering, University of North Texas, Denton, TX, USA.

Design of environmentally friendly lubricants derived from renewable resources is highly desirable for many practical applications. Here, Orychophragmus violaceus (Ov) seed oil is found to have superior lubrication properties, and this is based on the unusual structural features of the major lipid species-triacylglycerol (TAG) estolides. Ov TAG estolides contain two non-hydroxylated, glycerol-bound fatty acids (FAs) and one dihydroxylated FA with an estolide branch. Estolide branch chains vary in composition and length, leading to their thermal stability and functional properties. Using this concept, nature-guided estolides of castor oil were synthesized. As predicted, they showed improved lubrication properties similar to Ov seed oil. Our results demonstrate a structure-based design of novel lubricants inspired by natural materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-48165-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6690888PMC
August 2019

Mouse Fat-Specific Protein 27 (FSP27) expressed in plant cells localizes to lipid droplets and promotes lipid droplet accumulation and fusion.

Biochimie 2020 Feb 7;169:41-53. Epub 2019 Aug 7.

BioDiscovery Institute, Department of Biological Sciences, University of North Texas, Denton, TX, USA. Electronic address:

Fat-Specific Protein 27 (FSP27) belongs to a small group of vertebrate proteins containing a Cell-death Inducing DNA fragmentation factor-α-like Effector (CIDE)-C domain and is involved in lipid droplet (LD) accumulation and energy homeostasis. FSP27 is predominantly expressed in white and brown adipose tissues, as well as liver, and plays a key role in mediating LD-LD fusion. No orthologs have been identified in invertebrates or plants. In this study, we tested the function of mouse FSP27 in stably-transformed Arabidopsis thaliana leaves and seeds, as well as through transient expression in Nicotiana tabacum suspension-cultured cells and N. benthamiana leaves. Confocal microscopic analysis of plant cells revealed that, similar to ectopic expression in mammalian cells, FSP27 produced in plants 1) correctly localized to LDs, 2) accumulated at LD-LD contact sites, and 3) induced an increase in the number and size of LDs and also promoted LD clustering and fusion. Furthermore, FSP27 increased oil content in transgenic A. thaliana seeds. Given that plant oils have uses in human and animal nutrition as well as industrial uses such as biofuels and bioplastics, our results suggest that ectopic expression of FSP27 in plants represents a potential strategy for increasing oil content and energy density in bioenergy or oilseed crops.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biochi.2019.08.002DOI Listing
February 2020

Mechanisms of lipid droplet biogenesis.

Biochem J 2019 07 9;476(13):1929-1942. Epub 2019 Jul 9.

Department of Molecular Cell Biology, University of Guelph, Guelph, Ontario, Canada.

Lipid droplets (LDs) are organelles that compartmentalize nonbilayer-forming lipids in the aqueous cytoplasm of cells. They are ubiquitous in most organisms, including in animals, protists, plants and microorganisms. In eukaryotes, LDs are believed to be derived by a budding and scission process from the surface of the endoplasmic reticulum, and this occurs concomitantly with the accumulation of neutral lipids, most often triacylglycerols and steryl esters. Overall, the mechanisms underlying LD biogenesis are difficult to generalize, in part because of the involvement of different sets of both evolutionarily conserved and organism-specific LD-packaging proteins. Here, we briefly compare and contrast these proteins and the allied processes responsible for LD biogenesis in cells of animals, yeasts and plants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1042/BCJ20180021DOI Listing
July 2019

iCURE (iterative course-based undergraduate research experience): A case-study.

Biochem Mol Biol Educ 2019 09 1;47(5):565-572. Epub 2019 Jul 1.

University of North Texas, Denton, Texas, 76203.

Several models suggest ways to expose undergraduates at minority serving institutions or institutions with limited research infrastructures to the iterative process of research. Apprentice-based research experiences allow students to work one-on-one with a research mentor in the hands-on discovery process, but with teaching being a priority for faculty at the aforementioned institutions, financial, spatial, and time limitations for research progress exist. Course-based undergraduate research experiences (CUREs) provide opportunities for a greater number of undergraduates to become familiar with the questions, techniques, and failure involved in research. However, designing projects that a group of students can complete in a semester can be challenging. Inclusive Research Education Communities are intended to promote retention in STEM courses for early college students but have limited benefit for upper-level courses. We sought to create an iterative CURE between fall semester BIOL3900 at the University of North Texas and spring semester CHE397 at Bethel University (Saint Paul, MN) to promote collaboration between unique learning communities. The research goal was to use a tobacco (Nicotiana benthamiana) transient expression system as a platform to test gene functions and to engineer valuable bioproducts in plant vegetative tissues. The outcomes of this 2-year integrative module included novel discoveries leading to publications in peer-reviewed journals, cost benefits due to shared resources, continual movement of the project, course-based training for future independent research projects, and improved student attitudes about research. © 2019 International Union of Biochemistry and Molecular Biology, 47(5):565-572, 2019.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/bmb.21279DOI Listing
September 2019

The effects of tetrahydrocurcumin compared to curcuminoids on human platelet aggregation and blood coagulation in vitro.

Thromb Res 2019 Jul 30;179:28-30. Epub 2019 Apr 30.

Haematology Department, Calvary Mater Newcastle, Australia; Hunter Medical Research Institute, New Lambton, Australia; Hunter Cancer Research Alliance, NSW, Australia; School of Biomedical Sciences and Pharmacy, University of Newcastle, Australia. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.thromres.2019.04.029DOI Listing
July 2019

Mouse lipogenic proteins promote the co-accumulation of triacylglycerols and sesquiterpenes in plant cells.

Planta 2019 Jul 27;250(1):79-94. Epub 2019 Mar 27.

Department of Biological Sciences, Biodiscovery Institute, University of North Texas, 1155 Union Circle #305220, Denton, TX, 76203-5017, USA.

Main Conclusion: Mouse FIT2 protein redirects the cytoplasmic terpene biosynthetic machinery to lipid-droplet-forming domains in the ER and this relocalization supports the efficient compartmentalization and accumulation of sesquiterpenes in plant cells. Mouse (Mus musculus) fat storage-inducing transmembrane protein 2 (MmFIT2), an endoplasmic reticulum (ER)-resident protein with an important role in lipid droplet (LD) biogenesis in mammals, can function in plant cells to promote neutral lipid compartmentalization. Surprisingly, in affinity capture experiments, the Nicotiana benthamiana 5-epi-aristolochene synthase (NbEAS), a soluble cytoplasm-localized sesquiterpene synthase, was one of the most abundant proteins that co-precipitated with GFP-tagged MmFIT2 in transient expression assays in N. benthamiana leaves. Consistent with results of pull-down experiments, the subcellular location of mCherry-tagged NbEAS was changed from the cytoplasm to the LD-forming domains in the ER, only when co-expressed with MmFIT2. Ectopic co-expression of NbEAS and MmFIT2 together with mouse diacylglycerol:acyl-CoA acyltransferase 2 (MmDGAT2) in N. benthamiana leaves substantially increased the numbers of cytoplasmic LDs and supported the accumulation of the sesquiterpenes, 5-epi-aristolochene and capsidiol, up to tenfold over levels elicited by Agrobacterium infection alone. Taken together, our results suggest that MmFIT2 recruits sesquiterpene synthetic machinery to ER subdomains involved in LD formation and that this process can enhance the efficiency of sesquiterpene biosynthesis and compartmentalization in plant cells. Further, MmFIT2 and MmDGAT2 represent cross-kingdom lipogenic protein factors that may be used to engineer terpene accumulation more broadly in the cytoplasm of plant vegetative tissues.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00425-019-03148-9DOI Listing
July 2019

Structural analysis of a plant fatty acid amide hydrolase provides insights into the evolutionary diversity of bioactive acylethanolamides.

J Biol Chem 2019 05 20;294(18):7419-7432. Epub 2019 Mar 20.

From the BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203 and

-Acylethanolamines (NAEs) are fatty acid derivatives that in animal systems include the well-known bioactive metabolites of the endocannabinoid signaling pathway. Plants use NAE signaling as well, and these bioactive molecules often have oxygenated acyl moieties. Here, we report the three-dimensional crystal structures of the signal-terminating enzyme fatty acid amide hydrolase (FAAH) from in its apo and ligand-bound forms at 2.1- and 3.2-Å resolutions, respectively. This plant FAAH structure revealed features distinct from those of the only other available FAAH structure (rat). The structures disclosed that although catalytic residues are conserved with the mammalian enzyme, AtFAAH has a more open substrate-binding pocket that is partially lined with polar residues. Fundamental differences in the organization of the membrane-binding "cap" and the membrane access channel also were evident. In accordance with the observed structural features of the substrate-binding pocket, kinetic analysis showed that AtFAAH efficiently uses both unsubstituted and oxygenated acylethanolamides as substrates. Moreover, comparison of the apo and ligand-bound AtFAAH structures identified three discrete sets of conformational changes that accompany ligand binding, suggesting a unique "squeeze and lock" substrate-binding mechanism. Using molecular dynamics simulations, we evaluated these conformational changes further and noted a partial unfolding of a random-coil helix within the region 531-537 in the apo structure but not in the ligand-bound form, indicating that this region likely confers plasticity to the substrate-binding pocket. We conclude that the structural divergence in bioactive acylethanolamides in plants is reflected in part in the structural and functional properties of plant FAAHs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1074/jbc.RA118.006672DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6509493PMC
May 2019

Tissue-specific differences in metabolites and transcripts contribute to the heterogeneity of ricinoleic acid accumulation in Ricinus communis L. (castor) seeds.

Metabolomics 2019 01 3;15(1). Epub 2019 Jan 3.

Department of Biological Sciences, University of North Texas, Denton, TX, USA.

Introduction: Castor (Ricinus communis L.) seeds are valued for their production of oils which can comprise up to 90% hydroxy-fatty acids (ricinoleic acid). Castor oil contains mono-, di- and tri- ricinoleic acid containing triacylglycerols (TAGs). Although the enzymatic synthesis of ricinoleic acid is well described, the differential compartmentalization of these TAG molecular species has remained undefined.

Objectives: To examine the distribution of hydroxy fatty acid accumulation within the endosperm and embryo tissues of castor seeds.

Methods: Matrix assisted laser desorption/ionization mass spectrometry imaging was used to map the distribution of triacylglycerols in tissue sections of castor seeds. In addition, the endosperm and embryo (cotyledons and embryonic axis) tissues were dissected and extracted for quantitative lipidomics analysis and Illumina-based RNA deep sequencing.

Results: This study revealed an unexpected heterogeneous tissue distribution of mono-, di- and tri- hydroxy-triacylglycerols in the embryo and endosperm tissues of castor seeds. Pathway analysis based on transcript abundance suggested that distinct embryo- and endosperm-specific mechanisms may exist for the shuttling of ricinoleic acid away from phosphatidylcholine (PC) and into hydroxy TAG production. The embryo-biased mechanism appears to favor removal of ricinoleic acid from PC through phophatidylcholine: diacylglycerol acyltransferase while the endosperm pathway appears to remove ricinoleic acid from the PC pool by preferences of phospholipase A (PLAα) and/or phosphatidylcholine: diacylglycerol cholinephosphotransferase.

Conclusions: Collectively, a combination of lipidomics and transcriptomics analyses revealed previously undefined spatial aspects of hydroxy fatty acid metabolism in castor seeds. These studies underscore a need for tissue-specific studies as a means to better understand the regulation of triacylglycerol accumulation in oilseeds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11306-018-1464-3DOI Listing
January 2019

Discontinuous fatty acid elongation yields hydroxylated seed oil with improved function.

Nat Plants 2018 09 27;4(9):711-720. Epub 2018 Aug 27.

National Key Lab of Crop Genetic Improvement and College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China.

The biosynthesis of 'unusual' fatty acids with structures that deviate from the common C and C fatty acids has evolved numerous times in the plant kingdom. Characterization of unusual fatty acid biosynthesis has enabled increased understanding of enzyme substrate properties, metabolic plasticity and oil functionality. Here, we report the identification of a novel pathway for hydroxy fatty acid biosynthesis based on the serendipitous discovery of two C fatty acids containing hydroxyl groups at the 7 and 18 carbon atoms as major components of the seed oil of Orychophragmus violaceus, a China-native Brassicaceae. Biochemical and genetic evidence are presented for premature or 'discontinuous' elongation of a 3-OH intermediate by a divergent 3-ketoacyl-CoA (coenzyme A) synthase during a chain extension cycle as the origin of the 7-OH group of the dihydroxy fatty acids. Tribology studies revealed superior high-temperature lubricant properties for O. violaceus seed oil compared to castor oil, a high-performance vegetable oil lubricant. These findings provide a direct pathway for designing a new class of environmentally friendly lubricants and unveil the potential of O. violaceus as a new industrial oilseed crop.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41477-018-0225-7DOI Listing
September 2018

Spatial analysis of lipid metabolites and expressed genes reveals tissue-specific heterogeneity of lipid metabolism in high- and low-oil Brassica napus L. seeds.

Plant J 2018 06;94(6):915-932

National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.

Despite the importance of oilseeds to worldwide human nutrition, and more recently to the production of bio-based diesel fuels, the detailed mechanisms regulating seed oil biosynthesis remain only partly understood, especially from a tissue-specific perspective. Here, we investigated the spatial distributions of lipid metabolites and transcripts involved in oil biosynthesis from seeds of two low-erucic acid genotypes of Brassica napus with high and low seed-oil content. Integrated results from matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) of lipids in situ, lipidome profiling of extracts from seed tissues, and tissue-specific transcriptome analysis revealed complex spatial distribution patterns of lipids and transcripts. In general, it appeared that many triacylglycerol and phosphatidylcholine species distributed heterogeneously throughout the embryos. Tissue-specific transcriptome analysis identified key genes involved in de novo fatty acid biosynthesis in plastid, triacylglycerols assembly and lipid droplet packaging in the endoplasmic reticulum (ER) that may contribute to the high or low oil phenotype and heterogeneity of lipid distribution. Our results imply that transcriptional regulation represents an important means of impacting lipid compartmentalization in oil seeds. While much information remains to be learned about the intricacies of seed oil accumulation and distribution, these studies highlight the advances that come from evaluating lipid metabolism within a spatial context and with multiple omics level datasets.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/tpj.13959DOI Listing
June 2018