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1.
Eye (Lond) ; 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-39014208

ABSTRACT

BACKGROUND/OBJECTIVES: Giant cell arteritis (GCA) is an inflammatory vascular disease in which prompt and accurate diagnosis is critical. The efficacy of temporal artery biopsy (TAB) is limited by 'skip' lesions and a delay in histological analysis. This first-in-man ex-vivo study aims to assess the accuracy of optical frequency domain imaging (OFDI) in diagnosing GCA. SUBJECTS/METHODS: 29 TAB samples of patients with suspected GCA were submerged in 0.9% sodium chloride and an OFDI catheter was passed through the lumen to create cross-sectional images prior to histological analysis. The specimens were then preserved in formalin for histological examination. Mean intimal thickness (MIT) on OFDI was measured, and the presence of both multinucleate giant cells (MNGCs) and fragmentation of the internal elastic lamina (FIEL) was assessed and compared with histology, used as the diagnostic gold standard. RESULTS: MIT in patients with/without histological evidence of GCA was 0.425 mm (±0.43) and 0.13 mm (±0.06) respectively compared with 0.215 mm (±0.09) and 0.135 mm (±0.07) on OFDI. MIT measured by OFDI was significantly higher in patients with histologically diagnosed arteritis compared to those without (p = 0.0195). For detecting FIEL and MNGCs, OFDI had a sensitivity of 75% and 28.6% and a specificity of 100% and 77.3% respectively. Applying diagnostic criteria of MIT > 0.20 mm, or the presence of MNGCs or FIEL, the sensitivity of detecting histological arteritis using OFDI was 91.4% and the specificity 94.1%. CONCLUSIONS: OFDI provided rapid imaging of TAB specimens achieving a diagnostic accuracy comparable to histological examination. In-vivo imaging may allow imaging of a longer arterial section.

2.
Front Genet ; 14: 1121462, 2023.
Article in English | MEDLINE | ID: mdl-36968584

ABSTRACT

Climate change is significantly impacting agricultural production worldwide. Peanuts provide food and nutritional security to millions of people across the globe because of its high nutritive values. Drought and heat stress alone or in combination cause substantial yield losses to peanut production. The stress, in addition, adversely impact nutritional quality. Peanuts exposed to drought stress at reproductive stage are prone to aflatoxin contamination, which imposes a restriction on use of peanuts as health food and also adversely impact peanut trade. A comprehensive understanding of the impact of drought and heat stress at physiological and molecular levels may accelerate the development of stress tolerant productive peanut cultivars adapted to a given production system. Significant progress has been achieved towards the characterization of germplasm for drought and heat stress tolerance, unlocking the physiological and molecular basis of stress tolerance, identifying significant marker-trait associations as well major QTLs and candidate genes associated with drought tolerance, which after validation may be deployed to initiate marker-assisted breeding for abiotic stress adaptation in peanut. The proof of concept about the use of transgenic technology to add value to peanuts has been demonstrated. Advances in phenomics and artificial intelligence to accelerate the timely and cost-effective collection of phenotyping data in large germplasm/breeding populations have also been discussed. Greater focus is needed to accelerate research on heat stress tolerance in peanut. A suits of technological innovations are now available in the breeders toolbox to enhance productivity and nutritional quality of peanuts in harsh environments. A holistic breeding approach that considers drought and heat-tolerant traits to simultaneously address both stresses could be a successful strategy to produce climate-resilient peanut genotypes with improved nutritional quality.

3.
Photosynth Res ; 154(2): 169-182, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36163583

ABSTRACT

Rubisco activase (Rca) facilitates the catalytic repair of Rubisco, the CO2-fixing enzyme of photosynthesis, following periods of darkness, low to high light transitions or stress. Removal of the redox-regulated isoform of Rubisco activase, Rca-α, enhances photosynthetic induction in Arabidopsis and has been suggested as a strategy for the improvement of crops, which may experience frequent light transitions in the field; however, this has never been tested in a crop species. Therefore, we used RNAi to reduce the Rca-α content of soybean (Glycine max cv. Williams 82) below detectable levels and then characterized the growth, photosynthesis, and Rubisco activity of the resulting transgenics, in both growth chamber and field conditions. Under a 16 h sine wave photoperiod, the reduction of Rca-α contents had no impact on morphological characteristics, leaf expansion rate, or total biomass. Photosynthetic induction rates were unaltered in both chamber-grown and field-grown plants. Plants with reduced Rca-α content maintained the ability to regulate Rubisco activity in low light just as in control plants. This result suggests that in soybean, Rca-α is not as centrally involved in the regulation of Rca oligomer activity as it is in Arabidopsis. The isoform stoichiometry supports this conclusion, as Rca-α comprises only ~ 10% of the Rubisco activase content of soybean, compared to ~ 50% in Arabidopsis. This is likely to hold true in other species that contain a low ratio of Rca-α to Rca-ß isoforms.


Subject(s)
Arabidopsis , Ribulose-Bisphosphate Carboxylase , Ribulose-Bisphosphate Carboxylase/metabolism , Glycine max/metabolism , Arabidopsis/metabolism , Tissue Plasminogen Activator , Plant Proteins/metabolism , Photosynthesis/physiology , Protein Isoforms , Oxidation-Reduction
4.
Front Genome Ed ; 4: 901444, 2022.
Article in English | MEDLINE | ID: mdl-35647579

ABSTRACT

Peanut (Arachis hypogaea L.), an allotetraploid legume of the Fabaceae family, is able to thrive in tropical and subtropical regions and is considered as a promising oil seed crop worldwide. Increasing the content of oleic acid has become one of the major goals in peanut breeding because of health benefits such as reduced blood cholesterol level, antioxidant properties and industrial benefits such as longer shelf life. Genomic sequencing of peanut has provided evidence of homeologous AhFAD2A and AhFAD2B genes encoding Fatty Acid Desaturase2 (FAD2), which are responsible for catalyzing the conversion of monounsaturated oleic acid into polyunsaturated linoleic acid. Research studies demonstrate that mutations resulting in a frameshift or stop codon in an FAD2 gene leads to higher oleic acid content in oil. In this study, two expression vectors, pDW3873 and pDW3876, were constructed using Cas9 fused to different deaminases, which were tested as tools to induce point mutations in the promoter and the coding sequences of peanut AhFAD2 genes. Both constructs harbor the single nuclease null variant, nCas9 D10A, to which the PmCDA1 cytosine deaminase was fused to the C-terminal (pDW3873) while rAPOBEC1 deaminase and an uracil glycosylase inhibitor (UGI) were fused to the N-terminal and the C-terminal respectively (pDW3876). Three gRNAs were cloned independently into both constructs and the functionality and efficiency were tested at three target sites in the AhFAD2 genes. Both constructs displayed base editing activity in which cytosine was replaced by thymine or other bases in the targeted editing window. pDW3873 showed higher efficiency compared to pDW3876 suggesting that the former is a better base editor in peanut. This is an important step forward considering introgression of existing mutations into elite varieties can take up to 15 years making this tool a benefit for peanut breeders, farmers, industry and ultimately for consumers.

5.
Front Genet ; 13: 849961, 2022.
Article in English | MEDLINE | ID: mdl-35571035

ABSTRACT

Peanut (Arachis hypogaea L.) seed is a rich source of edible oil, comprised primarily of monounsaturated oleic acid and polyunsaturated linoleic acid, accounting for 80% of its fatty acid repertoire. The conversion of oleic acid to linoleic acid, catalyzed by Fatty Acid Desaturase 2 (FAD2) enzymes, is an important regulatory point linked to improved abiotic stress responses while the ratio of these components is a significant determinant of commercial oil quality. Specifically, oleic acid has better oxidative stability leading to longer shelf life and better taste qualities while also providing nutritional based health benefits. Naturally occurring FAD2 gene knockouts that lead to high oleic acid levels improve oil quality at the potential expense of plant health though. We undertook a CRISPR/Cas9 based site-specific genome modification approach designed to downregulate the expression of two homeologous FAD2 genes in seed while maintaining regulation in other plant tissues. Two cis-regulatory elements the RY repeat motif and 2S seed protein motif in the 5'UTR and associated intron of FAD2 genes are potentially important for regulating seed-specific gene expression. Using hairy root and stable germ line transformation, differential editing efficiencies were observed at both CREs when targeted by single gRNAs using two different gRNA scaffolds. The editing efficiencies also differed when two gRNAs were expressed simultaneously. Additionally, stably transformed seed exhibited an increase in oleic acid levels relative to wild type. Taken together, the results demonstrate the immense potential of CRISPR/Cas9 based approaches to achieve high frequency targeted edits in regulatory sequences for the generation of novel transcriptional alleles, which may lead to fine tuning of gene expression and functional genomic studies in peanut.

6.
Plants (Basel) ; 11(10)2022 May 20.
Article in English | MEDLINE | ID: mdl-35631786

ABSTRACT

Peanuts are an economically important crop cultivated worldwide. However, several limitations restrained its productivity, including biotic/abiotic stresses. CRISPR/Cas9-based gene-editing technology holds a promising approach to developing new crops with improved agronomic and nutritional traits. Its application has been successful in many important crops. However, the application of this technology in peanut research is limited, probably due to the lack of suitable constructs and protocols. In this study, two different constructs were generated to induce insertion/deletion mutations in the targeted gene for a loss of function study. The first construct harbors the regular gRNA scaffold, while the second construct has the extended scaffold plus terminator. The designed gRNA targeting the coding sequence of the FAD2 genes was cloned into both constructs, and their functionality and efficiency were validated using the hairy root transformation system. Both constructs displayed insertions and deletions as the types of edits. The construct harboring the extended plus gRNA terminator showed a higher editing efficiency than the regular scaffold for monoallelic and biallelic mutations. These two constructs can be used for gene editing in peanuts and could provide tools for improving peanut lines for the benefit of peanut breeders, farmers, and industry.

7.
Plant Physiol ; 187(4): 2637-2655, 2021 12 04.
Article in English | MEDLINE | ID: mdl-34618092

ABSTRACT

Programmable site-specific nucleases, such as the clustered regularly interspaced short palindromic repeat (CRISPR)/ CRISPR-associated protein 9 (Cas9) ribonucleoproteins (RNPs), have allowed creation of valuable knockout mutations and targeted gene modifications in Chlamydomonas (Chlamydomonas reinhardtii). However, in walled strains, present methods for editing genes lacking a selectable phenotype involve co-transfection of RNPs and exogenous double-stranded DNA (dsDNA) encoding a selectable marker gene. Repair of the dsDNA breaks induced by the RNPs is usually accompanied by genomic insertion of exogenous dsDNA fragments, hindering the recovery of precise, scarless mutations in target genes of interest. Here, we tested whether co-targeting two genes by electroporation of pairs of CRISPR/Cas9 RNPs and single-stranded oligodeoxynucleotides (ssODNs) would facilitate the recovery of precise edits in a gene of interest (lacking a selectable phenotype) by selection for precise editing of another gene (creating a selectable marker)-in a process completely lacking exogenous dsDNA. We used PPX1 (encoding protoporphyrinogen IX oxidase) as the generated selectable marker, conferring resistance to oxyfluorfen, and identified precise edits in the homolog of bacterial ftsY or the WD and TetratriCopeptide repeats protein 1 genes in ∼1% of the oxyfluorfen resistant colonies. Analysis of the target site sequences in edited mutants suggested that ssODNs were used as templates for DNA synthesis during homology directed repair, a process prone to replicative errors. The Chlamydomonas acetolactate synthase gene could also be efficiently edited to serve as an alternative selectable marker. This transgene-free strategy may allow creation of individual strains containing precise mutations in multiple target genes, to study complex cellular processes, pathways, or structures.


Subject(s)
Algal Proteins/genetics , CRISPR-Cas Systems , Chlamydomonas/genetics , Gene Editing/methods , Ribonucleoproteins/genetics
8.
Front Cell Dev Biol ; 8: 723, 2020.
Article in English | MEDLINE | ID: mdl-32850839

ABSTRACT

Probiotics are used as microbial food supplements for health and well-being. They are thought to have immunomodulatory effects although their exact physiological mechanism of action is not clear. This study investigated the influence of probiotic Lactobacillus rhamnosus GG conditioned media (LGG-CM) on macrophage phagocytosis of non-pathogenic Escherichia coli HfrC. The gentamicin protection assay was used to study the bacterial killing phases of phagocytosis. Macrophages co-incubated with E. coli for an hour allowed them to ingest bacteria and then the rate of E. coli killing was monitored for up to 300 min to determine the killing or digestion of the bacteria by recovering them from the macrophage lysate. We found that the LGG-CM significantly increased the bacterial killing by approximately 6-fold when compared with that of controls. By contrast, this killing process was found to be associated with enhanced free radical production via the activation of NADPH oxidase, stimulated by the LGG conditioned medium. We also found that the conditioned medium had small effect on nitric oxide (NO) generation, albeit to a lesser extent. This work suggests that LGG-CM may play an important role in suppressing the total microbial load within the macrophages and hence, the extent to which pro-inflammatory molecules such as free radicals and NO are generated. The modulation of inflammation-promoting signals by LGG-CM may be beneficial as it modulates bacterial killing, and thereby prevents any collateral damage to host.

9.
Pest Manag Sci ; 76(12): 4150-4158, 2020 Dec.
Article in English | MEDLINE | ID: mdl-32592433

ABSTRACT

BACKGROUND: Yersinia entomophaga is an entomopathogenic bacterium that is active against scarab beetles, among other insects. In New Zealand, the African black beetle, Heteronychus arator (Coleoptera: Scarabaeidae), is a major pest of pastures and arable crops but very few control options exist and no insecticides are registered for use in established pastures. RESULTS: In laboratory bioassays, H. arator adults were susceptible to a bait containing Y. entomophaga at low doses. This bait was more effective against H. arator adults during spring than autumn in small-scale field plots (320 mm diameter). A large-scale field trial (40 × 40 m plots) reduced adult numbers substantially: approximately twice as many beetles were captured in pitfall traps from untreated plots compared with plots treated with the Y. entomophaga bait at 70 kg ha-1 . This single bait application in spring also reduced subsequent larval populations in summer. CONCLUSIONS: Heteronychus arator is a difficult pest to manage using chemical insecticides. This biopesticide with Y. entomophaga as the active ingredient offers a new solution for New Zealand pastures, with potential for application to other crops affected by H. arator and for control of other pests. © 2020 Society of Chemical Industry.


Subject(s)
Coleoptera , Black or African American , Animals , Biological Control Agents , Humans , New Zealand , Yersinia
10.
Plant J ; 103(6): 2250-2262, 2020 09.
Article in English | MEDLINE | ID: mdl-32593186

ABSTRACT

Rubisco activase (Rca) facilitates the release of sugar-phosphate inhibitors from the active sites of Rubisco and thereby plays a central role in initiating and sustaining Rubisco activation. In Arabidopsis, alternative splicing of a single Rca gene results in two Rca isoforms, Rca-α and Rca-ß. Redox modulation of Rca-α regulates the function of Rca-α and Rca-ß acting together to control Rubisco activation. Although Arabidopsis Rca-α alone less effectively activates Rubisco in vitro, it is not known how CO2 assimilation and plant growth are impacted. Here, we show that two independent transgenic Arabidopsis lines expressing Rca-α in the absence of Rca-ß ('Rca-α only' lines) grew more slowly in various light conditions, especially under low light or fluctuating light intensity, and in a short day photoperiod compared to wildtype. Photosynthetic induction was slower in the Rca-α only lines, and they maintained a lower rate of CO2 assimilation during both photoperiod types. Our findings suggest Rca oligomers composed of Rca-α only are less effective in initiating and sustaining the activation of Rubisco than when Rca-ß is also present. Currently there are no examples of any plant species that naturally express Rca-α only but numerous examples of species expressing Rca-ß only. That Rca-α exists in most plant species, including many C3 and C4 food and bioenergy crops, implies its presence is adaptive under some circumstances.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Oxidation-Reduction , Photosynthesis , Arabidopsis/growth & development , Arabidopsis/physiology , Arabidopsis Proteins/genetics , Gene Expression Regulation, Plant , Light , Phenotype , Plants, Genetically Modified , Protein Isoforms
11.
Pest Manag Sci ; 76(1): 350-359, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31207111

ABSTRACT

BACKGROUND: Porina is the common name for moths and larvae of the genus Wiseana (Lepidoptera: Hepialidae), some of which are significant pasture pests in New Zealand. Because of environmental concerns and the non-target effects of insecticide control measures, biological alternatives for the control of insect pests such as porina are required. RESULTS: Using a food preference assay and time-lapse photography, a range of low-cost food ingredients were assessed for their palatability to porina larvae. Lead candidates were combined into extruded bait variants, allowing assessment of their palatability to porina larvae. A composite bait consisting of palatable ingredients was developed, into which the porina-active entomopathogen Yersinia entomophaga was incorporated. A 7 day minimum median lethal dose of approximately 6.0 × ±1 × 106 Y. entomophaga cells per 0.02 g of bait was defined. Field trials showed that the mean change in larval density over time differed between treatments, with Y. entomophaga bait applied at 87 kg ha-1 resulting in a mean 65% reduction in larval density relative to the control plots, and diflubenzuron treatment resulting in a mean 77% reduction relative to the control plots. The mean dry matter yields over the course of the trial were highest for diflubenzuron (5029 kg ha-1 ), followed by the Y. entomophaga (4783 kg ha-1 ) and control (4673 kg ha-1 ) treatments. CONCLUSIONS: The bacterium Y. entomophaga applied as a composite bait offers an environmentally sustainable approach for porina pest control. © 2019 Society of Chemical Industry.


Subject(s)
Moths , Yersinia , Animals , Grassland , Larva , New Zealand
12.
Sci Rep ; 9(1): 19902, 2019 12 27.
Article in English | MEDLINE | ID: mdl-31882637

ABSTRACT

An important advantage of delivering CRISPR reagents into cells as a ribonucleoprotein (RNP) complex is the ability to edit genes without reagents being integrated into the genome. Transient presence of RNP molecules in cells can reduce undesirable off-target effects. One method for RNP delivery into plant cells is the use of a biolistic gun. To facilitate selection of transformed cells during RNP delivery, a plasmid carrying a selectable marker gene can be co-delivered with the RNP to enrich for transformed/edited cells. In this work, we compare targeted mutagenesis in rice using three different delivery platforms: biolistic RNP/DNA co-delivery; biolistic DNA delivery; and Agrobacterium-mediated delivery. All three platforms were successful in generating desired mutations at the target sites. However, we observed a high frequency (over 14%) of random plasmid or chromosomal DNA fragment insertion at the target sites in transgenic events generated from both biolistic delivery platforms. In contrast, integration of random DNA fragments was not observed in transgenic events generated from the Agrobacterium-mediated method. These data reveal important insights that must be considered when selecting the method for genome-editing reagent delivery in plants, and emphasize the importance of employing appropriate molecular screening methods to detect unintended alterations following genome engineering.


Subject(s)
CRISPR-Cas Systems/genetics , Oryza/genetics , Plasmids/genetics , RNA, Plant/genetics , Agrobacterium/genetics , DNA Fragmentation , Ribonucleoproteins/genetics , Ribonucleoproteins/metabolism
13.
Biochem Biophys Rep ; 6: 68-75, 2016 Jul.
Article in English | MEDLINE | ID: mdl-28955864

ABSTRACT

Phagocytes such as macrophages are capable of detecting and killing pathogenic bacteria by producing reactive oxygen and nitrogen species. Formation of free radicals in macrophages may be regulated by probiotics or by factors released by probiotics but yet to be identified. Thus, studies were carried out to determine whether cell-free conditioned medium obtained from cultures of Lactobacillus rhamnosus GG (LGG-CM) regulate production of reactive oxygen species (ROS) and/or nitric oxide (NO) in macrophages. J774 macrophages in culture were loaded with either H2DCFDA for monitoring ROS or with DAFFM-DA for NO detection. Free radical production was measured on a fluorescence microplate reader and changes were analysed by Cumulative sum (CuSum) calculations. Low concentration of LGG-CM (10% LGG-CM) or LPS did not cause any significant change in basal levels of ROS or NO production. In contrast, high concentration of LGG-CM (75% and 100%) significantly enhanced ROS generation but also significantly reduced NO level. These findings are novel and suggest for the first time that probiotics may release factors in culture which enhance ROS production and may additionally reduce deleterious effects associated with excessive nitrogen species by suppressing NO level. These events may account, in part, for the beneficial bactericidal and anti-inflammatory actions ascribed to probiotics and may be of clinical relevance.

14.
BMC Ophthalmol ; 15: 129, 2015 Oct 07.
Article in English | MEDLINE | ID: mdl-26447043

ABSTRACT

We present a paediatric case of infectious mononucleosis in a 13-year old, manifesting with follicular conjunctivitis and a conjunctival mass in one eye with no evidence of leucocytosis on the blood count. The diagnosis was confirmed following surgical excision and biopsy. The case represented a diagnostic challenge due to its atypism and given the steady increase in the prevalence of EBV-related ocular diseases in the last years, this report can serve as an example to prompt earlier serological tests to identify the aetiology in similar cases. This is important because EBV can be treated with acyclovir early in the active viral phase.


Subject(s)
Conjunctivitis, Viral/diagnosis , Epstein-Barr Virus Infections/diagnosis , Eye Infections, Viral/diagnosis , Adolescent , Antibodies, Viral/blood , Conjunctivitis, Viral/surgery , Conjunctivitis, Viral/virology , Epstein-Barr Virus Infections/surgery , Epstein-Barr Virus Infections/virology , Epstein-Barr Virus Nuclear Antigens/immunology , Eye Infections, Viral/surgery , Eye Infections, Viral/virology , Humans , Immunoglobulin G/blood , Infectious Mononucleosis/diagnosis , Infectious Mononucleosis/surgery , Infectious Mononucleosis/virology , Male , Ophthalmologic Surgical Procedures
15.
Environ Sci Technol ; 49(15): 9048-55, 2015 Aug 04.
Article in English | MEDLINE | ID: mdl-26168359

ABSTRACT

An extensively diverse array of brominated disinfection byproducts (DBPs) were generated following electrochemical disinfection of natural coastal/estuarine water, which is one of the main treatment methods currently under consideration for ballast water treatment. Ultra-high-resolution mass spectrometry revealed 462 distinct brominated DBPs at a relative abundance in the mass spectra of more than 1%. A brominated DBP with a relative abundance of almost 22% was identified as 2,2,4-tribromo-5-hydroxy-4-cyclopentene-1,3-dione, which is an analogue to several previously described 2,2,4-trihalo-5-hydroxy-4-cyclopentene-1,3-diones in drinking water. Several other brominated molecular formulas matched those of other known brominated DBPs, such as dibromomethane, which could be generated by decarboxylation of dibromoacetic acid during ionization, dibromophenol, dibromopropanoic acid, dibromobutanoic acid, bromohydroxybenzoic acid, bromophenylacetic acid, bromooxopentenoic acid, and dibromopentenedioic acid. Via comparison to previously described chlorine-containing analogues, bromophenylacetic acid, dibromooxopentenoic acid, and dibromopentenedioic acid were also identified. A novel compound at a 4% relative abundance was identified as tribromoethenesulfonate. This compound has not been previously described as a DBP, and its core structure of tribromoethene has been demonstrated to show toxicological implications. Here we show that electrochemical disinfection, suggested as a candidate for successful ballast water treatment, caused considerable production of some previously characterized DBPs in addition to novel brominated DBPs, although several hundred compounds remain structurally uncharacterized. Our results clearly demonstrate that electrochemical and potentially direct chlorination of ballast water in estuarine and marine systems should be approached with caution and the concentrations, fate, and toxicity of DBP need to be further characterized.


Subject(s)
Disinfection/methods , Electrochemistry/methods , Halogenation , Organic Chemicals/analysis , Seawater/chemistry , Water Pollutants, Chemical/analysis , Water Purification/methods , Isotopes , Mass Spectrometry , Solubility
16.
Plant J ; 82(1): 1-11, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25660294

ABSTRACT

The CO2 concentrating mechanism (CCM) is a key component of the carbon assimilation strategy of aquatic microalgae. Induced by limiting CO2 and tightly regulated, the CCM enables these microalgae to respond rapidly to varying environmental CO2 supplies and to perform photosynthetic CO2 assimilation in a cost-effective way. A functional CCM in eukaryotic algae requires Rubisco sequestration, rapid interconversion between CO2 and HCO3(-) catalyzed by carbonic anhydrases (CAs), and active inorganic carbon (Ci) uptake. In the model microalga Chlamydomonas reinhardtii, a membrane protein HLA3 is proposed to be involved in active Ci uptake across the plasma membrane. In this study, we use an artificially designed transcription activator-like effector (dTALE) to activate the expression of HLA3. The successful activation of HLA3 expression demonstrates dTALE as a promising tool for gene-specific activation and investigation of gene function in Chlamydomonas. Activation of HLA3 expression in high CO2 acclimated cells, where HLA3 is not expressed, resulted in increased Ci accumulation and Ci-dependent photosynthetic O2 evolution specifically in very low CO2 concentrations, which confirms that HLA3 is indeed involved in Ci uptake, and suggests it is mainly associated with HCO3(-) transport in very low CO2 concentrations, conditions in which active CO2 uptake is highly limited.


Subject(s)
Bicarbonates/metabolism , Carbon Dioxide/metabolism , Carbon/metabolism , Chlamydomonas reinhardtii/genetics , Membrane Transport Proteins/metabolism , Transcriptional Activation , Algal Proteins/genetics , Algal Proteins/metabolism , Biological Transport , Carbonic Anhydrases/genetics , Carbonic Anhydrases/metabolism , Chlamydomonas reinhardtii/metabolism , Gene Expression Regulation, Plant , Membrane Transport Proteins/genetics , Oxygen/metabolism , Photosynthesis , Promoter Regions, Genetic/genetics
17.
GM Crops Food ; 6(4): 266-76, 2015.
Article in English | MEDLINE | ID: mdl-26745836

ABSTRACT

Targeted genome editing is now possible in nearly any organism and is widely acknowledged as a biotech game-changer. Among available gene editing techniques, the CRISPR-Cas9 system is the current favorite because it has been shown to work in many species, does not necessarily result in the addition of foreign DNA at the target site, and follows a set of simple design rules for target selection. Use of the CRISPR-Cas9 system is facilitated by the availability of an array of CRISPR design tools that vary in design specifications and parameter choices, available genomes, graphical visualization, and downstream analysis functionality. To help researchers choose a tool that best suits their specific research needs, we review the functionality of various CRISPR design tools including our own, the CRISPR Genome Analysis Tool (CGAT; http://cropbioengineering.iastate.edu/cgat ).


Subject(s)
CRISPR-Cas Systems , Internet , Software , Animals , Computational Biology , Genetic Engineering/methods , Genome , RNA/chemistry , Sequence Analysis, RNA , Species Specificity
18.
Biochem J ; 462(1): 15-24, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-25057889

ABSTRACT

Genome editing is the practice of making predetermined and precise changes to a genome by controlling the location of DNA DSBs (double-strand breaks) and manipulating the cell's repair mechanisms. This technology results from harnessing natural processes that have taken decades and multiple lines of inquiry to understand. Through many false starts and iterative technology advances, the goal of genome editing is just now falling under the control of human hands as a routine and broadly applicable method. The present review attempts to define the technique and capture the discovery process while following its evolution from meganucleases and zinc finger nucleases to the current state of the art: TALEN (transcription-activator-like effector nuclease) technology. We also discuss factors that influence success, technical challenges and future prospects of this quickly evolving area of study and application.


Subject(s)
DNA End-Joining Repair , Genetic Engineering/methods , Genome , Recombinational DNA Repair , Transcription Factors/genetics , Animals , DNA Repair , Endonucleases/genetics , Humans , Plants/genetics , Recombination, Genetic , Transcriptional Activation
19.
Plant Biotechnol J ; 12(7): 872-82, 2014 Sep.
Article in English | MEDLINE | ID: mdl-24702864

ABSTRACT

The genetically tractable microalga Chlamydomonas reinhardtii has many advantages as a model for renewable bioproducts and/or biofuels production. However, one limitation of C. reinhardtii is its relatively low-lipid content compared with some other algal species. To overcome this limitation, we combined ethane methyl sulfonate mutagenesis with fluorescence-activated cell sorting (FACS) of cells stained with the lipophilic stain Nile Red to isolate lipid hyperaccumulating mutants of C. reinhardtii. By manipulating the FACS gates, we sorted mutagenized cells with extremely high Nile Red fluorescence signals that were rarely detected in nonmutagenized populations. This strategy successfully isolated several putative lipid hyperaccumulating mutants exhibiting 23% to 58% (dry weight basis) higher fatty acid contents than their progenitor strains. Significantly, for most mutants, nitrogen starvation was not required to attain high-lipid content nor was there a requirement for a deficiency in starch accumulation. Microscopy of Nile Red stained cells revealed that some mutants exhibit an increase in the number of lipid bodies, which correlated with TLC analysis of triacyglycerol content. Increased lipid content could also arise through increased biomass production. Collectively, our findings highlight the ability to enhance intracellular lipid accumulation in algae using random mutagenesis in conjunction with a robust FACS and lipid yield verification regime. Our lipid hyperaccumulating mutants could serve as a genetic resource for stacking additional desirable traits to further increase lipid production and for identifying genes contributing to lipid hyperaccumulation, without lengthy lipid-induction periods.


Subject(s)
Chlamydomonas reinhardtii/metabolism , Flow Cytometry/methods , Lipid Metabolism/genetics , Chlamydomonas reinhardtii/cytology , Fatty Acids/metabolism , Mesylates/pharmacology , Mutagenesis , Starch/metabolism , Triglycerides/metabolism
20.
J Orthop Res ; 31(12): 1980-5, 2013 Dec.
Article in English | MEDLINE | ID: mdl-23940014

ABSTRACT

Current analysis of displaced acetabular fractures is limited in its ability to predict functional outcome. This study aimed to (1) quantify initial acetabular damage following acetabular fracture through measurement of subchondral bone density and fracture lines, and (2) evaluate associations between acetabular damage and functional outcomes following fracture. Subchondral bone intensity maps were created for 24 patients with unilateral acetabular fractures. Measures of crack length and density differences between corresponding regions in the fractured acetabuli, normalized by the unfractured side, were generated from preoperative CT images. Damage measures were compared to quality of life survey data collected for each patient at least 2 years post-injury (Musculoskeletal Functional Assessment [MFA] and Short Form-36 [SF-36], with specific focus on parameters that best describe patients' physical health). CT image quantification of initial damage to acetabular subchondral bone was associated with functional outcome post-injury. In general, damage as quantified through differences in density in the superior dome region (zones 8 and 12) and the central anterior region of the acetabulum (zone 3) were found to be the strongest significant predictors of functional outcome (adjusted R(2) = 0.3-0.45, p < 0.05). Damage to the superior dome was predictive of worse functional outcome whereas damage to the central anterior region indicated a better functional outcome. Once automated, this approach may form a basis to score acetabular fractures toward improving clinical prognoses.


Subject(s)
Acetabulum/injuries , Fractures, Bone/surgery , Acetabulum/pathology , Acetabulum/physiopathology , Adult , Aged , Bone Density , Female , Fractures, Bone/pathology , Fractures, Bone/physiopathology , Humans , Male , Middle Aged , Tomography, X-Ray Computed , Treatment Outcome
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