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1.
Bioorg Med Chem Lett ; 109: 129814, 2024 Sep 01.
Article in English | MEDLINE | ID: mdl-38815872

ABSTRACT

High temperature requirement A serine peptidase 1 (HTRA1) is a serine protease involved in an array of signaling pathways. It is also responsible for the regulation of protein aggregates via refolding, translocation, and degradation. It has subsequently been found that runaway proteolytic HTRA1 activity plays a role in a variety of diseases, including Age-Related Macular Degeneration (AMD), osteoarthritis, and Rheumatoid Arthritis. Selective inhibition of serine protease HTRA1 therefore offers a promising new strategy for the treatment of these diseases. Herein we disclose structure-activity-relationship (SAR) studies which identify key interactions responsible for binding affinity of small molecule inhibitors to HTRA1. The study results in highly potent molecules with IC50's less than 15 nM and excellent selectivity following a screen of 35 proteases.


Subject(s)
High-Temperature Requirement A Serine Peptidase 1 , Serine Endopeptidases , High-Temperature Requirement A Serine Peptidase 1/metabolism , Structure-Activity Relationship , Humans , Serine Endopeptidases/metabolism , Serine Proteinase Inhibitors/pharmacology , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/chemical synthesis , Molecular Structure , Dose-Response Relationship, Drug , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacology , Small Molecule Libraries/chemical synthesis
2.
Biochemistry ; 61(21): 2398-2408, 2022 11 01.
Article in English | MEDLINE | ID: mdl-36223199

ABSTRACT

The phytocannabinoid cannabigerol (CBG) is the central biosynthetic precursor to many cannabinoids, including Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Though the use of CBG has recently witnessed a widespread surge because of its beneficial health effects and lack of psychoactivity, its metabolism by human cytochrome P450s is largely unknown. Herein, we describe comprehensive in vitro and in vivo cytochrome P450 (CYP)-mediated metabolic studies of CBG, ranging from liquid chromatography tandem mass spectrometry-based primary metabolic site determination, synthetic validation, and kinetic behavior using targeted mass spectrometry. These investigations revealed that cyclo-CBG, a recently isolated phytocannabinoid, is the major metabolite that is rapidly formed by selected human cytochrome P450s (CYP2J2, CYP3A4, CYP2D6, CYP2C8, and CYP2C9). Additionally, in vivo studies with mice administered with CBG supported these studies, where cyclo-CBG is the major metabolite as well. Spectroscopic binding studies along with docking and modeling of the CBG molecule near the heme in the active site of P450s confirmed these observations, pointing at the preferred site selectivity of CBG metabolism at the prenyl chain over other positions. Importantly, we found out that CBG and its oxidized CBG metabolites reduced inflammation in BV2 microglial cells stimulated with LPS. Overall, combining enzymological studies, mass spectrometry, and chemical synthesis, we showcase that CBG is rapidly metabolized by human P450s to form oxidized metabolites that are bioactive.


Subject(s)
Cannabidiol , Cannabinoids , Animals , Humans , Mice , Cannabidiol/metabolism , Cannabinoids/metabolism , Cytochrome P-450 Enzyme System/metabolism
3.
J Org Chem ; 87(9): 6075-6086, 2022 05 06.
Article in English | MEDLINE | ID: mdl-35476908

ABSTRACT

Despite centuries-long use of Cannabis in human culture and the now ubiquitous claims of its medicinal value, only a small handful of phytocannabinoids have been rigorously evaluated for pharmacological properties. While more than 100 distinct minor cannabinoids have been documented to date, a paucity of studies on their biological activities have been conducted due to a lack of routine access to sufficient quantities for testing. Herein, we report a strategy to prepare several structurally diverse minor cannabinoids deriving synthetically from readily available cannabidiol. Furthermore, we examined their ability to polarize activated microglia toward an anti-inflammatory phenotype using LPS-stimulated BV2 microglial cells. The minor cannabinoids studied, especially cannabielsoin, dehydrocannabielsoin, cannabimovone, and 3'-epicannabimovone, inhibited the production of prototypical pro-inflammatory biomarkers. This study represents the beginning of a systematic mapping of the roles minor cannabinoids may play in the medicinal properties of cannabis used for the treatment of pain and inflammation.


Subject(s)
Cannabidiol , Cannabinoids , Cannabis , Anti-Inflammatory Agents/pharmacology , Cannabidiol/pharmacology , Cannabinoids/pharmacology , Cannabinoids/therapeutic use
4.
RSC Adv ; 11(19): 11714-11723, 2021 Mar 16.
Article in English | MEDLINE | ID: mdl-35423635

ABSTRACT

Dabbing and vaping cannabis extracts have gained large popularity in the United States as alternatives to cannabis smoking, but diversity in both available products and consumption habits make it difficult to assess consumer exposure to psychoactive ingredients and potentially harmful components. This work studies the how relative ratios of the two primary components of cannabis extracts, Δ9-tetrahydrocannabinol (THC) and terpenes, affect dosage of these and exposure to harmful or potentially harmful components (HPHCs). THC contains a monoterpene moiety and has been previously shown to emit similar volatile degradation products to terpenes when vaporized. Herein, the major thermal degradation mechanisms for THC and ß-myrcene are elucidated via analysis of their aerosol gas phase products using automated thermal desorption-gas chromatography-mass spectrometry with the aid of isotopic labelling and chemical mechanism modelling. Four abundant products - isoprene, 2-methyl-2-butene, 3-methylcrotonaldehyde, and 3-methyl-1-butene - are shown to derive from a common radical intermediate for both THC and ß-myrcene and these products comprise 18-30% of the aerosol gas phase. The relative levels of these four products are highly correlated with applied power to the e-cigarette, which indicates formation of these products is temperature dependent. Vaping THC-ß-myrcene mixtures with increasing % mass of ß-myrcene is correlated with less degradation of the starting material and a product distribution suggestive of a lower aerosolization temperature. By contrast, dabbing THC-ß-myrcene mixtures with increasing % mass of ß-myrcene is associated with higher levels of HPHCs, and isotopic labelling showed this is due to increased reactivity of ß-myrcene relative to THC.

5.
Resuscitation ; 158: 151-156, 2021 01.
Article in English | MEDLINE | ID: mdl-33278521

ABSTRACT

OBJECTIVE: While emphasized in clinical practice, the association between advanced airway insertion first-pass success (FPS) and patient outcomes is incompletely understood. We sought to determine the association of airway insertion FPS with adult out-of-hospital cardiac arrest (OHCA) outcomes in the Pragmatic Airway Resuscitation Trial (PART). METHODS: We performed a secondary analysis of PART, a multicenter clinical trial comparing LT and ETI upon adult OHCA outcomes. We defined FPS as successful LT insertion or ETI on the first attempt as reported by EMS personnel. We examined the outcomes return of spontaneous circulation (ROSC), 72-h survival, hospital survival, and hospital survival with favorable neurologic status (Modified Rankin Scale ≤3). Using multivariable GEE (generalized estimating equations), we determined the association between FPS and OHCA outcomes, adjusting for age, sex, witnessed arrest, bystander CPR, initial rhythm, and initial airway type. RESULTS: Of 3004 patients enrolled in the trial, 1423 received LT, 1227 received ETI, 354 received bag-valve-mask ventilation only. FPS was: LT 86.2% and ETI 46.7%. FPS was associated with increased ROSC (aOR 1.23; 95%CI: 1.07-1.41)), but not 72-h survival (1.22; 0.94-1.58), hospital survival (0.90; 0.68-1.19) or hospital survival with favorable neurologic status (0.66; 0.37-1.19). CONCLUSION: In adult OHCA, airway insertion FPS was associated with increased ROSC but not other OHCA outcomes. The influence of airway insertion FPS upon OHCA outcomes is unclear.


Subject(s)
Cardiopulmonary Resuscitation , Emergency Medical Services , Out-of-Hospital Cardiac Arrest , Adult , Humans , Intubation, Intratracheal , Out-of-Hospital Cardiac Arrest/therapy , Treatment Outcome
6.
Entropy (Basel) ; 22(10)2020 Oct 04.
Article in English | MEDLINE | ID: mdl-33286895

ABSTRACT

Recent direct numerical simulations (DNS) and experiments in turbulent channel flow have found intermittent low- and high-drag events in Newtonian fluid flows, at Reτ=uτh/ν between 70 and 100, where uτ, h and ν are the friction velocity, channel half-height and kinematic viscosity, respectively. These intervals of low-drag and high-drag have been termed "hibernating" and "hyperactive", respectively, and in this paper, a further investigation of these intermittent events is conducted using experimental and numerical techniques. For experiments, simultaneous measurements of wall shear stress and velocity are carried out in a channel flow facility using hot-film anemometry (HFA) and laser Doppler velocimetry (LDV), respectively, for Reτ between 70 and 250. For numerical simulations, DNS of a channel flow is performed in an extended domain at Reτ = 70 and 85. These intermittent events are selected by carrying out conditional sampling of the wall shear stress data based on a combined threshold magnitude and time-duration criteria. The use of three different scalings (so-called outer, inner and mixed) for the time-duration criterion for the conditional events is explored. It is found that if the time-duration criterion is kept constant in inner units, the frequency of occurrence of these conditional events remain insensitive to Reynolds number. There exists an exponential distribution of frequency of occurrence of the conditional events with respect to their duration, implying a potentially memoryless process. An explanation for the presence of a spike (or dip) in the ensemble-averaged wall shear stress data before and after the low-drag (or high-drag) events is investigated. During the low-drag events, the conditionally-averaged streamwise velocities get closer to Virk's maximum drag reduction (MDR) asymptote, near the wall, for all Reynolds numbers studied. Reynolds shear stress (RSS) characteristics during these conditional events are investigated for Reτ = 70 and 85. Except very close to the wall, the conditionally-averaged RSS is higher than the time-averaged value during the low-drag events.

7.
Plant J ; 104(6): 1535-1550, 2020 12.
Article in English | MEDLINE | ID: mdl-33048399

ABSTRACT

Heat stress occurring at reproductive stages can result in significant and permanent damage to crop yields. However, previous genetic studies in understanding heat stress response and signaling were performed mostly on seedling and plants at early vegetative stages. Here we identify, using a developmentally defined, gain-of-function genetic screen with approximately 18 000 Arabidopsis thaliana activation-tagged lines, a mutant that maintained productive seed set post-severe heat stress during flowering. Genome walking indicated this phenotype was caused by the insertion of 35S enhancers adjacent to a nuclear localized transcription factor AtMYB68. Subsequent overexpression analysis confirmed that AtMYB68 was responsible for the reproductive heat tolerance of the mutant. Furthermore, these transgenic Arabidopsis plants exhibited enhanced abscisic acid sensitivity at and post-germination, reduced transpirational water loss during a drought treatment, and enhanced seed yield under combined heat and drought stress during flowering. Ectopic expression of AtMYB68 in Brassica napus driven either by 35S or by heat-inducible promoter recapitulated the enhanced reproductive heat stress and drought tolerance phenotypes observed in the transgenic Arabidopsis. The improvement to heat stress is likely due to enhanced pollen viability observed in the transgenic plants. More importantly, the transgenic canola showed significant yield advantages over the non-transgenic controls in multiple locations, multiple season field trials under various drought and heat stress conditions. Together these results suggest that AtMYB68 regulate plant stress tolerance at the most important yield determining stage of plant development, and is an effective target for crop yield protection under current global climate volatility.


Subject(s)
Arabidopsis Proteins/physiology , Arabidopsis/physiology , Transcription Factors/physiology , Arabidopsis/genetics , Arabidopsis/growth & development , Arabidopsis Proteins/genetics , Brassica napus , Dehydration , Flowers/growth & development , Gain of Function Mutation , Gene Expression Regulation, Plant , Plants, Genetically Modified , Reproduction , Thermotolerance , Transcription Factors/genetics
8.
J Am Chem Soc ; 141(26): 10193-10198, 2019 07 03.
Article in English | MEDLINE | ID: mdl-31244190

ABSTRACT

Anthracyclines are archetypal representatives of the tetracyclic type II polyketide natural products that are widely used in cancer chemotherapy. Although the synthesis of this class of compounds has been a subject of several investigations, all known approaches are based on annulations, relying on the union of properly prefunctionalized building blocks. Herein, we describe a conceptually different approach using a polynuclear arene as a starting template, ideally requiring only functional decorations to reach the desired target molecule. Specifically, tetracene was converted to (±)-idarubicinone, the aglycone of the FDA approved anthracycline idarubicin, through the judicious orchestration of Co- and Ru-catalyzed arene oxidation and arenophile-mediated dearomative hydroboration. Such a global functionalization strategy, the combination of site-selective arene and dearomative functionalization, provided the key anthracycline framework in five operations and enabled rapid and controlled access to (±)-idarubicinone.


Subject(s)
Idarubicin/analogs & derivatives , Naphthacenes/chemistry , Idarubicin/chemical synthesis , Idarubicin/chemistry , Molecular Structure , Stereoisomerism
9.
European J Org Chem ; 2019(38): 6496-6503, 2019 Oct 17.
Article in English | MEDLINE | ID: mdl-33041648

ABSTRACT

Rapid and reproducible access to a series of unique porphyrin and bacteriochlorin glycoconjugates, including meso-glycosylated porphyrins and bacteriochlorins, and beta-glycosylated porphyrins, via copper catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) is reported for the first time. The work presented highlights the system-dependent reaction conditions required for glycosylation to porphyrins and bacteriochlorins based on the unique electronic properties of each ring system. Attenuated reaction conditions were used to synthesize fifteen new glycosylated porphyrin and bacteriochlorin analogs in 74 - 99% yield, and were extended to solid support to produce the first oligo(amidoamine)-based porphyrin glycoconjugate. These compounds hold significant potential as next generation water soluble catalysts and photodynamic therapy/photodynamic inactivation (PDT/PDI) agents.

10.
J Surg Educ ; 75(4): 1022-1027, 2018.
Article in English | MEDLINE | ID: mdl-28989010

ABSTRACT

BACKGROUND: The Luke Commission, a provider of comprehensive mobile health outreach in rural Swaziland, focuses on human immunodeficiency virus testing and prevention, including the performance of over 100 circumcisions weekly. Educational objectives for medical student global health electives are essential. Learning research methodology while engaging in clinical activities reinforces curriculum goals. Medical care databases can produce clinically significant findings affecting international health policy. Engaging in academic research exponentially increased the educational value of student experiences during an international medical elective. METHODS: Staff of the Luke Commission, a nongovernmental organization, collected and deidentified information from 1500 Swazi male patients undergoing circumcision from January through June of 2014. Medical students designed studies and analyzed these data to produce research projects on adverse event rates, pain perception, and penile malformations. Institutional review board approval was obtained from the home institution and accompanying senior surgical faculty provided mentorship. RESULTS: First-year medical students enrolled in an international medical elective to explore resource availability, cultural awareness, health care provision, and developing world endemic diseases. While in country, students learned research methodology, collected data, and engaged in research projects. Following the trip, students presented posters at over 10 regional and national meetings. All 4 articles are accepted or under consideration for publication by major journals. CONCLUSIONS: During international medical electives the combination of clinical experiences and access to databases from health aid organizations provides the foundation for productive medical student research. All participants benefit from the relationships formed by aid organizations, medical students, and patient populations. Global health research has many complexities, but through careful planning and cultural awareness, medical students can increase their research skills and contribute to the medical literature, bringing attention to and improving health care policies around the world. In sum, the educational experience of medical students is enhanced through the interaction of delivering patient care and completing clinical research studies.


Subject(s)
Biomedical Research/education , Circumcision, Male , Education, Medical, Undergraduate/organization & administration , Global Health , Curriculum , Eswatini , Humans , Male , Pain, Postoperative , Penis/abnormalities , Rural Population
11.
J Med Entomol ; 52(6): 1183-92, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26336267

ABSTRACT

Early-phase transmission (EPT) of Yersinia pestis by unblocked fleas is a well-documented, replicable phenomenon with poorly defined mechanisms. We review evidence demonstrating EPT and current knowledge on its biological and biomechanical processes. We discuss the importance of EPT in the epizootic spread of Y. pestis and its role in the maintenance of plague bacteria in nature. We further address the role of EPT in the epidemiology of plague.


Subject(s)
Insect Vectors/microbiology , Plague/transmission , Siphonaptera/microbiology , Yersinia pestis , Animals , Disease Outbreaks , Humans , Plague/epidemiology
12.
An Acad Bras Cienc ; 87(2): 1161-93, 2015.
Article in English | MEDLINE | ID: mdl-26062112

ABSTRACT

The inherent difficulty of understanding turbulence has led to researchers attacking the topic in many different ways over the years of turbulence research. Some approaches have been more successful than others, but most only deal with part of the problem. One approach that has seen reasonable success (or at least popularity) is that of attempting to deconstruct the complex and disorganised turbulent flow field into to a set of motions that are in some way organised. These motions are generally called "coherent structures". There are several strands to this approach, from identifying the coherent structures within the flow, defining their characteristics, explaining how they are created, sustained and destroyed, to utilising their features to model the turbulent flow. This review considers research on coherent structures in wall-bounded turbulent flows: a class of flow which is extremely interesting to many scientists (mainly, but not exclusively, physicists and engineers) due to their prevalence in nature, industry and everyday life. This area has seen a lot of activity, particularly in recent years, much of which has been driven by advances in experimental and computational techniques. However, several ideas, developed many years ago based on flow visualisation and intuition, are still both informative and relevant. Indeed, much of the more recent research is firmly indebted to some of the early pioneers of the coherent structures approach. Therefore, in this review, selected historical research is discussed along with the more contemporary advances in an attempt to provide the reader with a good overview of how the field has developed and to highlight the perspicacity of some of the early researchers, as well as providing an overview of our current understanding of the role of coherent structures in wall-bounded turbulent flows.

13.
Phys Rev Lett ; 113(23): 234501, 2014 Dec 05.
Article in English | MEDLINE | ID: mdl-25526130

ABSTRACT

Organizational states of turbulence are identified through novel analysis of large scale pipe flow experiments at a Reynolds number of 35 000. The distinct states are revealed by an azimuthal decomposition of the two-point spatial correlation of the streamwise velocity fluctuation. States with dominant azimuthal wave numbers corresponding to k_{θ}=2,3,4,5,6 are discovered and their structure revealed as a series of alternately rotating quasistreamwise vortices. Such organizational states are highly reminiscent of the nonlinear traveling wave solutions previously identified at Reynolds numbers an order of magnitude lower.

15.
Vaccine ; 31(40): 4368-74, 2013 Sep 13.
Article in English | MEDLINE | ID: mdl-23911781

ABSTRACT

Influenza virus infections result in considerable morbidity and mortality both in the temperate and tropical world. Influenza surveillance over multiple years is important to determine the impact and epidemiology of influenza and to develop a national vaccine policy, especially in countries developing influenza vaccine manufacturing capacity, such as Vietnam. We conducted surveillance of influenza and influenza-like illness in Vietnam through the National Influenza Surveillance System during 2006-2010. At 15 sentinel sites, the first two patients presenting each weekday with influenza-like illness (ILI), defined as fever and cough and/or sore throat with illness onset within 3 days, were enrolled and throat specimens were collected and tested for influenza virus type and influenza A subtype by RT-PCR. De-identified demographic and provider reported subsequent hospitalization information was collected on each patient. Each site also collected information on the total number of patients with influenza-like illness evaluated per week. Of 29,804 enrolled patients presenting with influenza-like illness, 6516 (22%) were influenza positive. Of enrolled patients, 2737 (9.3%) were reported as subsequently hospitalized; of the 2737, 527 (19%) were influenza positive. Across all age groups with ILI, school-aged children had the highest percent of influenza infection (29%) and the highest percent of subsequent hospitalizations associated with influenza infection (28%). Influenza viruses co-circulated throughout most years in Vietnam during 2006-2010 and often reached peak levels multiple times during a year, when >20% of tests were influenza positive. Influenza is an important cause of all influenza-like illness and provider reported subsequent hospitalization among outpatients in Vietnam, especially among school-aged children. These findings may have important implications for influenza vaccine policy in Vietnam.


Subject(s)
Epidemiological Monitoring , Influenza A virus/isolation & purification , Influenza, Human/epidemiology , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Hospitalization , Humans , Infant , Infant, Newborn , Influenza Vaccines/therapeutic use , Male , Middle Aged , Vietnam/epidemiology , Young Adult
16.
Influenza Other Respir Viruses ; 7(6): 1151-7, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23137010

ABSTRACT

BACKGROUND: Vietnam is currently developing domestic capability to manufacture influenza vaccines but information on the genetic and antigenic characteristics of locally circulating seasonal influenza viruses is limited. To assess the relevance of WHO recommended vaccine strains to the situation in Vietnam, we analyzed the genetic relatedness of the hemagglutinin (HA) gene of seasonal influenza A viruses circulating in Vietnam from 2001 to 2009 to WHO recommended vaccine strains over the same period. METHODS AND PRINCIPAL FINDINGS: We sequenced the HA gene of 32 H1N1 and 44 H3N2 seasonal influenza A isolates from laboratory-based sentinel surveillance sites in Hanoi from 2001 to 2005 and from a national influenza surveillance system from 2005 to 2009. H1 and H3 HA phylogenetic trees rooted to vaccine strains A/Beijing/295/1995 (H1N1) and A/Moscow/10/1999 (H3N2), respectively, were constructed with contemporary HA sequences of isolates from neighboring countries. We found some genetic differences between seasonal influenza H3N2 viruses and three WHO influenza vaccine strains recommended for use in the Northern and Southern Hemispheres for the 2001-2004 and 2007-2008 seasons and close genetic identity of circulating H3N2 strains with the recommended WHO Southern Hemisphere vaccine strains for 2004 and 2009 seasons. The genetic similarity of circulating H1N1 strains with the WHO recommended vaccine strains are described for the study period 2001-2009. CONCLUSIONS: The HA gene of seasonal influenza virus strains in Vietnam (especially influenza A/H3N2) showed varying degrees of genetic identity compared with those of the Northern or Southern Hemisphere vaccine strains recommended by WHO. The close relatedness of the HA of Vietnamese strains and contemporary strains from nearby countries indicate a good genetic match of circulating strains during study period. Greater representation of virus isolates from South East Asia in the vaccine strain selection process is desirable of influenza vaccine development in Vietnam.


Subject(s)
Hemagglutinin Glycoproteins, Influenza Virus/genetics , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza A Virus, H3N2 Subtype/isolation & purification , Influenza A virus/genetics , Influenza Vaccines/genetics , Influenza, Human/prevention & control , Influenza, Human/virology , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Cluster Analysis , Female , Humans , Infant , Infant, Newborn , Influenza A Virus, H1N1 Subtype/classification , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H3N2 Subtype/classification , Influenza A Virus, H3N2 Subtype/genetics , Influenza A virus/classification , Male , Middle Aged , Molecular Sequence Data , Phylogeny , RNA, Viral/genetics , Sequence Analysis, DNA , Vietnam , Young Adult
17.
Vaccine ; 28(2): 398-402, 2009 Dec 11.
Article in English | MEDLINE | ID: mdl-19853073

ABSTRACT

In 2006, national influenza surveillance was implemented in Vietnam. Epidemiologic and demographic data and a throat swab for influenza testing were collected from a subset of outpatients with influenza-like illness (ILI). During January 1, 2006 through December 31, 2007, of 184,521 ILI cases identified at surveillance sites, 11,082 were tested and 2112 (19%) were positive for influenza by reverse transcription polymerase chain reaction. Influenza viruses were detected year-round, and similar peaks in influenza activity were observed in all surveillance regions, coinciding with cooler and rainy periods. Studies are needed to ascertain the disease burden and impact of influenza in Vietnam.


Subject(s)
Influenza, Human/epidemiology , Adolescent , Adult , Age Distribution , Child , Child, Preschool , Geography , Humans , Infant , Infant, Newborn , Middle Aged , Population Surveillance , Vietnam/epidemiology , Young Adult
19.
Plant J ; 43(3): 413-24, 2005 Aug.
Article in English | MEDLINE | ID: mdl-16045476

ABSTRACT

Protecting crop yield under drought stress is a major challenge for modern agriculture. One biotechnological target for improving plant drought tolerance is the genetic manipulation of the stress response to the hormone abscisic acid (ABA). Previous genetic studies have implicated the involvement of the beta-subunit of Arabidopsis farnesyltransferase (ERA1) in the regulation of ABA sensing and drought tolerance. Here we show that molecular manipulation of protein farnesylation in Arabidopsis, through downregulation of either the alpha- or beta-subunit of farnesyltransferase enhances the plant's response to ABA and drought tolerance. To test the effectiveness of tailoring farnesylation in a crop plant, transgenic Brassica napus carrying an ERA1 antisense construct driven by a drought-inducible rd29A promoter was examined. In comparison with the non-transgenic control, transgenic canola showed enhanced ABA sensitivity, as well as significant reduction in stomatal conductance and water transpiration under drought stress conditions. The antisense downregulation of canola farnesyltransferase for drought tolerance is a conditional and reversible process, which depends on the amount of available water in the soil. Furthermore, transgenic plants were more resistant to water deficit-induced seed abortion during flowering. Results from three consecutive years of field trial studies suggest that with adequate water, transgenic canola plants produced the same amount of seed as the parental control. However, under moderate drought stress conditions at flowering, the seed yields of transgenic canola were significantly higher than the control. Using protein farnesyltransferase as an effective target, these results represent a successful demonstration of engineered drought tolerance and yield protection in a crop plant under laboratory and field conditions.


Subject(s)
Adaptation, Physiological/physiology , Arabidopsis/metabolism , Protein Prenylation , Abscisic Acid/metabolism , Analysis of Variance , Arabidopsis/genetics , Arabidopsis/growth & development , Brassica napus/genetics , Brassica napus/metabolism , Disasters , Down-Regulation , Plant Transpiration , Plants, Genetically Modified , Seeds/growth & development , Seeds/metabolism
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