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1.
JAMA Netw Open ; 3(3): e201809, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32227181

RESUMO

Importance: Compared with traditional Medicare (TM) fee-for-service plans, Medicare Advantage (MA) plans may provide more-efficient care for beneficiaries with Alzheimer disease and related dementias (ADRD) without compromising care quality. Objective: To determine differences in health care utilization, care satisfaction, and health status for MA and TM beneficiaries with and without ADRD. Design, Setting, and Participants: A cohort study was conducted of MA and TM beneficiaries with and without ADRD from all publicly available years of the Medicare Current Beneficiary Survey between 2010 and 2016. To address advantageous selection into MA plans, county-level MA enrollment rate was used as an instrument. Data were analyzed between July 2019 and December 2019. Exposures: Enrollment in MA. Main Outcomes and Measures: Self-reported health care utilization, care satisfaction, and health status. Results: The sample included 47 100 Medicare beneficiaries (25 900 women [54.9%]; mean [SD] age, 72.2 [11.4] years). Compared with TM beneficiaries with ADRD, MA beneficiaries with ADRD had lower utilization across the board, including a mean of -22.3 medical practitioner visits (95% CI, -24.9 to -19.8 medical practitioner visits), -2.3 outpatient hospital visits (95% CI, -3.6 to -1.1 outpatient hospital visits), -0.2 inpatient hospital admissions (95% CI, -0.3 to -0.1 inpatient hospital admissions), and -0.1 long-term care facility stays (95% CI, -0.2 to -0.1 long-term care facility stays). A similar trend was observed among beneficiaries without ADRD, but the difference was greater between MA and TM beneficiaries with ADRD than between MA and TM beneficiaries without ADRD (mean, -15.0 medical practitioner visits [95% CI, -18.7 to -11.3 medical practitioner visits], -1.7 outpatient hospital visits [95% CI, -3.0 to -0.3 outpatient hospital visits], and -0.1 inpatient hospital admissions [95% CI, -1.0 to 0.0 inpatient hospital admissions]). Overall, no or negligible differences were detected in care satisfaction and health status between MA and TM beneficiaries with and without ADRD. Conclusions and Relevance: Compared with TM beneficiaries, MA beneficiaries had lower health care utilization without compromising care satisfaction and health status. This difference was more pronounced among beneficiaries with ADRD. These findings suggest that MA plans may be delivering health care more efficiently than TM, especially for beneficiaries with ADRD.

2.
Med Care ; 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32049878

RESUMO

BACKGROUND: Starting in 2014, the Affordable Care Act mandated that Medicare Advantage (MA) contracts spend at least 85% of total revenue on claims and quality improvement [ie, the medical loss ratio (MLR)] and submit revenue and cost data annually in MLR reports. These reports can improve transparency of the financial performance of MA contracts. However, little is known about revenues and costs of insurers that participate in MA and its impacts on status changes in the following year. OBJECTIVE: To characterize revenues and costs of MA contracts in 2014, with a focus on MLRs and gross margins, and to assess heterogeneity in subsequent-year plan renewal and termination rates by gross margins. RESEARCH DESIGN: Cross-sectional data from MLR reports submitted in 2014 by MA contracts and from 2015 Part C & D Plan Crosswalk Files regarding plan renewal, termination, and other status changes from 2014 to 2015. SUBJECTS: Three hundred eighty-nine MA contracts. MEASURES: Primary outcomes are MLRs and gross margins. RESULTS: MLRs averaged 93% in 2014; 11% of contracts reported MLRs of at least 100%. Fifty-six percent reported negative margins, or costs that exceeded revenues. Seventeen percent of plans in contracts in the lowest quartile of gross margins were terminated in 2015, compared to under 5% of plans in the highest-margin contracts. CONCLUSIONS: In 2014, MA contracts reported MLRs greater than the mandatory minimum of 85%. Gross margins likely contribute to trends in plan and insurer availability. MLR reports from subsequent years can help explain fluctuations in insurers' participation in MA.

3.
Perm J ; 242020.
Artigo em Inglês | MEDLINE | ID: mdl-31852048

RESUMO

INTRODUCTION: Previous research has reported switching from traditional Medicare (TM) to Medicare Advantage (MA) plans increased from 2006 to 2011 at the aggregate level, and switching from MA plans to TM also increased. However, little is known about switching behavior among individuals with specific chronic diseases. OBJECTIVE: To examine disease-specific switching patterns between TM and MA to understand the impact on MA plans. METHODS: Using the 2006 to 2012 Medicare Current Beneficiary Survey, we examined disease-specific switching rates between TM and MA and disease-specific ratios of mean baseline total Medicare expenditures of beneficiaries remaining in the same plan (stayers) vs those switching to another plan (switchers), respectively. We focused on beneficiaries with 1 or more of 10 incident diagnoses. RESULTS: Beneficiaries with a new diagnosis of Alzheimer disease and related dementias, hypertension, and psychiatric disorders had relatively high rates of switching into MA plans and low rates of switching out of MA plans. Among those with new diagnoses of psychiatric disorders and diabetes, more costly beneficiaries (those with higher costs) switched into MA plans. For cancer, more costly beneficiaries remained in MA plans. CONCLUSION: Together, these results suggest that MA plans may have not only higher caseloads but also a more costly case mix of beneficiaries with certain diseases than historically was the case. Our findings can help inform MA plans to understand their beneficiaries' disease burden and prepare for provision of relevant services.

4.
Health Econ ; 2019 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-31802569

RESUMO

The substantial social and economic burden attributable to smoking is well-known, with heavy smokers at higher risk of chronic disease and premature mortality than light smokers and nonsmokers. In aging societies with high rates of male smoking such as in East Asia, smoking is a leading preventable risk factor for extending lives (including work-lives) and healthy aging. However, little is known about whether smoking interventions targeted at heavy smokers relative to light smokers lead to disproportionately larger improvements in life expectancy and prevalence of chronic diseases and how the effects vary across populations. Using a microsimulation model, we examined the health effects of smoking reduction by simulating an elimination of smoking among subgroups of smokers in South Korea, Singapore, and the United States. We found that life expectancy would increase by 0.2 to 1.5 years among light smokers and 2.5 to 3.7 years among heavy smokers. Whereas both interventions led to an increased life expectancy and decreased the prevalence of chronic diseases in all three countries, the life-extension benefits were greatest for those who would otherwise have been heavy smokers. Our findings illustrate how smoking interventions may have significant economic and social benefits, especially for life extension, that vary across countries.

5.
Acad Pediatr ; 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31733360

RESUMO

OBJECTIVE: We examined changes in insurance coverage and health care utilization associated with the Affordable Care Act (ACA) among subgroups of Asian youth relative to non-Latino white youth. METHODS: Data were from the 2010 to 2017 American Community Survey and National Health Interview Survey. Difference-in-difference models were used to examine changes in insurance coverage and health care utilization associated with the ACA among subgroups of Asian youth relative to white youth and subgroups of Asian youth in households below 200% of the federal poverty level relative to comparable white youth. RESULTS: Since the implementation of the ACA, insurance coverage increased among all Asian subgroups and white youth. The magnitude of the increase in insurance coverage was larger among Asian subgroups than white youth. More pronounced increases were found among almost all Asian subgroups in households below 200% federal poverty level. Changes in health care utilization were limited and varied by subgroup. Increases in well-child visits were observed only among Chinese and "other" Asian youth. CONCLUSIONS: Insurance coverage increased among Asian youth after the implementation of the ACA. Improvements in health care utilization were limited and differed by subgroups. Programs to improve health care utilization should be tailored to Asian youth according to subgroup.

6.
Med Care ; 57(11): 861-868, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31634267

RESUMO

OBJECTIVES: We examined changes in health care access and utilization associated with the Patient Protection and Affordable Care Act (ACA) for different Asian American subgroups relative to non-Latino whites (whites). RESEARCH DESIGN: Using 2003-2017 California Health Interview Survey data, we examined changes in 4 health care access measures and 2 utilization measures among whites and 7 Asian American subgroups. We estimated the unadjusted and adjusted percentage point changes on the absolute scale from the pre-ACA to post-ACA periods. Adjusted estimates were obtained from multivariable logistic regression models that controlled for predisposing, enabling, and need factors. We also estimated the pre-ACA to post-ACA changes between whites and Asian American subgroups using a difference-in-difference approach. RESULTS: After the ACA was implemented, uninsurance decreased among all Asian American subgroups, but improvements in disparities relative to whites in these measures were limited. In particular, Koreans had the largest absolute reduction in uninsurance (-16.8 percentage points) and were the only subgroup with a significant reduction in terms of disparities relative to whites (-10.1 percentage points). However, little or no improvement was observed in the other 3 access measures (having a usual source of care, delayed medical care in past year, or delayed prescription drug use in past year) and 2 utilization measures (having a physician visit or emergency department visit in past year). CONCLUSIONS: Despite coverage gains among Asian American subgroups, especially Koreans, disparities in access and utilization persisted across all Asian American subgroups.


Assuntos
Americanos Asiáticos/estatística & dados numéricos , Utilização de Instalações e Serviços/estatística & dados numéricos , Acesso aos Serviços de Saúde/estatística & dados numéricos , Aceitação pelo Paciente de Cuidados de Saúde/etnologia , Patient Protection and Affordable Care Act , Adulto , Estudos Transversais , Grupo com Ancestrais do Continente Europeu/estatística & dados numéricos , Feminino , Disparidades em Assistência à Saúde , Humanos , Cobertura do Seguro/estatística & dados numéricos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Estados Unidos , Adulto Jovem
7.
Med Care Res Rev ; : 1077558719874212, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31524050

RESUMO

Using a nationally representative sample from the 2013 to 2016 Medical Expenditure Panel Survey, we examined differences among non-Latino Whites and Asian subgroups (Asian Indians, Chinese, Filipinos, and other Asians) across distributions of total health care expenditures and out-of-pocket (OOP) expenditures. For total health care expenditures, differences between Asian and White adults persisted throughout the distribution, but the magnitude of the difference was larger at no or low levels of expenditures than at high expenditure levels. A similar pattern was observed in OOP expenditures, but the magnitude of the difference was substantially larger at low levels of expenditures. The extent of the difference varied by Asian subgroup, but this trend persisted across all the subgroups. Similar trends were observed by nativity and limited English proficiency. Our findings suggest that differences in health care expenditures between Whites and Asians are more pronounced at low expenditure levels.

8.
Plant Cell Rep ; 38(11): 1403-1415, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31367772

RESUMO

KEY MESSAGE: IbSPF1, a novel target of IbMPK3/IbMPK6, regulates biotic stress response in sweetpotato. Environmental stresses due to biotic and abiotic factors negatively affect crop quality and productivity. To minimize the damage caused by these factors, numerous stress signaling pathways are activated in plants. Among these, the mitogen-activated protein kinase (MAPK) signaling cascade plays a pivotal role in diverse plant stress responses. MPK3 and MPK6 function in several cellular signaling pathways by phosphorylating downstream partner proteins in response to environmental stresses. However, little is known about the MPK3/MPK6 signaling pathway in sweetpotato [Ipomoea batatas (L.) Lam]. We recently confirmed that IbMPK3 and IbMPK6, two pathogen-responsive MAPKs, play essential roles in defense gene activation in sweetpotato. In this study, we show that sweetpotato SP8-binding factor (IbSPF1), a substrate of IbMPK3/IbMPK6, functions as a transcriptional regulator of biotic stress signaling in sweetpotato. IbSPF1 specifically interacts with IbMPK3 and IbMPK6, which phosphorylate Ser75 and Ser110 residues of IbSPF1. This increases the affinity of IbSPF1 for the W-box element in target gene promoters. Additionally, the expression of IbSPF1 was up-regulated under various stress conditions and different hormone treatments involved in plant defense responses. Interestingly, the phospho-mimicking mutant of IbSPF1 showed enhanced resistance to Pseudomonas syringae pv. tabaci, and transient expression of mutant IbSPF1 induced the expression of pathogenesis-related genes. These results indicate that the phosphorylation of IbSPF1 by IbMPK3/IbMPK6 plays a critical role in plant immunity by up-regulating the expression of downstream genes.

9.
Am J Manag Care ; 25(8): e247-e253, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31419102

RESUMO

OBJECTIVES: We conducted a systematic review of studies reporting the direct healthcare costs of treating older adults with diagnosed Alzheimer disease and related dementias (ADRD) within private Medicare managed care plans. STUDY DESIGN: A systematic review of all studies published in English reporting original empirical analyses of direct costs for older adults with ADRD in Medicare managed care. METHODS: All papers indexed in PubMed or Web of Science reporting ADRD costs within Medicare managed care plans from 1983 through 2018 were identified and reviewed. RESULTS: Despite the growth in Medicare managed care enrollment, only 9 papers report the costs of care for individuals with ADRD within these plans, and only 1 study reports data less than 10 years old. This limited literature reports wide ranges for ADRD-attributable costs, with estimates varying from $3738 to $8726 in annual prevalent costs and $8938 to $38,794 in 1-year immediate postdiagnosis incident costs. Reviewed studies also used varied study populations, case and cost ascertainment methods, and analytic methods, making cross-study comparisons difficult. CONCLUSIONS: The expected continued growth in Medicare managed care enrollment, coupled with the large and growing impact of ADRD on America's healthcare delivery and finance systems, requires more research on the cost of ADRD within managed care. This research should use more consistent approaches to identify ADRD prevalence and provide more detail regarding which components of care are included in analyses and how the costs of care are captured and measured.

10.
J Clin Med ; 8(7)2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31295896

RESUMO

Osteoarthritis (OA) is considered to be one of the most disabling diseases. The intra-articular opioid injection has been widely studied for its simplicity, safety, and efficacy in OA. In this study, however, we suggest a novel method of buprenorphine transdermal patch (BTDP) to painful knee joints of OA patients, instead of intra-articular opioid injection, and subsequently compared the knee application with conventional chest application. We retrospectively enrolled 213 patients with knee OA who did not respond to conventional therapy. The Numeric Rating Scale (NRS), adverse effects, and compliance were recorded before and after the application of the BTDP. All parameters were compared between the knee applied group and the chest applied group. After the BTDP application, the NRS score in the knee applied group was lower than that of the chest applied group (p = 0.007). NRS scores after buprenorphine patch decreased to 2.21 ± 0.77, and 2.55 ± 0.71 in the chest applied group and the knee applied group, respectively. The adverse effects were 19.32% in the knee applied group, and 64.00% in the chest applied group. The compliances were 82.95% and 37.60% in the knee applied group and chest applied group, respectively. This novel application of BTDP directly to the painful knee joint of knee OA patients led to a decrease in the NRS score, adverse effects, and an increase in compliance compared with the chest application method.

11.
JAMA Netw Open ; 2(7): e197136, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31314115

RESUMO

Importance: Although nearly 1 in 5 persons in the United States has a physical or mental disability, little is known about the association of the Patient Protection and Affordable Care Act (ACA) with health insurance coverage among persons with a disability. Objective: To determine the association of Medicaid expansion with health insurance coverage among persons with a disability. Design, Setting, and Participants: Cross-sectional analysis of adults eligible for Medicaid expansion (aged 26-64 years with incomes up to 138% of the federal poverty level), using a triple-differences (difference-in-difference-in-difference) approach to compare the pre-ACA with post-ACA trend in health insurance rates by disability status between expansion and nonexpansion states using nationally representative, repeated cross-sectional sample data obtained from the American Community Survey in the United States from January 1, 2010, to December 31, 2016. Time was defined as either pre-ACA (January 1, 2010, to December 31, 2013) or post-ACA (January 1, 2014, to December 31, 2016). Treatment status was defined as whether a state implemented Medicaid expansion after January 1, 2014. States that expanded Medicaid between January 1, 2014, to December 31, 2016, were classified as the treatment group, and states that did not expand Medicaid during the study period were classified as the control group. Data were analyzed from December 12, 2018, to May 21, 2019. Main Outcomes and Measures: Self-reported health insurance coverage (uninsured, Medicaid, private) and self-reported disability status (≥1 condition limiting activity, including cognitive, ambulatory, self-care, independent living, and sensory difficulties). Results: Of 2 549 376 Medicaid-eligible adults, 1 348 620 (52.9%) were female; 1 218 602 (47.8%) were non-Hispanic white, 497 128 (19.5%) were non-Hispanic black, 211 598 (8.3%) were Hispanic, and 206 499 (8.1%) were of other race/ethnicity; and 619 498 (24.3%) reported at least 1 disability. The percentage of persons without health insurance was greatest for persons without a disability who lived in a nonexpansion state before the ACA's Medicaid expansion provision went into effect (236 645 of 426 387 [55.5%]), and the smallest proportion of persons without health insurance was reported for persons with a disability living in an expansion state after the ACA went into effect (19 552 of 176 145 [11.1%]). Triple-differences analysis suggested that Medicaid expansion was associated with a decrease in the uninsured rate for both persons with a disability (7.1% - 16.2% = -9.1%) and without a disability (21.2% - 34.9% = -13.7%) and that Medicaid expansion was associated with a 4.6% decrease in the uninsurance rate for persons without a disability and a 2.6% decrease in persons with a disability (P < .001). Although Medicaid expansion was associated with an increase in Medicaid coverage for both persons with a disability (49.3% pre-ACA to 62.3% post-ACA; change, 13.0%) and persons without a disability (21.6% pre-ACA to 40.3% post-ACA; change, 17.7%), the triple difference-estimated Medicaid coverage was -4.7% for persons with a disability and 0.4% for persons without a disability, a difference of 5.1% (P < .001). Medicaid expansion was associated with a 3% higher private insurance rate for persons with a disability than for persons without a disability. Conclusions and Relevance: Medicaid expansion appeared to be associated with lower uninsurance rates and higher Medicaid and private insurance coverage for persons with a disability. This study's findings suggest that the reduction in the uninsured rate and gains in Medicaid coverage were greater for persons without a disability than for persons with a disability.

12.
Gene ; 700: 23-30, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-30898711

RESUMO

Sweetpotato [Ipomoea batatas (L.) Lam] is an important crop used for food, animal feed, and production of industrial materials. Although it is adapted to a wide range of unfavorable conditions, including drought and high salt, sweetpotato is vulnerable to low temperature, making it difficult to cultivate in low temperature regions. To understand the molecular responses occurring in sweetpotato leaves under low temperature stress, de novo transcriptome assembly was performed in leaves under low temperature stress (LT) and during recovery (RC). In comparison with non-treated controls (NT), 2461 and 1017 differentially expressed genes (DEGs) were identified in LT and RC leaves, respectively. When expression in RC and LT samples was directly compared, 2053 DEGs were detected. To increase understanding of the DEGs, the three datasets were analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genome (KEGG) database. The CBF transcriptional cascade, a well-known cold response pathway, was investigated using transcriptomic analysis. In contrast with reports from the cold-tolerant Arabidopsis thaliana, none of the COR genes identified in sweetpotato showed increased expression in response to low temperature. Genes involved in antioxidant enzyme pathways mediating responses to reactive oxygen species (ROS) were investigated during low temperature response. This work provides insight into the molecular basis of the responses of sweetpotato to cold stress. This increased understanding of gene regulation in response to cold stress in sweetpotato will be beneficial for future research into molecular-assisted breeding.


Assuntos
Perfilação da Expressão Gênica/métodos , Ipomoea batatas/crescimento & desenvolvimento , Proteínas de Plantas/genética , Estresse Fisiológico , Temperatura Baixa , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Anotação de Sequência Molecular , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Análise de Sequência de RNA/métodos
13.
J Agric Food Chem ; 66(16): 4099-4105, 2018 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-29630360

RESUMO

Isoflavonoids are a class of biologically active natural products that accumulate in soybean ( Glycine max L.) seeds during development, play vital roles in plant defense, and act as phytoestrogens with important human health benefits. Plant cell suspension cultures represent an excellent source of biologically important secondary metabolites. We found that methyl jasmonate (MJ) treatment increased isoflavone production in soybean suspension cell cultures. To investigate the underlying mechanism, we examined the expression of structural genes ( CHS6, CHS7, CHI1, IFS1, IFS2, IFMaT, and HID) in the isoflavonoid biosynthesis pathways in soybean suspension cells under various abiotic stress conditions. MJ treatment had the most significant effect on gene expression and increased the production of three glycosidic isoflavones (daidzin, malonyldaidzin, and malonylgenistin), with the maximum total isoflavone production (∼10-fold increase) obtained on day 9 after MJ application. MJ treatment significantly increased total phenolic contents and upregulated isoflavonoid biosynthesis genes, shedding light on the underlying mechanism.


Assuntos
Acetatos/farmacologia , Ciclopentanos/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Isoflavonas/biossíntese , Oxilipinas/farmacologia , Proteínas de Plantas/genética , Soja/efeitos dos fármacos , Células Cultivadas , Proteínas de Plantas/metabolismo , Soja/genética , Soja/metabolismo
14.
Health Econ ; 27(6): 984-1010, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29577489

RESUMO

Risk adjustment is instituted to counter risk selection by accurately equating payments with expected expenditures. Traditional risk-adjustment methods are designed to estimate accurate payments at the group level. However, this generates residual risks at the individual level, especially for high-expenditure individuals, thereby inducing health plans to avoid those with high residual risks. To identify an optimal risk-adjustment method, we perform a comprehensive comparison of prediction accuracies at the group level, at the tail distributions, and at the individual level across 19 estimators: 9 parametric regression, 7 machine learning, and 3 distributional estimators. Using the 2013-2014 MarketScan database, we find that no one estimator performs best in all prediction accuracies. Generally, machine learning and distribution-based estimators achieve higher group-level prediction accuracy than parametric regression estimators. However, parametric regression estimators show higher tail distribution prediction accuracy and individual-level prediction accuracy, especially at the tails of the distribution. This suggests that there is a trade-off in selecting an appropriate risk-adjustment method between estimating accurate payments at the group level and lower residual risks at the individual level. Our results indicate that an optimal method cannot be determined solely on the basis of statistical metrics but rather needs to account for simulating plans' risk selective behaviors.


Assuntos
Interpretação Estatística de Dados , Modelos Estatísticos , Risco Ajustado/métodos , Bases de Dados Factuais , Gastos em Saúde/estatística & dados numéricos , Humanos
15.
J Exp Bot ; 69(14): 3393-3400, 2018 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-29385615

RESUMO

Carotenoids play essential roles in various light-harvesting processes in plants and help protect the photosynthetic machinery from photo-oxidative damage. Orange genes, which play a role in carotenoid accumulation, have recently been isolated from several plant species, and their functions have been intensively investigated. The Orange gene (IbOr) of sweet potato [Ipomoea batatas (L.) Lam] helps maintain carotenoid homeostasis to improve plant tolerance to environmental stress. IbOr, a protein with strong holdase chaperone activity, directly interacts with phytoene synthase, a key enzyme involved in carotenoid biosynthesis, in plants under stress conditions, resulting in increased carotenoid accumulation and abiotic stress tolerance. In addition, IbOr interacts with the oxygen-evolving enhancer protein 2-1, a member of a protein complex in photosystem II that is denatured under heat stress. Transgenic sweet potato plants overexpressing IbOr showed enhanced tolerance to high temperatures (47 °C). These findings indicate that IbOr protects plants from environmental stress not only by controlling carotenoid biosynthesis, but also by directly stabilizing photosystem II. In this review, we discuss the functions of IbOr and Or proteins in other plant species and their possible biotechnological applications for molecular breeding for sustainable development on marginal lands.


Assuntos
Carotenoides/fisiologia , Meio Ambiente , Ipomoea batatas/fisiologia , Proteínas de Plantas/fisiologia , Agricultura , Homeostase , Estresse Fisiológico
16.
Planta ; 247(4): 973-985, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29313103

RESUMO

MAIN CONCLUSION: We demonstrated successful overexpression of porcine reproductive and respiratory syndrome virus (PRRSV)-derived GP4D and GP5D antigenic proteins in Arabidopsis. Pigs immunized with transgenic plants expressing GP4D and GP5D proteins generated both humoral and cellular immune responses to PRRSV. Porcine reproductive and respiratory syndrome virus (PRRSV) causes PRRS, the most economically significant disease affecting the swine industry worldwide. However, current commercial PRRSV vaccines (killed virus or modified live vaccines) show poor efficacy and safety due to concerns such as reversion of virus to wild type and lack of cross protection. To overcome these problems, plants are considered a promising alternative to conventional platforms and as a vehicle for large-scale production of recombinant proteins. Here, we demonstrate successful production of recombinant protein vaccine by expressing codon-optimized and transmembrane-deleted recombinant glycoproteins (GP4D and GP5D) from PRRSV in planta. We generated transgenic Arabidopsis plants expressing GP4D and GP5D proteins as candidate antigens. To examine immunogenicity, pigs were fed transgenic Arabidopsis leaves expressing the GP4D and GP5D antigens (three times at 2-week intervals) and then challenged with PRRSV at 6-week post-initial treatment. Immunized pigs showed significantly lower lung lesion scores and reduced viremia and viral loads in the lung than pigs fed Arabidopsis leaves expressing mYFP (control). Immunized pigs also had higher titers of PRRSV-specific antibodies and significantly higher levels of pro-inflammatory cytokines (TNF-α and IL-12). Furthermore, the numbers of IFN-γ+-producing cells were higher, and those of regulatory T cells were lower, in GP4D and GP5D immunized pigs than in control pigs. Thus, plant-derived GP4D and GP5D proteins provide an alternative platform for producing an effective subunit vaccine against PRRSV.


Assuntos
Vírus da Síndrome Respiratória e Reprodutiva Suína/imunologia , Animais , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Arabidopsis/genética , Arabidopsis/metabolismo , Western Blotting , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Imunidade Celular , Imunidade Humoral , Leucócitos Mononucleares/imunologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Suínos/imunologia , Suínos/virologia , Vacinas Sintéticas/biossíntese , Vacinas Sintéticas/imunologia
17.
Front Plant Sci ; 8: 989, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28642783

RESUMO

The Orange (Or) protein regulates carotenoid biosynthesis and environmental stress in plants. Previously, we reported that overexpression of the sweetpotato [Ipomoea batatas (L.) Lam] Or gene (IbOr) in transgenic Arabidopsis (referred to as IbOr-OX/At) increased the efficiency of photosystem II (PSII) and chlorophyll content after heat shock. However, little is known about the role of IbOr in PSII-mediated protection against abiotic stress. In this study, comparative proteomics revealed that expression of PsbP (an extrinsic subunit of PSII) is up-regulated in heat-treated IbOr-OX/At plants. We then identified and functionally characterized the PsbP-like gene (IbPsbP) from sweetpotato. IbPsbP is predominantly localized in chloroplast, and its transcripts are tissue-specifically expressed and up-regulated in response to abiotic stress. In addition, IbOr interacts with IbPsbP and protects it from heat-induced denaturation, consistent with the observation that transgenic sweetpotato overexpressing IbOr maintained higher PSII efficiency and chlorophyll content upon exposure to heat stress. These results indicate that IbOr can protect plants from environmental stress not only by controlling carotenoid biosynthesis but also by directly stabilizing PSII.

18.
Plant Physiol Biochem ; 117: 24-33, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28587990

RESUMO

ß-carotene, a carotenoid that plays a key photo-protective role in plants is converted into zeaxanthin by ß-carotene hydroxylase (CHY-ß). Previous work showed that down-regulation of IbCHY-ß by RNA interference (RNAi) results in higher levels of ß-carotene and total carotenoids, as well as salt stress tolerance, in cultured transgenic sweetpotato cells. In this study, we introduced the RNAi-IbCHY-ß construct into a white-fleshed sweetpotato cultivar (cv. Yulmi) by Agrobacterium-mediated transformation. Among the 13 resultant transgenic sweetpotato plants (referred to as RC plants), three lines were selected for further characterization on the basis of IbCHY-ß transcript levels. The RC plants had orange flesh, total carotenoid and ß-carotene contents in storage roots were 2-fold and 16-fold higher, respectively, than those of non-transgenic (NT) plants. Unlike storage roots, total carotenoid and ß-carotene levels in the leaves of RC plants were slightly increased compared to NT plants. The leaves of RC plants also exhibited tolerance to methyl viologen (MV)-mediated oxidative stress, which was associated with higher 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical-scavenging activity. In addition, RC plants maintained higher levels of chlorophyll and higher photosystem II efficiency than NT plants after 250 mM NaCl stress. Yield of storage roots did not differ significantly between RC and NT plants. These observations suggest that RC plants might be useful as a nutritious and environmental stress-tolerant crop on marginal lands around the world.


Assuntos
Ipomoea batatas/enzimologia , Ipomoea batatas/metabolismo , Oxigenases de Função Mista/metabolismo , beta Caroteno/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/genética , Ipomoea batatas/efeitos dos fármacos , Oxigenases de Função Mista/genética , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Paraquat/farmacologia , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/enzimologia , Plantas Geneticamente Modificadas/metabolismo , Tolerância ao Sal/genética , Cloreto de Sódio/farmacologia
19.
Plant Physiol Biochem ; 116: 27-35, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28486137

RESUMO

The transition from vegetative to reproductive growth, a key event in the lifecycle of a plant, is affected by environmental stresses. The flowering-time regulator GIGANTEA (GI) may be contributing to susceptibility of the regulation of photoperiodic flowering, circadian rhythm control, and abiotic stress resistance in Arabidopsis. However, the role of GI in sweet potato remains unknown. Here, we isolated and characterized a GI gene (IbGI) from sweet potato (Ipomoea batatas [L.] Lam). The IbGI cDNA sequence was isolated based on information from a sweet potato transcriptome database. IbGI mRNA transcript levels showed robust circadian rhythm control during the light-dark transition, and the expression of IbGI was stronger in leaves and roots than in stems. IbGI protein is predominantly localized to the nucleus. IbGI expression was upregulated by high temperature, drought, and salt stress but downregulated by cold stress. Overexpressing IbGI in the Arabidopsis gi-2 mutant background rescued its late flowering phenotype and reduced its salt tolerance. Taken together, these results indicate that IbGI shares functions in regulating flowering, the circadian rhythm, and tolerance to some stresses with other GI orthologs.


Assuntos
Ipomoea batatas/metabolismo , Proteínas de Plantas/metabolismo , Ritmo Circadiano/genética , Ritmo Circadiano/fisiologia , Flores/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Ipomoea batatas/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo
20.
Breed Sci ; 67(1): 27-34, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28465665

RESUMO

Sweetpotato [Ipomoea batatas (L.) Lam], which contains high levels of antioxidants such as ascorbate and carotenoids in its storage root, is one of the healthiest foods, as well as one of the best starch crops for growth on marginal lands. In plants, carotenoid pigments are involved in light harvesting for photosynthesis and are also essential for photo-protection against excess light. As dietary antioxidants in humans, these compounds benefit health by alleviating aging-related diseases. The storage root of sweetpotato is a good source of both carotenoids and carbohydrates for human consumption. Therefore, metabolic engineering of sweetpotato to increase the content of useful carotenoids represents an important agricultural goal. This effort has been facilitated by cloning of most of the carotenoid biosynthetic genes, as well as the Orange gene involved in carotenoid accumulation. In this review, we describe our current understanding of the regulation of biosynthesis, accumulation and catabolism of carotenoids in sweetpotato. A deeper understanding of these topics should contribute to development of new sweetpotato cultivars with higher levels of nutritional carotenoids and abiotic stress tolerance.

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