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1.
J Integr Plant Biol ; 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31161629

RESUMO

Arabidopsis thaliana CERK1 is an essential receptor-like kinase in the chitin signal transduction pathway. The juxtamembrane (JM) domain of CERK1 regulates the kinase activity of this receptor. Here we demonstrate that the JM domains of LysM-RLKs, CERK1, and OsCERK1 play a functionally conserved role in the activation of chitin signaling in Arabidopsis. The C-termini of the JM domains of both CERK1 and OsCERK1 are indispensable for their function. Moreover, after replacing the JM domain of CERK1 with that of the nonhomologous RLK, BAK1 (CJBa) or FLS2 (CJFl), the chimeric CERK1 receptors maintained their ability to activate chitin signaling in Arabidopsis. Interestingly, the heterologous expression of CJBa and CJFl did not induce cell death in Nicotiana benthamiana leaves. These results suggest that the JM domains of CERK1, BAK1, and FLS2 play a conserved role in chitin signaling via a mechanism not related to sequence homology.

2.
Obes Surg ; 29(3): 835-842, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30536018

RESUMO

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) has been proved to be the most effective treatment strategy for the treatment of type 2 diabetes mellitus (T2DM) with a body mass index ≥ 30 kg/m2 achieving high remission rates. However, there are few clinical studies on the treatment of T2DM patients with a body mass index less than 30 kg/m2 by LSG. This study aims to study the effect of LSG on type 2 diabetes mellitus(T2DM) in patients with a body mass index (BMI) less than 30 kg/m2. METHODS: The clinical data of 25 patients with type 2 diabetes mellitus (T2DM) and body mass index 23.23-29.97 kg/m2 who were treated by LSG at the Department of Bariatric and Metabolic Surgery in China-Japan Union Hospital of Jilin University from May 2016 to May 2017 were retrospectively analyzed. The changes of fasting plasma glucose, glycosylated hemoglobin, insulin resistance index, body weight, body mass index, waist circumference, blood pressure, heart rate, blood lipids, and uric acid were analyzed at 3 months, 6 months, and 12 months after operation, respectively. All the clinical data were analyzed by SPSS 22.0. They were tested with a single-sample K-S test to determine whether they were normal distribution data. The normal distribution data were analyzed by a matched t test, and the Mann-Whitney test was used to examine skewed data. RESULTS: All patients (9 males, 16 females) with a median age of 57(24~65) years were treated successfully by laparoscopic sleeve gastrectomy. The median duration of type 2 diabetes mellitus was 10(0~20)years. The preoperative fasting plasma glucose, glycosylated hemoglobin, body weight, body mass index, and waist circumference were 10.32 ± 2.66 mmol/L,8.20 ± 1.47%,76.54 ± 10.02 kg,27.92 ± 1.72 kg/m2, and 99.88 ± 5.38 cm, respectively. The meaning fasting plasma glucose was 7.26 ± 1.36 mmol/L, 6.90 ± 1.07 mmol/L, and 6.62 ± 0.97 mmol/L, respectively, at 3, 6, and 12 months after operation. The mean HbAlc in the same observation intervals was 6.88 ± 1.23%,6.54 ± 1.02%, and 6.51 ± 0.89%, respectively. The body weight was 62.18 ± 8.38 kg,59.07 ± 8.58 kg, and 58.62 ± 8.53 kg, respectively. The corresponding body mass index was 22.56 ± 1.56 kg/m2, 21.35 ± 1.58 kg/m2, and 21.24 ± 1.86 kg/m2, respectively. The waist circumference was 82.84 ± 5.10 cm,78.60 ± 5.21 cm, and 76.92 ± 5.21 cm, respectively. The complete remission rates of type 2 diabetes mellitus were 40%, 60%, and 68%, respectively, at 3, 6, and 12 months after operation. The complete remission rates for insulin resistance index were 52.4%, 80%, and 80%, postoperatively, at 3, 6, and 12 months, respectively. The complete remission rates of hypertension were 22.2%, 50%, and 75%,respectively, at 3,6, and 12 months after operation. The complete remission rates of hypertriglyceridemia were 66.7%, 66.7%, and 100%,and the complete remission rates of hypercholesterolemia were 41.7%, 60%, and 100%;the abnormal elevations of plasma cholesterol in two patients with normal cholesterol before operation were significantly higher, postoperatively, at 3 monthsand 6 months, respectively. The complete remission rates of hyperuricemia were 37.5%, 33.3%, and 100% in the same observation period, respectively. The abnormal elevations of uric acid in two patients with normal uricemia before operation were significantly higher at postoperative 3 months. CONCLUSION: LSG has a significant effect on patients with type 2 diabetes mellitus whose BMI less than 30 kg/m2 in a short time, but its long-term effectiveness needs to be further followed up.

3.
Zhonghua Wei Chang Wai Ke Za Zhi ; 21(9): 1075-1080, 2018 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-30269329

RESUMO

With the development of social economy and the change of lifestyle and working environment, the number of obese and diabetic population has increased significantly. Obesity is closely related to diabetes mellitus with interaction. Among the patients with type 1 diabetes mellitus (T1DM), the cardiovascular risk of T1DM with obesity is significantly higher than those of lean T1DM. The mortality of T1DM with obesity is significantly higher than that of the general population, which poses a great threat to human health, making it become one of the serious public health problems we have to face at present. However, the traditional treatment method of obesity and diabetes has limited effects and fails to effectively solve obesity, diabetes mellitus and its complications. The birth of bariatric surgery brings a new hope to the treatment of obesity and diabetes. After more than half of a century progress, bariatric surgery has become an effective way to cure or relieve obesity, type 2 diabetes and other metabolic syndromes, which is included in the diabetes treatment guidelines. In patients with diabetes, there are a large number of T1DM patients with obesity being in urgent need of surgical treatment, but only a few patients were reported. From the existing papers and case reports , we can see parameters in many aspects, such as BMI, insulin requirement per day, blood pressure and blood plasma lipid, were significantly reduced after bariatric surgery as well as insulin resistance, diabetic complications, polycystic ovarian syndrome and obstructive sleep apnea hypopnea syndrome were improved or even reversed. However, bariatric surgery in treating T1DM with obesity has not yet reached a consensus in the medical community and not been written to diabetes treatment guidelines. In this paper, the operation methods and mechanism, curative effects, disadvantages and its preventive measures, current status and perspective of bariatric surgery in treating T1DM with obesity are reviewed so as to provide reference for clinical practice.


Assuntos
Cirurgia Bariátrica , Diabetes Mellitus Tipo 1/cirurgia , Obesidade/cirurgia , Humanos , Insulina
4.
Proc Natl Acad Sci U S A ; 115(26): E6075-E6084, 2018 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-29891689

RESUMO

Photosystem II (PSII), a multisubunit protein complex of the photosynthetic electron transport chain, functions as a water-plastoquinone oxidoreductase, which is vital to the initiation of photosynthesis and electron transport. Although the structure, composition, and function of PSII are well understood, the mechanism of PSII biogenesis remains largely elusive. Here, we identified a nuclear-encoded pentatricopeptide repeat (PPR) protein LOW PHOTOSYNTHETIC EFFICIENCY 1 (LPE1; encoded by At3g46610) in Arabidopsis, which plays a crucial role in PSII biogenesis. LPE1 is exclusively targeted to chloroplasts and directly binds to the 5' UTR of psbA mRNA which encodes the PSII reaction center protein D1. The loss of LPE1 results in less efficient loading of ribosome on the psbA mRNA and great synthesis defects in D1 protein. We further found that LPE1 interacts with a known regulator of psbA mRNA translation HIGH CHLOROPHYLL FLUORESCENCE 173 (HCF173) and facilitates the association of HCF173 with psbA mRNA. More interestingly, our results indicate that LPE1 associates with psbA mRNA in a light-dependent manner through a redox-based mechanism. This study enhances our understanding of the mechanism of light-regulated D1 synthesis, providing important insight into PSII biogenesis and the functional maintenance of efficient photosynthesis in higher plants.


Assuntos
Proteínas de Arabidopsis/biossíntese , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Regulação da Expressão Gênica de Plantas , Luz , Proteínas de Membrana Transportadoras/metabolismo , Complexo de Proteína do Fotossistema II/biossíntese , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Fatores de Iniciação em Eucariotos/genética , Proteínas de Membrana Transportadoras/genética , Complexo de Proteína do Fotossistema II/genética
5.
J Biol Eng ; 12: 5, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29713373

RESUMO

Background: Islet transplantation is increasingly used in the diabetic patients to control the blood glucose level. However, the functional output of transplanted islets remains hampered due to the local inflammation, loss of islets, etc. To that end, in this study we explored to enhance the functional output of transplanted islets in diabetic mice by employing a drug-eluting scaffold with a payload of interleukin 4 (IL-4). Results: According to the in vitro studies, the scaffold showed no cytotoxicity, a rapid release of IL-4 within a week and the IL-4 retained its bioactivity. During the 4-week time window after the islet transplantation, in vivo studies showed that the levels of blood insulin and C-peptide 2 in diabetic mice in the drug-eluting scaffold group significantly increased since week 2, which effectively reduced the blood glucose level. In addition, these mice demonstrated a stronger capability to withstand a rapid glucose spike as evidenced by the tolerance of sudden oral glucose challenge test result. A further mechanistic study suggested that the enhanced functional output could be attributed to the M2 polarization of macrophages as evidenced by the increase of CD163+/CD68+ macrophages in the islet tissues. A M2 polarization of macrophages is widely believed to exert an anti-inflammatory influence on local tissues, which could accelerate the resolution of local inflammation following the islet transplantation. Conclusion: Our study shed a new light on the hyperglycemia management of diabetic patients following the islet transplantation.

6.
Cell Host Microbe ; 23(2): 241-253.e6, 2018 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-29396039

RESUMO

Plants initiate immunity by cell-surface pattern-recognition receptors (PRRs), which perceive non-self molecules. PRRs are predominantly receptor serine/threonine (Ser/Thr) kinases that are evolutionarily related to animal interleukin-1 receptor-associated kinase (IRAK)/Pelle-soluble kinases. However, how the activity of these receptor kinases is modulated remains poorly understood. We report that the Arabidopsis PRR chitin elicitor receptor kinase 1 (CERK1) is autophosphorylated in unstimulated cells at tyrosine428 (Tyr428), a modification that is required for CERK1 activation upon binding to the fungal cell wall component chitin. Upon chitin activation, CERK1 recruits the CERK1-interacting protein phosphatase 1 (CIPP1), a predicted Ser/Thr phosphatase, to dephosphorylate Tyr428 and dampen CERK1 signaling. CIPP1 subsequently dissociates from Tyr428-dephosphorylated CERK1, allowing CERK1 to regain Tyr428 autophosphorylation and return to a standby state. This work sheds light onto plant chitin signaling and shows that a receptor kinase and phosphatase can coordinately regulate signal transduction of a receptor kinase through a phosphorylation cycle.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Botrytis/imunologia , Imunidade Vegetal/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Reconhecimento de Padrão/imunologia , Arabidopsis/genética , Arabidopsis/microbiologia , Quitina/metabolismo , Ativação Enzimática , Fosforilação , Plantas Geneticamente Modificadas/genética , Proteínas Quinases/metabolismo , Tirosina/química
7.
Plant Cell Rep ; 37(2): 279-291, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29080907

RESUMO

KEY MESSAGE: M-type thioredoxins are required to regulate zeaxanthin epoxidase activity and to maintain the steady-state level of the proton motive force, thereby influencing NPQ properties under low-light conditions in Arabidopsis. Non-photochemical quenching (NPQ) helps protect photosynthetic organisms from photooxidative damage via the non-radiative dissipation of energy as heat. Energy-dependent quenching (qE) is a major constituent of NPQ. However, the mechanism underlying the regulation of qE is not well understood. In this study, we demonstrate that the m-type thioredoxins TRX-m1, TRX-m2, and TRX-m4 (TRX-ms) interact with the xanthophyll cycle enzyme zeaxanthin epoxidase (ZE) and are required for maintaining the redox-dependent stabilization of ZE by regulating its intermolecular disulfide bridges. Reduced ZE activity and accumulated zeaxanthin levels were observed under TRX-ms deficiency. Furthermore, concurrent deficiency of TRX-ms resulted in a significant increase in proton motive force (pmf) and acidification of the thylakoid lumen under low irradiance, perhaps due to the significantly reduced ATP synthase activity under TRX-ms deficiency. The increased pmf, combined with acidification of the thylakoid lumen and the accumulation of zeaxanthin, ultimately contribute to the elevated stable qE in VIGS-TRX-m2m4/m1 plants under low-light conditions. Taken together, these results indicate that TRX-ms are involved in regulating NPQ-dependent photoprotection in Arabidopsis.


Assuntos
Arabidopsis/metabolismo , Clorofila/metabolismo , Tiorredoxinas de Cloroplastos/metabolismo , Luz , Fotossíntese/efeitos da radiação , Xantofilas/metabolismo , Proteínas de Arabidopsis/metabolismo , Oxirredução , Oxirredutases/metabolismo , Ligação Proteica , Força Próton-Motriz/efeitos da radiação , Tilacoides/metabolismo , Zeaxantinas/metabolismo
8.
Plant Physiol ; 175(2): 652-666, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28827456

RESUMO

In chloroplasts, thioredoxin (TRX) isoforms and NADPH-dependent thioredoxin reductase C (NTRC) act as redox regulatory factors involved in multiple plastid biogenesis and metabolic processes. To date, less is known about the functional coordination between TRXs and NTRC in chlorophyll biosynthesis. In this study, we aimed to explore the potential functions of TRX m and NTRC in the regulation of the tetrapyrrole biosynthesis (TBS) pathway. Silencing of three genes, TRX m1, TRX m2, and TRX m4 (TRX ms), led to pale-green leaves, a significantly reduced 5-aminolevulinic acid (ALA)-synthesizing capacity, and reduced accumulation of chlorophyll and its metabolic intermediates in Arabidopsis (Arabidopsis thaliana). The contents of ALA dehydratase, protoporphyrinogen IX oxidase, the I subunit of Mg-chelatase, Mg-protoporphyrin IX methyltransferase (CHLM), and NADPH-protochlorophyllide oxidoreductase were decreased in triple TRX m-silenced seedlings compared with the wild type, although the transcript levels of the corresponding genes were not altered significantly. Protein-protein interaction analyses revealed a physical interaction between the TRX m isoforms and CHLM. 4-Acetoamido-4-maleimidylstilbene-2,2-disulfonate labeling showed the regulatory impact of TRX ms on the CHLM redox status. Since CHLM also is regulated by NTRC (Richter et al., 2013), we assessed the concurrent functions of TRX m and NTRC in the control of CHLM. Combined deficiencies of three TRX m isoforms and NTRC led to a cumulative decrease in leaf pigmentation, TBS intermediate contents, ALA synthesis rate, and CHLM activity. We discuss the coordinated roles of TRX m and NTRC in the redox control of CHLM stability with its corollary activity in the TBS pathway.


Assuntos
Arabidopsis/enzimologia , Tiorredoxina Dissulfeto Redutase/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Clorofila/metabolismo , Cloroplastos/metabolismo , NADP/metabolismo , Oxirredução , Folhas de Planta/enzimologia , Folhas de Planta/genética , Isoformas de Proteínas , Plântula/enzimologia , Plântula/genética , Tetrapirróis/metabolismo , Tiorredoxina Dissulfeto Redutase/genética , Tiorredoxinas/metabolismo
9.
J Integr Plant Biol ; 59(4): 234-239, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28225199

RESUMO

In Arabidopsis, both the membrane-anchored receptor-like kinase (RLK) BAK1 and the receptor-like cytoplasmic kinase (RLCK) BIK1 are important mediators of transmembrane signal transduction that regulate plant development and immunity. However, little attention has been paid to their genetic association. This study found the bak1 bik1 double mutant of Arabidopsis displayed a severe dwarfism phenotype due to constitutive immunity and cell death in developing plants. These data suggest that BIK1 cooperates with BAK1 to regulate constitutive immunity and cell death.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citologia , Arabidopsis/imunologia , Imunidade Vegetal , Proteínas Serina-Treonina Quinases/metabolismo , Morte Celular , Mutação/genética , Fenótipo
10.
Rice (N Y) ; 10(1): 6, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28220451

RESUMO

BACKGROUND: The receptor-like cytoplasmic kinase, OsRLCK176 has been reported to participate in both chitin- and PGN-induced immunity in rice. Here, we further researched the function of the homologous proteins, OsRLCK57, OsRLCK107 and OsRLCK118, in chitin- and PGN immunity in rice. FINDINGS: Silencing of OsRLCK57,OsRLCK107 and OsRLCK118 suppressed chitin- and PGN-induced immunity responses, including reactive oxygen species generation, defense gene expression. Furthermore, OsRLCK107 could interact with OsCERK1 in a MAMP induced way, which suggested a possible physiological relevance of OsRLCKs107 to OsCERK1 pathway. CONCLUSIONS: OsRLCK57, OsRLCK107 and OsRLCK118, positively regulate chitin- and PGN- induced responses in rice, similar to that observed in OsRLCK176.

11.
Plant Cell Physiol ; 57(12): 2586-2599, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27818379

RESUMO

Chloroplast development is an essential process for plant growth that is regulated by numerous proteins. Plastid-encoded plastid RNA polymerase (PEP) is a large complex that regulates plastid gene transcription and chloroplast development. However, many proteins in this complex remain to be identified. Here, through large-scale screening of Arabidopsis mutants by Chl fluorescence imaging, we identified a novel protein, DELAYED GREENING 238 (DG238), which is involved in regulating chloroplast development and plastid gene expression. Loss of DG238 retards plant growth, delays young leaf greening, affects chloroplast development and lowers photosynthetic efficiency. Moreover, blue-native PAGE (BN-PAGE) and Western blot analysis indicated that PSII and PSI protein levels are reduced in dg238 mutants. DG238 is mainly expressed in young tissues and is regulated by light signals. Subcellular localization analysis showed that DG238 is a nuclear-encoded chloroplast nucleoid protein. More interestingly, DG238 was co-expressed with FLN1, which encodes an essential subunit of the PEP complex. Bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation (Co-IP) assays showed that DG238 can also interact with FLN1. Taken together, these results suggest that DG238 may function as a component of the PEP complex that is important for the early stage of chloroplast development and helps regulate PEP-dependent plastid gene expression.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Cloroplastos/ultraestrutura , RNA Polimerases Dirigidas por DNA/metabolismo , Proteínas Nucleares/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Arabidopsis/enzimologia , Arabidopsis/efeitos da radiação , Arabidopsis/ultraestrutura , Proteínas de Arabidopsis/genética , Cloroplastos/enzimologia , RNA Polimerases Dirigidas por DNA/genética , Regulação da Expressão Gênica de Plantas , Luz , Mutação , Proteínas Nucleares/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Filogenia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/efeitos da radiação , Folhas de Planta/ultraestrutura , Plastídeos/enzimologia , Plastídeos/ultraestrutura , Transporte Proteico , Transcrição Genética
12.
Plant Physiol ; 172(3): 1720-1731, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27609860

RESUMO

Maximizing light capture by light-harvesting pigment optimization represents an attractive but challenging strategy to improve photosynthetic efficiency. Here, we report that loss of a previously uncharacterized gene, HIGH PHOTOSYNTHETIC EFFICIENCY1 (HPE1), optimizes light-harvesting pigments, leading to improved photosynthetic efficiency and biomass production. Arabidopsis (Arabidopsis thaliana) hpe1 mutants show faster electron transport and increased contents of carbohydrates. HPE1 encodes a chloroplast protein containing an RNA recognition motif that directly associates with and regulates the splicing of target RNAs of plastid genes. HPE1 also interacts with other plastid RNA-splicing factors, including CAF1 and OTP51, which share common targets with HPE1. Deficiency of HPE1 alters the expression of nucleus-encoded chlorophyll-related genes, probably through plastid-to-nucleus signaling, causing decreased total content of chlorophyll (a+b) in a limited range but increased chlorophyll a/b ratio. Interestingly, this adjustment of light-harvesting pigment reduces antenna size, improves light capture, decreases energy loss, mitigates photodamage, and enhances photosynthetic quantum yield during photosynthesis. Our findings suggest a novel strategy to optimize light-harvesting pigments that improves photosynthetic efficiency and biomass production in higher plants.


Assuntos
Arabidopsis/fisiologia , Complexos de Proteínas Captadores de Luz/metabolismo , Fotossíntese , Pigmentos Biológicos/metabolismo , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Biomassa , Metabolismo dos Carboidratos/efeitos da radiação , Núcleo Celular/metabolismo , Núcleo Celular/efeitos da radiação , Clorofila/metabolismo , Regulação para Baixo/genética , Regulação para Baixo/efeitos da radiação , Genes de Plantas , Luz , Metaboloma/efeitos da radiação , Mutação/genética , Fotossíntese/efeitos da radiação , Plastídeos/genética , Plastídeos/efeitos da radiação , Processamento de RNA/genética , Processamento de RNA/efeitos da radiação , Tilacoides/metabolismo , Tilacoides/efeitos da radiação
13.
World J Surg Oncol ; 14: 90, 2016 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-27030355

RESUMO

BACKGROUND: The objective of this study was to evaluate the feasibility, safety, and potential benefits of laparoscopic gastrectomy (LG) comparing with open gastrectomy (OG) in elderly population. METHODS: Studies comparing LG with OG for elderly population with gastric cancer, published between January 1994 and July 2015, were identified in the PubMed, Embase, and ISI Web of Science databases. Operative outcomes (intraoperative blood loss, operative time, and the number of lymph nodes harvested) and postoperative outcomes (time to first ambulation, time to first flatus, time to first oral intake, postoperative hospital stay, postoperative morbidity) were included and analyzed. The Newcastle-Ottawa Scale was used to assess the quality of the pooled study. A funnel plot was used to evaluate the publication bias. RESULTS: Seven studies totaling 845 patients were included in the meta-analysis. LG in comparison to OG showed less intraoperative blood loss (weighted mean difference (WMD) -127.47; 95% confidence interval (CI) -202.79 to -52.16; P < 0.01), earlier time to first ambulation (WMD -2.07; 95% CI -2.84 to -1.30; P < 0.01), first flatus (WMD -1.04; 95% CI -1.45 to -0.63; P < 0.01), and oral intake (WMD -0.94; 95% CI -1.11 to -0.77; P < 0.01), postoperative hospital stay (WMD -5.26; 95% CI -7.58 to -2.93; P < 0.01), lower overall postoperative complication rate (odd ratio (OR) 0.39; 95% CI 0.28 to 0.55; P < 0.01), less surgical complications (OR 0.47; 95% CI 0.32 to 0.69; P < 0.01), medical complication (OR 0.35; 95% CI 0.22 to 0.56; P < 0.01), incisional complication (OR 0.40; 95% CI 0.19 to 0.85; P = 0.02), and pulmonary infection (OR 0.49; 95% CI 0.26 to 0.93; P = 0.03). No significant differences were observed between LG and OG for the number of harvested lymph nodes. However, LG had longer operative times (WMD 15.73; 95% CI 6.23 to 25.23; P < 0.01). CONCLUSIONS: LG is a feasible and safe approach for elderly patients with gastric cancer. Compared with OG, LG has less blood loss, faster postoperative recovery, and reduced postoperative morbidity.


Assuntos
Gastrectomia/métodos , Laparoscopia/métodos , Complicações Pós-Operatórias , Neoplasias Gástricas/cirurgia , Idoso , Humanos , Resultado do Tratamento
14.
Plant Cell ; 27(3): 787-805, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25794933

RESUMO

Iron (Fe) is an indispensable micronutrient for plant growth and development. The regulation of Fe homeostasis in plants is complex and involves a number of transcription factors. Here, we demonstrate that a basic helix-loop-helix (bHLH) transcription factor, bHLH104, belonging to the IVc subgroup of bHLH family, acts as a key component positively regulating Fe deficiency responses. Knockout of bHLH104 in Arabidopsis thaliana greatly reduced tolerance to Fe deficiency, whereas overexpression of bHLH104 had the opposite effect and led to accumulation of excess Fe in soil-grown conditions. The activation of Fe deficiency-inducible genes was substantially suppressed by loss of bHLH104. Further investigation showed that bHLH104 interacted with another IVc subgroup bHLH protein, IAA-LEUCINE RESISTANT3 (ILR3), which also plays an important role in Fe homeostasis. Moreover, bHLH104 and ILR3 could bind directly to the promoters of Ib subgroup bHLH genes and POPEYE (PYE) functioning in the regulation of Fe deficiency responses. Interestingly, genetic analysis showed that loss of bHLH104 could decrease the tolerance to Fe deficiency conferred by the lesion of BRUTUS, which encodes an E3 ligase and interacts with bHLH104. Collectively, our data support that bHLH104 and ILR3 play pivotal roles in the regulation of Fe deficiency responses via targeting Ib subgroup bHLH genes and PYE expression.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Homeostase/efeitos dos fármacos , Ferro/farmacologia , Adaptação Fisiológica/efeitos dos fármacos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Imunoprecipitação da Cromatina , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Técnicas de Inativação de Genes , Genes de Plantas , Ferro/deficiência , Modelos Biológicos , Mutação/genética , Motivos de Nucleotídeos/genética , Fenótipo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/genética , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real , Solo
15.
Plant J ; 80(6): 1072-84, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25335639

RESUMO

Microbe-associated molecular pattern (MAMP)-triggered immunity plays critical roles in the basal resistance defense response in plants. Chitin and peptidoglycan (PGN) are major molecular patterns for fungi and bacteria, respectively. Two rice (Oryza sativa) lysin motif-containing proteins, OsLYP4 and OsLYP6, function as receptors that sense bacterial PGN and fungal chitin. These membrane receptors, which lack intracellular kinase domains, likely contain another component for transmembrane immune signal transduction. Here, we demonstrate that the rice LysM receptor-like kinase OsCERK1, a key component of the chitin elicitor signaling pathway, also plays an important role in PGN-triggered immunity in rice. Silencing of OsCERK1 suppressed PGN-induced (and chitin-induced) immunity responses, including reactive oxygen species generation, defense gene expression, and callose deposition, indicating that OsCERK1 is essential for both PGN and chitin signaling initiated by OsLYP4 and OsLYP6. OsLYP4 associated with OsLYP6 and the rice chitin receptor chitin oligosaccharide elicitor-binding protein (CEBiP) in the absence of PGN or chitin, and treatment with PGN or chitin led to their disassociation in vivo. OsCERK1 associated with OsLYP4 or OsLYP6 when induced by PGN but it associated with OsLYP4, OsLYP6, or CEBiP under chitin treatment, suggesting the presence of different patterns of ligand-induced heterooligomeric receptor complexes. Furthermore, the receptor-like cytoplasmic kinase OsRLCK176 functions downstream of OsCERK1 in the PGN and chitin signaling pathways, suggesting that these MAMPs share overlapping intracellular signaling components. Therefore, OsCERK1 plays dual roles in PGN and chitin signaling in rice innate immunity and as an adaptor involved in signal transduction at the plasma membrane in conjunction with OsLYP4 and OsLYP6.


Assuntos
Quitina/metabolismo , Oryza/genética , Peptidoglicano/metabolismo , Doenças das Plantas/imunologia , Proteínas de Plantas/metabolismo , Transdução de Sinais , Motivos de Aminoácidos , Membrana Celular/metabolismo , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/imunologia , Oryza/fisiologia , Imunidade Vegetal , Proteínas de Plantas/genética
17.
Plant Cell ; 26(3): 1213-29, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24632535

RESUMO

Under high-irradiance conditions, plants must efficiently protect photosystem II (PSII) from damage. In this study, we demonstrate that the chloroplast protein HYPERSENSITIVE TO HIGH LIGHT1 (HHL1) is expressed in response to high light and functions in protecting PSII against photodamage. Arabidopsis thaliana hhl1 mutants show hypersensitivity to high light, drastically decreased PSII photosynthetic activity, higher nonphotochemical quenching activity, a faster xanthophyll cycle, and increased accumulation of reactive oxygen species following high-light exposure. Moreover, HHL1 deficiency accelerated the degradation of PSII core subunits under high light, decreasing the accumulation of PSII core subunits and PSII-light-harvesting complex II supercomplex. HHL1 primarily localizes in the stroma-exposed thylakoid membranes and associates with the PSII core monomer complex through direct interaction with PSII core proteins CP43 and CP47. Interestingly, HHL1 also directly interacts, in vivo and in vitro, with LOW QUANTUM YIELD OF PHOTOSYSTEM II1 (LQY1), which functions in the repair and reassembly of PSII. Furthermore, the hhl1 lqy1 double mutants show increased photosensitivity compared with single mutants. Taken together, these results suggest that HHL1 forms a complex with LQY1 and participates in photodamage repair of PSII under high light.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Membrana/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Isomerases de Dissulfetos de Proteínas/metabolismo , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Cloroplastos/metabolismo , Mutação , Ligação Proteica , Espécies Reativas de Oxigênio/metabolismo
18.
Plant Physiol ; 163(4): 1710-28, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24151299

RESUMO

Chloroplastic m-type thioredoxins (TRX m) are essential redox regulators in the light regulation of photosynthetic metabolism. However, recent genetic studies have revealed novel functions for TRX m in meristem development, chloroplast morphology, cyclic electron flow, and tetrapyrrole synthesis. The focus of this study is on the putative role of TRX m1, TRX m2, and TRX m4 in the biogenesis of the photosynthetic apparatus in Arabidopsis (Arabidopsis thaliana). To that end, we investigated the impact of single, double, and triple TRX m deficiency on chloroplast development and the accumulation of thylakoid protein complexes. Intriguingly, only inactivation of three TRX m genes led to pale-green leaves and specifically reduced stability of the photosystem II (PSII) complex, implying functional redundancy between three TRX m isoforms. In addition, plants silenced for three TRX m genes displayed elevated levels of reactive oxygen species, which in turn interrupted the transcription of photosynthesis-related nuclear genes but not the expression of chloroplast-encoded PSII core proteins. To dissect the function of TRX m in PSII biogenesis, we showed that TRX m1, TRX m2, and TRX m4 interact physically with minor PSII assembly intermediates as well as with PSII core subunits D1, D2, and CP47. Furthermore, silencing three TRX m genes disrupted the redox status of intermolecular disulfide bonds in PSII core proteins, most notably resulting in elevated accumulation of oxidized CP47 oligomers. Taken together, our results suggest an important role for TRX m1, TRX m2, and TRX m4 proteins in the biogenesis of PSII, and they appear to assist the assembly of CP47 into PSII.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Tiorredoxinas de Cloroplastos/metabolismo , Cloroplastos/metabolismo , Complexo de Proteína do Fotossistema II/biossíntese , Tiorredoxinas/metabolismo , Arabidopsis/genética , Arabidopsis/ultraestrutura , Proteínas de Arabidopsis/genética , Clorofila/metabolismo , Tiorredoxinas de Cloroplastos/genética , Cloroplastos/ultraestrutura , Sequência Conservada , Dissulfetos/metabolismo , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Genes de Plantas , Proteínas de Fluorescência Verde/metabolismo , Immunoblotting , Oxirredução , Fenótipo , Folhas de Planta/metabolismo , Subunidades Proteicas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Reprodutibilidade dos Testes , Espectrometria de Fluorescência , Tiorredoxinas/genética , Tilacoides/metabolismo
19.
Plant J ; 76(5): 861-74, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24118453

RESUMO

Photosynthetic electron transport is the major energy source for cellular metabolism in plants, and also has the potential to generate excess reactive oxygen species that cause irreversible damage to photosynthetic apparatus under adverse conditions. Ferredoxins (Fds), as the electron-distributing hub in the chloroplast, contribute to redox regulation and antioxidant defense. However, the steady-state levels of photosynthetic Fd decrease in plants when they are exposed to environmental stress conditions. To understand the effect of Fd down-regulation on plant growth, we characterized Arabidopsis thaliana plants lacking Fd2 (Fd2-KO) under long-term high light (HL) conditions. Unexpectedly, Fd2-KO plants exhibited efficient photosynthetic capacity and stable thylakoid protein complexes. At the transcriptional level, photoprotection-related genes were up-regulated more in the mutant plants, suggesting that knockout Fd2 lines possess a relatively effective photo-acclimatory responses involving enhanced plastid redox signaling. In contrast to the physiological characterization of Fd2-KO under short-term HL, the plastoquinone pool returned to a relatively balanced redox state via elevated PGR5-dependent cyclic electron flow during extended HL. fd2 pgr5 double mutant plants displayed severely impaired photosynthetic capacity under HL treatment, further supporting a role for PGR5 in adaptation to HL in the Fd2-KO plants. These results suggest potential benefits of reducing Fd levels in plants grown under long-term HL conditions.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Ferredoxinas/metabolismo , Luz , Fotossíntese/fisiologia , Aclimatação , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Cloroplastos/metabolismo , Ferredoxinas/genética , Técnicas de Inativação de Genes , Dados de Sequência Molecular , Complexo de Proteínas do Centro de Reação Fotossintética/genética , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Estresse Fisiológico
20.
PLoS One ; 8(7): e71190, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23936263

RESUMO

The nongreen plastids, such as etioplasts, chromoplasts, etc., as well as chloroplasts, are all derived from proplastids in the meristem. To date, the Min system members in plants have been identified as regulators of FtsZ-ring placement, which are essential for the symmetrical division of chloroplasts. However, the regulation of FtsZ-ring placement in nongreen plastids is poorly understood. In this study, we investigated the division site placement of nongreen plastids by examining the etioplasts as representative in Arabidopsis Min system mutants. Surprisingly, the shape and number of etioplasts in cotyledons of arc3, arc11 and mcd1 mutants were similar to that observed in wild-type plants, whereas arc12 and parc6 mutants exhibited enlarged etioplasts that were reduced in number. In order to examine nongreen plastids in true leaves, we silenced the ALB3 gene in these Min system mutant backgrounds to produce immature chloroplasts without the thylakoidal network using virus induced gene silencing (VIGS). Interestingly, consistent with our observations in etioplasts, enlarged and fewer nongreen plastids were only detected in leaves of parc6 (VIGS-ALB3) and arc12 (VIGS-ALB3) plants. Further, the FtsZ-ring assembled properly at the midpoint in nongreen plastids of arc3, arc11 and mcd1 (VIGS-ALB3) plants, but organized into multiple rings in parc6 (VIGS-ALB3) and presented fragmented filaments in arc12 (VIGS-ALB3) plants, suggesting that division site placement in nongreen plastids requires fewer components of the plant Min system. Taken together, these results suggest that division site placement in nongreen plastids is different from that in chloroplasts.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Regulação da Expressão Gênica de Plantas , Mutação , Fenótipo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Plastídeos/genética , Plastídeos/metabolismo
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