Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
Econ Hum Biol ; 53: 101365, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38340650

RESUMO

During the early outbreak phase of COVID-19 in China, lockdowns prevailed as the only available policy tools to mitigate the spread of infection. To evaluate the impact of lockdown policies in the context of the first phase of COVID-19 pandemic, we leverage data on daily confirmed cases per million people and related characteristics of a large set of cities. The study analyzed 369 Chinese cities, among which 188 implemented lockdowns of varying severity levels from January 23 to March 31, 2020. We use nationwide Baidu Mobility data to estimate the impact of lockdown policies on mitigating COVID-19 cases through reducing human mobility. We adopt a heterogeneous treatment effect model to quantify the effect of lockdown policies on containing confirmed case counts. Our results suggest that lockdowns substantially reduced human mobility, and larger reduction in mobility occurred within-city compared to between-city. The COVID-19 daily confirmed cases per million people decreased by 9% - 9.2% for every ten-percentage point fall in within-city travel intensity in t+7 timeframe. We also find that one city's lockdowns can effectively reduce the spillover cases of the traveler's destination cities. We find no evidence that stricter lockdowns are more effective at mitigating COVID-19 risks. Our findings provide practical insights about the effectiveness of NPI during the early outbreak phase of the unprecedented pandemic.


Assuntos
COVID-19 , Cidades , Quarentena , SARS-CoV-2 , Viagem , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , COVID-19/transmissão , China/epidemiologia , Controle de Doenças Transmissíveis/métodos , Controle de Doenças Transmissíveis/legislação & jurisprudência , Pandemias/prevenção & controle , Heterogeneidade da Eficácia do Tratamento
2.
J Ophthalmol ; 2024: 6525136, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38264273

RESUMO

Purpose: To assess the differences in accommodation and binocular vision in children with myopic anisometropia and determine the correlation with anisometropia. Method: A total of 110 patients with myopia aged 8-15 years were recruited from June 2021 to February 2022 from the Affiliated Hospital of Xuzhou Medical University. Based on the interocular differences of spherical equivalent refraction, patients were divided into the isometropia (35 children), low anisometropia (LA group, 42 children), and high anisometropia (HA group, 33 children). The variables assessed were refraction, heterophoria, amplitude of accommodation (AMP), accommodative response (AR), gradient AC/A, positive and negative relative accommodation (PRA/NRA), and near stereopsis in the three groups. Pearson's correlation coefficient tests were used to investigate the possible association between each parameter and interocular differences (IODs). Results: Among 110 subjects, there were 49 males and 61 females with a mean age of 11.39 ± 2.28 years. Compared with those in the isometropia group, AMP was lower and near stereopsis was higher in the LA group, and the distance and near heterophoria, PRA, AR, and near stereopsis were higher, and PRA, AMP, and gradient AC/A were lower in the HA group (all P < 0.05). Compared with those in the LA group, the near stereopsis, AR, and the near stereopsis were higher in the HA group, and the gradient AC/A was lower (all P < 0.05). However, no significant differences existed in the negative relative accommodation (P > 0.05). The distance and near heterophoria, AR, AMP, and near stereopsis were observed to be correlated with IODs, respectively (r = -0.259, p = 0.006; r = -0.201, p = 0.036; r = 0.306, p = 0.001; r = -0.315, p = 0.001; r = 0.535, p < 0.001). Conclusion: Our results suggested that with the increase of anisometropia, distance and near heterophoria, AR, AMP, and near stereopsis had a tendency to get worse in children with myopic anisometropia.

3.
Cortex ; 154: 62-76, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35753183

RESUMO

Scale invariant neural dynamics are a relatively new but effective means of measuring changes in brain states as a result of varied cognitive load and task difficulty. This study tests whether scale invariance (as measured by the Hurst exponent, H) can be used with functional near-infrared spectroscopy (fNIRS) to quantify cognitive load, paving the way for scale-invariance to be measured in a variety of real-world settings. We analyzed H extracted from the fNIRS time series while participants completed an N-back working memory task. Consistent with what has been demonstrated in fMRI, the current results showed that scale-invariance analysis significantly differentiated between task and rest periods as calculated from both oxy- (HbO) and deoxy-hemoglobin (HbR) concentration changes. Results from both channel-averaged H and a multivariate partial least squares approach (Task PLS) demonstrated higher H during the 1-back task than the 2-back task. These results were stronger for H derived from HbR than from HbO. This suggests that scale-free brain states are a robust signature of cognitive load and not limited by the specific neuroimaging modality employed. Further, as fNIRS is relatively portable and robust to motion-related artifacts, these preliminary results shed light on the promising future of measuring cognitive load in real life settings.


Assuntos
Mapeamento Encefálico , Espectroscopia de Luz Próxima ao Infravermelho , Encéfalo , Cognição , Humanos , Memória de Curto Prazo
4.
BMC Med Educ ; 22(1): 316, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35473565

RESUMO

BACKGROUND: Physicians report increasing burnout and declining career-related satisfaction, negatively impacting physician well-being and patient care quality. For physicians with academic affiliations, these issues can directly affect future generations of physicians. Previous research on burnout and satisfaction has focused on factors like work hours, gender, race, specialty, and work setting. We seek to contribute to the literature by examining these associations while controlling for demographic, family, and work-related characteristics. Furthermore, we aim to determine any differential effects of faculty rank. METHODS: We analyzed data on practicing physicians in the U.S. from the Association of American Medical College's (AAMC) 2019 National Sample Survey of Physicians (NSSP,) which includes variables adapted from the Maslach Burnout Inventory. We used ordinal logistic regressions to explore associations between academic affiliation and burnout. We conducted a factor analysis to consolidate satisfaction measures, then examined their relationship with academic affiliation using multivariate linear regressions. All regression analyses controlled for physicians' individual, family, and work characteristics. RESULTS: Among respondents (n = 6,000), 40% were affiliated with academic institutions. Physicians with academic affiliations had lower odds than their non-affiliated peers for feeling emotional exhaustion every day (Odds Ratio [OR] 0.87; 95% CI: 0.79-0.96; P < .001) and reported greater career-related satisfaction (0.10-0.14, SE, 0.03, 0.02; P < .001). The odds of feeling burnt out every day were higher for associate professors, (OR 1.57; 95% CI: 1.22-2.04; P < .001) assistant professors, (OR 1.64; 95% CI: 1.28-2.11; P < .001), and instructors (OR 1.72; 95% CI, 1.29-2.29; P < .001), relative to full professors. CONCLUSIONS: Our findings contribute to the literature on burnout and career satisfaction by exploring their association with academic affiliation and examining how they vary among different faculty ranks. An academic affiliation may be an essential factor in keeping physicians' burnout levels lower and career satisfaction higher. It also suggests that policies addressing physician well-being are not "one size fits all" and should consider factors such as academic affiliation, faculty rank and career stage, gender identity, the diversity of available professional opportunities, and institutional and social supports. For instance, department chairs and administrators in medical institutions could protect physicians' time for academic activities like teaching to help keep burnout lower and career satisfaction higher.


Assuntos
Esgotamento Profissional , Médicos , Esgotamento Profissional/psicologia , Feminino , Identidade de Gênero , Humanos , Satisfação no Emprego , Masculino , Satisfação Pessoal , Médicos/psicologia , Inquéritos e Questionários , Estados Unidos
5.
Asian J Androl ; 24(4): 380-385, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34643549

RESUMO

Prostate cancer (PCa) is one of the most frequent cancers in men, and its biomolecular targets have been extensively studied. This study aimed to analyze the expression of toll-like receptor 9 (TLR9) and vascular endothelial growth factor C (VEGF-C) and the clinical value of the coexpression of TLR9 and VEGF-C in PCa. We retrospectively evaluated 55 patients with clinically localized, intermediate-risk, or high-risk PCa who underwent laparoscopic radical prostatectomy (LRP) and extended pelvic lymph node dissection (ePLND) without neoadjuvant hormonal therapy at a single institution from June 2013 to December 2016. In all 55 patients, the median number of lymph nodes (LNs) resected was 23 (range: 18-31), and a total of 1269 LNs were removed, of which 78 LNs were positive. Seventeen patients had positive LNs, with a positive rate of 30.9%. In addition, the immunohistochemical results in the above patients revealed that high TLR9 expression was correlated with higher Gleason score (GS) (P = 0.049), increased LN metastasis (P = 0.004), and more perineural invasion (PNI) (P = 0.033). Moreover, VEGF-C expression was associated with GS (P = 0.040), pathological stage (pT stage) (P = 0.022), LN metastasis (P = 0.003), and PNI (P = 0.001). Furthermore, a significant positive correlation between TLR9 and VEGF-C was found (P < 0.001), and the TLR9/VEGF-C phenotype was associated with LN metastasis (P = 0.047). Collectively, we propose that TLR9 stimulation may promote LN metastasis in PCa cells through the upregulation of VEGF-C expression, thereby affecting the prognosis of PCa patients. Therefore, these markers may serve as valuable targets for the treatment of PCa.


Assuntos
Neoplasias da Próstata , Fator C de Crescimento do Endotélio Vascular/metabolismo , Humanos , Excisão de Linfonodo/métodos , Linfonodos/patologia , Metástase Linfática/patologia , Masculino , Prostatectomia/métodos , Neoplasias da Próstata/patologia , Neoplasias da Próstata/cirurgia , Estudos Retrospectivos , Receptor Toll-Like 9
6.
Appl Ergon ; 82: 102946, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31487560

RESUMO

BACKGROUND: Consumer virtual reality (VR) devices are becoming more prevalent in the market, but cybersickness induced by VR devices limits their potential application and promotion. Acustimulation has been found effective in reducing cybersickness symptoms. However, in previous forms, the more effective way of acustimulation is either intrusive or electrical which is hard to be applied to daily VR use. PURPOSE: In this study, we aimed to find a both simple and more effective acustimulation approach, acupressure plus acupaste (AcP+) to reducing the adverse effects caused by cybersickness from VR applications. METHOD: In this study, we set three conditions: acupressure plus acupaste (AcP+) (main condition of interest), acupressure with fake acupaste (AcP), and a no acustimulation condition (NoAcP). In AcP and AcP + conditions, we applied acupressure or acupressure with true acupaste on P6 point before conducting video-watching tasks using VR headsets, while in NoAcP condition, participants received no special treatment before video-watching tasks. We used questionnaires to measure symptoms of cybersickness and compared the results between these 3 conditions, especially between acupressure plus acupaste (AcP+) and acupressure (AcP) to examine the effect of AcP+, and compared AcP and AcP+ with NoAcP to confirm the effect of acustimulation. RESULT: Participants reported significant fewer symptoms of cybersickness nausea feelings in both acustimulation methods, compared with NoAcP; and AcP+ was more effective than AcP against cybersickness on visual oculomotor aspect, and facilitated cybersickness recovery. IMPLICATION: It would be promising to develop acupressure equipment and apply stimulation before VR application to reduce cybersickness.


Assuntos
Acupressão/métodos , Enjoo devido ao Movimento/etiologia , Enjoo devido ao Movimento/prevenção & controle , Realidade Virtual , Feminino , Humanos , Masculino , Inquéritos e Questionários , Adulto Jovem
7.
Front Hum Neurosci ; 13: 120, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31024278

RESUMO

The behavioral differentiation of positive emotions has recently been studied in terms of their discrete adaptive functions or appraising profiles. Some preliminary neurophysiological evidences have been found with electroencephalography or autonomic nervous system measurements such as heart rate, skin conductance, etc. However, the brain's hemodynamic responses to different positive emotions remain largely unknown. In the present study, the functional near-infrared spectroscopy (fNIRS) technique was employed. With this tool, we for the first time reported recognizable discrete positive emotions using fNIRS signals. Thirteen participants watched 30 emotional video clips to elicit 10 typical kinds of positive emotions (joy, gratitude, serenity, interest, hope, pride, amusement, inspiration, awe, and love), and their frontal neural activities were simultaneously recorded with a 24-channel fNIRS system. The multidimensional scaling analysis of participants' subjective ratings on these 10 positive emotions revealed three distinct clusters, which could be interpreted as "playfulness" for amusement, joy, interest, "encouragement" for awe, gratitude, hope, inspiration, pride, and "harmony" for love, serenity. Hemodynamic responses to these three positive emotion clusters showed distinct patterns, and HbO-based individual-level binary classifications between them achieved an averaged accuracy of 73.79 ± 11.49% (77.56 ± 7.39% for encouragement vs. harmony, 73.29 ± 11.87% for playfulness vs. harmony, 70.51 ± 13.96% for encouragement vs. harmony). Benefited from fNIRS's high portability, low running cost and the relative robustness against motion and electrical artifacts, our findings provided support for implementing a more fine-grained emotion recognition system with subdivided positive emotion categories.

8.
PLoS One ; 9(7): e101589, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25033450

RESUMO

The retrieval-extinction paradigm, which disrupts the reconsolidation of fear memories in humans, is a non-invasive technique that can be used to prevent the return of fear in humans. In the present study, unconditioned stimulus revaluation was applied in the retrieval-extinction paradigm to investigate its promotion of conditioned fear extinction in the memory reconsolidation window after participants acquired conditioned fear. This experiment comprised three stages (acquisition, unconditioned stimulus revaluation, retrieval-extinction) and three methods for indexing fear (unconditioned stimulus expectancy, skin conductance response, conditioned stimulus pleasure rating). After the acquisition phase, we decreased the intensity of the unconditioned stimulus in one group (devaluation) and maintained constant for the other group (control). The results indicated that both groups exhibited similar levels of unconditioned stimulus expectancy, but the devaluation group had significantly smaller skin conductance responses and exhibited a growth in conditioned stimulus + pleasure. Thus, our findings indicate unconditioned stimulus revaluation effectively promoted the extinction of conditioned fear within the memory reconsolidation window.


Assuntos
Condicionamento Clássico/fisiologia , Extinção Psicológica/fisiologia , Medo/psicologia , Consolidação da Memória/fisiologia , Adulto , Emoções/fisiologia , Feminino , Resposta Galvânica da Pele , Humanos , Masculino , Adulto Jovem
9.
Yi Chuan Xue Bao ; 32(5): 514-8, 2005 May.
Artigo em Chinês | MEDLINE | ID: mdl-16018263

RESUMO

The TAC clone (NK15) containing a ca.50 kb DNA insert was introduced into Agrobacterium tumefaciens strain LBA4404 by electroporation. The NK15 was stable in Agrobacterium tumefaciens strain LBA4404 under kanamycin selection for many generations. The calli of mature embryo of Nongken58S were infected with the Agrobacterium tumefaciens strain LBA4404 carrying NK15. PCR and Southern analyses of transgenic plants indicated that the 50 kb of foreign DNA was transferred into the rice genome, and most of transgenic plants had one copy of the insertion. Genetic and PCR analyses of T1 progeny confirmed that the inserted forgein DNA was stably inherited.


Assuntos
DNA de Plantas/genética , Oryza/genética , Plasmídeos/genética , Transformação Genética , Southern Blotting , Cromossomos Artificiais , Eletroporação , Genoma de Planta , Oryza/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Rhizobium/genética
10.
Dis Esophagus ; 18(1): 46-50, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15773842

RESUMO

An association between viral infection, particularly the human papillomavirus, and the development of esophageal carcinoma (EC) has been reported. However, reports concerning the relationship between herpes simplex virus (HSV) and Epstein-Barr virus (EBV) with EC are few. There are geographic variations in infection rates. This study was aimed to determine the co-incidence of infection of the two viruses' with esophageal carcinoma and the differentiation of cancer tissues and lymphocytes infiltration in the tumor stroma of the high-incidence area of Shantou China. To determine the association between viral infection (HSV and EBV) and EC, we applied in situ hybridization (ISH) and immunohistochemistry (IHC) in 164 esophageal carcinoma surgical specimens from the high-incidence area of Shantou China. HSV DNA and HSVI, II protein expression were found in 52 (31.7%) of the 164 tumors; EBV EBER and LMP-1 proteins were identified in only 10 (6.1%) carcinoma specimens by in situ hybridization and immunohistochemistry. In histopathology analysis, the positive cases of HSV appeared to be more predominant in well and moderately differentiated squamous cell carcinomas, and the positive cases of EBV were found in poorly differentiated squamous cell carcinomas or undifferentiated carcinomas with intense lymphoid infiltration. Our results confirm the involvement of HSV and EBV in esophageal carcinomas and the relationship between HSV and EBV infection and esophageal carcinoma cell differentiation with lymphocyte infiltration in the tumor stroma. However, the two herpes viruses, HSV and EBV, particularly the human HSV may be one of the etiological factors in development of this malignancy among the high-incidence population of Shantou China.


Assuntos
Carcinoma de Células Escamosas/virologia , Infecções por Vírus Epstein-Barr/complicações , Neoplasias Esofágicas/virologia , Herpes Simples/complicações , Herpesvirus Humano 4/isolamento & purificação , Simplexvirus/isolamento & purificação , China/epidemiologia , Infecções por Vírus Epstein-Barr/epidemiologia , Herpes Simples/epidemiologia , Humanos , Imuno-Histoquímica , Hibridização In Situ , Incidência
11.
World J Gastroenterol ; 10(4): 476-80, 2004 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-14966901

RESUMO

AIM: To examine the expression of Egr-1, c-fos and cyclin D1 at both transcript and protein levels in esophageal carcinoma and to correlate the level of their expressions with precancerous and paracancerous esophageal lesions and esophageal carcinoma. METHODS: In situ hybridization and immunohistochemistry were used respectively to detect the expression of mRNA and proteins of Egr-1, c-fos and cyclin D1 in 70 cases of esophageal squamous cell carcinoma and their corresponding para-cancerous mucosa and upper cut edge mucosa. RESULTS: In situ hybridization and immunohistochemistry showed positive staining of all three mRNAs in the cytoplasm and those of the proteins in nuclei. Overexpression of Egr-1, c-fos and cyclin D1 mRNAs and their proteins was found in dysplasia and squamous carcinomas. The expression level of Egr-1 and c-fos was high, and cyclin D1 was low in dysplasia mucosa, whereas the expression of Egr-1 was decreased, c-fos was maintained and cyclin D1 was increased in the cancers. The expression of both c-fos and cyclinD1 was consistent between the mRNA and protein in their corresponding high expression lesions. CONCLUSION: The expression of Egr-1, c-fos and cyclin D1 varies in esophageal precancerous lesions and cancer tissues, suggesting an involvement of these genes in the development of esophageal carcinoma.


Assuntos
Ciclina D1/genética , Proteínas de Ligação a DNA/genética , Neoplasias Esofágicas/fisiopatologia , Proteínas Imediatamente Precoces , Proteínas Proto-Oncogênicas c-fos/genética , Fatores de Transcrição/genética , Ciclina D1/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteína 1 de Resposta de Crescimento Precoce , Neoplasias Esofágicas/metabolismo , Neoplasias Esofágicas/secundário , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Hibridização In Situ , Metástase Linfática , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/patologia , Lesões Pré-Cancerosas/fisiopatologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , RNA Mensageiro/análise , Fatores de Transcrição/metabolismo
12.
Zhonghua Nan Ke Xue ; 9(3): 170-4, 2003 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-12861826

RESUMO

OBJECTIVES: To study the effect of testicular local heating on spermatogenic cell apoptosis in rat. METHODS: Seventy male SD rats were divided into heat treatment group (43 degrees C) and control group (22 degrees C). Each group was further divided into seven sub-groups respectively according to the time of 12 hours and 1 days, 3 days, 6 days, 10 days, 50 days and 80 days after testicular local treatment. The spermatogenic cell apoptosis in all sub-groups was examined by means of electron microscopy, flow cytometry and terminal deoxynucleotidyl transferase-mediated dUDP-nick end labeling(TUNEL) method. RESULTS: In the groups of heat treatment, spermatogenic cell apoptosis was detected by electron microscopy; flow cytometry showed that the percentage of cells with sub-haploid increased(P < 0.01); the percentage of positive TUNEL cells in the heat treatment groups was higher than that in the control group(P < 0.01). Initiation of spermatogenic cell apoptosis after testicular heating was not random but was highly selective. CONCLUSIONS: Local testicular heating could increase the spermatogenic cell apoptosis. The most sensitive cell is spermatocyte. Spermatid and sperm also display apparent changes. Heating can increase the apoptosis of spermatogonia in a long period.


Assuntos
Apoptose , Temperatura Alta , Espermatogônias/citologia , Testículo/patologia , Animais , Citometria de Fluxo , Marcação In Situ das Extremidades Cortadas , Masculino , Microscopia Eletrônica , Ratos , Ratos Sprague-Dawley , Espermatogônias/ultraestrutura , Testículo/ultraestrutura
13.
World J Gastroenterol ; 8(6): 971-5, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12439908

RESUMO

AIM: To study the expression of early growth response gene-1 (Egr-1 gene) and Bcl-X/(L) protein and its relationship with the cell apoptosis in human esophageal carcinoma (EC) and precancerous lesions. METHODS: In situ hybridization(ISH), immunohistochemistry (IHC) and TUNEL method were used respectively to detect Egr-1mRNA, Egr-1 protein, apoptosis related-protein Bcl-X/(L) and cell apoptosis in situ from 66 cases of esophageal squamous cell carcinoma and their upper cut edge and paracancerous mucosa. RESULTS: Egr-1 gene in situ hybridization, Bcl-X/(L) immunohistochemistry positive products were located in the cytoplasm, while Egr-1 immunohistochemistry and TUNEL positive signal were located in the nuclei. The apoptosis index(AI) and the frequency of apoptosis occurrence were increased gradually from precancerous lesion to cancer (P<0.01) and the expression of Egr-1mRNA and Egr-1 protein in dysplasia was the highest among all specimens (P<0.01). The AI of Egr-1 positive cancer tissues was much higher than that of Egr-1 negative cancer tissues (P<0.01), while the AI of Bcl-X/(L) positive cancer tissues was much lower than that of Bcl-X/(L) negative cancer tissues (P<0.01). The AI and Egr-1 expression were not correlated with invasiveness and lymphatic metastasis in EC. CONCLUSION: Cell apoptosis was present through esophageal carcinogenesis. The expression of Egr-1 mRNA and Egr-1 protein were high in precancerous lesion of esophagus. The AI was increased significantly in Egr-1 positive squamous cell carcinoma. Egr-1 might promote apoptotic effect. Egr-1 expression and cell apoptosis may have an important biological significance in esophageal carcinogenesis.


Assuntos
Apoptose/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Proteínas de Ligação a DNA/genética , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Proteínas Imediatamente Precoces , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/patologia , Fatores de Transcrição/genética , Carcinoma de Células Escamosas/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteína 1 de Resposta de Crescimento Precoce , Neoplasias Esofágicas/metabolismo , Expressão Gênica , Humanos , Imuno-Histoquímica , Hibridização In Situ , Marcação In Situ das Extremidades Cortadas , Lesões Pré-Cancerosas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Fatores de Transcrição/metabolismo , Proteína bcl-X
14.
Yi Chuan Xue Bao ; 29(8): 700-5, 2002.
Artigo em Chinês | MEDLINE | ID: mdl-12200861

RESUMO

S-b is one locus for F1 pollen sterility in cultivated rice (Oryza sativa L.), and the genotype of Taichung 65 (abridged as T65) is Sj/Sj, while its isogenic line, TISL2 is Si/Si at this locus. The results of pollen fertility analysis showed that the pollen of T65 and TISL2 were fertile, but the F1 plant from T65 x TISL2 produced only 40.6% fertile pollens, and the type of sterile pollen was stainable abortive. In F2 population from the cross T65 x TISL2 and BC1F1 population from the cross T65/TISL2/T65, the individuals could be classified into plants with normal pollens and plants with semi-sterile pollens, and the ratio of number of these two types of plants agreed well with the Mendel segregation ratio in 1:1. A total of 53 fertile F2 plants were testcrossed with T65, and all of them showed sterility F1 pollen in. These results demonstrate that the F1 pollen sterility is controlled by a single gene locus S-b, and the allelic interaction of S-bi and S-bj causes the pollen carrying S-bj allele abortive. A total of 187 RFLP markers and 500 RAPD primers were used to screen the polymorphism between T65 and TISL2; only H08-1300 and Y09-1500, two bands amplified by RAPD primer H08 and Y09 were found to be polymorphic. Purified H08-1300 and Y09-1500 were used as probe to hybridize with DNAs from T65 and TISL2, and the results indicated that H08-1300 and Y09-1500 appeared to be single copy in the T65 and TISL2 genome, then the RAPD marker were successfully converted into RFLP marker. The two markers were then used to perform segregation analysis, the results from co-segregation analysis of the genotypes of these two markers and the phenotypes of pollen fertility with F2 population indicated that the S-b was linked to H08-1300 and Y09-1500, and the genetic distances between each marker and the locus were 1.3 cM and 6.6 cM, respectively. To determine the chromosomal position of the S-b locus, H08-1300 was cloned and its two ends were partially sequenced. The homologous comparative analysis of these sequences with published rice sequences with BLAST was performed, and 540 bp of left end sequence of H08-1300 showed 86% homologous with the sequence of rice PAC clone P0033D06 (Accession No. AC079357), and 94% homologies of 101 bp at right end were also observed. Clone P0033D06 had been anchored by RFLP markers R3166 that was located on 18.8 cM position of rice chromosome 5 by Japan Rice Genome Program, which suggested that the S-b locus was mapped on chromosome 5 and tightly linked with R3166. The gene mapping result from this study suggests that using the rice genomic sequences published to determine the chromosome position of RAPD marker, as well as linked genes, would be a useful approach in tagging new genes.


Assuntos
Oryza/genética , Pólen/genética , Sequência de Bases , Mapeamento Cromossômico , Clonagem Molecular , DNA de Plantas/química , DNA de Plantas/genética , Fertilidade/genética , Dados de Sequência Molecular , Técnica de Amplificação ao Acaso de DNA Polimórfico , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA