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1.
Zhonghua Yi Xue Za Zhi ; 102(33): 2634-2637, 2022 Sep 06.
Artigo em Zh | MEDLINE | ID: mdl-36058691

RESUMO

A retrospective study was performed on 8 patients, including 7 males and 1 female, aged 47 to 77 (59±3) years, with intracranial artery stenosis in General Hospital of Eastern Theater Command from November 2018 to May 2019, who underwent CT angiography (CTA), digital subtraction angiography (DSA) and invasive fractional flow reserve (FFR) assessment. Three-dimensional (3D) prototyping models of intracranial artery based on image data of CTA was constructed and the hemodynamic parameters were obtained using computational fluid dynamics methods. The results showed that CT-FFR value was 0.59±0.18, and invasive FFR value was 0.60±0.22, from which we propased that noninvasive hemodynamic analyses can be used to evaluate the physiological significance of intracranial arterial stenosis.


Assuntos
Angiografia por Tomografia Computadorizada , Reserva Fracionada de Fluxo Miocárdico , Artérias , Constrição Patológica , Angiografia Coronária/métodos , Estudos de Viabilidade , Feminino , Humanos , Hidrodinâmica , Masculino , Estudos Retrospectivos
2.
Zhonghua Zhong Liu Za Zhi ; 41(3): 229-234, 2019 Mar 23.
Artigo em Zh | MEDLINE | ID: mdl-30917461

RESUMO

Objective: To assess the safety, feasibility and short-term outcome of totally laparoscopic distal gastrectomy(TLDG). Methods: Seventy-five patients who underwent laparoscopic distal gastrectomy in Cancer Hospital of Chinese Academy of Medical Science between August 2015 and April 2018 were enrolled in this study. A total of 46 laparoscopy-assisted distal gastrectomy (LADG) cases and 29 TLDG cases were included. The Short-term outcomes and safeties of the two groups were compared. Results: The operation time of TLDG group was significantly longer than that of LADG group (207±41 vs. 156±34 min, P<0.001), while the length of wound was shorter in the TLDG group (3.6±0.6 vs. 5.8±0.8 cm, P<0.001). The time to first flatus in TLDG group was (3.3±0.6) days, significantly shorter than (3.7±0.8) days in LADG group (P=0.034). There were no significant differences between the two groups in the estimated blood loss, intraoperative blood transfusion, extraction of gastric tube, drainage tube removal, interval of the first time to eat semi-liquid food, postoperative hospital stays, surgical complications, number of retrieved lymph nodes, proximal and distal resection margin lengths (all P>0.05). The white blood cell count at postoperative day 1 in the TLDG group was (10.96±1.96) ×10(9)/L, significantly lower than (12.49±3.46)×10(9)/L of the LADG group (P=0.017). While the CRP level at postoperative day 1 in the TLDG group were lower than that of LADG group, no statistical difference was observed (P=0.072). Conclusions: Our study shows that TLDG is safe and feasible. TLDG has better cosmesis, less blood loss, and faster recovery compared to LADG.


Assuntos
Gastrectomia/métodos , Laparoscopia/métodos , Neoplasias Gástricas/cirurgia , Perda Sanguínea Cirúrgica , Estudos de Viabilidade , Gastrectomia/efeitos adversos , Humanos , Laparoscopia/efeitos adversos , Tempo de Internação , Duração da Cirurgia , Complicações Pós-Operatórias , Segurança , Resultado do Tratamento
3.
Zhonghua Yi Xue Za Zhi ; 98(3): 217-221, 2018 Jan 16.
Artigo em Zh | MEDLINE | ID: mdl-29374918

RESUMO

Objectives: To evaluate the value of hysteroscopy in the diagnosis and treatment of cesarean scar pregnancy (CSP) incomplete abortion. Methods: A total of 42 patients with incomplete cesarean circumcision from January 2014 to March 2017 were retrospectively analyzed.Twenty-one patients underwent bilateral uterine artery embolization.Twenty patients underwent hysteroscopy Electrocardiose resection of pregnancy tissue and coagulation hemostasis, the control group of 22 patients underwent conventional uterine artery embolization surgery. Results: One patient in the study group was changed to laparoscopic surgery.In the control group, 2 patients were changed to laparoscopic surgery and 2 patients underwent laparotomy.The duration of hospitalization, the amount of postoperative bleeding and the duration of bleeding were significantly lower in the study group than in the control group.The recovery time of HCG in the study group was significantly shorter than that in the control group. Conclusion: Compared with traditional uterine artery embolization, hysteroscopic resection of cesarean section scar residual tissue less bleeding, higher success rate of surgery, less trauma, faster recovery, treatment Cesarean section scar scar pregnancy abortion is the ideal method.


Assuntos
Curetagem , Histeroscopia , Perda Sanguínea Cirúrgica , Cesárea , Cicatriz , Feminino , Humanos , Gravidez , Gravidez Ectópica , Estudos Retrospectivos , Resultado do Tratamento
4.
J Appl Microbiol ; 122(6): 1579-1585, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28256039

RESUMO

AIMS: To isolate a novel endophytic bacterium from Panax ginseng that could have excellent properties in converting ginsenoside Rb1 to ginsenoside Rg3. METHODS AND RESULTS: Based on a 16S rDNA gene sequence, the strain named GE 17-7 was identified as Burkholderia sp. This strain has shown the highest activity in converting ginsenoside Rb1 to 20(S)-ginsenoside Rg3. During the biotransformation of ginsenoside Rb1, the final metabolite was identified by nuclear magnetic resonance analysis and the transformation pathway of ginsenoside Rb1 was also identified by thin-layer chromatography and high performance liquid chromatography analysis in this study. CONCLUSIONS: We have successfully isolated a ß-glucosidase-producing endophytic bacterium GE 17-7 from P. ginseng. Ginsenoside Rg3 was produced by strain GE 17-7 from ginsenoside Rb1 via ginsenoside Rd. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of the conversion of major ginsenoside Rb1 into minor ginsenoside Rg3 by fermentation with Burkholderia sp. endophytic bacteria in P. ginseng. These results suggest a new preparation method for ginsenoside Rg3 using strain GE 17-7 in the pharmaceutical industry.


Assuntos
Burkholderia/metabolismo , Ginsenosídeos/metabolismo , Panax/microbiologia , Biotransformação , Burkholderia/genética , Cromatografia Líquida de Alta Pressão , Cromatografia em Camada Fina , Fermentação , Ressonância Magnética Nuclear Biomolecular
5.
Lett Appl Microbiol ; 63(3): 196-201, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27316666

RESUMO

UNLABELLED: This research aimed to isolate ß-glycosidase-producing endophytic fungus in Panax ginseng to achieve biotransformation of ginsenoside Rb1 to ginsenoside C-K. Of these 15 ß-glucosidase-producing endophytic fungus isolated from ginseng roots, a ß-glucosidase-producing endophytic fungi GE 17-18 could hydrolyse major ginsenosides Rb1 to minor ginsenoside C-K with metabolic pathways: ginsenoside Rb1→ginsenoside Rd→ginsenoside F2→ginsenoside C-K. Phylogenetic analysis of ITS gene sequences indicated that the strain GE 17-18 belongs to the genus Arthrinium and is most closely related to Arthrinium sp. HQ832803.1. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to provide information of cultivable ß-glycosidase-producing Endophytic fungus in Panax ginseng. The strain GE 17-18 has potential to be applied on the preparation for minor ginsenoside C-K in pharmaceutical industry.


Assuntos
Biotransformação/fisiologia , Ginsenosídeos/metabolismo , Panax/microbiologia , Xylariales/metabolismo , beta-Glucosidase/metabolismo , Hidrólise , Filogenia , Xylariales/isolamento & purificação
6.
Eur Rev Med Pharmacol Sci ; 27(16): 7459-7469, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37667922

RESUMO

OBJECTIVE: The COVID-19 pandemic caused by SARS-CoV-2 in 2019 has greatly impacted global health, leading to high morbidity and mortality rates. Rheumatoid arthritis (RA) patients have faced numerous challenges during the pandemic, including concerns about infection, limited medical resources, and shortages of medication. While vaccination is a crucial strategy against COVID-19, the reasons behind vaccine hesitancy (VH) among people with RA remain largely unexplored. SUBJECTS AND METHODS: We conducted a cross-sectional, single-arm study in China from July 18 to August 18, 2021. Using a self-administered questionnaire and a convenient sampling method, we investigated vaccine attitudes and VH among RA patients. The questionnaire developed by the investigators was validated by two public health experts and one senior rheumatologist. It covered sociodemographics, disease-related variables, vaccination attitudes, and willingness, etc. We employed Chi-squared and regression analyses to identify factors associated with VH toward COVID-19 vaccination. RESULTS: A total of 184 RA patients were enrolled in the survey, with 113 (61.41%) expressing unwillingness to be vaccinated. The Chi-squared test revealed significant differences in employment status and related systemic damage (p < 0.05). Among the unvaccinated RA patients, 71.68% believed COVID-19 vaccination might impact their disease. Binary and multicollinearity logistic regression analyses showed that the acute stage of RA (p < 0.001, OR = -3.165, 95% CI: 0.035 - 0.164) and fear of disease development caused by drug discontinuation during vaccination (p < 0.001, OR = -3.591, 95% CI: 0.005 - 0.157) were the restricting factors influencing the COVID-19 vaccine inoculation rate in RA patients. CONCLUSIONS: The COVID-19 vaccination rate among RA patients in China is low due to limited knowledge, misconceptions, and insufficient promotion. Boosting confidence and understanding of the vaccine's effectiveness and safety is crucial to improve vaccination success.


Assuntos
Artrite Reumatoide , COVID-19 , Febre Reumática , Humanos , Vacinas contra COVID-19/uso terapêutico , Estudos Transversais , Pandemias , COVID-19/prevenção & controle , SARS-CoV-2
7.
Eur Rev Med Pharmacol Sci ; 25(5): 2318-2326, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33755969

RESUMO

OBJECTIVE: Previous systematic review has shown the safety and efficiency of EPO (erythropoietin) for neonatal hypoxic-ischemic encephalopathy (HIE). To date, the evidence is limited that EPO is beneficial to therapeutic hypothermia as an adjuvant. There has not a brief discussion about the neuroprotection effects of EPO without hypothermia. To evaluate the long-term prognosis of HIE treated with EPO alone, we carried out this study that can be a supplement to the previous meta-analysis. MATERIALS AND METHODS: 7 databases (including PubMed, EMBASE, Cochrane, CKNI, CBM, WanFang, and VIP) and the ClinicalTrials.gov were retrieved from inception to 1 March 2020. The inclusion criteria were RCTs with EPO treatment without hypothermia. The outcomes were tested by using the Bayley Scales of Infant Development (BSID), including the Bayley Mental Development Index Score (MDI) and the Bayley Psychomotor Development Index Score (PDI). This meta-analysis was done to compare the Risk Ratio (RR) for the scores of BSID less than 70 after over 6 months of follow-up. RESULTS: 11 RCTs (1099 newborns) were included, excluding deaths and lost visits, and 917 patients finally were performed the statistical analysis. In neonatal HIE infants, investigation results showed a lower risk of cognitive impairment and psychomotor disability with EPO monotherapy. The pooled event rates of MDI <70 saw a reduction of 36% (95% CI 24%-54%) compared to the control group. There was a decrease of 37% (95% CI 24%-56%) of Psychomotor abnormal (PDI <70) in the EPO group. CONCLUSIONS: EPO administration alone could improve the scores of mental and psychomotor in neonates with HIE. However, the level of evidence is low to moderate for the insufficient sample size, so large-scale, multicenter clinical trials are still needed.


Assuntos
Eritropoetina/uso terapêutico , Hipóxia-Isquemia Encefálica/tratamento farmacológico , Comportamento Materno/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Eritropoetina/administração & dosagem , Humanos , Hipóxia-Isquemia Encefálica/diagnóstico , Recém-Nascido , Fármacos Neuroprotetores/administração & dosagem
8.
Epidemiol Infect ; 137(12): 1766-75, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19393118

RESUMO

We obtained a list of all reported cases of haemorrhagic fever with renal syndrome (HFRS) in Shenyang, China, during 1990-2003, and used GIS-based scan statistics to determine the distribution of HFRS cases and to identify key areas and periods for future risk-factor research. Spatial cluster analysis suggested three areas were at increased risk for HFRS. Temporal cluster analysis suggested one period was at increased risk for HFRS. Space-time cluster analysis suggested six areas from 1995 to 1996 and four areas from 1998 to 2003 were at increased risk for HFRS. We also discussed the likely reasons for these clusters. We conclude that GIS-based scan statistics may provide an opportunity to classify the epidemic situation of HFRS, and we can pursue future investigations to study the likely factors responsible for the increased disease risk based on the classification.


Assuntos
Febre Hemorrágica com Síndrome Renal/epidemiologia , China/epidemiologia , Análise por Conglomerados , Sistemas de Informação Geográfica , Humanos , Fatores de Tempo
9.
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 54(10): 760-763, 2019 Oct 07.
Artigo em Zh | MEDLINE | ID: mdl-31606989

RESUMO

Objective: To investigate the key issues in the diagnosis and treatment of foreign body aspiration in children with tracheobronchial variations. Methods: A retrospective study was performed for 11 pediatric patients who were treated in Department of Otorhinolaryngology and Head and Neck Surgery, Henan Province People's Hospital after a diagnosis of foreign body aspiration with tracheobronchial variations between January 2015 and December 2017. There were 7 males and 4 females among the 11 cases of foreign body aspiration with tracheobronchial variations, ranging between 9 months and 11 years of age. Results: Among 11 cases, the types of variationswere tracheal bronchus in 9 cases, bridging bronchus in 1 case and simple tracheal stenosis in 1 case. All of the pediatric patients were under general anesthesia, and the foreign bodies were removed by bronchoscopy successfully with no significant complications. Conclusions: The possibility of tracheobronchial variations should be considered in children with recurrent wheezing and poor efficacy of regular treatment before foreign body aspiration. Removal of foreign body via rigid bronchoscope under general anesthesia is a safe and effective treatment. These children are needed to combine the situation oftracheobronchial variations and the location of foreign bodies to guide the operation, and strengthened the perioperative treatment.


Assuntos
Corpos Estranhos/diagnóstico , Corpos Estranhos/terapia , Aspiração Respiratória/diagnóstico , Aspiração Respiratória/terapia , Doenças Respiratórias/complicações , Brônquios/anormalidades , Broncoscopia , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Anormalidades do Sistema Respiratório/complicações , Estudos Retrospectivos , Traqueia/anormalidades , Estenose Traqueal/complicações
10.
Artigo em Zh | MEDLINE | ID: mdl-29774695

RESUMO

Summary Acute invasive fungal rhino-sinisitis(AIFRS) is a kind of acute fungus infectious disease.It ofen deteriorates rapidly and abruptly,which occurs in the nose and sinuses with somepeople who have low immunological function.This paper reviewed the progress about the acute invasive fungal rhino-sinisitis's clinical characteristics,diagnosis,treatment and prognosis to improve the level of early diagnosis and reduce the mortality.


Assuntos
Antifúngicos/uso terapêutico , Micoses/diagnóstico , Rinite/diagnóstico , Rinite/terapia , Sinusite/diagnóstico , Sinusite/terapia , Humanos , Micoses/microbiologia , Micoses/terapia , Mucosa Nasal/microbiologia , Mucosa Nasal/patologia , Rinite/microbiologia , Sinusite/microbiologia
11.
Lin Chuang Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 31(15): 1195-1198, 2017 Aug 05.
Artigo em Zh | MEDLINE | ID: mdl-29798357

RESUMO

Objective:To explore the early diagnosis, the treatment and theprognosis of invasive fungal rhinosinusitis.Method:By summarizing the clinical data of 18 patients, CT and MRI images, pathological diagnosis and follow-up results to analysis the early diagnosis and the treatment.Result:All 5 patients with invasive fungal sinusitis were infected with mucor, 3 of whom died of intracranial complications. Among 13 patients with chronic invasive fungal rhinosinusitis, 9 were aspergillus, 3 were mucor, and 1 was negative. There were 9 cases of diabetes, 1 cases of ankylosing spondylitis, 3 cases of hypoproteinemia, 1 cases of organ transplantation, and 1 cases of leukemia. There were 3 cases of death who unenforced the operation, 15 patients received enlarged endoscopic surgery, postoperative antifungal therapy. Followed up 1-3 years, relapse in 3 cases, 1 case of death.Conclusion:The diagnosis of FRS needs to be combined with clinical manifestations, imaging features and pathological findings. The treatment requires surgery to completely remove diseased tissue (enlarged sinus open surgery) combined with antifungal use in sufficient quantities.


Assuntos
Micoses/cirurgia , Rinite/cirurgia , Sinusite/cirurgia , Antifúngicos/uso terapêutico , Endoscopia , Humanos , Micoses/diagnóstico por imagem , Seios Paranasais , Rinite/diagnóstico por imagem , Rinite/microbiologia , Sinusite/diagnóstico por imagem , Sinusite/microbiologia
12.
Photosynth Res ; 63(1): 97-107, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-16252168

RESUMO

This paper describes a study into the potential of plants to acclimate to light environments that fluctuate over time periods between 15 min and 3 h. Plants of Arabidopsis thaliana (L.) Heynh., Digitalis purpurea L. and Silene dioica (L.) Clairv. were grown at an irradiance 100 mumol m(-2) s(-1). After 4-6 weeks, they were transferred to light regimes that fluctuated between 100 and either 475 or 810 mumol m(-2) s(-1), in a regular cycle, for 7 days. Plants were shown, in most cases, to be able to undergo photosynthetic acclimation under such conditions, increasing maximum photosynthetic rate. The extent of acclimation varied between species. A more detailed study with S. dioica showed that this acclimation involved changes in both Rubisco protein and cytochrome f content, with only marginal changes in pigment content and composition. Acclimation to fluctuating light, at the protein level, did not fully reflect the acclimation to continuous high light - Rubisco protein increased more than would be expected from the mean irradiance, but less than expected from the high irradiance; cytochrome f increased when neither the mean nor the high irradiance would be expected to induce an increase.

13.
Yao Xue Xue Bao ; 27(1): 22-5, 1992.
Artigo em Zh | MEDLINE | ID: mdl-1529708

RESUMO

Degradation of the side chain of beta-sitosterol (Ib) gave delta 4-androstene-3,17-dione (II) and a small amount of delta 1,4-androstene-3,17-dione (III) by Mycobacterium vaccae 209-20. The yield of the product II was 32%.


Assuntos
Androstenodiona/biossíntese , Mycobacterium/metabolismo , Sitosteroides/metabolismo
16.
Nanotechnology ; 19(21): 215708, 2008 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-21730587

RESUMO

The current-voltage (I-V) characteristics and electrical resistivity of isolated potassium manganese oxide (K(0.27)MnO(2)·0.5H(2)O) nanowires prepared by a simple hydrothermal method were investigated over a wide temperature range from 300 to 4 K. With lowering temperature, a transition from linear to nonlinear I-V curves was observed around 50 K, and a clear zero bias anomaly (i.e., Coulomb gap-like structure) appeared on the differential conductance (dI/dV) curves, possibly due to enhanced electron-electron interaction at low temperatures. The temperature dependence of resistivity, [Formula: see text], follows the Efros-Shklovskii (ES) law, as expected in the presence of a Coulomb gap. Here we note that both the ES law and Coulomb blockade can in principle lead to a reduced zero bias conductance at low temperatures; in this study we cannot exclude the possibility of Coulomb-blockade transport in the measured nanowires, especially in the low-temperature range. It is still an open question how to pin down the origin of the observed reduction to a Coulomb gap (ES law) or Coulomb blockade.

17.
Acta Gastroenterol Belg ; 70(3): 271-6, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18074736

RESUMO

AIMS: With a prehepatic portal hypertensive rat model, we explored the involvement of humoral factors to the occurrence of portal hypertensive colopathy (PHC), another clinical entity besides portal hypertensive gastropathy (PHG) in portal hypertension, by investigating the expression of inducible nitric oxide synthase (iNOS), endothelial constitutive NOS (ecNOS), endothelin-1 (ET-1), tumour necrosis factor alpha (TNF-alpha) and vascular endothelial growth factor (VEGF) in the colonic and gastric mucosa. METHODS: Portal hypertension was produced by a two-stage ligation of portal vein plus ligation of the left adrenal vein in male Sprague-Dawley rats. Two weeks after complete obstruction of the portal vein, the portal pressure was measured and the expression of iNOS, ecNOS, ET-1, TNF-alpha and VEGF in the colonic and gastric mucosa were detected by RT-PCR and immunohistochemistry methods. RESULTS: A 1.8 fold (P < 0.01) elevation of the portal pressure was detected in the portal hypertensive rats as compared to control. Significantly up-regulation of the mRNA levels of iNOS (P < 0.01), ET-1 (P < 0.05) and TNF-alpha (P < 0.01), but not ecNOS and VEGF, were detected in the colonic mucosa of portal hypertensive rats compared with control. The mRNA of iNOS, ecNOS, ET-1, TNF-alpha and VEGF were all significantly increased at varied levels in the gastric mucosa as compared to control (P all < 0.05). No difference of the appearance and localization of immunostaining of iNOS, ecNOS, ET-1, TNF-alpha and VEGF in the colonic and gastric mucosa were seen between two groups. CONCLUSIONS: These data suggest the involvement of the upregulation of iNOS, ET-1 and TNF-alpha in the colonic mucosal lesion of portal hypertensive rats.


Assuntos
Doenças do Colo/metabolismo , Hipertensão Portal/complicações , Mucosa Intestinal/metabolismo , Glândulas Suprarrenais/irrigação sanguínea , Animais , Doenças do Colo/etiologia , Modelos Animais de Doenças , Endotelina-1/análise , Mucosa Gástrica/irrigação sanguínea , Mucosa Gástrica/metabolismo , Hipertensão Portal/fisiopatologia , Imuno-Histoquímica , Mucosa Intestinal/irrigação sanguínea , Ligadura , Masculino , Óxido Nítrico Sintase Tipo II/análise , Óxido Nítrico Sintase Tipo III/análise , Pressão na Veia Porta/fisiologia , Veia Porta/cirurgia , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Necrose Tumoral alfa/análise , Regulação para Cima , Fator A de Crescimento do Endotélio Vascular/análise
18.
J Virol ; 79(24): 15460-6, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16306617

RESUMO

The 2004 outbreaks of highly pathogenic avian influenza H5N1 disease in China led to a great poultry loss and society attention. A survey of avian influenza viruses was conducted on tree sparrows (Passer montanus) collected in China in 2004. Four viruses were isolated from free-living tree sparrows. The results of the whole-genome analysis indicated that an H5N1 virus with a new genotype is circulating among tree sparrows. The hemagglutinin and neuraminidase genes of the new genotype were derived from Gs/Gd/96-like viruses and the nuclear protein gene descended from the 2001 genotype A H5N1 viruses, while the other inner genes originated from an unknown influenza virus. In experimental infection, all four viruses were highly pathogenic to chickens but not pathogenic to ducks or mice. The four tree sparrow viruses were different from the 2003 tree sparrow strain (genotype Z) in Hong Kong. The results suggested that H5N1 viruses might be distributed widely in tree sparrows.


Assuntos
Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/virologia , Pardais/virologia , Animais , China/epidemiologia , Genótipo , Glicoproteínas de Hemaglutininação de Vírus da Influenza/isolamento & purificação , Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/epidemiologia , Influenza Aviária/patologia , Filogenia
19.
Planta ; 182(2): 244-52, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24197103

RESUMO

Chloroplasts, mesophyll protoplasts, cytoplasts, vacuoplasts, vacuoles and leaves were stained with pH-indicating fluorescent dyes of differing pK values. Fluorescence microscopy was used to obtain information on the intracellular and intercellular distribution of the probes. The kinetics of blue or green fluorescence emitted from chloroplasts, protoplasts, cytoplasts and leaves was measured during illumination with red light. The intensity of light used for fluorescence excitation was so low that it had little effect on photosynthesis. In leaves, fluorescence signals emitted from chloroplasts were small and usually insignificant compared to signals originating from the cytosol. Both indicated light-dependent alkalization and reversal of alkalization on darkening. Vacuolar signals were opposite in sign to cytosolic signals. They indicated acidification of the vacuole in the light-dark transient and reversal of this effect on darkening.

20.
Planta ; 182(2): 253-61, 1990 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24197104

RESUMO

Illumination of leaves of C3 plants caused cytosolic alkalization and vacuolar acidification in the mesophyll cells. Both phenomena were particularly pronounced when CO2 was absent, were suppressed by CO2, and were related to the activation state of the photosynthetic apparatus. The cytosolic alkalization reaction has at least two major components. Trivalent cytosolic phosphoglycerate must be protonated before it can be transferred into the chloroplasts for reduction. Pumping of protons from the cytosol into the vacuole also contributes to cytosolic alkalization. The dependence of light scattering by chloroplast thylakoids on the energy fluence rate was closely related to that of vacuolar acidification under different conditions for chloroplast energization. This indicates (i) transport of energy from the chloroplasts to the cytosol in the light and (ii) use of this energy for the transport of protons into the vacuoles. The light-dependent vacuolar acidification is interpreted to be caused by the increase in the activity of a proton-translocating enzyme of the tonoplast. The decrease of vacuolar acidification during photosynthetic carbon reduction or photorespiration is indicative of decreased cytosolic energization. In low light, the light-dependent vacuolar acidification was stimulated in the absence of CO2 when photorespiration was inhibited. The data do not support the view that photorespiration is capable of increasing the cytosolic energy state in the light.

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