ABSTRACT
Many hexose transporters (HTs) have been reported to play roles in sucrose-transporting plants. However, little information about roles of HTs in RFOs (raffinose family oligosaccharides)-transporting plants has been reported. Here, three hexose transporters (CsHT2, CsHT3, and CsHT4) were cloned from Cucumis sativus L. Heterologous expression in yeast demonstrated that CsHT3 transported glucose, galactose and mannose, with a K(m) of 131.9 µM for glucose, and CsHT4 only transported galactose, while CsHT2 was non-functional. Both CsHT3 and CsHT4 were targeted to the plasma membrane of cucumber protoplasts. Spatio-temporal expression indicated that transcript level of CsHT3 was much higher than that of CsHT2 and CsHT4 in most tissues, especially in peduncles and fruit tissues containing vascular bundles. GUS staining of CsHT3-promoter-ß-glucuronidase (GUS) transgenic Arabidopsis plants revealed CsHT3 expression in tissues with high metabolic turnover, suggesting that CsHT3 is involved in sugar competition among different sink organs during plant development. The transcript levels of CsHT3 and cell wall invertase genes increased in peduncles and fruit tissues along with cucumber fruit enlargement, and CsHT3 localized to phloem tissues by immunohistochemical localization; These results suggest that CsHT3 probably plays an important role in apoplastic phloem unloading of cucumber fruit.
Subject(s)
Cucumis sativus/metabolism , Monosaccharide Transport Proteins/metabolism , Phloem/metabolism , Arabidopsis/genetics , Carbohydrate Metabolism , Cell Wall/enzymology , Cucumis sativus/genetics , Fruit/genetics , Fruit/metabolism , Gene Expression Regulation, Plant , Genes, Reporter , Monosaccharide Transport Proteins/genetics , Phloem/genetics , Plant Proteins/genetics , Plant Proteins/metabolism , Plants, Genetically Modified , Protoplasts , beta-Fructofuranosidase/genetics , beta-Fructofuranosidase/metabolismABSTRACT
OBJECTIVE: To observe the effects of electroacupuncture (EA) of different intensities on lactate dehydrogernase (LDH), succinate dehydrogenase (SDH) and ATPase in brain tissue of rats with cerebral ischemia-reperfusion injury (CI/R). METHODS: Forty male SD rats were uniformly randomized into sham operation group (group A), CI/R group (group B), CI/R+5 mA EA (group C), CI/R+3 mA EA (group D) and CI/R+1 mA EA (group E) groups with eight rats in each group. Transient general brain ischemia was induced by four-vessel occlusion and reperfusion. The rats in group C, group D and group E were punctured and stimulated at Baihui (GV20), Mingmen (GV4) and Zusanli (ST36) with the same intermittent and rarefaction-dense wave (30 to 50 Hz) and different electric current intensities: 5 mA, 3 mA and 1 mA for 20 min after CI/R. Then the activities of Na(+)-K(+)-ATPase, SDH and LDH in mitochondria of brain tissue were measured by spectrophotometry. The ischemic cerebral cortex tissue was taken for observing the ultrastructure changes of impaired nerve cells. RESULTS: Compared with group A, the activities of LDH, SDH and Na(+)-K(+)-ATPase were lowerer in the group B (P<0.05 or P<0.01). However, the activities of LDH, SDH and Na(+)-K(+)-ATPase were higher in the group D than those in the group B (P<0.05 orP<0.01). In group A, the anatomical structure of the cerebral cortex cells was basically normal; in group B, the neuronal cellular structures were severely damaged, the neuronal mitochondria got swelling, the mitochondrial cristae were broken, the medullated nerve fifibers were not integrated. In group C, group D and group E, the ultrastructure of impaired neuron were improved. Group D was the best among three groups above. CONCLUSION: EA of 3 mA intensity could strengthen aerobic metabolism by elevating the activities of SDH and LDH, meanwhile maintaining the ionic equilibrium in the exterior and interior brain cell and relieving the cellular edema by reinforcing the activities of Na(+)-K(+)-ATPase.
Subject(s)
Brain/metabolism , Electroacupuncture , Energy Metabolism , Mitochondria/metabolism , Reperfusion Injury/metabolism , Animals , Male , Rats , Rats, Sprague-DawleyABSTRACT
OBJECTIVE: To investigate the protein levels of phospho-ERK and phospho-APE/Ref-1 in hippocampal neurons after global cerebral ischemia reperfusion in rats, and observe the relationship between transmembrane signal transduction and repair of DNA damage. The role of ERK signal transduction pathway following global cerebral ischemia reperfusion in rats is further discussed. METHODS: Ninety healthy male SD rats were divided into 3 groups randomly: Sham group (S group), Ischemia reperfusion group (IR group) and Pd98059 pretreatment/ischemia reperfusion group (PD group). Global cerebral ischemia reperfusion model was established by four-vessel occlusion (4-VO) method, and reperfusion was performed 5 minutes following ischemia. Protein levels of phospho-ERK and phospho-APE/Ref-1 were detected using immunohistochemical method at 2 h, 6 h, 12 h, 24 h, 48 h and 72 h after reperfusion, and neuron apoptosis was observed by HE and TUNEL staining. RESULTS: In CA1 region of IR group, TUNEL positive cells began to appear at 6 h after IR, and reached the apex during 24 h to 48 h. However, TUNEL positive was most strongly exhibited in PD group. In IR group, phospho-ERK was obviously detected in CA3 region at 2 h after IR, and its level was gradually decreased from 6 h until totally absent at 48 h. Besides, phospho-ERK expression in PD group was weaker than that in IR group. For phospho-APE/Ref-1, its expression began to appear in CA1 region in IR group at 2 h after IR, with no obvious changes during 2 h to 12 h. Phospho-APE/Ref-1 expression began to decrease at 24 h and this decrease continued thereafter. Expression level of phospho-APE/Ref-1 in PD group was lower than that in IR group. Results showed the concurrence of decreased phospho-ERK expression level and increased neuron apoptosis after cerebral ischemia reperfusion, the former of which was consistent with the decrease of phospho-APE/Ref-1 expression. Also, the greater the inhibition of ERK phosphorylation was, the greater decrease of APE/Ref-1 expression occurred. CONCLUSION: Activation of ERK signal transduction pathway increased the expression of phospho-APE/Ref-1, and thus faciliated the repair of DNA damage. So, activation of ERK signal transduction pathway may protect neurons from apoptosis after cerebral ischemia reperfusion.
Subject(s)
Brain Ischemia/pathology , Brain Ischemia/physiopathology , DNA Repair/physiology , Reperfusion/adverse effects , Signal Transduction/physiology , Animals , Brain Ischemia/prevention & control , DNA-(Apurinic or Apyrimidinic Site) Lyase/metabolism , Disease Models, Animal , Enzyme Inhibitors/pharmacology , Extracellular Signal-Regulated MAP Kinases/metabolism , Flavonoids/pharmacology , Gene Expression Regulation/drug effects , Gene Expression Regulation/physiology , Hippocampus/drug effects , Hippocampus/metabolism , Hippocampus/physiopathology , In Situ Nick-End Labeling/methods , Male , Rats , Rats, Sprague-Dawley , Signal Transduction/drug effects , Time FactorsABSTRACT
OBJECTIVE: To observe the effect of Sappan wood (SW) on the expression of perforin mRNA in myocardium of rats after allogeneic cardiac transplantation. METHODS: The animal model of allogeneic (abdominal) cardiac transplantation was established by taking Wistar rat as provider and SD rat as receptor, perforin mRNA expression in the model's myocardium was detected by RT-PCR. RESULTS: SW could obviously reduce the perforin mRNA expression, it also could alleviate the pathological morphology and ultrastructural damage of myocardial cells. CONCLUSION: SW has obvious effect in antagonizing immune rejection after transplantation, the mechanism of its immunosuppression could be through lowering the perforin mRNA expression.
