广东垦区2008年橡胶中幼龄树寒害调查及建议

2008年1月下旬至2月中旬,我国南方出现了连续低温阴雨天气,给广东垦区橡胶生产造成了巨大损失。对广东垦区橡胶寒害情况进行了调查,结果显示:橡胶中幼龄树寒害以爆皮流胶及干枯混合型为主,品系间存在耐寒性差异,树龄、砧木和环境也显著影响橡胶中幼龄树的受害程度,建议广东省垦区注重使用抗寒品系及抗寒砧木。     

开花期红掌耐寒性评判方法研究

【目的】探究开花期红掌(Anthurium andraeanum)耐寒性判定方法,为不同耐寒性红掌品种的分级管理提供理论依据。【方法】以20个开花期红掌品种为试材,在上海地区冬季大棚自然低温环境下进行种植,观察叶柄、叶片、花柄、苞片的冷害症状,统计各器官冷害指数,通过主成分和聚类分析进行耐寒性研究;根据聚类结果分别在不同耐寒性组中选择1～3个品种再次进行低温试验,并测定低温处理前后叶片的叶绿素荧光参数F_v/F_m、相对电导率和丙二醛、可溶性蛋白、可溶性糖含量以及过氧化物酶、超氧化物歧化酶活性,进行各指标变化率与耐寒性的相关性分析。【结果】对供试红掌品种各器官冷害指数进行主成分分析,得到20个品种的耐寒性综合得分,结合聚类分析结果将其分为3组,高耐寒组品种包括‘阿拉巴马’、‘艾美拉’、‘粉阿拉巴马’、‘黑皇后’、‘红宝贝’、‘马都拉’、‘潘多拉’、‘紫罗兰’、‘红丰收’、‘红成功’、‘红赢家’、‘白塞拉’、‘紫雷鸟’和‘特伦萨’,中耐寒组品种包括‘皇家布加迪’、‘轰动’、‘红阿里克斯’和‘白雪阿莱西亚’,低耐寒组品种有‘粉冠军’和‘粉爱’,其中‘阿拉巴马’、‘潘多拉’、‘特伦萨’、‘皇家布加迪’、‘轰动’和‘粉冠军’6个品种的耐寒性得到了再次验证。相关性分析结果表明,红掌在低温处理前后叶绿素荧光参数F_v/F_m的变化率与耐寒性显著正相关,相对电导率变化率与耐寒性极显著负相关,其他指标与耐寒性则没有表现出显著相关性。【结论】自然低温下器官冷害指数的观测可以作为判定开花期红掌耐寒性的一种有效方法,而叶绿素荧光参数F_v/F_m和相对电导率可以作为较为可靠的生理指标应用于红掌耐寒性的分析中。     

Study on apoptotic and nonapoptotic injuries induced by hydrogen peroxide in cardiac myocytes

AIM: To study apoptotic injury induced by reactive oxygen species-hydrogen peroxide (H₂O₂) on cardiac myocytes.METHODS:Cultured rat neonatal cardiac myocytes were treated with H₂O₂ of various concentration to observe apoptotic injury of cardiomyocytes by agarose gel electrophoresis, Giemsa-stained smears of cell, and flow cytometry, meanwhile lactate dehydrogenas (LDH) and malondialdehyde(MDA) were determined to assess the effect of H₂O₂ on lipid peroxidation and permeability of the plasma membrane. RESULTS: 5 mmol/L H₂O₂ caused cultured cardiomyocytes apoptotic morphological characteristics, including nucleosomal DNA fragmentation in myocytes by agarose gel electrophoresis (DNA ladder), cell shrinkage, nuclear condensation, and chromatin margin by Giemsa-stained cell smears, and aneuploid peak(AP)-apoptotic bodies occurrence by flow cytometry.CONCLUSIONS: H₂O₂-induced apoptosis in myocytes was a time-and concentration-dependent process. Treatment with low concentration of H₂O₂(＜1 mmol/L) only caused cardiomyocyted early biochemical changes, such as increase of free radicals level and membrane permeability ,which were pro-apoptotic injurious features. High concentration of H₂O₂ (＞10 mmol/L) rapidly induced a necrotic form of death characterized by smeared patterns of DNA digestion on agarose gel electrophoresis and lethal membrane disruption (as measured by LDH release). Exposure of 5~10 mmol/L H₂O₂ induced cardiomyocytes apoptosis concurrently with biochemical changes of LDH and MDA increase in the medium.     

Effects of calmodulin antagonist and slow calcium channel antagonist on reperfusion injury of isolated rat hearts in calcium paradox

AIM: To observe the protective effect of calmodulin antagonist trifluoperazine(TFP) and slow calcium channel antagonist verapamil (VP) upon calcium overload injury. METHODS: The calcium content of the myocardium, lactate dehydrogenase (LDH) release, protein loss and coronary flow were measured after the isolated rat hearts were perfused by TFP and VP. RESULTS: TFP could significantly reduce the tissue calcium , LDH release and protein loss of the myocardium ( P <0.01) while VP had no such effects.The above indexes were further reduced when TFP and VP were used simutaneously( P <0.01).CONCLUSION:TFP can effectively alleviate the severity of the myocardium injury during calcium paradox while VP has no such effects.The simultanous use of VP and TFP is more effective in preventing tissue damage of the heart than the use of TFP alone.The massive influx of Ca²⁺ in calcium paradox is mainly a calmodulin related process.     

Effects of HSP90 on complement-mediated hypoxia/reoxygenation injury of H9c2 cardiomyocytes during hypoxic postconditioning

AIM To investigate the effects and mechanisms of heat shock protein 90 （HSP90） on complement-mediated hypoxia/reoxygenation （H/R） injury of rat H9c2 cardiomyocytes during hypoxic postconditioning （HPC）. METHODS Rat H9c2 cardiomyocytes were divided into 7 groups according to different treatments： （1） control group （cultured for 10 h under normal oxygen）; （2） H/R group （hypoxia for 4 h and reoxygenation for 6 h）; （3） HPC group （3 cycles of 5 min H/R after hypoxia for 4 h, followed by reoxygenation for 6 h）; （4） HPC+geldanamycin （GA） group （1 μmol/L HSP90 inhibitor GA was added 20 min before HPC）; （5） negative control group （empty plasmid was transfected before HPC）; （6） C3 over-expression group （C3a plasmid was transfected before HPC）; （7） C5 over-expression group （C5a plasmid was transfected before HPC）. Morphological changes of the H9c2 cells were detected by Hoechst 33242 staining. The effects of HPC on the apoptosis of H9c2 cells were examined by flow cytometry. The protein levels of HSP90, C3a, C5a, NF-κB p65, TNF-α, IL-1β, IL-6, Bcl-2 and Bax were determined by Western blot. RESULTS With up-regulation of HSP90, HPC significantly reduced H/R-induced apoptosis of the H9c2 cells, inhibited the expression of C3a, C5a, NF-κB p65, TNF-α, IL-1β, IL-6 and Bax, and increased the expression of Bcl-2. These effects were blocked by GA. The inhibitory effects of HPC on NF-κB p65 expression and H9c2 cell apoptosis were offset after over-expression of C3a or C5a. CONCLUSION HSP90 attenuates H/R injury of H9c2 cardiomyocytes by inhibiting complement-NF-κB signaling pathway during HPC.     

Role of retinoic acid X receptor in regulation of autophagy in rat alveolar type Ⅱ epithelial cells induced by hypoxia/reoxygenation

AIM To investigate the regulatory effect of retinoic acid X receptor （RXR） on autophagy induced by hypoxia/reoxygenation （H/R） in rat alveolar type Ⅱ epithelial cells （AEC Ⅱ） and its molecular mechanism. METHODS AEC Ⅱ were cultured in normoxia. The cells growing to logarithmic growth phase were randomly divided into 5 groups： （1） control （Con） group： cells were cultured for 30 h under normal operation; （2） H/R group： cells were cultured in hypoxia condition for 6 h and then in reoxygenation condition for 24 h; （3） DMSO group： cells were pretreated 1.5 h with medium containing less than 0.1% DMSO before modeling, and the rest were treated the same as the H/R group; （4） 9-cis-retinoic acid （9-RA） group： cells were pretreated for 1 h with 9-RA （100 nmol/L） before hypoxia; （5） HX531 group： cells were treated with 9-RA （100 nmol/L） for 0.5 h, then treatment with HX531 （2.5 μmol/L） for 1 h. CCK-8 assay was used to detect the cell viability. Immunofluorescence staining was used to observe the expression of RXRα. Transmission electron microscope was used to observe the changes of intracellular ultrastructure, and the mRNA expression of adenosine AMP-activated protein kinase （AMPK）, beclin 1, LC3, mammalian target of rapamycin （mTOR） and P62 was detected by RT-PCR. Western blot was used to detected the protein levels of p-AMPK, beclin 1, LC3-Ⅱ, p-mTOR and P62. RESULTS Compared with Con group, the cell viability in H/R, DMSO, 9-RA and HX531 groups were significantly decreased. The mRNA expression of AMPK, beclin 1 and LC3 was significantly increased, and the protein levels of p-AMPK, beclin 1 and LC3-Ⅱ were also increased. The mRNA expression of mTOR and P62 was decreased, and the protein levels of p-mTOR and P62 were also decreased （P<0.05）. The cell injury in 9-RA group was alleviated and autophagy level was significantly lower than that in H/R, DMSO and HX531 groups （P<0.05）, and no significant difference among H/R, DMSO and HX531 groups was observed （P>0.05）. CONCLUSION H/R induces autophagy of AEC Ⅱ. Activating RXR reduce the damage of AEC Ⅱ cells induced by H/R, and its mechanism may be related to the inhibition of autophagy.     

Effect of continuous renal replacement therapy on mRNA expression of autophagy-related molecules and prognosis in patients with acute kidney injury

AIM To explore the effect of continuous renal replacement therapy （CRRT） on mRNA expression of autophagy-related molecules and the prognosis in the patients with acute kidney injury （AKI）. METHODS A total of 174 patients from our hospital who were diagnosed to have AKI and underwent CRRT between February 2015 and March 2018 were involved in this study. The plasma levels of interleukin-1β （IL-1β） and interleukin-6 （IL-6）, the serum creatinine （SCr） level, and the mRNA expression levels of autophagy-related molecules, including microtubule-associated protein 1 light chain 3-II （LC3-II）, autophagy-related protein 5 （Atg5） and beclin-1, in the monocytes from peripheral blood were compared before and after CRRT. According to the survival of AKI patients after 4 weeks of CRRT, the enrolled patients were divided into death group （n=43） and survival group （n=131）, and the mRNA expression levels of the above molecules were compared between the 2 groups. RESULTS After CRRT treatment, the plasma levels of IL-1β and IL-6, the level of SCr, and the mRNA expression levels of LC3-II, Atg5 and beclin-1 in the monocytes were significantly lower than those before CRRT treatment （P<0.05）. The mRNA expression levels of LC3-II, Atg5 and beclin-1 in death group were significantly higher than those in survival group （P<0.05）. The positive correlation between SCr and IL-1β, IL-6, LC3-II or beclin-1 was observed （P<0.05）, and no correlation between SCr and Atg5 was found （P>0.05）. CONCLUSION CRRT decreases the mRNA expression levels of autophagy-related molecules in the patients with AKI and reduces the autophagy activity, which is protective for the patients. These autophagy-related molecules may be applied as a potential markers to predict the prognosis of CRRT.     

Using a bioenergetic model to assess growth reduction from catch-and-release fishing and hooking injury in rainbow trout, Oncorhynchus mykiss

Abstract  A bioenergetic model was used to predict the potential effects of feeding cessation caused by catch-and-release capture and a reduction in feeding efficiency from hooking injuries on rainbow trout, Oncorhynchus mykiss (Walbaum), growth in southwest Alaska, USA. Simulations indicated that a 1-day feeding cessation for a rainbow trout captured one to two times during summer months resulted in deviations from expected growth of −3% to −15%. To represent debilitating hooking injuries, the proportion of the maximum feeding potential was decreased by 5–50% resulting in deviations from expected growth of −9% to −164%. Simulated growth effects were most prominent from captures during months when salmon eggs and flesh constituted the majority of the trout diet. Simulated growth effects from reduced foraging efficiency were most prominent when hooking injuries occurred early in the fishing season. These simulations suggest that rainbow trout are most vulnerable to decreases in growth when salmon are abundant and spawning and, coincidentally, during the months when most fishing occurs.     

贮藏模式对大久宝桃果实冷害和品质的影响

对大久宝桃在4种不同贮藏温度模式下的品质变化进行了研究。结果显示：大久宝桃在0℃恒温贮藏条件下,30d以后开始出现冷害症状,20℃货架期3d的果实软化能力下降,出汁率下降;8℃预冷15d的果实没有出现冷害症状,但显著促进了果实的后熟软化,导致果实的商品性能下降,失去应用价值;而8℃预冷5d的果实在贮藏期间能够保持一定的硬度和TSS含量,出汁率较稳定,出库后能够正常后熟软化,在预防冷害的同时．较好地保持了果实品质。     

Burn-induced subepicardial injury in frog heart: a simple model mimicking ST segment changes in ischemic heart disease

To mimic ischemic heart disease in humans, several animal models have been created, mainly in rodents by surgically ligating their coronary arteries. In the present study, by simply inducing burn injuries on the bullfrog heart, we reproduced abnormal ST segment changes in the electrocardiogram (ECG), mimicking those observed in ischemic heart disease, such as acute myocardial infarction and angina pectoris. The “currents of injury” created by a voltage gradient between the intact and damaged areas of the myocardium, negatively deflected the ECG vector during the diastolic phase, making the ST segment appear elevated during the systolic phase. This frog model of heart injury would be suitable to explain the mechanisms of ST segment changes observed in ischemic heart disease.