外源水杨酸对干旱胁迫下小冠花叶片活性氧水平及抗氧化系统的影响

本研究以小冠花幼苗叶片为材料,用0.25,0.5,1和2 mmol/L外源水杨酸(SA)对植株进行叶面喷施,通过盆栽模拟干旱胁迫处理,测定幼苗叶片在连续干旱下膜脂过氧化指标、抗氧化酶活性和非酶抗氧化物含量,研究外源水杨酸对干旱胁迫下小冠花幼苗活性氧水平及抗氧化系统的影响。结果表明,0.5~2.0 mmol/L的水杨酸显著降低了干旱胁迫下小冠花叶片中超氧阴离子(O₂^-·)的产生速率、过氧化氢(H₂O₂)含量、丙二醛(MDA)含量及细胞膜透性,显著提高了过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性,提升了抗氧化指数,但对抗坏血酸(ASA)和谷胱甘肽(GSH)含量的影响不显著。在干旱胁迫第11天,1 mmol/L SA处理的小冠花叶片O₂^-·产生速率、MDA含量、细胞膜透性显著低于干旱处理79.78%,34.42%,36.96%(P<0.05);CAT酶活性显著高于干旱处理2.45倍(P<0.05);到干旱胁迫第 16天,SOD、POD酶活性比干旱处理提高了3.85和3.63倍。表明外源水杨酸能够降低干旱胁迫下小冠花叶片的活性氧水平,提高小冠花叶片抗氧化能力,缓解干旱胁迫造成的细胞膜脂过氧化损伤,提高了小冠花的抗旱性,尤其以1 mmol/L水杨酸效果最佳。     

大豆异黄酮抵抗体外培养猪脂肪细胞氧化损伤的作用

为了探明大豆异黄酮对猪脂肪细胞氧化损伤的保护效应,试验分别用含0、10、20、40μmol/L和80μmol/L异黄酮S(一种合成的大豆异黄酮)或三羟基异黄酮(GEN)的完全培养液培养猪脂肪细胞48h,用终浓度为100μmol/L的FeSO4和H2O2溶液进行氧化处理1 h。结果表明:与正常对照组相比,氧化对照组细胞内活性氧(ROS)水平和脂质过氧化产物丙二醛(MDA)含量分别升高了1.61倍和2.74倍(P<0.01);与氧化对照组相比,添加10、20、40μmol/L和80μmol/L异黄酮S使细胞内ROS水平分别下降了24.62%(P<0.05)、20.03%(P<0.05)、37.88%(P<0.01)和41.20%(P<0.01);添加10、20、40μmol/L和80μmol/L GEN均显著降低了细胞内ROS水平(P<0.01)和MDA含量(P<0.05)。试验结果提示在本试验条件下,异黄酮S和GEN能通过抑制猪脂肪细胞的脂质过氧化、降低ROS产生,抵抗羟自由基对猪脂肪细胞的氧化损伤。     

活性氧对哺乳动物早期胚胎发育的影响

活性氧(ROS)是自然界普遍存在的含氧化合物的总称,它对哺乳动物早期胚胎发育具有不良影响。本文综述了活性氧对哺乳动物早期胚胎发育的影响以及它与胚胎体外发育阻滞的内在联系,对深入探讨哺乳动物早期胚胎体外发育阻滞的机理具有一定的意义。     

日循环高温对肉鸡线粒体活性氧产生量、钙泵活性及胸肌品质的影响

通过研究日循环高温对肉鸡线粒体活性氧产生量、钙泵活性的影响，探讨高温影响肉鸡胸肌品质的机制。研究发现，日循环高温显著升高肝脏线粒体H2O2的产生量（P〈0．05），对胸肌线粒体H2O2产生量有提高趋势（P=0．0674），导致肝脏和胸肌脂质过氧化（P〈0．05），并抑制胸肌和肝脏线粒体钙泵活性（P〈0．05），影响肌纤维膜的完整性，使血液中肌酸激酶（CK）和乳酸脱氢酶（LDH）活性升高（P〈0．01，P〈0．05），表明日循环高温影响肌浆钙离子调控功能，导致肌肉中乳酸含量升高（P=0．0703），最终使肉鸡屠宰后胸肌pH1显著降低（P〈0．05），胸肌L^＊、滴水损失和剪切力显著升高（P〈0．01）。配对组与适温组在线粒体H2O2产生量、钙泵活性、脂质过氧化、乳酸含量以及胸肌pH、L^＊、滴水损失等指标上无显著差异（P〉0．05）。结果表明，日循环高温引起肉鸡氧化应激，影响线粒体钙离子转移系统功能，增加胸肌乳酸的积聚，使屠宰后胸肌pH下降速度加快，导致胸肌蛋白质变性，影响胸肌肉色和持水力，日循环高温对肉鸡线粒体功能及肉品质的影响与高温降低肉鸡采食量无关。     

猪精液常温保存抗氧化剂研究进展

猪的人工授精技术被广泛用于我国生猪养殖业。用于人工授精的公猪精液质量直接关系到人工授精后母猪的受胎率和产仔数。猪精子质膜中胆固醇/磷脂比值低致使其对冷应激十分敏感,这决定了常温保存(16~18℃)成为目前最常用的猪精液保存方法。猪精液常温保存过程会累积活性氧自由基,而猪精子质膜中多不饱和脂肪酸比例高,使精子极易受到氧化应激伤害。稀释液中添加抗氧化剂有助于维持精子质量的各项指标。抗氧化剂主要包括超氧化物歧化酶等酶类抗氧化剂和还原型谷胱甘肽等非酶类抗氧化剂。本文综述了猪精子的生物学特征和常温保存过程中猪精液累积活性氧的原因,并总结了猪精液常温保存中抗氧化剂的研究进展,旨在为猪精液的保存及人工授精提供参考。     

Rutin protects boar sperm from cryodamage via enhancing the antioxidative defense

This study was aimed to investigate whether and how Rutin protects boar sperm against cryoinjury during cryopreservation. Five concentrations of Rutin with 0.2, 0.4, 0.6, 1.0, and 2.0 mM were added to the freezing extender of boar sperm, respectively, and the effects on quality and function of boar sperm after freezing‐thawing were assessed. The results showed that the sperm motility, mitochondrial activity, plasma membrane integrity, and acrosomal integrity were significantly improved in 0.4 mM and 0.6 mM Rutin groups (p < .05). Compared with ganoderma lucidum polysaccharide (GLP) or Tanshinone IIA, Rutin exhibited higher rates of mitochondrial activity and acrosome integrity (p < .05). Mechanistically, the addition of Rutin at the concentration of 0.6, 0.8, and 1.0 mM significantly attenuated ROS accumulation and MDA production by improving antioxidant enzymatic activity, including SOD, CAT, and GSH‐Px (p < .05). Functionally, a higher penetration rate and the increased total efficiency of fertilization were observed in the 0.4, 0.6, and 1.0 mM Rutin groups than in the control group (p < .05). Moreover, the addition of Rutin (0.6 mM) significantly induced an increase in both the cleavage and blastocyst rates (p < .05). In summary, supplementation with Rutin in cryopreservation medium protects boar sperm against ROS attack by enhancing the antioxidative defense.     

一氧化氮调控种子休眠与萌发的研究进展

作为一种生物活性分子,一氧化氮(Nitric oxide,NO)对植物许多生理过程都具有重要影响,包括对植物种子的休眠解除和萌发的促进作用。简要综述了NO及其相关化合物在种子休眠解除和萌发上的研究进展,对NO在种子休眠解除和萌发过程中与植物激素、活性氧(Reactive oxygen species,ROS)及光照等因子的互作加以讨论,以此阐述它们在休眠解除和萌发过程中的关系,同时讨论NO的生态学意义,并且展望未来种子休眠与萌发中NO的研究重点和方向。     

Foliar application of chitosan activates artemisinin biosynthesis in Artemisia annua L.

There has been much interest in artemisinin owing to its excellent activity against malaria, an infectious disease threatening the tropical world. However, the low artemisinin content (0.01-0.8%, DW) in Artemisia annua, which is the only commercial source of artemisinin, makes artemisinin expensive to produce and not yet available on a global scale. Here we show that foliar application of 100 mg l⁻¹ chitosan improved artemisinin biosynthesis in A. annua. The content of dihydroartemisinic acid and artemisinin in chitosan-treated leaves increased by 72% and 53% compared with control values, respectively. Chitosan induced the expression of ADS and DBR2, which could explain the increase in level of artemisinic metabolites. After chitosan treatment, the amounts of hydrogen peroxide (H₂O₂) and superoxide anion (O₂⁻) in leaves of A. annua were 1.4 and 3.0 times higher than those of the control, respectively. Accumulation of reactive oxygen species (ROS) probably accelerated the conversion of dihydroartemisinic acid to artemisinin. Foliar application of 100 mg l⁻¹ chitosan had no harmful effect on A. annua growth. The simple method described here could be an effective method to improve artemisinin production in A. annua field cultivation.     

Characterization of chilling injury in Heliotropium arborescens and Lantana camara cuttings

Simulated low-temperature shipment of Heliotropium arborescens and Lantana camara cuttings inflicted chilling injury, which was manifested in increased ion leakage in both species. Morning-harvested cuttings of both Lantana and Heliotropium were more sensitive to chilling temperatures than noon-harvested cuttings. However, this difference was expressed only during the summer in Lantana, but both in the winter and summer in Heliotropium cuttings. These results suggest that the chilling injury that occurs during shipment might be alleviated in both species by avoidance of early morning picking of cuttings.

Chilling injury in Lantana was associated with increases in reactive oxygen species (ROS) levels and ethylene production rate. On the other hand, in Heliotropium cuttings ROS levels were increased and the ethylene production rate was reduced after storage at all simulated shipment temperatures. Our results may indicate that different mechanisms of chilling injury exist in Lantana and Heliotropium.     

Avermectin exposure induces apoptosis in King pigeon brain neurons

The effect of avermectin was studied on King pigeon brain nerve cells by cytotoxicity [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide, MTT] and apoptosis [acridine orange/ethidium bromide (AO/EB) assay, transmission electron microscope (TEM) evaluation, measurement of mitochondrial membrane potential (Δψm), phosphatidylserine (PS) exposure, caspases activities, DNA fragmentation, reactive oxygen species (ROS) and caspase-3 mRNA expression] within the 2.5–10 μg L⁻¹ concentration-range. The results revealed that within the concentrations of 2.5–10 μg L⁻¹, avermectin showed obvious cytotoxicity and induced apoptosis in a dose-dependent manner to neurons of King pigeon in vitro. Cell viability were 99.93 ± 8.52%, 82.02 ± 4.99% and 78.23 ± 5.67% after 24 h of treatment with avermectin at the concentrations of 0, 2.5 and 5 μg L⁻¹, which decreased to 56.36 ± 2.17% of 10 μg L⁻¹. Treated cells showed typical apoptosis morphological changes including cytoplasmic vacuolation, chromatin condensation, unclear nuclear membrane and decreased/swollen mitochondria. Typical biochemical hallmarks of apoptosis including Δψm loss, PS exposure, activations of caspase-3, caspase-8 and caspase-9, DNA fragmentation were observed too. Moreover, the levels of ROS in the avermectin treatment groups increased significantly compared to control group. Furthermore, the caspase-3 mRNA levels increased significantly following AVM treatment. In conclusion, our experimental results show that avermectin has cytotoxicity to brain neurons of King pigeon in vitro and the mechanism of neurotoxicity induced by avermectin is closely related to apoptosis.