气温和根区温度对葡萄叶片光合荧光特性的影响

为探究气温和根区温度对葡萄(Vitis vinifera)叶片光合荧光特性的影响,以一年生巨峰葡萄为试材,设置对照、高气温、高根区温度和两者交叉作用共4组处理。结果表明,相较于对照和高气温,高根区温度以及交叉处理叶片最大光化学效率(Fv/Fm)降低更明显;与对照相比,高根区温度以及高气温与高根区温度交叉处理下光系统II (PSII)实际光化学效率Y(II)显著降低,非调节能量耗散的量子产量Y(NPQ)及QA氧化还原状态(1–qP)值显著上升。同时,高根区温度以及高气温与高根区温度交叉处理显著增加了J点的可变荧光(Vj),而用于电子传递的量子产额(φEo)及性能指数(PIABS)显著降低。此外,高根区温度以及高气温与高根区温度交叉处理下单位面积有活性的反应中心数目(RC/CSm)也显著下降,K点相对可变荧光(Wk)明显上升。综上所述,高根区温度是高气温与根区高温交叉胁迫的主导因子, PSII受体侧是主要的伤害位点,高气温加剧了高根区温度对PSII造成的伤害。     

青海湖裸鲤自然产卵场的生境特征及无人机遥测判别——以泉吉河为例

自然产卵场是维持物种延续最关键的栖息地,青海湖裸鲤（Gymnocypris przewalskii）的自然繁殖栖息地状况和生境特征尚缺乏详细的定量研究。以青海湖入湖河流泉吉河为例,在平水期采用现场调查和无人机遥测的方法对青海湖裸鲤的自然产卵场分布及生境状况进行调查,确定其产卵场生境特征参数,建立基于无人机遥测识别产卵场的方法并进行复核验证。结果表明：泉吉河河道形态可分为弯曲型、分汊型和顺直型等三种典型河型,青海湖裸鲤自然产卵场主要分布在弯曲型和分汊型河道中,分汊型河道几乎100%都有产卵场分布,弯曲型河道有70%为产卵场;产卵场河道平均长度（135.13±61.13） m,平均宽度（30.01±17.51） m,平均曲折度1.09±0.07;平均面积（4586.6±4201.61） m²;产卵场常位于缓水浅滩处,平均水深（0.19±0.10） m （范围：0.03-0.44m）,平均流速（0.24±0.20） m/s （范围：0.01-0.81m/s）,河床质为含有沙粒的卵石（粒径：163-256mm）底质。河道形态、沙洲分布、水深特征等特征参数可作为无人机遥测识别产卵场的判断条件,并实现验证成功。研究结果可为开展整个流域的青海湖裸鲤自然产卵场现状评估及保护对策制定提供技术支撑。     

独岛枝芽胞杆菌MCCC 1A00493产生的4-乙烯基苯酚鉴定和作用南方根结线虫特性研究

[目的]根结线虫危害严重,难防难控,前期研究发现一株深海来源的独岛枝芽胞杆菌(Virgibacillus dokdonensis)MCCC 1A00493对南方根结线虫具有良好的体外拮抗效果,本研究分离鉴定菌株发酵液中杀线虫活性物质,对其作用线虫的多种模式进行研究,为菌株有效控制植物病原线虫的应用奠定理论基础.[方法]...     

致病性念珠菌对常见抗真菌药物的耐药性研究进展

近年来,致病性念珠菌感染引起的侵袭性念珠菌病患者人数逐年增多。白念珠菌仍是引起感染的主要致病菌,但是由非白念念珠菌引起的感染比例显著升高。致病性念珠菌对常见抗真菌药物的耐药现象呈上升趋势,这是导致临床治疗其所致的侵袭性感染失败的重要原因之一。本文就致病性念珠菌耐药性的流行病学以及其耐药机制方面的研究进展进行了介绍。     

Robust Swing‐Structured Triboelectric Nanogenerator for Efficient Blue Energy Harvesting

Ocean wave energy is a promising renewable energy source, but harvesting such irregular, “random,” and mostly ultra‐low frequency energies is rather challenging due to technological limitations. Triboelectric nanogenerators (TENGs) provide a potential efficient technology for scavenging ocean wave energy. Here, a robust swing‐structured triboelectric nanogenerator (SS‐TENG) with high energy conversion efficiency for ultra‐low frequency water wave energy harvesting is reported. The swing structure inside the cylindrical TENG greatly elongates its operation time, accompanied with multiplied output frequency. The design of the air gap and flexible dielectric brushes enable mininized frictional resistance and sustainable triboelectric charges, leading to enhanced robustness and durability. The TENG performance is controlled by external triggering conditions, with a long swing time of 88 s and a high energy conversion efficiency, as well as undiminished performance after continuous triggering for 4 00 000 cycles. Furthermore, the SS‐TENG is demonstrated to effectively harvest water wave energy. Portable electronic devices are successfully powered for self‐powered sensing and environment monitoring. Due to the excellent performance of the distinctive mechanism and structure, the SS‐TENG in this work provides a good candidate for harvesting blue energy on a large scale.     

Ischemic Preconditioning Increases Endothelial Progenitor Cell Number to Attenuate Partial Nephrectomy-Induced Ischemia/Reperfusion Injury

Objectives

The objective of this study was to investigate the role of endothelial progenitor cells (EPCs) in the modulation of ischemia-reperfusion injury (IRI) in a partial nephrectomy (PN) rat model using early-phase ischemic preconditioning (IPC).

Materials and Methods

Ninety male Sprague-Dawley rats were randomly divided into three groups following right-side nephrectomy: Sham-operated rats (surgery without vascular clamping); PN rats (renal blood vessels were clamped for 40 min and PN was performed); and IPC rats (pretreated with 15 min ischemia and 10 min reperfusion). At 1, 3, 6, 12, 24 h, and 3 days after reperfusion, the pool of circulating EPCs and kidneys were harvested. The extent of renal injury was assessed, along with EPC number, cell proliferation, angiogenesis, and vascular growth factor expression.

Results

Pretreated rats exhibited significant improvements in renal function and morphology. EPC numbers in the kidneys were increased at 12 h following reperfusion in the IPC group as compared to the PN or Sham groups. Cell proliferation (including endothelial and tubular epithelial cells) and angiogenesis in peritubular capillaries were markedly increased in kidneys treated with IPC. In addition, vascular endothelial growth factor-A (VEGF-A) and stromal cell-derived factor-1α (SDF-1α) expression in the kidneys of pretreated rats was increased compared to rats subjected to PN.

Conclusions

Our investigation suggested that: (1) the early phase of IPC may attenuate renal IRI induced by PN; (2) EPCs play an important role in renal protection, involving promotion of cell proliferation and angiogenesis through release of several angiogenic factors.     

Multiple mechanisms compensate to enhance tumor-protective CD8(+) T cell response in the long-term despite poor CD8(+) T cell priming initially: comparison between an acute versus a chronic intracellular bacterium expressing a model antigen

We evaluated CD8(+) T cell responses against the dominant CTL epitope, OVA(257-264), expressed by an acute (Listeria monocytogenes (LM) OVA) vs a chronic pathogen (Mycobacterium bovis bacillus Calmette-Guérin (BCG) OVA) to reveal the influence on CD8(+) T cell memory and consequent protection against a challenge with OVA-expressing tumor cells. Infection with lower doses of both pathogens resulted in stronger bacterial growth but weaker T cell memory indicating that memory correlates with pathogen dose but not with bacterial expansion. The CD8(+) T cell response induced by LM-OVA was helper T cell-independent and was characterized by a rapid effector response followed by a rapid, but massive, attrition. In contrast, BCG-OVA induced a delayed and weak response that was compensated for by a longer effector phase and reduced attrition. This response was partly dependent on CD4(+) T cells. CD8(+) T cell response induced by BCG-OVA, but not LM-OVA, was highly dependent on pathogen persistence to compensate for the weak initial CD8(+) T cell priming. Despite a stronger initial T cell response with LM-OVA, BCG-OVA provided more effective tumor (B16OVA) control at both local and distal sites due to the induction of a persistently activated acquired, and a more potent innate, immunity.