HtrA3的调控机制及其在心血管疾病中的作用

高温需求因子A3(high-temperature requirement factor A3, HtrA3)是一种丝氨酸蛋白酶,目前已被研究证实是癌症、妊娠并发症等疾病的重要靶分子,该分子的调控作用得益于其广泛的生物学功能,但目前尚缺乏对这一方面的有效整合和系统阐述。本文针对HtrA3的生物学功能如参与蛋白质质量控制、免疫调控;调节线粒体稳态和细胞凋亡、细胞外基质降解和上皮间质转化;调节细胞的增殖和迁移等进行了论述。此外,研究证实HtrA3在心脏中的表达量最高,目前已有该分子在心肌纤维化、心力衰竭、缺血再灌注损伤中的相关报道。基于其功能广泛,HtrA3或可作为心血管疾病的重要调节因子,在心血管疾病的发展中具有重要研究价值。     

复合菌剂施用方式对连作土栽培菜心生长、根系构型及光合特性的影响

【目的】考察复合菌剂施用方式对菜心幼苗生长、根系形态及光合特性的影响,为应用复合菌剂缓解菜心连作障碍提供理论依据。【方法】以菜心品种‘尖叶-70’、连作9年菜心土壤及微生物菌剂为试材,设置不施（对照）、叶面喷施、土施及叶面喷施+土施复合菌剂4个处理的盆栽试验,播种30 d后观测植株生长、根系构型和叶片光合指标。【结果】各复合菌剂施用方式均能提高幼苗生长指标、根系构型指标以及净光合速率（P_n）、实际光化学效率(Φ_PSⅡ)、光化学淬灭系数（q_p）等光合指标,降低蒸腾速率（T_r）、胞间CO₂浓度（C_i）、非光化学淬灭系数（NPQ）等指标,并以叶面喷施处理效果最优,其地上干重、地下干重、根长分别比对照显著增加了128.57%、85.71%、91.81%,P_n、q_p、Φ_PSⅡ分别显著增加了24.55%、22.68%、23.93%,而T_r、C_i、NPQ分别显著降低72.73%、20.01%、39.78%。【结论】叶面喷施复合菌剂能有效促进连作菜心幼苗生长,改善根系构型,提高植株光合作用效率,是复合菌剂的最佳施用方式。     

Human brain aminopeptidase A: biochemical properties and distribution in brain nuclei

Aminopeptidase A (APA) generated brain angiotensin III, one of the main effector peptides of the brain renin angiotensin system, exerting a tonic stimulatory effect on the control of blood pressure in hypertensive rats. The distribution of APA in human brain has not been yet studied. We first biochemically characterized human brain APA (apparent molecular mass of 165 and 130 kDa) and we showed that the human enzyme exhibited similar enzymatic characteristics to recombinant mouse APA. Both enzymes had similar sensitivity to Ca(2+). Kinetic studies showed that the K(m) (190 mumol/L) of the human enzyme for the synthetic substrate-l-glutamyl-beta-naphthylamide was close from that of the mouse enzyme (256 mumol/L). Moreover, various classes of inhibitors including the specific and selective APA inhibitor, (S)-3-amino-4-mercapto-butyl sulfonic acid, had similar inhibitory potencies toward both enzymes. Using (S)-3-amino-4-mercapto-butyl sulfonic acid, we then specifically measured the activity of APA in 40 microdissected areas of the adult human brain. Significant heterogeneity was found in the activity of APA in the various analyzed regions. The highest activity was measured in the choroids plexus and the pineal gland. High activity was also detected in the dorsomedial medulla oblongata, in the septum, the prefrontal cortex, the olfactory bulb, the nucleus accumbens, and the hypothalamus, especially in the paraventricular and supraoptic nuclei. Immunostaining of human brain sections at the level of the medulla oblongata strengthened these data, showing for the first time a high density of immunoreactive neuronal cell bodies and fibers in the motor hypoglossal nucleus, the dorsal motor nucleus of the vagus, the nucleus of the solitary tract, the Roller nucleus, the ambiguus nucleus, the inferior olivary complex, and in the external cuneate nucleus. APA immunoreactivity was also visualized in vessels and capillaries in the dorsal motor nucleus of the vagus and the inferior olivary complex. The presence of APA in several human brain nuclei sensitive to angiotensins and involved in blood pressure regulation suggests that APA in humans is an integral component of the brain renin angiotensin system and strengthens the idea that APA inhibitors could be clinically tested as an additional therapy for the treatment of certain forms of hypertension.     

A Model System for the Study of the Release of Luteinizing Hormone-Releasing Hormone from Isolated Storage Granules

Abstract: We have developed an in vitro system for the study of the release of luteinizing hormone-releasing hormone (LH-RH) from its storage granules. In this system, homogenates of hypothalamic tissue are subjected to hypoosmotic shock, and the LH-RH-containing granules are isolated by means of differential centrifugation. The isolated granules are then incubated in a buffered medium, and the incubation is terminated by passing the incubation mixture through LH-RH affinity columns. The LH-RH associated with the granules passes freely through the columns, whereas the LH-RH released into the medium binds to the columns and is subsequently eluted with an acid solution. LH-RH is quantified by radioimmunoassay (RIA). We tested the effects of various concentrations of KCl on LH-RH release, which was found to be dependent on the concentration of KCl in the medium over the range 40–160 mM. We then studied the effects of pH on the release of LH-RH. Incubation of granules at pH 7.8 in the presence of 160 mM-KC1 resulted in the release from the granules of 14% of the stored LH-RH, whereas incubation at pH 6.2 resulted in the release of approximately 30% of the LH-RH. In addition, granules were incubated at pH 7.8 with MgATP and KCl. MgATP elicited a marked release of LH-RH that was approximately twice that seen in the absence of MgATP. In summary, in this in vitro system, granules containing LH-RH are stable under defined biochemical conditions, and LH-RH release from these granules is stimulated by ions and MgATP.     

基于CRISPR-Cas系统的微生物基因编辑与调控技术

CRISPR-Cas系统的基因编辑与调控技术为原核和真核微生物的遗传改造提供了高效且精确的工具,显著提升了工业底盘细胞的生产能力和多样性。在原核微生物中,大肠杆菌、枯草芽孢杆菌、谷氨酸棒杆菌等工业重要菌株通过CRISPR-Cas系统实现了代谢网络的重构和多基因位点的精确编辑,显著优化了细胞工厂的生产性能。在真核微生物中,酿酒酵母、毕赤酵母、解脂耶氏酵母等模式生物也得益于CRISPR-Cas系统的发展,尤其是CRISPR-Cas9、CRISPR-Cas12a和碱基编辑工具等在基因组精确编辑和调控中的应用,实现了代谢途径的高效优化。高通量基因组编辑技术,如CHASE、CREATE、iCREATE等,结合了CRISPR-Cas系统的强大工具,能够同时对多个基因进行编辑和调控,加速了对复杂表型的优化和代谢网络的解析。本文总结了CRISPR-Cas系统在原核、真核微生物中的应用及其高通量基因组编辑技术的发展,展望了这些技术在工业微生物细胞工厂构建中的潜在应用。