广西防城港黑翅长脚鹬的繁殖行为

本研究于2021年3～9月,采用目标观察和全事件记录法,对广西防城港市钦州湾八路水湿地黑翅长脚鹬（Himantopus himantopus）的繁殖习性进行全过程观察记录。黑翅长脚鹬的栖息生境主要在盐田、虾塘和鱼塘,而巢主要分布在盐田生境。共发现39巢,雌雄共同营巢,按照主要巢材将其巢分为干草巢、碎石巢、泥皮巢和牛毛毡草巢4种;巢材包括禾本科（Gramineae）和莎草科（Cyperaceae）植物以及碎石、贝壳等;巢外径为（23.3±10.7）cm,巢内径为（11.2±1.9）cm,巢深为（1.6±0.5）cm,巢高为（6.5±4.3）cm(n=39);筑巢需（3±2）d(n=6)。窝卵数2～4枚,1～2 d产1枚卵,7 d内产完满窝卵（n=6）。雌雄均参与孵卵,雄性孵卵时间比雌性长,但二者差异不显著（P> 0.05）,雄性（8 550±245.9）min,雌性（7 530±263.3）min,孵卵期为（25±2）d(n=6)。育雏期（26±3）d(n=6),雌雄轮流育雏,育雏前、中期（雏鸟1～20d日龄）,雌性育雏时间比雄性长,是雄性的2倍,育雏后期（雏鸟大于20 d日龄）,...     

Recombinant protein purification by self-cleaving aggregation tag

A simple technique is presented for non-chromatographic purification of recombinant proteins expressed in Escherichia coli. This method is based on a reversibly precipitating, self-cleaving purification tag. The tag is made up of two components: an elastin-like polypeptide (ELP), which reversibly self-associates in high-salt buffers at temperatures above 30 degrees C; and an intein, which causes the ELP tag to self-cleave in response to a mild pH shift. Thus, a tripartite ELP-intein-target protein precursor can be purified by cycles of salt addition, heating and centrifugation. Once purified, intein-mediated self-cleavage, followed by precipitation of the cleaved ELP tag, allows easy and effective isolation of the pure, native target protein without the need for chromatographic separations. Recoveries of 50-100 mg of cleaved, native target protein per liter of shake-flask culture have been achieved for over a dozen proteins, typically in 8-24 h depending on specific process parameters.     

与转染Endostatin基因的角朊细胞共培养时内皮细胞增殖特性变化

构建含Endostatin基因的腺病毒载体,将Endostatin基因导入培养的角朊细胞,并采用套皿法共培养角朊细胞与内皮细胞,测定培养液中Endostatin含量、内皮细胞增殖周期各时相比例、内皮细胞凋亡及细胞抑制率。结果表明转染Endostatin基因的角朊细胞可有效表达并分泌Endostatin,连续培养3天后,培养液中Endostatin含量可达226ng/ml;与转基因角朊细胞共培养的内皮细胞凋亡百分数与抑制率分别为(32.7±7.1)%、(60.5±8.3)%,均显著高于对照组[(7.3±2.0)%,(13.8±1.6)%],且G0/G1期比例明显高于对照组,而S期、G2/M期比例及增殖指数显著低于对照组。因此,转染Endostatin基因角朊细胞与内皮细胞共培养时,角朊细胞可通过分泌Endostatin促进内皮细胞凋亡,并抑制其增殖。     

严重烧伤早期心肌线粒体Ca2+转运变化及外源性ATP的影响

细胞Ca2+稳态的维持是其生命活动正常进行的重要条件.病理条件下,细胞Ca2+稳态紊乱,将导致其功能和结构的严重损害.线粒体具有完整的Ca2+转运系统,可参与细胞Ca2+浓度的调节.我所既往研究表明,严重烧伤早期心肌细胞内Ca2+浓度升高,且分布异常.本研究探讨严重烧伤早期心肌线粒体Ca2+转运变化及外源性ATP的影响,以期阐明烧伤后心肌线粒体Ca2+超载的发生机制.     

A fusion protein composed of receptor binding domain of vascular endothelial growth factor-A and constant region fragment of antibody: angiogenesis antagonistic activity

Vascular endothelial growth factor (VEGF) promotes the growth of solid tumor mainly via VEGF receptor-1 and receptor-2, which are expressed preferentially in proliferating endothelial cells. Therefore, a strategy for simultaneous blockage of both VEGF receptors may have a useful therapeutic effect in tumor growth. In this study, we utilized a fusion protein which is composed of receptor binding domain of VEGF-A (RBDV) and the constant region fragment (Fc) of a human immunoglobulin G1 (IgG1), to interfere with the growth of human umbilical vein endothelial cells (HUVECs) via VEGF receptors. The results showed that RBDV-IgG1 Fc was able to bind with both VEGF receptor-1 and receptor-2. In addition, RBDV-IgG1 Fc could decrease VEGF-induced proliferation and tube formation among HUVECs. Moreover, the cytotoxic test showed RBDV-IgG1 Fc could also enhance the cytotoxic activity of human natural killing cells. The data are suggesting that the fusion protein, RBDV-IgG1 Fc, may have potential as an angiogenesis antagonist for future tumor therapy.     

Signals in pathological CNS extracts of ALS mice promote hMSCs neurogenic differentiation in vitro

The capability of MSCs to differentiate into neurons has been proven by many studies. Recently, other studies have cast doubt on MSCs neurogenic differentiation with non-physiological chemical inducing agents in vitro. This present study was designed to use conditioned medium to investigate whether signals from pathological condition of ALS were competent to induce a program of neurogenic differentiation in expanded cultures of hMSCs. Incubation of hMSCs with conditioned medium prepared from CNS extracts of ALS mice (SOD1-G93A ALS mice) resulted in a time-dependent morphological change from fibroblast-like into neuron-like, concomitant with increase in the expression of Nestin and subsequent beta-tubulin III, NSE and GAP43. Moreover, signals in pathological CNS extracts of ALS mice were more effective in promoting hMSCs neurogenic differentiation than those in physiological extracts of normal adult mice. These results show that pathological condition of ALS is endowed with capacity to induce hMSCs neurogenic differentiation and hMSCs have shown a potential candidate in cellular therapy for ALS.