Medical Applications Department, Nuclear Applications Division, Nuclear Research Center of Algiers (CRNA), 02 Bd Frantz Fanon, P.O. Box 399, 16000, Algiers-Gare, Algiers, Algeria.
Environmental Engineering Department, National Polytechnic School of Algiers (ENP), 10 Rue des Frères Oudek, Hacène Badi, PO Box 182, 16200, El Harrach, Algiers, Algeria.
Curr Microbiol. 2020 Mar;77(3):405-414. doi: 10.1007/s00284-019-01841-2. Epub 2019 Dec 16.
Parasporins (PS), a class of non-insecticidal and non-hemolytic crystal proteins of Bacillus thuringiensis (Bt), are being explored as promising anti-cancer agents due to their specific toxicity to cancer cells. This work is considered as a first initiative aiming at investigating Algerian soil Bt isolates' activity and cytotoxic potential against cancer cells. A total of 48 Bacillus spp. were isolated from different sites in Algeria. Phenotypic and biochemical tests, 16S rDNA molecular identification, and microscopic observation of crystal have confirmed the identification of Bt for ten strains. A screening for non-hemolytic crystalline proteins was performed. Extraction, purification, and activation of non-hemolytic proteins by chromatographic analysis yielded several polypeptides of different molecular weights. A purified PS1, with pro-protein of 81 kDa and several peptides with different molecular weights (18-58 kDa) after activation by trypsin, has been identified from the strain BDzG. The NH-terminal sequence deciphered in BLAST analysis showed homology to a Bt PS1 protein. Moreover, the screening of parasporin-1 (PS1) gene has also been performed. Cytocidal activity against human epithelial type 2 (HEp2) cells, considered to originate from a human laryngeal carcinoma, was observed with an IC equal to 2.33 μg/ml, while moderate cytotoxicity against adenocarcinomic human alveolar basal epithelial (A549) cells has been shown with IC equal to 18.54 μg/ml. No cytotoxicity against normal cells was noted. Fluorescence microscopy revealed a condensed or fragmented chromatin indicating the apoptotic death of HEp2 cells. Thus, Bt PS-producer isolated from Algerian soil might have a potential to join the arsenal of natural anti-cancer drugs with high therapeutic potential.
类芽孢杆菌素（PS）是苏云金芽孢杆菌（Bt）的一类非杀虫和非溶血晶体蛋白，由于其对癌细胞的特异性毒性，正被探索作为有前途的抗癌药物。这项工作被认为是首次旨在研究阿尔及利亚土壤 Bt 分离物对癌细胞的活性和细胞毒性潜力。从阿尔及利亚不同地点共分离出 48 株芽孢杆菌属。表型和生化试验、16S rDNA 分子鉴定和晶体的显微镜观察证实了 10 株菌为 Bt。进行了非溶血晶体蛋白的筛选。通过色谱分析提取、纯化和激活非溶血蛋白，得到了几种不同分子量的多肽。从菌株 BDzG 中鉴定出一种纯化的 PS1，其前蛋白为 81 kDa，经胰蛋白酶激活后有几个不同分子量的肽（18-58 kDa）。BLAST 分析中破译的 NH-末端序列显示与 Bt PS1 蛋白同源。此外，还进行了 PS1 基因的筛选。对人上皮型 2 （HEp2）细胞的细胞毒性作用，被认为来源于人喉癌，观察到 IC 等于 2.33 μg/ml，而对腺癌细胞人肺泡基底上皮（A549）细胞的中度细胞毒性作用，IC 等于 18.54 μg/ml。对正常细胞没有观察到细胞毒性。荧光显微镜显示染色质浓缩或碎片化，表明 HEp2 细胞发生凋亡死亡。因此，从阿尔及利亚土壤中分离出的 Bt PS 产生菌可能具有加入具有高治疗潜力的天然抗癌药物库的潜力。
