Chromosome‐level genome assembly of an important pine defoliator,Dendrolimus punctatus (Lepidoptera; Lasiocampidae)

Dendrolimus spp. are important destructive pests of conifer forests, and Dendrolimus punctatus Walker (Lepidoptera; Lasiocampidae) is the most widely distributed Dendrolimus species. During periodic outbreaks, this species is said to make “fire without smoke” because large areas of pine forest can be quickly and heavily damaged. Yet, little is known about the molecular mechanisms that underlie the unique ecological characteristics of this forest insect. Here, we combined Pacific Biosciences (PacBio) RSII single‐molecule long reads and high‐throughput chromosome conformation capture (Hi‐C) genomics‐linked reads to produce a high‐quality, chromosome‐level reference genome for D. punctatus. The final assembly was 614 Mb with contig and scaffold N50 values of 1.39 and 22.15 Mb, respectively, and 96.96% of the contigs anchored onto 30 chromosomes. Based on the prediction, this genome contained 17,593 protein‐coding genes and 56.16% repetitive sequences. Phylogenetic analyses indicated that D. punctatus diverged from the common ancestor of Hyphantria cunea, Spodoptera litura and Thaumetopoea pityocampa ~ 108.91 million years ago. Many gene families that were expanded in the D. punctatus genome were significantly enriched for the xenobiotic biodegradation system, especially the cytochrome P450 gene family. This high‐quality, chromosome‐level reference genome will be a valuable resource for understanding mechanisms of D. punctatus outbreak and host resistance adaption. Because this is the first Lasiocampidae insect genome to be sequenced, it also will serve as a reference for further comparative genomics.     

Silencing LINC00504 inhibits cell proliferation,invasion as well as migration and promotes cell apoptosis in lung cancer cells via upregulating miR-876-3p

LINC00504 acts as an oncogene and associates with unfavorable prognosis in patients with lung cancer. Silencing LINC00504 may be a promising strategy for treatment of lung cancer and its effects were firstly investigated in lung cancer cells this study. The gene expression level of miR-876-3p as well as LINC00504 were measured via PCR assay. The cell proliferation was investigated through Cell Counting Kit-8 (CCK-8) assay and colony formation assay. Flow cytometry was applied for detection of cell apoptosis. Wound healing and transwell assay were performed for measurement of cell migration and invasion respectively. The apoptosis related protein expressions were measured by western blot. Luciferase report assay was conducted for verification the target gene. LINC00504 was higher expressed in five types of lung cancer cells studied herein when compared with the control normal cells. LINC00504 knockdown exerted inhibitory effects on cell apoptosis, cell migration as well as cell invasion and promoted cell apoptosis. All the effects mentioned above were counteracted by miR-876-3p inhibitor. Silencing LINC00504 possessed anti-proliferation, repression of cell invasion as well as migration and pro-apoptosis effects via targeting up-regulation of miR-876-3p in lung cancer cells, proving the new therapeutic targets and highlighting the potential application in future diagnosis and treatment in lung cancer.     

Glycine metabolomic changes induced by anticancer agents in A549 cells

Amino Acids - Glycine plays a key role in rapidly proliferating cancer cells such as A549 cells. Targeting glycine metabolism is considered as a potential means for cancer treatment. However, the...     

Rapid anti‐depressant‐like effects of ketamine and other candidates: Molecular and cellular mechanisms

Major depressive disorder takes at least 3 weeks for clinical anti‐depressants, such as serotonin selective reuptake inhibitors, to take effect, and only one‐third of patients remit. Ketamine, a kind of anaesthetic, can alleviate symptoms of major depressive disorder patients in a short time and is reported to be effective to treatment‐resistant depression patients. The rapid and strong anti‐depressant‐like effects of ketamine cause wide concern. In addition to ketamine, caloric restriction and sleep deprivation also elicit similar rapid anti‐depressant‐like effects. However, mechanisms about the rapid anti‐depressant‐like effects remain unclear. Elucidating the mechanisms of rapid anti‐depressant effects is the key to finding new therapeutic targets and developing therapeutic patterns. Therefore, in this review we summarize potential molecular and cellular mechanisms of rapid anti‐depressant‐like effects based on the pre‐clinical and clinical evidence, trying to provide new insight into future therapy.     

Research progress on gut health of farmers teleost fish: a viewpoint concerning the intestinal mucosal barrier and the impact of its damage

Reviews in Fish Biology and Fisheries - The intestinal mucosal barrier plays a critical role in the maintenance of host health. In farmed teleost fish, the intestinal epithelium is challenged by a...     

肝素C5异构酶的表达优化及分子改造

肝素和硫酸乙酰肝素是一类应用于临床抗凝血的糖胺聚糖。肝素葡萄糖醛酸C5异构酶(Heparosan-N-sulfate-glucuronate 5-epimerase,C5,EC 5.1.3.17) 是肝素和硫酸乙酰肝素合成过程中重要的修饰酶,催化N-硫酸化肝素前体 (N-sulfoheparosan) 的D-葡萄糖醛酸 (D-GlcA) 上5号位羧基翻转生成L-艾杜糖醛酸 (L-iduronic acid,L-IdoA)。文中以大肠杆菌Escherichia coli为宿主对斑马鱼来源的肝素葡萄糖醛酸C5异构酶基因Glce进行重组表达优化与分子改造。比较了3种不同的表达载体pET20b(+)、pET28a(+) 和pCold Ⅲ对C5表达的差异情况,其中以嗜冷启动型载体pCold Ⅲ表达酶活最高,达到(1 873.61±5.42) U/L。为了进一步提高C5的可溶表达量,在N端融合促溶标签SET2后,可溶蛋白表达量比对照提高了50%,酶活达到 (2 409.25±6.43) U/L。在此基础上,通过理性设计对底物结合口袋进行定点突变,获得最优突变体 (V153R) 的酶活和比酶活分别为 (5 804.32±5.63) U/L和(145.14±2.33) U/mg,是原始酶的2.41倍和2.28倍。肝素C5异构酶改造与表达优化为酶法催化合成肝素奠定了基础。     

肠激酶在毕赤酵母中的分泌表达优化

肠激酶 (Enterokinase,EK) 是一类特异性识别切割DDDDK序列的丝氨酸蛋白酶,作为一种工具酶广泛应用于生物医药领域。目前,EK在毕赤酵母Pichia pastoris中的表达水平较低,难以应用。本研究比较了6种不同的信号肽SP1、SP2、SP3、SP4、SP7和SP8对毕赤酵母分泌表达EK的影响。在摇瓶水平上,与α-factor信号肽相比,SP1信号肽显著提高了EK的分泌表达 (从6.8 mg/L提高至14.3 mg/L),酶活从 (2 390±212) U/mL提高至 (4 995±378) U/mL。在此基础上,通过共表达毕赤酵母内源蛋白Kex2,EK酶活提高至 (7 219±489) U/mL。另外,N端融合WLR三个氨基酸进一步提高酶活至 (15 145±920) U/mL,比酶活为 (1 174 600±53 100) U/mg。EK在毕赤酵母中的高效分泌表达为未来应用奠定了基础。     

枯草芽孢杆菌表达与调控工具相关研究进展

枯草芽孢杆菌作为革兰氏阳性模式微生物,由于其清晰的遗传背景、高效的分泌能力以及简单的培养条件等优势被广泛的应用于生物技术产业。近年来,随着代谢工程与合成生物学的发展,枯草芽孢杆菌相关表达系统与调控工具研究也取得了很大进展。围绕枯草芽孢杆菌动态调控工具的研究进展,分别从转录水平调控和转录后水平调控两个层面上进行综述,并对调控元件在生物技术中的应用进行了讨论。最后,对未来枯草芽孢杆菌表达与调控工具的发展进行了展望。