Knockdown of NFBD1/MDC1 enhances chemosensitivity to cisplatin or 5-fluorouracil in nasopharyngeal carcinoma CNE1 cells

Nasopharyngeal carcinoma (NPC) is a rare but highly invasive cancer that is prevalent among people of southern Chinese ancestry in southern China and Southeast Asia. Radiotherapy and cisplatin (CDDP)-based chemotherapy are the main treatment options. Unfortunately, disease response to concurrent chemoradiotherapy varies among patients with NPC, and many cases are resistant to CDDP and radiotherapy. NFBD1 functions in cell cycle checkpoint activation and DNA repair following DNA damage. In this study, we identified the NFBD1 as a tractable molecular target to chemosensitize NPC cells. NFBD1 expression in NPC CNE1 cell lines was depleted using lentivirus-mediated short hairpin RNA, and the elevated sensitivity of these NFBD1-inhibited NPC cells to therapeutic reagent CDDP and 5-fluorouracil (5-FU) was evaluated using MTS assays. Flow cytometry analysis also showed that NFBD1 knockdown led to an obvious induction of apoptosis in CDDP- or 5-FU-treated CNE1 cells. Furthermore, we implicated the involvement of NFBD1 in Rad51 and DNA-PKcs foci formation following CDDP or 5-FU chemotherapy. In conclusion, NFBD1 knockdown improves the chemosensitivity of NPC cells by inhibiting cell growth and promoting apoptosis through the impairment of DNA damage repair, suggesting NFBD1 as a novel therapeutic target for NPC.

     

湖南丹霞地貌区的苔藓植物多样性

丹霞地貌是一种特殊的红层地貌,拥有独特的植被和植物区系组成。苔藓植物在丹霞地貌植被演替中具有重要的生态意义,但其基本的种类组成和分布却不清楚。通过野外考察和标本鉴定,共发现湖南丹霞地貌区苔藓植物53科96属174种(包括变种和亚种),其中苔类植物21科24属36种,藓类植物32科72属138种,其中台湾曲柄藓(Campylopus taiwanensis)、芒尖毛口藓(Trichostomum zanderi)、小火藓(Schlotheimia pungens)、中华细枝藓(Lindergiasinensis)、疏叶叶苔(Jungermannia laxifolia)和刺叶拟蒴囊苔(Saccogynidium irregularispinosum)等6种为中国特有种;铜绿净口藓(Gymnostomum aeruginosum)、稀枝钱苔(Riccia huebeneriana)、羽枝片叶苔(Riccardia multifida)等30个种为湖南新记录种。在174种中,稀有种为87种,如梨蒴珠藓(Bartramia pomiformis)、小火藓、毛枝藓(Pilotrichopsisdentata)等,这些种大多生态幅狭窄,对生境要求较苛刻,常见种(22种)和非常常见种(30种)共52种,多为生境广泛种或世界广布种,如地钱(Marchantia polymorpha)等。文中还提供了详细的湖南丹霞地貌苔藓名录及其凭证标本信息,并建议优先保护崀山无底洞和万佛山三十六湾两个苔藓丰富的小区。     

湖南丹霞地貌区蕨类植物多样性

丹霞地貌是有别于石灰岩地貌和花岗岩地貌的特殊地貌类型,发育着较为独特的植被类型和植物区系。我们于2007-2010年间对湖南新宁崀山、茶陵浣溪、平江石牛寨、资兴程江口、浏阳达浒、通道万佛山、沅陵五强溪夸父山、溆浦思蒙等地丹霞地貌的蕨类植物进行了广泛调查,报道了湖南丹霞地貌区蕨类植物31科66属183种的详细名录。其中,无腺姬蕨(Hypolepis polypodioides)、隐囊蕨(Notholaena hirsuta)、仙霞铁线蕨(Adiantum juxtapo-situm)、百山祖短肠蕨(Allantodia baishanzuensis)、肉质短肠蕨(A.succulenta)、骨碎补铁角蕨(Asplenium ritoense)、钝齿耳蕨(Polystichum deltodon var.henryi)、无盖耳蕨(P.gymnocarpium)、单羽耳蕨(P.simplicipinnum)、二型肋毛蕨(Ctenitis dingnanensis)等9种为湖南新记录种。湖南丹霞地貌的蕨类植物种类组成主要有鳞毛蕨科、蹄盖蕨科、水龙骨科、金星蕨科、卷柏科、铁角蕨科等较大科及鳞毛蕨属(Dryopteris)、卷柏属(Selaginella)、铁角蕨属(Asplenium)、短肠蕨属(Allantodia)和凤尾蕨属(Pteris)等较大属。生态适应特点分析表明丹霞地貌既有喜钙质土的种类,也有喜酸性土的种类,仙霞铁线蕨和无盖耳蕨可能是丹霞地貌的特有植物,因而具有石灰岩地貌蕨类植物区系和花岗岩地貌蕨类植物区系之间的过渡性特点。建议将垫状卷柏(Selaginella pulvinata)、福建观音座莲(Angiopterisfokiensis)、仙霞铁线蕨、骨碎补铁角蕨、鞭叶蕨(Cyrtomidictyum lepidocaulon)、无盖耳蕨等种类列为丹霞地貌蕨类植物中的优先保护种类,将通道万佛山三十六湾、湖南沅陵夸父山列为丹霞地貌蕨类植物的优先保护地区。     

坡向差异对广东古兜山自然保护区蕨类植物多样性的生态影响

为揭示坡向差异对蕨类植物多样性的生态影响,作者在广东新会古兜山自然保护区海拔1,000 m以下的中低山植被东、南、西、北4个坡向,分别选取10个5 m×5 m的样方进行调查,分析蕨类植物群落多样性和种类组成的差异.结果表明:(1)东坡(半阴坡)与北坡(阴坡)物种多样性最丰富,而西坡(半阳坡)和南坡(阳坡)相对贫乏;(2)4个坡向的相似性系数均很低(不超过0.5),其中南坡(阳坡)与北坡(阴坡)间种类组成差异最大;(3)反映热量差异的区系地理性质分析显示,热带性质蕨类植物在阳坡占优势,而非热带性蕨类在阴坡占优势,南坡、西坡、东坡、北坡的热带成分比例依次下降;(4)反映光照条件的植物耐荫程度分析显示,阴性种类占优势,阳性和耐荫性种类较少,其阴性蕨类植物的比例依南坡、西坡、东坡、北坡顺序增加;阳性蕨类植物比例最高的坡面是西坡,而最低的是东坡.南坡的比例稍高于北坡.研究结果显示坡向差异对蕨类植物物种及其生态习性的多样性分布格局具有比较明显的影响,蕨类植物多样性可以作为环境和气候变化的一个较好的指示物种.     

An Isoform of Eukaryotic Initiation Factor 4E from Chrysanthemum morifolium Interacts with Chrysanthemum Virus B Coat Protein

Background

Eukaryotic translation initiation factor 4E (eIF4E) plays an important role in plant virus infection as well as the regulation of gene translation.

Methodology/Principal Findings

Here, we describe the isolation of a cDNA encoding CmeIF(iso)4E (GenBank accession no. {"type":"entrez-nucleotide","attrs":{"text":"JQ904592","term_id":"410111131","term_text":"JQ904592"}}JQ904592), an isoform of eIF4E from chrysanthemum, using RACE PCR. We used the CmeIF(iso)4E cDNA for expression profiling and to analyze the interaction between CmeIF(iso)4E and the Chrysanthemum virus B coat protein (CVBCP). Multiple sequence alignment and phylogenetic tree analysis showed that the sequence similarity of CmeIF(iso)4E with other reported plant eIF(iso)4E sequences varied between 69.12% and 89.18%, indicating that CmeIF(iso)4E belongs to the eIF(iso)4E subfamily of the eIF4E family. CmeIF(iso)4E was present in all chrysanthemum organs, but was particularly abundant in the roots and flowers. Confocal microscopy showed that a transiently transfected CmeIF(iso)4E-GFP fusion protein distributed throughout the whole cell in onion epidermis cells. A yeast two hybrid assay showed CVBCP interacted with CmeIF(iso)4E but not with CmeIF4E. BiFC assay further demonstrated the interaction between CmeIF(iso)4E and CVBCP. Luminescence assay showed that CVBCP increased the RLU of Luc-CVB, suggesting CVBCP might participate in the translation of viral proteins.

Conclusions/Significance

These results inferred that CmeIF(iso)4E as the cap-binding subunit eIF(iso)4F may be involved in Chrysanthemum Virus B infection in chrysanthemum through its interaction with CVBCP in spatial.