Latisemenia longshania,gen. et sp. nov., a new Late Devonian seed plant from China

The earliest known ovules in the Late Devonian (Famennian) are borne terminally on fertile branches and are typically enclosed in a cupule. Among these ovules are some that have terete integumentary lobes with little or no fusion. Here, we report a new taxon, Latisemenia longshania, from the Famennian of South China, which bears cupulate ovules that are terminal as well as opposite on the fertile axis. Each ovule has four broad integumentary lobes, which are extensively fused to each other and also to the nucellus. The cupule is uniovulate, and the five flattened cupule segments of each terminal ovule are elongate cuneate and shorter than the ovule. Associated but not attached pinnules are laminate and Sphenopteris-like, with an entire or lobate margin. Latisemenia is the earliest known plant with ovules borne on the side of the fertile axis and may foreshadow the diverse ovule arrangements found among younger seed plant lineages that emerge in the Carboniferous. Following the telome theory, Latisemenia demonstrates derived features in both ovules and cupules, and the shape and fusion of integumentary lobes suggest effective pollination and protection to the nucellus. Along with other recent discoveries from China, Latisemenia extends the palaeogeographic range of the earliest seed plants.     

16s rRNA基因克隆文库分析比较牙周炎患者和健康人口腔唾液微生物多样性

【目的】通过对同一地区、同一民族牙周炎患者和健康人的唾液微生物群落结构的分析,探寻牙周炎患者口腔微生物的多样性。【方法】采集甘肃东乡族自治县的东乡族牙周炎患者和健康人唾液各5例,分别记作DP(东乡牙周)和DH(东乡健康),提取细菌总DNA,构建16S r RNA基因克隆文库,测序后利用MOTHUR、MEGA 4.0、Clustal X 3.0等软件对测序结果进行分析。【结果】所有样本共检测出115个OTUs(DP 60,DH 75),归属于6个门,27个属。TM7是DP组特有的优势菌门。仅在DP组中检测到的优势菌属是梭菌属(Fusobacterium)、卟啉单胞菌属(Porphyromonas)、消化链球菌属(Peptostreptococcus)和TM7_genera。【结论】发现牙周炎患者与健康人口腔唾液微生物存在一定差异。其中,TM7、梭菌属和消化链球菌属在牙周病中的作用值得进一步研究。     

微波合成靶向核仁的荧光碳纳米颗粒研究

核仁是细胞内重要的亚核结构,其在恶性病的演变过程中扮演重要角色,是病理学家诊断癌症的重要指标.尽管核仁如此关键,但到目前为止,核仁的荧光探针寥寥无几.本文以水杨酸和1,8-二氨基萘为反应物,通过微波消解法合成了一种新型荧光碳纳米颗粒(FCNs),采用透射电子显微镜、动态光散射仪、傅里叶红外光谱仪、紫外分光光度计、荧光光谱仪等对其物理、化学、光学性质进行了表征、分析.借助激光扫描共聚焦等技术对FCNs的细胞摄取机制及分布进行了探究.实验结果表明,所合成碳纳米颗粒尺寸均匀,最佳激发波长在348 nm,对应的最大发射峰为432 nm,荧光量子产率为17.8%,荧光寿命为1.13 ns,其表面含有丰富的氨基和羟基,光稳定性强且毒性极低,可实现对细胞核仁染色,并且随着共孵育时间的延长,进入细胞的量越多,靶向核仁更明显.此外,经过对FCNs细胞摄取路径的考察,发现FCNs是通过小窝介导的路径被內吞.该研究为碳基纳米材料在亚细胞器靶向成像的应用方面提供了有力的工具和新思路.     

J亚群禽白血病病毒跨膜蛋白gp37基因克隆与表达

禽白血病病毒(ALV)跨膜蛋白(TM)在病毒-细胞融合过程中起关键作用,其蛋白内部存在的许多高度保守序列有可能成为抗病毒的重要靶点。对TM结构和功能的深入研究将为抗禽白血病病毒乃至其它反转录病毒相关制剂的研制提供科学的理论基础。本研究通过PCR从本实验室分离的ALV-J山东汶上毒株获得表达TM的gp37基因,克隆连接pMD18-T载体并测序,从已构建的质粒pMD18-T-gp37中酶切回收gp37基因,构建重组转移载体pFastBacHTb-gp37。利用昆虫杆状病毒表达系统对gp37基因进行表达,通过间接免疫荧光和Western blot检测gp37基因表达产物,间接免疫荧光显示,重组杆状病毒感染的sf9细胞呈现明显的强阳性反应;Western blot分析,重组病毒感染的sf9细胞蛋白显示出约21kD的阳性条带。结果表明,gp37基因在sf9细胞内表达成功。     

综述与专论: 低功率光照疗法对机体免疫应答的影响

最近几年,采用红至红外波长(600～1 100 nm)的低功率光照(low-dose light,LDL)疗法对组织代谢系统、神经系统、血液循环系统和免疫系统等方面的调节效应已经引起了广泛关注．同时,生物能学和光生物学基础研究的发展推动了低功率光照在疾病治疗领域的革新．有报道指出,巨噬细胞、肥大细胞、中性粒细胞和淋巴细胞等免疫细胞能响应低功率光照,产生细胞因子和保护性的蛋白质分子来缓解一些疾病的进程．因此,本文将从分子、细胞和组织水平对低功率光照改善的一些疾病的免疫学现象及机制进行归纳总结．     

土壤中棉花黄萎病菌SYBR Green Ⅰ荧光RT-PCR定量检测技术研究

为实现田间土壤棉花黄萎病菌的早期检测,建立了土壤中棉花黄萎病菌的SYBR GreenⅠ荧光定量PCR检测方法.以含342bp PCR扩增产物的阳性质粒为参考,构建了标准曲线,并对该曲线的特异性、敏感性、可重复性进行了评价.结果表明,该方法具有快速、特异性强、敏感度高等特点.检测范围在3.8×103-3.8×108cop...     

产甲烷古菌研究进展

产甲烷古菌是一类严格厌氧的古菌,只能利用简单的化合物进行产甲烷生长。产甲烷古菌在地球生命起源和进化、全球气候变化、碳生物地球化学循环和农业废弃物资源化利用等领域,都起着至关重要的作用。系统了解产甲烷古菌的生物学特征,将有助于在这些基础和应用领域的研究工作。本文主要从生理生化特征、代谢途径、能量储存和系统分类等方面介绍产甲烷古菌的研究进展。     

硝基苯酚胁迫下外源褪黑素对水稻幼苗生长及生理特性的影响

采用液体培养实验方法,研究硝基苯酚胁迫对水稻(Oryza sativa L.)幼苗生长、抗氧化特性、光系统Ⅱ(PSⅡ)光合特性的影响,以及添加外源褪黑素对缓解硝基苯酚胁迫的作用。结果显示,随着硝基苯酚胁迫浓度的升高,水稻幼苗株高、根长、地下部干重、地上部干重、全株干重和叶片PSⅡ实际光化学效率[Y(Ⅱ)]、光化学淬灭系数(q P)、PSⅡ电子传递速率(ETR)、叶绿素含量均有所下降,而叶片非光化学淬灭系数(qN、NPQ)上升;同时,根系活性氧[过氧化氢(H_2O_2)和超氧阴离子(O·-2)]积累量、抗氧化酶[超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)]活性,以及渗透调节物质(可溶性蛋白和可溶性糖)含量呈先升高后降低的趋势。在非硝基苯酚胁迫下,与对照组相比,添加外源褪黑素显著提高了幼苗地下部干重、根系可溶性糖含量和SOD活性、叶片PSⅡ光化学效率和叶绿素含量。与单独添加硝基苯酚处理相比,硝基苯酚+褪黑素复合处理显著缓解了硝基苯酚胁迫对幼苗生长、叶片PSⅡ光化学效率和叶绿素合成的抑制作用;降低了根系活性氧水平、抗氧化酶活性和渗透调节物质含量。研究结果表明添加外源褪黑素能够显著缓解硝基苯酚胁迫对水稻幼苗生长、根系活性氧水平、抗氧化酶活性、叶片PSⅡ光化学效率及叶绿素合成的不良影响,提高水稻幼苗对硝基苯酚胁迫的适应性。     

Quantitative proteomics reveal up-regulated protein expression of the SET complex associated with hepatocellular carcinoma

We combined culture-derived isotope tags (CDITs) with two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS) to extensively survey abnormal protein expression associated with hepatocellular carcinoma (HCC) in clinical tissues. This approach yielded an in-depth quantitated proteome of 1360 proteins. Importantly, 267 proteins were significantly regulated with a fold-change of at least 1.5. The proteins up-regulated in HCC tissues are involved in regulatory processes, such as the granzyme A-mediated apoptosis pathway (The GzmA pathway). The SET complex, a central component in the GzmA pathway, was significantly up-regulated in HCC tissue. The elevated expressions of all of the SET complex components were validated by Western blotting. Among them, ANP32A and APEX1 were further investigated by immunohistochemistry staining using tissue microarrays (59 cases), confirming their overexpression in tumors. The up-regulation and nuclear accumulations of APEX1 was associated not only with HCC malignancy but also with HCC differentiation in 96 clinical HCC cases. Our work provided a systematic and quantitative analysis and demonstrated key changes in clinical HCC tissues. These proteomic signatures could help to unveil the underlying mechanisms of hepatocarcinogenesis and may be useful for the discovery of candidate biomarkers.     

CRISPR FISHer enables high-sensitivity imaging of nonrepetitive DNA in living cells through phase separation-mediated signal amplification

The dynamic three-dimensional structures of chromatin and extrachromosomal DNA molecules regulate fundamental cellular processes and beyond. However, the visualization of specific DNA sequences in live cells, especially nonrepetitive sequences accounting for most of the genome, is still vastly challenging. Here, we introduce a robust CRISPR-mediated fluorescence in situ hybridization amplifier (CRISPR FISHer) system, which exploits engineered sgRNA and protein trimerization domain-mediated, phase separation-based exponential assembly of fluorescent proteins in the CRISPR-targeting locus, conferring enhancements in both local brightness and signal-to-background ratio and thus achieving single sgRNA-directed visualization of native nonrepetitive DNA loci in live cells. In one application, by labeling and tracking the broken ends of chromosomal fragments, CRISPR FISHer enables real-time visualization of the entire process of chromosome breakage, separation, and subsequent intra- or inter-chromosomal ends rejoining in a single live cell. Furthermore, CRISPR FISHer allows the movement of small extrachromosomal circular DNAs (eccDNAs) and invading DNAs to be recorded, revealing substantial differences in dynamic behaviors between chromosomal and extrachromosomal loci. With the potential to track any specified self or non-self DNA sequences, CRISPR FISHer dramatically broadens the scope of live-cell imaging in biological events and for biomedical diagnoses.Subject terms: Non-homologous-end joining, Biological techniques