Eimeria tenella: cloning of a novel Eimeria tenella cDNA encoding a protein related to rhomboid family from F2 hybrid strain

A novel cDNA sequence with an open reading frame of 774 bp from Eimeria tenella F2 hybrid strain (ETRH01) was isolated from a lambda cDNA library with a monoclonal antibody against sporozoite. Analysis of the genomic sequence suggests that this is an intronless gene. The deduced protein sequence has 257 amino acids with a calculated molecular weight of 28.349 kDa and an isoelectric point of 8.56. Sequence analysis revealed seven transmembrane domains and a rhomboid domain within the protein. RT-PCR result indicates that this gene was expressed in all of the five E. tenella isolates analyzed. To further study the role of this novel gene in the life cycle of E. tenella, ETRH01 was successfully expressed using pET28b(+) expression system.     

Decolorization of azo, triphenylmethane and anthraquinone dyes by a newly isolated Trametes sp. SQ01 and its laccase

A white-rot fungus, strain SQ01, was isolated from decayed wood in a temperate forest. The strain was identified as a member of genus Trametes, based on the morphological characteristics and a complete sequence analysis of its 18S rRNA gene and ITS region. Strain SQ01 was capable of decolorizing a variety of synthetic dyes, including azo, triphenylmethane, and anthraquinone dyes, with an optimal efficiency of decolorization obtained when dyes added after 5 days of culture, with the exception of Cresol Red, showing that the point of dye addition was an important influencing factor for decolorization by this fungus. All of the tested dyes were decolorized by the purified laccase in the absence of any redox mediators, but only a few were completely removed, while others were not completely degraded even with increased decolorization time.     

Frequency of the major histocompatibility complex Mamu‐A*01 allele in experimental rhesus macaques in China

Background In Indian rhesus macaques, the major histocompatibility complex Mamu gene, especially the Mamu‐A*01 allele, plays an important role in simian immunodeficiency virus susceptibility and disease progression. The Mamu‐A*01 allele is one of the protective genes mostly being studied in simian acquired immunodeficiency syndrome. Methods PCR was used to amplify the Mamu‐A*01 allele in 130 Chinese‐origin rhesus macaques. Identification of the allele was then confirmed by sequencing and IFN‐γ ELISPOT assay. Results The Mamu‐A*01 allele was detected in 3.85% (5 of 130) of the experimental Chinese‐origin rhesus macaques. The sequence homology reached 99.1% in comparison with Indian rhesus macaques. A significantly large number of spots were observed in Mamu‐A*01‐positive monkeys when analyzed by ELISPOT with Gag181‐189 epitope stimulation. Conclusions Our study suggests that Mamu‐A*01‐positive Chinese‐origin rhesus monkeys are suitable for use in AIDS studies.     

Microtubules and the organization of the Golgi complex

Electron microscopic and cytochemical studies indicate that microtubules play an important role in the organization of the Golgi complex in mammalian cells. During interphase microtubules form a radiating pattern in the cytoplasm, originating from the pericentriolar region (microtubule-organizing centre). The stacks of Golgi cisternae and the associated secretory vesicles and lysosomes are arranged in a circumscribed juxtanuclear area, usually centered around the centrioles, and show a defined orientation in relation to the rough endoplasmic reticulum. Exposure of cells to drugs such as colchicine, vinblastine and nocodazole leads to disassembly of microtubules and disorganization of the Golgi complex, most typically a dispersion of its stacks of cisternae throughout the cytoplasm. These alterations are accompanied by disturbances in the intracellular transport, processing and release of secretory products as well as inhibition of endocytosis. The observations suggest that microtubules are partly responsible for the maintenance and functioning of the Golgi complex, possibly by arranging its stacks of cisternae three-dimensionally within the cell and in relation to other organelles and ensuring a normal flow of material into and away from them. During mitosis, microtubules disassemble (prophase) and a mitotic spindle is built up (metaphase) to take care of the subsequent separation of the chromosomes (anaphase). The breaking up of the microtubular cytoskeleton is followed by vesiculation of the rough endoplasmic reticulum and partial atrophy, as well as dispersion of the stacks of Golgi cisternae. After completion of the nuclear division (telophase), the radiating microtubule pattern is re-established and the rough endoplasmic reticulum and the Golgi complex resume their normal interphase structure. This sequence of events is believed to fulfil the double function to provide tubulin units and space for construction of the mitotic spindle and to guarantee an approximately equal distribution of the rough endoplasmic reticulum and the Golgi complex on the two daughter cells.     

Diploidization and genome size change in allopolyploids is associated with differential dynamics of low‐ and high‐copy sequences

Recent advances have highlighted the ubiquity of whole‐genome duplication (polyploidy) in angiosperms, although subsequent genome size change and diploidization (returning to a diploid‐like condition) are poorly understood. An excellent system to assess these processes is provided by Nicotiana section Repandae, which arose via allopolyploidy (approximately 5 million years ago) involving relatives of Nicotiana sylvestris and Nicotiana obtusifolia. Subsequent speciation in Repandae has resulted in allotetraploids with divergent genome sizes, including Nicotiana repanda and Nicotiana nudicaulis studied here, which have an estimated 23.6% genome expansion and 19.2% genome contraction from the early polyploid, respectively. Graph‐based clustering of next‐generation sequence data enabled assessment of the global genome composition of these allotetraploids and their diploid progenitors. Unexpectedly, in both allotetraploids, over 85% of sequence clusters (repetitive DNA families) had a lower abundance than predicted from their diploid relatives; a trend seen particularly in low‐copy repeats. The loss of high‐copy sequences predominantly accounts for the genome downsizing in N. nudicaulis. In contrast, N. repanda shows expansion of clusters already inherited in high copy number (mostly chromovirus‐like Ty3/Gypsy retroelements and some low‐complexity sequences), leading to much of the genome upsizing predicted. We suggest that the differential dynamics of low‐ and high‐copy sequences reveal two genomic processes that occur subsequent to allopolyploidy. The loss of low‐copy sequences, common to both allopolyploids, may reflect genome diploidization, a process that also involves loss of duplicate copies of genes and upstream regulators. In contrast, genome size divergence between allopolyploids is manifested through differential accumulation and/or deletion of high‐copy‐number sequences.     

云南十个少数民族的F13A01、FESFPS和vWA位点遗传多态分析

短串联重度序列（STR）是由几个碱基对作为核心单位串联重复形成的一类DNA序列,应用3个位点在同一反应体系中进行互不干扰的多重PCR,采用高分辨力的聚丙烯酰胺凝胶电泳分离、银染法显影技术,对云南省特有的白族、傣族、阿昌族、景颇族、德昂族、拉祜族、布朗族、哈尼族、普米族和基诺族等10个少数民族的F13A01、FESFPS和vWA3位点等位基因的基因频率分布进行了调查,获得了满意的结果,在不同群体中发现一些有意义的遗传差异。     

Cell cycle checkpoints and their impact on anticancer therapeutic strategies

Cells contain numerous pathways designed to protect them from the genomic instability or toxicity that can result when their DNA is damaged. The p53 tumor suppressor is particularly important for regulating passage through G1 phase of the cell cycle, while other checkpoint regulators are important for arrest in S and G2 phase. Tumor cells often exhibit defects in these checkpoint proteins, which can lead to hypersensitivity; proteins in this class include ataxia-telangiectasia mutatated (ATM), Meiotic recanbination 11 (Mre11), Nijmegen breakage syndrome 1 (Nbs 1), breast cancer susceptibility genes 1 and 2 (BRCA1), and (BRCA2). Consequently, tumors should be assessed for these specific defects, and specific therapy prescribed that has high probability of inducing response. Tumors defective in p53 are frequently considered resistant to apoptosis, yet this defect also provides an opportunity for targeted therapy. When their DNA is damaged, p53-defective tumor cells preferentially arrest in S or G2 phase where they are susceptible to checkpoint inhibitors such as caffeine and UCN-01. These inhibitors preferentially abrogate cell cycle arrest in p53-defective cells, driving them through a lethal mitosis. Wild type p53 can prevent abrogation of arrest by elevating levels of p21(waf1) and decreasing levels of cyclins A and B. During tumorigenesis, tumor cells frequently loose checkpoint controls and this facilitates the development of the tumor. However, these defects also represent an Achilles heel that can be targeted to improve current therapeutic strategies.     

Cathodic electrochemiluminescence of Ru(bpy)/Nafion coated on graphite oxide electrode in purely aqueous solution

Two cathodic electrochemiluminescence (ECL) peaks have been obtained at ?0.99 and ?1.80 V (vs. SCE), respectively, from Ru(bpy)/Na?on coated onto a graphite oxide electrode in purely aqueous solution under cyclic voltammetric (CV) conditions, without addition of any reducing or oxidative reagents. These two ECL peaks were found to correlate to initial scan direction, pH, and reversal potential. Na?on played an important role in the generation of these two ECL peaks because no cathodic emission was observed in the system without Na?on. It seems that a part of Ru(bpy) electrogenerated at positive potential can remain in the Na?on, even at negative potentials. It was con?rmed that Ru(bpy)⁺ was formed at ?1.80 V by addition of S₂O. The ECL peak at ?0.99 V is attributed to the reaction of Ru(bpy)³⁺ and OH^?. The ECL peak at ?1.80 V is probably due to the annihilation reaction of Ru(bpy)³⁺ and Ru(bpy)⁺. Copyright © 2003 John Wiley & Sons, Ltd.