A new cell line from larval fat bodies of the bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae)

Summary A new cell line, designated IOZCAS-Ha-I, was initiated from the fat body of larvae of Helicoverpa armigera (Lepidoptera: Noctuidae) in TNM-FH medium containing 10% fetal bovine serum. Spherical cells were predominant among the various cell types. The cell line showed a typical lepidopteran chromosome pattern ranging from 58 to 239 chromosomes in the majority of the cells, it was confirmed to have originated from the H. armigera by the DNA amplification-fingerprinting polymerase chain reaction (DAF-PCR) technique. The new cell line was only slightly susceptible to the multiple nucleocapsid nuclear polyhedrosis viruses (NPV) from H. armigera.     

Carotenoid biosynthesis in cyanobacteria: structural and evolutionary scenarios based on comparative genomics

Carotenoids are widely distributed pigments in nature and their biosynthetic pathway has been extensively studied in various organisms. The recent access to the overwhelming amount genomic data of cyanobacteria has given birth to a novel approach called comparative genomics. The putative enzymes involved in the carotenoid biosynthesis among the cyanobacteria were determined by similarity-based tools. The reconstruction of biosynthetic pathway was based on the related enzymes. It is interesting to find that nearly all the cyanobacteria share quite similar pathway to synthesize beta-carotene except for Gloeobacter violaceus PCC 7421. The enzymes, crtE-B-P-Qb-L, involved in the upstream pathway are more conserved than the subsequent ones (crtW-R). In addition, many carotenoid synthesis enzymes exhibit diversity in structure and function. Such examples in the families of zeta -carotene desaturase, lycopene cylases and carotene ketolases were described in this article. When we mapped these crt genes to the cyanobacterial genomes, the crt genes showed great structural variation among species. All of them are dispersed on the whole chromosome in contrast to the linear adjacent distribution of the crt gene cluster in other eubacteria. Moreover, in unicellular cyanobacteria, each step of the carotenogenic pathway is usually catalyzed by one gene product, whereas multiple ketolase genes are found in filamentous cyanobacteria. Such increased numbers of crt genes and their correlation to the ecological adaptation were carefully discussed.     

Prediction of protein structural class with Rough Sets

Background  

A new method for the prediction of protein structural classes is constructed based on Rough Sets algorithm, which is a rule-based data mining method. Amino acid compositions and 8 physicochemical properties data are used as conditional attributes for the construction of decision system. After reducing the decision system, decision rules are generated, which can be used to classify new objects.     

Identification of transposon insertion mutants of Francisella tularensis tularensis strain Schu S4 deficient in intracellular replication in the hepatic cell line HepG2

Background  

Francisella tularensis is a zoonotic intracellular bacterial pathogen that causes tularemia. The subspecies tularensis is highly virulent and is classified as a category A agent of biological warfare because of its low infectious dose by an aerosol route, and its ability to cause severe disease. In macrophages F. tularensis exhibits a rather novel intracellular lifestyle; after invasion it remains in a phagosome for three to six hours before escaping to, and replicating in the cytoplasm. The molecular mechanisms that allow F. tularensis to invade and replicate within a host cell have not been well defined.     

Determination of the anamorph of Cordyceps sinensis inferred from the analysis of the ribosomal DNA internal transcribed spacers and 5.8S rDNA

The anamorph determination of Cordyceps sinensis remains problematic due to the lack of clear links between the sexual and conidial forms of the fungus. In this study, we applied molecular approaches to analyze the genetic variation of Cordyceps sinensis and its allies to identify the anamorph-teleomorph connection. The sequences of the internal transcribed spacers (ITS1 and ITS2) and 5.8S ribosomal RNA gene of Cordyceps sinensis (teleomorph) collected from Qingzang plateau (altitude over 4000m), Tibet and several related asexual conidial forms were determined. The sequence comparison showed that Cordyceps sinensis was most closely related to Hirsutella sinensis, and was clearly divergent from Paecilomyces sinensis, Stachybotrys sp. or Tolypocladium sp.; distance values, estimated according to Kimura two-parameter models between Cordyceps sinensis and Hirsutella sinensis, were extremely low (<0.02), whereas distance values between Cordyceps sinensis and Paecilomyces sinensis, Stachybotrys sp. and Tolypocladium sp. were 0.34, 0.21 and 0.25, respectively. Taken together, Hirsutella sinensis and Cordyceps sinensis are the different stages of the life cycle stages of the same organism. Hirsutella sinensis is therefore the anamorph of Cordyceps sinensis, rather than Paecilomyces sinensis or other species. The possible reasons as to why different taxa can be obtained when culturing Cordyceps sinensis are also discussed.     

甲醛对大鼠脑影响的实验形态学研究

２４只Ｗｉｓｔａｒ大鼠,体重２００～２８０ｇ。６只为正常对照组,１８只为实验性甲醛蒸气吸入组,每天定时吸入甲醛蒸气（２００ｍｇ／ｍ３）３０分钟,分别在７、１４和２１天后处死,然后观察大脑皮层神经细胞的酶组织化学变化及超微结构变化。酶组织化学结果显示：ＳＤＨ、Ｍｇ－ＭＴａｓｅ,ＣｈＥ活性降低↓;ＡＬＰ、ＡＣＰ、ＭＡＯ活性增强↑。超微结构变化可见（２１天）：皮层神经细胞线粒体嵴断裂、肿胀、空泡样变。表明甲醛对大脑皮层神经细胞的功能和结构均有影响。     

Low microRNA-199a expression in human amniotic epithelial cell feeder layers maintains human-induced pluripotent stem cell pluripotency via increased leukemia inhibitory factor expression

Human-induced pluripotent stem (iPS) cells share the same key properties as embryonic stem cells, and may be generated from patient- or disease-specific sources, which makes them attractive for personalized medicine, drug screens, or cellular therapy. Long-term cultivation and maintenance of normal iPS cells in an undifferentiated self-renewing state is a major challenge. Our previous studies have shown that human amniotic epithelial cells (HuAECs) could provide a good source of feeder cells for mouse and human embryonic stem cells, or spermatogonial stem cells, as they express endogenous leukemia inhibitory factor (LIF) at high levels. Here, we examined the effect of exogenous microRNA-199a regulation on endogenous LIF expression in HuAECs, and in turn on human iPS cell pluripotency. We found that HuAECs feeder cells transfected with microRNA-199a mutant expressed LIF at high levels, allowing iPS to maintain a high level of alkaline phosphatase activity in long-term culture and form teratomas in severe combined immunodeficient mice. The expression of stem cell markers was increased in iPS cultured on HuAECs feeder cells transfected with the microRNA-199a mutant, compared with iPS cultured on HuAECs transfected with microRNA-199a or mouse embryo fibroblasts. Taken together, these results suggested that LIF expression might be regulated by microRNA-199a, and LIF was a crucial component in feeder cells, and also was required for maintenance of human iPS cells in an undifferentiated, proliferative state capable of self-renewal.