抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

The lion's share of bacteria in various environments cannot be cloned in the laboratory and thus cannot be sequenced using existing technologies. A major goal of single-cell genomics is to complement gene-centric metagenomic data with whole-genome assemblies of uncultivated organisms. Assembly of single-cell data is challenging because of highly non-uniform read coverage as well as elevated levels of sequencing errors and chimeric reads. We describe SPAdes, a new assembler for both single-cell and standard (multicell) assembly, and demonstrate that it improves on the recently released E+V-SC assembler (specialized for single-cell data) and on popular assemblers Velvet and SoapDeNovo (for multicell data). SPAdes generates single-cell assemblies, providing information about genomes of uncultivatable bacteria that vastly exceeds what may be obtained via traditional metagenomics studies. SPAdes is available online ( http://bioinf.spbau.ru/spades ). It is distributed as open source software.

SPAdes, a new genome assembly algorithm and its applications to single-cell sequencing ( 7th Annual SFAF Meeting, 2012)

Biological activities and distribution of plant saponins.

Ginsenosides are a special group of triterpenoid saponins that can be classified into two groups by the skeleton of their aglycones, namely dammarane‐ and oleanane‐type. Ginsenosides are found nearly exclusively in Panax species (ginseng) and up to now more than 150 naturally occurring ginsenosides have been isolated from roots, leaves/stems, fruits, and/or flower heads of ginseng. Ginsenosides have been the target of a lot of research as they are believed to be the main active principles behind the claims of ginsengs efficacy. The potential health effects of ginsenosides that are discussed in this chapter include anticarcinogenic, immunomodulatory, anti‐inflammatory, antiallergic, antiatherosclerotic, antihypertensive, and antidiabetic effects as well as antistress activity and effects on the central nervous system. Ginsensoides can be metabolized in the stomach (acid hydrolysis) and in the gastrointestinal tract (bacterial hydrolysis) or transformed to other ginsenosides by drying and steaming of ginseng to more bioavailable and bioactive ginsenosides. The metabolization and transformation of intact ginsenosides, which seems to play an important role for their potential health effects, are discussed. Qualitative and quantitative analytical techniques for the analysis of ginsenosides are important in relation to quality control of ginseng products and plant material and for the determination of the effects of processing of plant material as well as for the determination of the metabolism and bioavailability of ginsenosides. Analytical techniques for the analysis of ginsenosides that are described in this chapter are thin‐layer chromatography (TLC), high‐performance liquid chromatography (HPLC) combined with various detectors, gas chromatography (GC), colorimetry, enzyme immunoassays (EIA), capillary electrophoresis (CE), nuclear magnetic resonance (NMR) spectroscopy, and spectrophotometric methods.

Ginsenosides: Chemistry, biosynthesis, analysis and potential health effects

The pharmacological activity and constituents of the sanchi ginseng Panax notoginseng have been reviewed. The bulk of pharmacological findings have been based on the saponins or steryl glycosides, although polysaccharides with immunopotentiating activity, proteins with antifungal, ribonuclease and xylanase activity, and a triacylglycerol (trilinolein) with antioxidant activity have been reported. Protective actions against cerebral ischaemia, beneficial effects on the cardiovascular system, and haemostatic, antioxidant, hypolipidaemic, hepatoprotective, renoprotective and estrogen-like activities have been described. Various methods for authentication of P. notoginseng are available.

Pharmacological activity of sanchi ginseng (Panax notoginseng).

Codonopsis, in the family Campanulaceae, is a genus containing 42 species of dicotyledonous herbaceous perennial plants, predominantly found in Central, East and South Asia. Several Codonopsis species are widely used in traditional medicine and are considered to have multiple medicinal properties. Among the Codonopsis species, Codonopsis pilosula (Franch.) Nannf. and C. lanceolata (Sieb. et Zucc.) Benth. & Hook. f. ex Trautv. are more popular than others according to the findings, especially phytochemical and bioactive studies. Phytochemical research shows that Codonopsis species contain mainly polyacetylenes, phenylpropanoids, alkaloids, triterpenoids and polysaccharides, which contribute to multiple bioactivities. However, the mechanisms of their bioactivities need to be further elucidated. The less popular Codonopsis species remain to be studied and exploited. In addition, although a series of methods for the quality evaluation of Codonopsis species have been developed, a feasible and reliable approach to the efficacious and safe use of various Codonopsis species is still needed, with considering botanical origin, chemical constituents and bioactive effects. This review aims to provide up-to-date and comprehensive information on the phytochemistry, bioactivity and quality control of medicinal plants in the genus Codonopsis and to highlight current gaps in knowledge, which is useful for the wider development of the Codonopsis genus.

/pdf/the-genus-codonopsis-campanulaceae-a-review-of-1c00itrvpd.pdf

The genus Codonopsis (Campanulaceae): a review of phytochemistry, bioactivity and quality control.

A comparative study on the triterpene saponins of 47 samples of Ginseng drugs derived from 12 Panax taxa was conducted using a reverse-phase high-performance liquid chromatography (HPLC)method. Eleven ginsenosides, which represent 4 types of typical sapogenins, were chosen as standards for quantitative determination in order to characterize the chemical constituent pattern of each Ginseng drug and investigate the relationship between genetic varieties and chemical constituent pattern. The results showed that the ginsenoside compositions in Ginseng drugs of different origins were of considerable variability. Total saponin contents varied by 10-fold from the highest drug to the lowest one. Chikusetsu-ninjin derived from P. japonicus (Japan) was found to have the highest content (192.80 - 296.18 mg/g) and Ginseng from P. ginseng to be the lowest (5.78 - 15.63 mg/g). Two main groups (I and II) suggested by phytochemical data were clearly observed; group I mainly containing dammarane saponins consisted of P. ginseng, P. quinquefolius, P. notoginseng, P. vietnamensis and P. vietnamensis var. fuscidiscus; and group II containing a large amount of oleanolic acid saponins was com-posed of P.japonicus (apan), P. zingiberensis, P.japonicus (China),P. japonicus var. angustifolius, P. japonicus var. major, P. japonicus var. bipinnatifidus and P. stipuleanatus. The ratios of the subtotal of dammarane saponins to that of oleanolic acid saponins (D/0) were found to be > 1.9 and < 0.25 for groups I and II, respectively. The drug samples derived from the same botanical origin revealed similar constituent patterns, in other words, each Panaxtaxon showed its own characteristic chromatographic profile,which appeared in the specific shape of an 11-direction radar graph constructed on the basis of the result of quantitative analysis. Similarities of chemical constitution were seen among the closely phylogenetically-related taxa, including P. ginseng and P.quinquefolius, P. vietnamensis and P. vietnamensis var.fuscidiscus,P. japonicus (China) and its varieties were demonstrated, except P. japonicus (Japan) and P. zingiberensis.

Comparative study on triterpene saponins of Ginseng drugs.

A systematic study on the influencing parameters and improvement of quantitative analysis of multi-component with single marker method using notoginseng as research subject.

Six new dammarane-type saponins (1-6), together with 11 known saponins (7-17), were isolated from Ye-Sanchi, the underground part of Panax japonicus collected in the South of Yunnan Province, China. Their structures were elucidated by chemical and spectroscopic means.

Dammarane-type triterpene saponins from Panax japonicus

Four new dammarane-type saponins (1-4), named yesanchinosides G-J, together with nine ginsenosides (5-13) were isolated from Ye-Sanchi, the underground part of Panax japonicus collected in the south of Yunnan Province, China. Their structures were elucidated on the basis of spectroscopic and chemical methods. Ginsenosides Rb(1) and Rb(3) and notoginsenosides R(4) (6) and Fa (7) showed significant neurite outgrowth enhancing activities in human neuroblastoma SK-N-SH cells.

Shu Zhu

Papers

The genus Codonopsis (Campanulaceae): a review of phytochemistry, bioactivity and quality control.

Comparative study on triterpene saponins of Ginseng drugs.

A systematic study on the influencing parameters and improvement of quantitative analysis of multi-component with single marker method using notoginseng as research subject.

Dammarane-type triterpene saponins from Panax japonicus

Dammarane-type Saponins from Panax japonicus and their neurite outgrowth activity in SK-N-SH cells.