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

1. Plant Nutrients. 2. The Soil as a Plant Nutrient Medium. 3. Nutrient Uptake and Assimilation. 4. Plant Water Relationships. 5. Plant Growth and Crop Production. 6. Fertilizer Application. 7. Nitrogen. 8. Sulphur. 9. Phosphorus. 10. Potassium. 11. Calcium. 12. Magnesium. 13. Iron. 14. Manganese. 15. Zinc. 16. Copper. 17. Molybdenum. 18. Boron. 19. Further Elements of Importance. 20. Elements with More Toxic Effects. General Readings. References. Index.

/pdf/principles-of-plant-nutrition-2k4wl46ou6.pdf

Principles of plant nutrition

The glutathione S-transferases (GST) represent a major group of detoxification enzymes. All eukaryotic species possess multiple cytosolic and membrane-bound GST isoenzymes, each of which displays distinct catalytic as well as noncatalytic binding properties: the cytosolic enzymes are encoded by at least five distantly related gene families (designated class alpha, mu, pi, sigma, and theta GST), whereas the membrane-bound enzymes, microsomal GST and leukotriene C, synthetase, are encoded by single genes and both have arisen separately from the soluble GST. Evidence suggests that the level of expression of GST is a crucial factor in determining the sensitivity of cells to a broad spectrum of toxic chemicals. In this article the biochemical functions of GST are described to show how individual isoenzymes contribute to resistance to carcinogens, antitumor drugs, environmental pollutants, and products of oxidative stress.A description of the mechanisms of transcriptional and posttranscriptional regulat...

The glutathione S-transferase supergene family: regulation of GST and the contribution of the isoenzymes to cancer chemoprotection and drug resistance.

The role of flavonoids as the major red, blue, and purple pigments in plants has gained these secondary products a great deal of attention over the years. From the first description of acid and base effects on plant pigments by Robert Boyle in 1664 to the characterization of structural and

Flavonoid Biosynthesis. A Colorful Model for Genetics, Biochemistry, Cell Biology, and Biotechnology

Small GTP-binding proteins (G proteins) exist in eukaryotes from yeast to human and constitute a superfamily consisting of more than 100 members. This superfamily is structurally classified into at least five families: the Ras, Rho, Rab, Sar1/Arf, and Ran families. They regulate a wide variety of cell functions as biological timers (biotimers) that initiate and terminate specific cell functions and determine the periods of time for the continuation of the specific cell functions. They furthermore play key roles in not only temporal but also spatial determination of specific cell functions. The Ras family regulates gene expression, the Rho family regulates cytoskeletal reorganization and gene expression, the Rab and Sar1/Arf families regulate vesicle trafficking, and the Ran family regulates nucleocytoplasmic transport and microtubule organization. Many upstream regulators and downstream effectors of small G proteins have been isolated, and their modes of activation and action have gradually been elucidated. Cascades and cross-talks of small G proteins have also been clarified. In this review, functions of small G proteins and their modes of activation and action are described.

Small GTP-Binding Proteins

Genes involved in the commitment of plant cells to differentiation

Mol Syst Biol. 9: 698

Land plants secure a constant supply of water and nutrients by developing a deep and densely branched root system. Nutrients are often distributed unevenly in the soil; formation of lateral roots must therefore be responsive to environmental conditions. Over time, lateral root initiation has become an accessible model system for studying the basic regulatory mechanisms that control postembryonic organ development. While there has been much interest in the phenomenology of root branching, it is only recently that the underlying molecular processes have started to be understood (Malamy, 2005).

The recent article by Bennett and colleagues (Peret et al , 2013) presents an exciting example of how an integrated experimental and mathematical approach can elucidate the signaling pathways that drive lateral root emergence. The authors chose their model plant wisely: Arabidopsis thaliana has a relatively simple root anatomy when compared to other plants such as grasses. Arabidopsis roots are composed of single concentric layers of epidermal, cortical, endodermal and pericycle cells, which surround a double‐stranded vascular cylinder (Figure 1). Lateral roots originate from a …

https://www.embopress.org/doi/pdf/10.1038/msb.2013.51

Root systems analysis branches out

Suspension cultures from Arabidopsis thaliana wild type and AtPIN1-deficient lines were initiated and maintained for more than 3 years. A protocol for efficient regeneration from long-term suspension cultures was established. Arabidopsis wild-type and respectively AtPIN1 mutant plants have been regenerated from these cultures and characterized. Additionally, transgenic suspension cultures expressing the uidA (β -glucuronidase) reporter gene under the control of AtPIN1 promoter have been used for morphogenic studies. Our studies suggest that a lack of AtPIN1 function affects shoot differentiation and development, but does not influence in vitro regeneration of plants.

Loss of AtPIN1 does not influence the in vitro morphogenic potential of Arabidopsis thaliana suspension cultures

lant scientists are easy to identify, one might think. That’s surely true when comparing them to the sometimes rath-er colourful variety of people gathered under the umbrellas of certain other biodisciplines. Okay, plant scientists do not only work in explicit plant science institutes; you’ll find them in bio-chemistry, genetics and developmental biology institutes as well, although that doesn’t matter. Actually, you only have to check which organism each researcher uses for her or his experiments – and you’ll easily filter out the plant scientists. Well, that certainly makes sense. Nevertheless, you might still encounter a problem or two. What to do for example with the structural biologist who particularly likes to pick photosynthet-ic membrane proteins for his NMR studies? Or the computation-al biologist who has just co-published a couple of software tools designed for the analysis of plant genome sequences? Are they “plant scientists”?We said ‘no’ for two main reasons. Firstly, we think that those people don’t place their main research focus on

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Cellular DNA can be damaged by endogenous or exogenous genotoxins. In plants, reduced genome stability can have a detrimental effect on development. Here, we show the identification of the fan mutant from an ethyl-methanesulfonate (EMS) mutagenized Arabidopsis Col-0 population on the basis of its short root and small leaf phenotype. The causative mutation was identified as a G-to-A transition at the border of the eighth intron and ninth exon of the At5G61330 gene, resulting in a mis-spliced mRNA transcript. FAN is a homolog of the mammalian AATF/Che-1 protein consisting of conserved AATF/Che-1 and TRAUB domains in Arabidopsis. In the fan mutant, under normal conditions, we detected DNA damage and cell death response at the root tip, while hypersensitivity to the exogenously applied hydroxyurea (HU) compared to Col-0, suggesting that FAN plays a role in the DNA damage response (DDR). Furthermore, our results showed that FAN is involved in DDR pathway regulated by ATM/RAD53-RELATED (ATR). Taken together, these suggest that FAN is required for meristem maintenance and the DNA damage response.

/pdf/fan-the-homolog-of-mammalian-apoptosis-antagonizing-1mdvc16x.pdf

FAN, the homolog of mammalian Apoptosis Antagonizing Transcription Factor AATF/Che-1 protein, is involved in safeguarding genome stability through the ATR induced pathway in Arabidopsis

Klaus Palme

Papers

Genes involved in the commitment of plant cells to differentiation

Root systems analysis branches out

Loss of AtPIN1 does not influence the in vitro morphogenic potential of Arabidopsis thaliana suspension cultures

Most Cited Authors... Most Cited Authors...

FAN, the homolog of mammalian Apoptosis Antagonizing Transcription Factor AATF/Che-1 protein, is involved in safeguarding genome stability through the ATR induced pathway in Arabidopsis