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

3.2.3. Hydroformylation 2467 3.2.4. Dimerization 2468 3.2.5. Oxidative Cleavage and Ozonolysis 2469 3.2.6. Metathesis 2470 4. Terpenes 2472 4.1. Pinene 2472 4.1.1. Isomerization: R-Pinene 2472 4.1.2. Epoxidation of R-Pinene 2475 4.1.3. Isomerization of R-Pinene Oxide 2477 4.1.4. Hydration of R-Pinene: R-Terpineol 2478 4.1.5. Dehydroisomerization 2479 4.2. Limonene 2480 4.2.1. Isomerization 2480 4.2.2. Epoxidation: Limonene Oxide 2480 4.2.3. Isomerization of Limonene Oxide 2481 4.2.4. Dehydroisomerization of Limonene and Terpenes To Produce Cymene 2481

Chemical Routes for the Transformation of Biomass into Chemicals

Fundamental features of microbial cellulose utilization are examined at successively higher levels of aggregation encompassing the structure and composition of cellulosic biomass, taxonomic diversity, cellulase enzyme systems, molecular biology of cellulase enzymes, physiology of cellulolytic microorganisms, ecological aspects of cellulase-degrading communities, and rate-limiting factors in nature. The methodological basis for studying microbial cellulose utilization is considered relative to quantification of cells and enzymes in the presence of solid substrates as well as apparatus and analysis for cellulose-grown continuous cultures. Quantitative description of cellulose hydrolysis is addressed with respect to adsorption of cellulase enzymes, rates of enzymatic hydrolysis, bioenergetics of microbial cellulose utilization, kinetics of microbial cellulose utilization, and contrasting features compared to soluble substrate kinetics. A biological perspective on processing cellulosic biomass is presented, including features of pretreated substrates and alternative process configurations. Organism development is considered for "consolidated bioprocessing" (CBP), in which the production of cellulolytic enzymes, hydrolysis of biomass, and fermentation of resulting sugars to desired products occur in one step. Two organism development strategies for CBP are examined: (i) improve product yield and tolerance in microorganisms able to utilize cellulose, or (ii) express a heterologous system for cellulose hydrolysis and utilization in microorganisms that exhibit high product yield and tolerance. A concluding discussion identifies unresolved issues pertaining to microbial cellulose utilization, suggests approaches by which such issues might be resolved, and contrasts a microbially oriented cellulose hydrolysis paradigm to the more conventional enzymatically oriented paradigm in both fundamental and applied contexts.

/pdf/microbial-cellulose-utilization-fundamentals-and-4yec12qx1c.pdf

Microbial cellulose utilization: fundamentals and biotechnology.

KEGG(Kyoto Encyclopedia of Genes and Genomes)〔和文〕 (特集 ゲノム医学の現在と未来--基礎と臨床) -- (データベース)

Although it is generally accepted that plant community composition is key for predicting rates of ecosystem processes in the face of global change, microbial community composition is often ignored in ecosystem modeling. To address this issue, we review recent experiments and assess whether microbial community composition is resistant, resilient, or functionally redundant in response to four different disturbances. We find that the composition of most microbial groups is sensitive and not immediately resilient to disturbance, regardless of taxonomic breadth of the group or the type of disturbance. Other studies demonstrate that changes in composition are often associated with changes in ecosystem process rates. Thus, changes in microbial communities due to disturbance may directly affect ecosystem processes. Based on these relationships, we propose a simple framework to incorporate microbial community composition into ecosystem process models. We conclude that this effort would benefit from more empirical data on the links among microbial phylogeny, physiological traits, and disturbance responses. These relationships will determine how readily microbial community composition can be used to predict the responses of ecosystem processes to global change.

https://www.pnas.org/content/pnas/105/Supplement_1/11512.full.pdf

Resistance, resilience, and redundancy in microbial communities

Improved technologies are needed for sustainable conversion of cellulosic waste to valuable products. Here we demonstrate the successful integration of a synthetic microbial consortium (SynCONS) based consolidated bioprocessing with pyrolysis to produce commodity chemicals from cellulose. Promising microbial partners were rationally identified from 7626 organisms via comparative metabolic mapping which led to establishing two promising SynCONS with abilities to convert cellulose to ethanol and lactate in bioreactors. The partners in the two SynCONS were a) the mesophilic fungus Trichoderma reesei grown sequentially with the thermophilic bacterium Parageobacillus thermoglucosidasius NCIMB 11955 (TrPt) and b) a thermophilic bacterium Thermobifida fusca grown together with Parageobacillus thermoglucosidasius NCIMB 11955 (TfPt). TrPt sequential bioprocessing resulted in 39% (g/g) cellulose consumption with product yields up to 9.3% g/g (ethanol + lactate). The TfPt co-cultures demonstrated a cellulose consumption of 30% (g/g) and combined yields of ethanol and lactic acid up to 23.7% g/g of consumed cellulose. The total product yields were further enhanced (51% g/g cellulose) when commercially available cellulases were used in place of T. fusca. Furthermore, when the metabolically engineered ethanol-producing strain of P. thermoglucosidasius TM242 (TfPt242) was substituted in the thermophilic TfPt co-culture consortium, ethanol yields were substantially higher (32.7% g/g of consumed cellulose). Finally, subjecting the residual cellulose and microbial biomass to pyrolysis resulted in carbon material with physicochemical properties similar to commercially available activated carbon as analysed using Scanning Electron Microscopy, X-Ray Diffraction and Raman spectroscopy. Overall, the integration of this synthetic microbial consortia-based bioprocessing strategy with pyrolysis demonstrated a promising strategy for conversion of waste cellulose to chemicals, biofuels, and industrial carbon potentially suitable for several industrial applications.

/pdf/integration-of-synthetic-microbial-consortia-based-2cb00oj9.pdf

David J. Leak

Papers

Integration of synthetic microbial consortia based bioprocessing with pyrolysis for efficient conversion of cellulose to valuables

Production of cello-oligosaccharides through the biorefinery concept: A technical-economic and life-cycle assessment

34. Aromatic Oxidations

Enzymatic generation of short chain cello-oligosaccharides from Miscanthus using different pretreatments.

Venter creates synthetic life: Should we be scared?