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

Drafting Authors: Neil Adger, Pramod Aggarwal, Shardul Agrawala, Joseph Alcamo, Abdelkader Allali, Oleg Anisimov, Nigel Arnell, Michel Boko, Osvaldo Canziani, Timothy Carter, Gino Casassa, Ulisses Confalonieri, Rex Victor Cruz, Edmundo de Alba Alcaraz, William Easterling, Christopher Field, Andreas Fischlin, Blair Fitzharris, Carlos Gay García, Clair Hanson, Hideo Harasawa, Kevin Hennessy, Saleemul Huq, Roger Jones, Lucka Kajfež Bogataj, David Karoly, Richard Klein, Zbigniew Kundzewicz, Murari Lal, Rodel Lasco, Geoff Love, Xianfu Lu, Graciela Magrín, Luis José Mata, Roger McLean, Bettina Menne, Guy Midgley, Nobuo Mimura, Monirul Qader Mirza, José Moreno, Linda Mortsch, Isabelle Niang-Diop, Robert Nicholls, Béla Nováky, Leonard Nurse, Anthony Nyong, Michael Oppenheimer, Jean Palutikof, Martin Parry, Anand Patwardhan, Patricia Romero Lankao, Cynthia Rosenzweig, Stephen Schneider, Serguei Semenov, Joel Smith, John Stone, Jean-Pascal van Ypersele, David Vaughan, Coleen Vogel, Thomas Wilbanks, Poh Poh Wong, Shaohong Wu, Gary Yohe

Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change

From molecules to crystal engineering: supramolecular isomerism and polymorphism in network solids.

The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. 
The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. 
The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. 
The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption; influence on liquid, mixed phase, and ice clouds; and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related, namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr−1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models and should be increased by a factor of almost 3. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m−2 with 90% uncertainty bounds of (+0.08, +1.27) W m−2. Total direct forcing by all black carbon sources, without subtracting the preindustrial background, is estimated as +0.88 (+0.17, +1.48) W m−2. Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m−2 with 90% uncertainty bounds of +0.17 to +2.1 W m−2. Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m−2, is the second most important human emission in terms of its climate forcing in the present-day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short-lived species that may either cool or warm climate. Climate forcings from co-emitted species are estimated and used in the framework described herein. When the principal effects of short-lived co-emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy-related sources (fossil fuel and biofuel) have an industrial-era climate forcing of +0.22 (−0.50 to +1.08) W m−2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all short-lived emissions from these sources would reduce net climate forcing (i.e., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial-era climate forcing by all short-lived species from black-carbon-rich sources becomes slightly negative (−0.06 W m−2 with 90% uncertainty bounds of −1.45 to +1.29 W m−2). The uncertainties in net climate forcing from black-carbon-rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co-emitted organic carbon. In prioritizing potential black-carbon mitigation actions, non-science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near-term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black-carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.

/pdf/bounding-the-role-of-black-carbon-in-the-climate-system-a-1fc3novd9r.pdf

Bounding the role of black carbon in the climate system: A scientific assessment

Laboratory experiments with living planktic foraminifers show that the δ13C and δ18O values of shell calcite decrease with increasing sea water pH and/or carbonate ion concentration The effect has been quantified in symbiotic (Orbulina universa) and non-symbiotic (Globigerina bulloides) species and is independent of symbiont activity and temperature It is concluded that a kinetic fractionation process affects both the carbon and oxygen isotopic composition of the shell simultaneously At present it cannot be determined definitively whether the relationship is controlled by the pH dependent balance between hydration and hydroxylation of CO2 or by [CO3 2-] related variations in the calcification rate However, independent of which factor ultimately controls the relationship between the carbonate chemistry and isotopic fractionation, in the real ocean [CO3 2-] and pH covary linearly across the relevant pH range The true relationship between shell isotopic composition and the bulk carbonate chemistry is masked by the fact that host respiration and symbiont activity locally modify the carbonate system Respiration lowers and photosynthesis increases ambient pH and [CO3 2-] This translates into modified absolute shell values but leaves the slope between the shell isotopic composition and the bulk carbonate chemistry unaffected A second level of shell isotopic modification is introduced by the incorporation of respired carbon, enriched in 12C, which depletes the shell δ13C value In symbiont bearing species this depletion is partially negated by a shell δ13C enrichment in the light As an alternative to the RUBISCO hypothesis (enrichment via preferential removal of 12CO2), we propose that scavenging of respired CO2 during photosynthesis, raises the shell δ13C value Our results have partly been documented before (Spero et al 1997) and demonstrate that the carbonate chemistry is undoubtedly a major control on temporal geochemical variability in the fossil record For instance, the sea water carbonate system of the pre-Phanerozoic world (Berner 1994; Grotzinger and Kasting 1993) or during glacials (Sanyal et al 1995) was significantly different from today confounding direct interpretation of foraminiferal stable isotope data using existing relationships (see companion paper in this volume by Lea et al)

/pdf/reassessing-foraminiferal-stable-isotope-geochemistry-impact-542yrowq6s.pdf

Reassessing foraminiferal stable isotope geochemistry: Impact of the oceanic carbonate system (experimental results)

Reconstructing a 350 ky history of sea level using planktonic Mg/Ca and oxygen isotope records from a Cocos Ridge core

Intraspecific stable isotope variability in the planktic foraminiferaGlobigerinoides sacculifer: Results from laboratory experiments

The occurrence of carbon isotope minima at the beginning of glacial terminations is a common feature of planktic foraminifera carbon isotopic records from the Indo-Pacific, sub-Antarctic, and South Atlantic. We use the δ 13 C record of a thermocline-dwelling foraminifera, Neogloboquadrina dutertrei , and surface temperature estimates from the eastern equatorial Pacific to demonstrate that the onset of δ 13 C minimum events and the initiation of Southern Ocean warming occurred simultaneously. Timing agreement between the marine record and the δ 13 C minimum in an Antarctic atmospheric record suggests that the deglacial events were a response to the breakdown of surface water stratification, renewed Circumpolar Deep Water upwelling, and advection of low δ 13 C waters to the convergence zone at the sub-Antarctic front. On the basis of age agreement between the absolute δ 13 C minimum in surface records and the shift from low to high δ 13 C in the deep South Atlantic, we suggest that the δ 13 C rise that marks the end of the carbon isotope minima was due to the resumption of North Atlantic Deep Water influence in the Southern Ocean.

https://science.sciencemag.org/content/sci/296/5567/522.full.pdf

The Cause of Carbon Isotope Minimum Events on Glacial Terminations

[1] Recent studies suggest that benthic foraminiferal Mg/Ca may be useful in reconstructing deep water temperature changes during the Quaternary and on longer timescales [Rosenthal et al., 1997; Lear et al., 2000; Martin et al., 2002]. Because changes in deep water temperature may be small, sample preparation could play an important role in reconstructing accurate temperatures from shell Mg/Ca. A simple examination of changes in measured shell chemistry of benthic foraminifera from two intervals subjected to increasingly rigorous cleaning reveals that fossil benthic foraminiferal samples cleaned by oxidation yield lower Mg/Ca values than samples only rinsed and weak acid leached. Reductive cleaning further lowered the shell Mg/Ca of one of the two benthic species examined. Lower Mg/Ca values following oxidation and reduction appear to reflect removal of contaminant Mg associated with remnant organic matter and adsorbed phases.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2001GC000280

David W. Lea

Papers

Reassessing foraminiferal stable isotope geochemistry: Impact of the oceanic carbonate system (experimental results)

Reconstructing a 350 ky history of sea level using planktonic Mg/Ca and oxygen isotope records from a Cocos Ridge core

Intraspecific stable isotope variability in the planktic foraminiferaGlobigerinoides sacculifer: Results from laboratory experiments

The Cause of Carbon Isotope Minimum Events on Glacial Terminations

A simple evaluation of cleaning procedures on fossil benthic foraminiferal Mg/Ca