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

Soil Chemical Analysis

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

Reactive oxygen species (ROS) are produced as a normal product of plant cellular metabolism. Various environmental stresses lead to excessive production of ROS causing progressive oxidative damage and ultimately cell death. Despite their destructive activity, they are well-described second messengers in a variety of cellular processes, including conferment of tolerance to various environmental stresses. Whether ROS would serve as signaling molecules or could cause oxidative damage to the tissues depends on the delicate equilibrium between ROS production, and their scavenging. Efficient scavenging of ROS produced during various environmental stresses requires the action of several nonenzymatic as well as enzymatic antioxidants present in the tissues. In this paper, we describe the generation, sites of production and role of ROS as messenger molecules as well as inducers of oxidative damage. Further, the antioxidative defense mechanisms operating in the cells for scavenging of ROS overproduced under various stressful conditions of the environment have been discussed in detail.

https://downloads.hindawi.com/archive/2012/217037.pdf

Reactive Oxygen Species, Oxidative Damage, and Antioxidative Defense Mechanism in Plants under Stressful Conditions

http://directory.umm.ac.id/Data%20Elmu/jurnal/P/PlantScience/PlantScience_Elsevier/Vol151.Issue1.2000/5250.pdf

Oxidative stress and some antioxidant systems in acid rain-treated bean plants Protective role of exogenous polyamines

PROTOCOL: Agronomic biofortification strategies to increase grain zinc concentrations for improved nutritional quality of wheat, maize and rice: a systematic review

Maize Productivity and Grain Zinc Concentration as Affected by Different Soil Fertility Management Practices in Smallholder Farming Systems in Zimbabwe

http://r4d.dfid.gov.uk/PDF/Outputs/Misc_Crop/2011_zinccrops2011_kutman.pdf

Better Nitrogen Nutrition Results in Enhanced Uptake, Transport and Grain Deposition of Zinc in Wheat

Author(s): Peleg, zvi; Cakmak, Ismail; Yazici, Atilla Mustafa; Fahima, tzion; Saranga, Yehoshua | Abstract: Wheat is an important staple food crop for human consumption. Developing minerals-enriched cereals is the most promising and cost-effective approach for diminishing malnutrition. Wild emmer wheat [Triticum turgidum ssp. dicoccoides (Korn.) Thell.], the progenitor of domesticated wheats, offers a valuable allelic repertoire for economically important traits, including grain mineral concentrations. Twenty two wild emmer wheat accessions, representing a wide range of drought resistance capacity, as well as two durum wheat cultivars, were examined under two contrasting irrigation regimes (well-watered control and water-limited) for grain yield, total biomass production and grain Zn, Fe and protein concentrations. The obtained results demonstrated the presence of a large genetic diversity for grain protein and mineral nutrient concentrations in wild emmer germplasm and about two-fold greater values as compared with domesticated wheat. A strong positive association between GPC, Zn and Fe, and no association between any of these three variables and yield was noted. The genetic basis of grain mineral concentrations was further dissected using a population of 152 recombinant inbred lines, derived from a cross between durum wheat (cv. Langdon) and wild emmer (acc. G18-16). A total of 82 QTLs were mapped for 10 minerals. There was significant positive correlation between GPC, Zn and Fe, which was supported by a significant overlap between QTLs, suggesting a common physiological-genetic control of these compounds. The identified genetic resources and QTLs may facilitate the use of wild alleles for improvement of grain protein and mineral concentrations in elite wheat cultivars.

/pdf/genomic-physiological-dissection-of-grain-protein-and-1ae0nnp2qd.pdf

Genomic-Physiological Dissection of Grain Protein and Mineral Nutrient Concentrations in Wild Emmer Wheat Under Contrasting Water Availabilities

Experiments were carried out to study the role of phytosiderophore (PS) release and zinc (Zn) uptake in susceptibility of genotypes to Zn deficiency in nutrient solution under controlled environmental conditions using rye, triticale, bread wheat and durum wheat genotypes Similar to the field observations, visual deficiency symptoms, such as whitish-brown lesions on leaf blades occurred first and severely in durum wheat (cultivars ‘Kunduru-11459’ and ‘Ktziltan-91’) and in bread wheat (cultivars ‘Partizanka Niska’, ‘BDME-10’, and ‘Bul-63-68-7’), but zinc deficiency symptoms were less severe in the bread wheats (‘Dagdas-94’, ‘Bezostaja’, and ‘Gerek-79’) and very slight or absent in the triticale and rye, respectively ‘Presto’ and ‘Aslim’ Release rates of PS’s from roots could not be related to the differential Zn efficiency of cereal species with the exception of high sensitivity of durum wheat cultivars The results obtained on 65Zn uptake suggest that the high Zn efficiency of rye can be attributed to its greater Zn uptake capacity from soils and the inability of durum wheat cultivars to have a high Zn uptake capacity seems to be an important reason for its Zn efficiency Differential Zn efficiency between the bread wheat cultivars is not related to their capacity to take up inorganic Zn

Ismail Cakmak

Papers

PROTOCOL: Agronomic biofortification strategies to increase grain zinc concentrations for improved nutritional quality of wheat, maize and rice: a systematic review

Maize Productivity and Grain Zinc Concentration as Affected by Different Soil Fertility Management Practices in Smallholder Farming Systems in Zimbabwe

Better Nitrogen Nutrition Results in Enhanced Uptake, Transport and Grain Deposition of Zinc in Wheat

Genomic-Physiological Dissection of Grain Protein and Mineral Nutrient Concentrations in Wild Emmer Wheat Under Contrasting Water Availabilities

Possible role of phytosiderphore release and zinc uptake by roots in zinc efficiency of various cereal genotypes