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1.
A viable option for increasing nitrogen (N) use efficiency and mitigation of negative impacts of N on the environment is to capitalize on multi-element interactions through implementation of nutrient management programs that provide balanced nutrition. Numerous studies have demonstrated the immediate efficacy of this approach in the developing regions like China and India as well as developed countries in North America. Based on 241 site-years of experiments in these countries, the first-year N recovery efficiency (RE) for the conventional or check treatments averaged 21% while the balanced treatments averaged 54% RE, for an average increase of 33% in RE due to balanced nutrition. Effective policies to promote adoption are most likely those that enable site-specific approaches to nutrient management decisions rather than sweeping, nation-wide incentives supporting one nutrient over another. Local farmers, advisers and officials need to be empowered with tools and information to help them define necessary changes in practices to create more balanced nutrient management.  相似文献   
2.
高效利用土壤磷素的植物营养学研究   总被引:61,自引:4,他引:61  
论述磷在农业及生态系统中的重要地位,磷资源的危机以及磷土壤中的理化特性,探讨土壤的供磷潜力,不同植物品种以及相同品种不同基因型对土壤潜在磷资源的吸收利用差异,营养机制,遗传特性及其利用不同作物的基因型来活化,吸收利用土壤难溶态磷的可行性对策,从而为充分发挥植物自身潜力,提高土壤难溶态磷的生物有效性,高效利用土壤潜在磷资源,加快土壤磷素有效循环,节省资源,保护环境,真正达到生态系统的稳定与现代化农业  相似文献   
3.
The development of DNA sequencing technology has provided an effective method for studying foodborne and phytopathogenic microorganisms on fruits and vegetables (F & V). DNA sequencing has successfully proceeded through three generations, including the tens of operating platforms. These advances have significantly promoted microbial whole-genome sequencing (WGS) and DNA polymorphism research. Based on genomic and regional polymorphisms, genetic markers have been widely obtained. These molecular markers are used as targets for PCR or chip analyses to detect microbes at the genetic level. Furthermore, metagenomic analyses conducted by sequencing the hypervariable regions of ribosomal DNA (rDNA) have revealed comprehensive microbial communities in various studies on F & V. This review highlights the basic principles of three generations of DNA sequencing, and summarizes the WGS studies of and available DNA markers for major bacterial foodborne pathogens and phytopathogenic fungi found on F & V. In addition, rDNA sequencing-based bacterial and fungal metagenomics are summarized under three topics. These findings deepen the understanding of DNA sequencing and its application in studies of foodborne and phytopathogenic microbes and shed light on strategies for the monitoring of F & V microbes and quality control.  相似文献   
4.

Purpose

This study was intended to identify the disease causing genes in a large Chinese family with autosomal dominant retinitis pigmentosa and macular degeneration.

Methods

A genome scan analysis was conducted in this family for disease gene preliminary mapping. Snapshot analysis of selected SNPs for two-point LOD score analysis for candidate gene filter. Candidate gene PRPF31 whole exons'' sequencing was executed to identify mutations.

Results

A novel nonsense mutation caused by an insertion was found in PRPF31 gene. All the 19 RP patients in 1085 family are carrying this heterozygous nonsense mutation. The nonsense mutation is in PRPF31 gene exon9 at chr19:54629961-54629961, inserting nucleotide “A” that generates the coding protein frame shift from p.307 and early termination at p.322 in the snoRNA binding domain (NOP domain).

Conclusion

This report is the first to associate PRPF31 gene''s nonsense mutation and adRP and JMD. Our findings revealed that PRPF31 can lead to different clinical phenotypes in the same family, resulting either in adRP or syndrome of adRP and JMD. We believe our identification of the novel “A” insertion mutation in exon9 at chr19:54629961-54629961 in PRPF31 can provide further genetic evidence for clinical test for adRP and JMD.  相似文献   
5.
DNA-binding proteins are crucial for various cellular processes and hence have become an important target for both basic research and drug development. With the avalanche of protein sequences generated in the postgenomic age, it is highly desired to establish an automated method for rapidly and accurately identifying DNA-binding proteins based on their sequence information alone. Owing to the fact that all biological species have developed beginning from a very limited number of ancestral species, it is important to take into account the evolutionary information in developing such a high-throughput tool. In view of this, a new predictor was proposed by incorporating the evolutionary information into the general form of pseudo amino acid composition via the top-n-gram approach. It was observed by comparing the new predictor with the existing methods via both jackknife test and independent data-set test that the new predictor outperformed its counterparts. It is anticipated that the new predictor may become a useful vehicle for identifying DNA-binding proteins. It has not escaped our notice that the novel approach to extract evolutionary information into the formulation of statistical samples can be used to identify many other protein attributes as well.  相似文献   
6.
7.
高等植物对磷饥饿胁迫的自我拯救   总被引:1,自引:0,他引:1  
低磷营养胁迫下,高等植物会采取一系列自我拯救措施,包括将生长环境中的难溶性无机磷和无效态有机磷活化或水解释放有效磷(Pi)、对低浓度有效磷的有效吸收以及对吸收的有限磷源的有效利用.适于这些自我拯救措施,体内的许多生理生化过程将经受重大调整,这涉及到许多蛋白和酶的含量及活性的变化.与自我拯救密切相关的酶和蛋白的合成大量增加,有些则不同程度地减弱.有些酶,即使酶蛋白含量大大减少,但特殊的活性调节机制使其活性几乎未减弱甚至略有提高.本文主要概述磷饥饿状态下,呼吸和光合作用过程中的几种酶、与有机磷利用有关的酶的变化,例如酸性磷酸酶、RNA酶、有关的蛋白激酶以及高亲和力Pi转运蛋白等.  相似文献   
8.
Shi J  Jia B  Liu Z  Yang Z  Yu Z  Chen K  Chen X  Liu S  Wang F 《Bioconjugate chemistry》2008,19(6):1170-1178
In this report, we present the synthesis and evaluation of the (99m)Tc-labeled beta-Ala-BN(7-14)NH2 (ABN = beta-Ala-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2) as a new radiotracer for tumor imaging in the BALB/c nude mice bearing HT-29 human colon cancer xenografts. The gastrin releasing peptide receptor binding affinity of ABN and HYNIC-ABN (6-hydrazinonicotinamide) was assessed via a competitive displacement of (125)I-[Tyr4]BBN bound to the PC-3 human prostate carcinoma cells. The IC 50 values were calculated to be 24 +/- 2 nM and 38 +/- 1 nM for ABN and HYNIC-ABN, respectively. HYNIC is the bifunctional coupling agent for (99m)Tc-labeling, while tricine and TPPTS (trisodium triphenylphosphine-3,3',3'-trisulfonate) are used as coligands to prepare the ternary ligand complex [(99m)Tc(HYNIC-ABN)(tricine)(TPPTS)] in very high yield and high specific activity. Because of its high hydrophilicity (log P = -2.39 +/- 0.06), [(99m)Tc(HYNIC-ABN)(tricine)(TPPS)] was excreted mainly through the renal route with little radioactivity accumulation in the liver, lungs, stomach, and gastrointestinal tract. The tumor uptake at 30 min postinjection (p.i.) was 1.59 +/- 0.23%ID/g with a steady tumor washout over the 4 h study period. As a result, it had the best T/ B ratios in the blood (2.37 +/- 0.68), liver (1.69 +/- 0.41), and muscle (11.17 +/- 3.32) at 1 h p.i. Most of the injected radioactivity was found in the urine sample at 1 h p.i., and there was no intact [(99m)Tc(HYNIC-ABN)(tricine)(TPPTS)] detectable in the urine, kidney, and liver samples. Its metabolic instability may contribute to its rapid clearance from the liver, lungs, and stomach. Despite the steady radioactivity washout, the tumors could be clearly visualized in planar images of the BALB/c nude mice bearing the HT-29 human colon xenografts at 1 and 4 h p.i. The favorable excretion kinetics from the liver, lungs, stomach, and gastrointestinal tract makes [(99m)Tc(HYNIC-ABN)(tricine)(TPPTS)] a promising SPECT radiotracer for imaging colon cancer.  相似文献   
9.
大气质量提高与农业中的硫肥需求   总被引:1,自引:2,他引:1  
论述了植物对硫素的生理需求,大气中含硫化合物的来源、组成与含量以及对植物生态系统的硫素补充作用,植物对气态硫化物的吸收、同化能力及适宜浓度等.近年来由于人类健康与生态环境的需要,世界各国纷纷通过法律体制对工业含硫废气的排放标准进行了严格控制,却导致了作物缺硫现象的频繁发生,在某些地区硫已成为限制农业生产的最重要肥料限制因素.为此,全球农业中硫肥的需求量猛增且有效性范围不断扩大,进而对硫肥的研究与开发利用提出了新的要求  相似文献   
10.
The biotrophic fungal pathogen Ustilaginoidea virens causes rice false smut, a newly emerging plant disease that has become epidemic worldwide in recent years. The U. virens genome encodes many putative effector proteins that, based on the study of other pathosystems, could play an essential role in fungal virulence. However, few studies have been reported on virulence functions of individual U. virens effectors. Here, we report our identification and characterization of the secreted cysteine-rich protein SCRE1, which is an essential virulence effector in U. virens. When SCRE1 was heterologously expressed in Magnaporthe oryzae, the protein was secreted and translocated into plant cells during infection. SCRE1 suppresses the immunity-associated hypersensitive response in the nonhost plant Nicotiana benthamiana. Induced expression of SCRE1 in rice also inhibits pattern-triggered immunity and enhances disease susceptibility to rice bacterial and fungal pathogens. The immunosuppressive activity is localized to a small peptide region that contains an important ‘cysteine-proline-alanine-arginine-serine’ motif. Furthermore, the scre1 knockout mutant generated using the CRISPR/Cas9 system is attenuated in U. virens virulence to rice, which is greatly complemented by the full-length SCRE1 gene. Collectively, this study indicates that the effector SCRE1 is able to inhibit host immunity and is required for full virulence of U. virens.  相似文献   
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