昨天不是很了解光呼吸(photorespiration)，百无聊赖之下到google上去查，一下子就发现了很好的网页说明它，我很轻松的就了解了光呼吸这个概念。google真是功能强大。现在电脑对我来说主要就是三个功能：1使用office写文章；2上网完成一些交易及email；3就是搜索信息了。google搜索的功能真是很实用。设想在一本1000多页的教科书中想找到自己的问题真是要费上一番功夫。这样我头脑里蹦出什么问题就可以到google上去搜索。
昨晚跟新宇聊天，这家伙想的东西可真不少。我可没工夫想那么多东西。我觉得我还是要纯化一下自己，把自己的精力集中于一点，别的乱七八糟的东西少想，争取在某一点方面有所突破。现在发现自己的知识还是太少，很多东西都不知道，还是要抓紧时间多了解一些东西。
这两天想了解植物对磷的吸收，实在找不到什么很好的材料，于是去看对氮的吸收，觉得还是受益颇多。植物将外界的氨或者光呼吸产生的氨主要以四种amino acids的形式（天冬氨酸Aspartate、天冬酰胺Asparagine、谷氨酸glutamate和谷酰胺glutamine）吸收和储存到身体内。下面还是用英语写吧，增强自己的英语思维。
The concentrations of these transported amino acids are not static but are modulated by factors such as light. The enzymes that synthesize N-transport amino acids are glutamine synthetase (GS), glutamate synthetase (GOGAT), glutamate dehydrogenase (GDH), aspartate aminotransferase (AspAT), and asparagine synthetase (AS). Isoenzymes of these enzymes have non-overlapping functions in N assimilation in vivo. These isoenzymes can be isolated by ion-exchange chromatography. For example, GS1 is believed to exist in cytosol and function mainly in the primary N assimilation and GS2 exists in chloroplast and can absorb external ammonia and the ammonia released in photorespiration. The GS/GOGAT cycle is the principal nitrogen assimilation pathway in plants. GS has a very high affinity for ammonium. By tracing the fate of 15NH4+, we know that ammonium is incorporated into the amide group of glutamine, subsequently appearing in the amino groups of glutamate.
How to clone the genes encoding these enzymes?
This could be done by several methods like crosshybridization to animal GS cDNAs and complementation of microbial GS mutants. Plant GS cDNAs are able to complement bacterial GS mutants, despite the fact that their respective holoenzymes are distinct in subunit structure and sequence.
昨晚跟新宇聊天，这家伙想的东西可真不少。我可没工夫想那么多东西。我觉得我还是要纯化一下自己，把自己的精力集中于一点，别的乱七八糟的东西少想，争取在某一点方面有所突破。现在发现自己的知识还是太少，很多东西都不知道，还是要抓紧时间多了解一些东西。
这两天想了解植物对磷的吸收，实在找不到什么很好的材料，于是去看对氮的吸收，觉得还是受益颇多。植物将外界的氨或者光呼吸产生的氨主要以四种amino acids的形式（天冬氨酸Aspartate、天冬酰胺Asparagine、谷氨酸glutamate和谷酰胺glutamine）吸收和储存到身体内。下面还是用英语写吧，增强自己的英语思维。
The concentrations of these transported amino acids are not static but are modulated by factors such as light. The enzymes that synthesize N-transport amino acids are glutamine synthetase (GS), glutamate synthetase (GOGAT), glutamate dehydrogenase (GDH), aspartate aminotransferase (AspAT), and asparagine synthetase (AS). Isoenzymes of these enzymes have non-overlapping functions in N assimilation in vivo. These isoenzymes can be isolated by ion-exchange chromatography. For example, GS1 is believed to exist in cytosol and function mainly in the primary N assimilation and GS2 exists in chloroplast and can absorb external ammonia and the ammonia released in photorespiration. The GS/GOGAT cycle is the principal nitrogen assimilation pathway in plants. GS has a very high affinity for ammonium. By tracing the fate of 15NH4+, we know that ammonium is incorporated into the amide group of glutamine, subsequently appearing in the amino groups of glutamate.
How to clone the genes encoding these enzymes?
This could be done by several methods like crosshybridization to animal GS cDNAs and complementation of microbial GS mutants. Plant GS cDNAs are able to complement bacterial GS mutants, despite the fact that their respective holoenzymes are distinct in subunit structure and sequence.
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