 |
 |
 |
 |
 |
 |
||
 |
 |
 |
 |
 |
| 5 | 1/1 | 返回列表 |
| 查看: 1846 | 回復(fù): 16 | ||
| 當(dāng)前只顯示滿足指定條件的回帖，點(diǎn)擊這里查看本話題的所有回帖 | ||
[求助]
DNA測定
|
||
| 請問DNA測定體系中一般要考察什么條件��？ |
回復(fù)此樓» 猜你喜歡
342求調(diào)劑
已經(jīng)有3人回復(fù)
-
070300化學(xué)專業(yè)279調(diào)劑
已經(jīng)有9人回復(fù)
-
求調(diào)劑：085600材料與化工，考材科基，總分319
已經(jīng)有20人回復(fù)
-
一志愿華東理工大學(xué)，080500學(xué)碩，317分，求調(diào)劑
已經(jīng)有9人回復(fù)
-
一志愿a區(qū)211，085601-307分求調(diào)劑
已經(jīng)有23人回復(fù)
-
合肥區(qū)域性重點(diǎn)一本招收調(diào)劑
已經(jīng)有8人回復(fù)
-
材料調(diào)劑
已經(jīng)有10人回復(fù)
-
288求調(diào)劑 一志愿哈工大 材料與化工
已經(jīng)有13人回復(fù)
-
材料科學(xué)與工程339求調(diào)劑
已經(jīng)有3人回復(fù)
-
化學(xué)308分調(diào)劑
已經(jīng)有11人回復(fù)
3樓2012-03-19 14:58:40
gaoyang636
木蟲 (著名寫手)
- BioEPI: 17
- 應(yīng)助: 202 (大學(xué)生)
- 金幣: 4111.4
- 散金: 7
- 紅花: 14
- 帖子: 1108
- 在線: 159.8小時
- 蟲號: 384065
- 注冊: 2007-05-27
- 專業(yè): 基因組學(xué)
2樓2012-03-19 08:38:52
xstarsky
鐵桿木蟲 (正式寫手)
- BioEPI: 2
- 應(yīng)助: 60 (初中生)
- 金幣: 6806.4
- 紅花: 2
- 帖子: 536
- 在線: 221.3小時
- 蟲號: 67896
- 注冊: 2005-05-15
- 專業(yè): 作物分子育種
【答案】應(yīng)助回帖
★ ★
感謝參與，應(yīng)助指數(shù) +1
王壽梅: 金幣+2 2012-03-22 14:32:58
感謝參與，應(yīng)助指數(shù) +1
王壽梅: 金幣+2 2012-03-22 14:32:58
|
Spectrophotometry and fluorometry are commonly used to measure DNA concentration. Spectrophotometrycan be used to measure microgram quantities of pure DNA samples (i.e., DNA that is not contaminated by proteins, phenol, agarose, or RNA). Fluorometry is more sensitive, allowing measurement of nanogram quantities of DNA, and furthermore the use of Hoechst 33258 dye allows specific analysis of DNA. 1。Spectrophotometry DNA concentration can be determined by measuring the absorbance at 260 nm (A260) in a spectrophotometer using a quartz cuvette. For greatest accuracy, readings should be between 0.1 and 1.0. An absorbance of 1 unit at 260 nm corresponds to 50 μg genomic DNA per ml (A260 =1 ⇒ 50 μg/ml)*. This relation is valid only for measurements made at neutral pH, therefore, samples should be diluted in a low-salt buffer with neutral pH (e.g., Tris·Cl, pH 7.0). An example of the calculation involved in nucleic acid quantification when using a spectrophotometer is provided in “Spectrophotometric Measurement of Nucleic Acid Concentration” 1）If you will use more than one cuvette to measure multiple samples, the cuvettes must be matched. 2）Spectrophotometric measurements do not differentiate between DNA and RNA, so RNA contamination can lead to overestimation of DNA concentration. 3）Phenol has an absorbance maximum of 270–275 nm, which is close to that of DNA. Phenol contamination mimics both higher yields and higher purity, because of an upward shift in the A260 value. 2.Fluorometry Fluorometry allows specific and sensitive measurement of DNA concentration by use of the fluorochrome Hoechst 33258, which shows increased emission at 458 nm when bound to DNA. This dye has little affinity for RNA, allowing accurate quantification of DNA samples that are contaminated with RNA.DNA standards and samples are mixed with Hoechst 33258 and measured in glass or acrylic cuvettes using a scanning fluorescence spectrophotometer or a dedicated filter fluorometer set at an excitation wavelength of 365 nm and an emission wavelength of 460 nm. The sample measurements are then compared to the standards to determine DNA concentration. 1）As Hoechst 33258 preferentially binds AT-rich DNA, use standards with a similar base composition to the sample DNA. |
4樓2012-03-19 17:29:28
gaoyang636
木蟲 (著名寫手)
- BioEPI: 17
- 應(yīng)助: 202 (大學(xué)生)
- 金幣: 4111.4
- 散金: 7
- 紅花: 14
- 帖子: 1108
- 在線: 159.8小時
- 蟲號: 384065
- 注冊: 2007-05-27
- 專業(yè): 基因組學(xué)
5樓2012-03-20 09:01:30
| 最具人氣熱帖推薦 [查看全部] | 作者 | 回/看 | 最后發(fā)表 | |
|---|---|---|---|---|
|
[考研] 材料科學(xué)與工程339求調(diào)劑 +3 | hyz0119 2026-03-31 | 3/150 |
|
|---|---|---|---|---|
|
[考研] 286分調(diào)劑 +11 | Faune 2026-03-30 | 13/650 |
|
|
|
[考研] 本科211生物醫(yī)學(xué)工程085409求調(diào)劑339分 +7 | 里子木yy 2026-03-29 | 7/350 |
|
|
|
[考研] 土木304求調(diào)劑 +3 | 頂級擦擦 2026-03-31 | 3/150 |
|
|
|
[考研] 266求調(diào)劑 +3 | 哇呼哼呼哼 2026-03-29 | 3/150 |
|
|
|
[考研] 085600材料與化工調(diào)劑 +16 | kikiki7 2026-03-30 | 16/800 |
|
|
|
[考研] 282求調(diào)劑 +3 | 呼吸都是減肥 2026-03-31 | 3/150 |
|
|
|
[考研] 一志愿 南京航空航天大學(xué) ，080500材料科學(xué)與工程學(xué)碩 +5 | @taotao 2026-03-30 | 5/250 |
|
|
|
[考研] 285求調(diào)劑 +6 | AZMK 2026-03-29 | 9/450 |
|
|
|
[考研] 生物學(xué)學(xué)碩，一志愿湖南大學(xué)，初試成績338 +7 | YYYYYNNNNN 2026-03-26 | 9/450 |
|
|
|
[考研] 材料化工340求調(diào)劑 +3 | jhx777 2026-03-30 | 3/150 |
|
|
|
[考研] 0703 化學(xué) 求調(diào)劑，一志愿山東大學(xué) 342 分 +7 | Shern—- 2026-03-28 | 7/350 |
|
|
|
[考研] 085600，材料與化工321分求調(diào)劑 +10 | 大饞小子 2026-03-28 | 10/500 |
|
|
|
[考研] 340求調(diào)劑 +6 | Amber00 2026-03-26 | 6/300 |
|
|
|
[考研] 298求調(diào)劑 +3 | 種圣賜 2026-03-29 | 3/150 |
|
|
|
[考研] 305求調(diào)劑 +8 | RuiFairyrui 2026-03-28 | 8/400 |
|
|
|
[考研] 071000生物學(xué)求調(diào)劑，初試成績343 +7 | 小小甜面團(tuán) 2026-03-25 | 7/350 |
|
|
|
[考研] 085701環(huán)境工程，267求調(diào)劑 +16 | minht 2026-03-26 | 16/800 |
|
|
|
[考研] 315調(diào)劑 +4 | 0860求調(diào)劑 2026-03-26 | 5/250 |
|
|
|
[考研] 347求調(diào)劑 +4 | L when 2026-03-25 | 4/200 |
|