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Wednesday, November 19, 2008

Khilaf Manusia

بسم الله الرحمن الرحيم

يُرِيدُ اللّهُ أَن يُخَفِّفَ عَنكُمْ وَخُلِقَ الإِنسَانُ ضَعِيفاً
Allah (sentiasa) hendak meringankan (beban hukumnya) daripada kamu, kerana manusia itu dijadikan berkeadaan lemah.
(An-Nisa': 28)

Baru sahaja selesai lunch, aku pulang ke bilik lalu terus membuka laptop dan melayari emel Imperialku. Terdapat beberapa emel baru. Salah satunya daripada Dr Ed Hendriks yg bagi emel berkenaan eksperimen Gel Electrophoresis kami minggu lepas. Rupe2nya, terdapat kesilapan oleh yang menyediakan solution tu. Ade tersilap masuk bakteria la dan sebagainya. Padanla macam pening je aku tgk result aku. Jadi, Dr Hendriks mengemelkan result baru untuk kami gunerkan. Yeayyy!!!

Students performing the Molecular Biology 1 practical – Isolation and Analysis of DNA, from GROUP A will have completed this on Friday 14th of November 2008. I checked each gel and although the isolation of DNA (plasmid and genomic) was performed extremely well by students and indeed the digests of the appropriate samples and the electrophoresis of these conducted well by about 30 of the 35 pairs of students, you will not be able to use your own gels for the writeup.

It became apparent that a sample was mixed up by the technical staff when the reagents were distributed on the Thursday, such that the Lambda DNA labelled tube actually contained the MW Marker (lambda DNA already digested with BstEII) and that the MW Marker labelled tube actually contained intact regular undigested Lambda DNA. Consequently, this means that you will end up with intact lambda DNA in the lane you thought you were loading with the MW marker and MW marker in the lane you thought you loaded as undigested lambda DNA. This unto itself does not present a problem as you can simply swap these lanes and get the right patterns for electrophoresis. The problem arises as the lane you think contains lambda DNA digested with HindIII – will actually be Lambda DNA digested with BstEII (the MW marker) and HindIII. This will not allow it to be used as an appropriate size standard in the practical. I noted that this problem occurred in about 90% of gels.

THUS, to save any confusion I have attached a model gel with the sample loading order listed below. Please use this gel and the loading information below for writing your reports.


This may seem very unsatisfying (it is for me), as the great majority of you performed each element of the practical very well. However, this is the only solution I have to this problem that will not disadvantage any pairs within group A or Group A with Group B in the assessment of the practical report.


The attached PDF should be printed at a reasonable size and stuck into your report or incorporated directly into your report electronically, again at an appropriate size. The wells are clearly visible on the left hand side and the loading order from bottom to top is:

1. MW marker DNA (Lambda cut with BstEII)
2. Undigested lambda
3. Undigested genomic Drosphila DNA
4. Undigested plasmid DNA strain 1 sample A

5. Undigested plasmid DNA strain 1 sample B

6. Undigested plasmid DNA strain 2 sample A

7. Undigested plasmid DNA strain 2 sample B
8. Lambda DNA digested with HindIII
9. Genomic Drosophila DNA digested with HindIII

10. Plasmid DNA Strain 1 sample A digested with HindIII

11. Plasmid DNA Strain 1 sample A digested with HindIII
12. Very top lane is blank.


Best Regards,

Dr Ed Hendriks


Gambar Gel Electrophoresis yg perlu kitorg guner dalam report:

Setelah aku fikir2kan, mmg terbukti yg manusia lemah dan sentiasa buat kesilapan. Walaupun di dalam makmal Imperial yg kononnya gah sgt tu, still, manusia melakukan kesilapan. Terasa kerdil diri ini di hadapanMu Ya Allah.

OK, da kurang kekeliruan tentang resultku. Moga aku dapat menyiapkan report dgn cemerlang.

Photobucket

1 comment:

Anonymous said...

titis la imperial.....