The study of the molecular processes of the nucleus and cell function.

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2answers
100 views

Is it possible to create a restriction map using python? [closed]

I have some fragments of DNA from single and double digests using three different restriction enzymes. I'm trying to construct a restriction map of a linear fragment of DNA. The map needs indicate the ...
4
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1answer
58 views

Negative feedback loop and oscillations

According to the textbook Alberts Molecular Biology of the Cell (5th ed., p. 902), negative feedback loops cause oscillations when they are long delayed. I just can't figure out why. Except for ...
4
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1answer
146 views

How does NHEJ cause indels?

I was reading up on CRISPR-cas9 and how it works and I am having trouble wrapping my head around how NHEJ to repair the DSB can cause indels to occur. Shouldn't the NHEJ just stick the two strands of ...
4
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1answer
180 views

Why do some protocols require prewarming a liquid medium before inoculating?

For example, in this protocol for E. coli competent cell preparation, it says: Plate 10 uL E. coli BL21(DE3) cells on a LB-agar plate; incubate overnight (12 hours). Prepare 500 mL SOB medium ...
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43 views

Transformation efficiency

I accidentally spun down the cells after heat shock treatment before adding the media into the tubes while doing transformation? will the transformation work?
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1answer
90 views

Influence of temperature on transcription, protein binding and decay rates

I am the kind of biologist who doesn't know much about molecular genetics and about the dynamic of biochemical reactions. Question My question concerns the influence of temperature on the dynamic of ...
4
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1answer
127 views

Topology of closed circular DNA

Why are covalently closed circular plasmid DNAs naturally found in an underwound state ? Is it because this makes it easier for the DNA replication machinery to access and unwind DNA ? Or is it ...
4
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1answer
46 views

A good software for agent based modelling?

Hello i'm gonna start my master degree in systems biology and i'm thinking of working with agent based modelling, but i really don´t know which platform can be the best to simulate interactions ...
4
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1answer
50 views

Is HSV-vector-mediated miRNA expression in dorsal root ganglia stable?

My question is on the following article: "Reduction of voltage gated sodium channel protein in DRG by vector mediated miRNA reduces pain in rats with painful diabetic neuropathy" My question is, do ...
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2answers
1k views

Why is the DNA helix anti-parallel? [duplicate]

Why is it that DNA strands are running in anti-parallel fashion? Given the chemical base-pairing, they could have been parallel just as well.
4
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2answers
86 views

How can (or did) Deinococcus radiodurans continue to evolve after developing resistance to mutation?

Deinococcus radiodurans has a remarkable ability to resist damage to its DNA due to radiation, dehydration or (to my knowledge) any other source. It keeps multiple copies of its genome and has a ...
4
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1answer
97 views

How is the type of genetic manipulation determined in CRISPR-Cas9?

I've been reading up a bit on the CRISPR-Cas9 system for gene manipulation. From what I read, it introduces double-strand breaks at specific points determined by the choice of sgRNA. But how do you ...
4
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1answer
60 views

What's up with all the vague protocols? [closed]

I have lost count of how many protocols I've seen, including those supposed to be professionally written (such as manuals that come with kits from well known brands, or methods sections of papers in ...
4
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1answer
592 views

Are there any organisms that lack ATP synthase?

ATP synthase is used by cells to synthesise ATP from ADP using energy from a proton gradient. Depending on which sites I look at, this is either a universal feature of living cells, or it's "almost ...
4
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1answer
118 views

Ribosomal RNA amount in a Drosophila cell

I am isolation RNA from Drosophila larvae brain with TRIzol method. What percentage of extracted RNA will be ribosomal RNA? I am only interested in mRNA, so I am trying to figure out whether I need to ...
4
votes
1answer
665 views

DNA content in plant seeds vs. fruit flesh

Is there a publication comparing DNA yield and/or PCR-amplifiability after extraction from fruit flesh (like apples, oranges, cherries etc) in comparison to seeds of the same fruits? I would prefer a ...
4
votes
1answer
617 views

Effect of single nucleotide deletion or insertion on primer annealing

How is primer annealing, and, consequently, PCR amplification affected by single nucleotide deletion or insertion inside the primer ? Imagine a primer like this: GCGTCATAAAGGGGACGTG (primer) and ...
4
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2answers
289 views

Is AT or GC content important in electrophoresis?

Will it make a difference in running speed if we run samples of same no of bases but different AT - GC content ?
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2answers
211 views

Randomness in living systems

The point of my question is not to talk about events that are uncontrolled by living organisms. My question is about controlled randomness, or I'd like to say adaptive random process. Process that are ...
4
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2answers
758 views

Does bleach destroy RNAse activity, and if so, how does it do it?

I am working with RNA samples, and I'm trying to be very careful about RNAse contamination. I have some questions about bleach, though. Some people say that a solution of bleach is enough to destroy ...
4
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1answer
45 views

Directed evolution: Point mutation vs Insertion-Deletion vs Shuffling

When attempting enzyme function improvement via Directed Evolution I can see three different strategies to generating variation for the gene sequence: Point mutations Insertion / Deletions Shuffling ...
4
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2answers
143 views

Does suffocation pain involve nociceptors?

I never suffocated myself so not entirely sure, but when you suffocate, it's painful, right? But of course different kind of pain than being injured or sick. What I'm wondering is, if the "painful" ...
4
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1answer
43 views

Oligonucleotide purification with desalting

I have ordered 36bp oligonucleotides that anneal to each other and create sticky ends to be cloned in a vector afterwards. I have tried cloning many times with different methods and I failed. Now I ...
4
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1answer
130 views

Redundancy of the genetic code

One particular codon codes only for one amino acid, but an amino acid can be coded for by several different codons. Now according to the genetic code, the codon UUU ...
4
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1answer
82 views

protein-binding sRNAs

I am actually a computational biologist, pardon me if my question description is a bit off-note, my curiosity is driving me on A bit of background and context: In bacteria, a regulatory protein ...
4
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1answer
163 views

No digested product bands, but markers are visible. What could be the reasons?

I had to digest my insert containing plasmid and another vector into which my insert has to be ligated, each with BamHI and NotI. Upon digestion, I ran the gel to check for results. The digestion ...
4
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1answer
104 views

Do mitochondria use ATP in order make another ATP from glucose?

Do mitochondria use ATP in order make another ATP from glucose, or does it use another source of energy to convert glucose to ATP?
4
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1answer
574 views

RNA isolation from Drosophila head

I need to isolate RNA from Drosophila head. I basically chop the head off and first homogenize it with a homogenizer (similar to this: ...
4
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1answer
107 views

Large scale reverse transcription?

I need to make RNA:DNA duplexes. I can make 100 to 200 ug of mRNA through in vitro transcription, and I know how to use reverse transcription to make a cDNA library, but I have questions with this. ...
4
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1answer
1k views

How to secrete a recombinant protein from E. coli?

What are some secretory pathways that can be used to secrete a recombinant bacterial enzyme from E. coli? I have a recombinant protein (29kDa) that I will express in E. coli BL21 cells. For now I ...
4
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1answer
396 views

Can I heat Trizol?

I wonder if I can heat Trizol reagent for 30 min 65C. The goal is to disrupt protein-RNA complex while inhibiting nucleases. (I can't use RNasin cause it's inactivated in 65C, and can't use RVC cause ...
4
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1answer
39 views

Can you knockout specific receptors in an adult?

Sorry I don't have a good understanding of this topic, but I'm guessing that "receptor knockout" is related to/a part of "gene knockout"? And If I understand correctly, gene knockout is currently ...
4
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1answer
51 views

Function of NaCl in yeast shuttle prep of plasmids

What is the role of NaCl in plasmid isolation from yeast cells using plasmid rescue solution? If the basic theory behind the method is alkaline lysis, then we is NaCl used and not NaOH?
4
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1answer
53 views

What was Protein G named after?

Protein G (the bacterial antibody binding protein) is often used to pulldown antibodies, for example in chromatin immunoprecipitation (ChIP) experiments. However, I was unable to find a site ...
4
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1answer
80 views

Why is an A-U bond less stable than an A-T bond?

I have encountered the following fact many times, but have not yet encountered a possible explanation for it. Will you please help me understand the molecular mechanism by which the bond between ...
4
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2answers
253 views

How to Extract RNA and perform RT-qPCR from very few cells ( ~5,000)?

I am currently conducting an experiment which involves FACS-sorting a specific population of cells using an antibody of interest. In order to validate the type of cells I have collected using this ...
4
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1answer
210 views

blue/white screening - results are opposite as expected

We inserted GFP-gene into plasmid Bluescript SK+, transformed E. coli with this construct, and then plated on an agar plate with Ampicillin and X-gal to do a blue/white screening. We got blue colonies ...
4
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1answer
42 views

A few questions regarding immunology [closed]

I know that there is a variable region on antibodies which can recognize a wide variety of antigens, and that germinal centers create more "fit" antibodies to respond to an infection. So I was just ...
4
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1answer
503 views

How much does the Hayflick limit/telomere length vary across taxa and within humans?

Since they seem to be quite connected, I'm curious if anyone knows of research comparing the Hayflick limit (and presumably by extension telomere length) between different taxa. I've heard the ...
4
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1answer
257 views

Cloning two fluorescent proteins with different promoters in the same plasmid?

I want to clone two fluorescent proteins both driven by different promoters in a plasmid to be used to transform B. subtilis at the amyE locus. For this I want to use plasmid pSG1729 (Lewis and ...
4
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1answer
73 views

How can I save bacillus strains on filter paper without an -80 degree freezer?

I want to save my bacillus strains but I don't have access to a -80 degree freezer. What are possible alternatives?
4
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1answer
376 views

What is a simple protocol for staining cells in suspension?

I am an engineering student studying how electric fields affect cells, specifically the phenomena of electroporation in living cells. I know that electroporation is widely used for introducing genes ...
4
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1answer
507 views

Why am I getting low transformation efficiency with DB3.1 E.coli cells?

I am making competent cells using DB3.1 E. coli cells. Even after following the exact protocol (Inoue method for ultracompetent cells) given in 'Sambrook and Russel', I am not getting transformation ...
4
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1answer
54 views

How to find ion/water channel related genes

We now have a collection of transcripts at hand. We would like to investigate some particular ones, which are ion/water channel related. How to perform this? Could anybody point out how to find the ...
4
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0answers
27 views

Artificial reduction of NADP into NADPH by means of an electrical current

I've recently been attempting to artificially drive the formation of NADPH via the NADP reduction mechanism utilized by Ferredoxin-NADP Reductase in the Light-Dependent Reactions of Photosynthesis in ...
4
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2answers
752 views

What are the “minimum requirements” for a single cell?

I saw a description of the "minimum requirements" for a cell at http://creation.com/origin-of-life in the section called "What are the minimum requirements for a cell to live?" and I'm wondering if ...
4
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0answers
43k views

Does CPH4 exists? [closed]

What is the purpose of CPH-4? Is it well represented in the movie Lucy?
3
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2answers
399 views

How are DNA segments selected in PCR?

I understand that in PCR we're able to amplify only selected portions of the DNA... however despite reading it from multiple sources, I cannot figure out how this selection actually takes place. I ...
3
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4answers
187 views

Translation of mRNA?

We inserted an insulin gene from human into bacteria. Will translation of the gene (protein formation) occur in bacteria? If translation occurs then why does it occurs, give a reason for this?
3
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1answer
294 views

What happens to the precursor protein's signal sequence after it is cleaved?

Where does this signal sequence "go" after it has been cleaved by signal peptidase and what is its next function?