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Questions tagged [molecular-biology]

The study of the molecular processes underlying life.

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What is the half-life of dNTPs at 95⁰C?

I'm looking for the half-life of dNTPs, either as a whole or broken into individual bases, at 95 degrees C (or similar). A titration would be great if that exists. I can provide more specifics if need ...
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85 views

Travelling with tissue samples in RNAlater

I've been in Brazil collecting some samples (ants) and need to travel back to to the UK with - I've got their brains stored in RNAlater, which have been in the freezer at -4C for a bit less than a ...
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126 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 ...
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0answers
2k views

How much salt [NaCl] is too much in DNA precipitation?

In DNA extractions, how much is too much salt in a CTAB extraction buffer? Protocols hover around 2.5 molar; if you go over this (e.g. 25 molar), will you saturate your solution, and precipitate the ...
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51 views

Is there recent info about the hypothetical ancient two-codon genetic code?

Here is the latest I have found. link This is the basic idea: Evolution does not look ahead and make plans. It would not create a system of mRNA with giant ribosomes to create proteins, until ...
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48 views

Antibody staining

I am staining tissue sections and I did a mistake, I was supposed to have mixed 3 primary antibodies but I stained only with one of them. After the 1h incubation I washed 10 min with PBS and then I ...
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67 views

Proteins folds: relation to splicing and post-translational modification?

Is the secondary structure pattern of protein folds related in any way to alternative splicing and post-translational modification?
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62 views

What's the ratio of saturated to unsaturated fatty acids in human cell membrane?

It's well established that the fluidity of a cell is largely dependent upon the ratio of saturated to unsaturated fatty acids that exist within the membrane, but, what exactly are the values for this ...
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50 views

Why do I see so many kinetochores?

I am analysing RPE-1 cells from humans and I do not understand why I see so many kinetochores by immunofluorescence (more than 100 in many cells). They are in prometaphase.
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67 views

Regulation of the concentration of precursors of DNA and RNA synthesis

What is the specific cellular process for regulating the amount of the four DNA bases (adenine, thymine, cytosine, and guanine) that are present in the cytoplasm of a cell? Basically, how do the cell'...
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25 views

Does Pre replication complex sit on both strands?

In case of prokaryotes, the ori site have a definite nucleotide sequence. Each ori site have 5 9base-pair consensus sequences and 4 non-consensus sequences. DNAa binds to both types of sequences with ...
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734 views

What is the structure of DNA polymerase III?

According to Snustard and Simmons the structure of DNA polymerase III is the following, where the clamp loader( γ -δ complex ) is present on one side: But according to Lehninger the clamp loader is ...
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128 views

Why does a broad-leaved evergreen (Mahonia aquifolium) has red leaves?

To my knowledge, oregon grape (Mahonia aquifolium) is purportedly an evergreen shrub? Deciduous broadleaf plants lose their leaves in autumn usually and before that as the leaves die they oxidize and ...
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432 views

L-tryptophan in mammalian cell culture

Why must the concentration of L-tryptophan be kept to a relatively low level when culturing mammalian cells? It's an essential amino acid, so I cannot fathom why low concentrations as opposed to ...
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73 views

What Chemical Trigger Causes Ectomycorrhiza To Change From Asexual To Sexual?

I want to know the trigger behind the change of asexual to sexual ectomycorrhiza when symbiosis with a tree root is formed. As ectomycorrhiza attaches itself to a root, it forms a relationship wherein ...
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725 views

Can I leave BL21(DE3) cells in room temperature?

I am preparing competent cells, and I finished inoculating a single colony in SOB. It has been incubating at 37 degrees Celsius for almost 16 hours since, and it's getting very late where I live. I ...
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47 views

Does blood typing still provide a use for ancient tissue analysis?

Modern techniques. In recent years, DNA sequencing has become extremely cheap. This, compounded by the ability to PCR miniscule samples to viable samples for analysis, means that aDNA can be ...
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246 views

How does estrogen influence collagen synthesis?

Through what mechanisms does estrogen interact with collagen synthesis? Especially in the context of elevated estrogen levels and genesis of purpura simplex .
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494 views

How to prevent e coli from clumping (for FACS)?

I'm performing FACS on e coli, but the cells are clumping together so each event is multiple cells. I ran a control where I had one flask of e coli expressing GFP, and one flask expressing RFP. Run ...
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253 views

Gibson assembly using NeBuilder

I am supposed to construct a plasmid that contains features from two other plasmids. My strategy is to generate three fragments form the two other plasmids. I was encouraged to try Gibson assembly, ...
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50 views

Adenosine metabolism

Are adenosine or its catabolites increased in inflamed airways? How can I assess this? I am trying to use inhibitors for adenosine deaminase, xanthine oxidase, and purine nucleoside phosphorylase, but ...
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Using expression vector to express arsenite oxidase genes in E. coli

So I am trying to express a gene cluster that can oxidize arsenite into arsenite autotrophically. The arsenite oxidase gene cluster sequence is linked here: https://www.ncbi.nlm.nih.gov/nuccore/...
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61 views

Why does M1 RNA together with C5 protein in 100mM Mg(II) fail to cleave tRNA?

Sidney Altman discovered that RNA moeity of RNAse P (M1 RNA) alone is able to perform enzymatic cleavage of ptRNA, which won him the Nobel Prize of Chemistry in 1989. However, when I read the Nobel ...
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57 views

How do molecular biologists determine biochemical pathways?

I'm new to this community, so hopefully this is the right place to ask this question. I know my question is really general, but in all of my biology courses we are merely taught the chemical pathways ...
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50 views

Molecular Docking Enzyme Inhibitor Biosensor?

I had some task to study Molecular Docking relations with Biosensor and I am really new with this discipline (beginner). I am docking C60 with Glucose Oxidase and my question is: what would happen if ...
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34 views

how can I get stronger staining for my lymph node sections

I am using the same protocol and same antibodies that the literature says but still I cannot get good staining for my lymph node sections, I tried to change the fixation method and I am using now ...
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46 views

Sucrose inhibit onion root mitosis? Why?

I am doing an experiment about onion root growing. I had put an onion in different solutions of $C_{11} H_{22} O_1$ in H2O —with the root touching the water—: 0,1M; 0,2M; 0,3M; 0,4M; 0,5M. The ...
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78 views

Would I expect salt precipitate on fibres of DNA in a NaCl water solution?

I just recently conducted an experiment in my biochemistry class where we had to add DNA to distilled water, isotonic saline and 2.5M NaCl. I noticed different physical aspects depending on the ...
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0answers
154 views

How is the effect of proof-reading on error frequency during DNA replication determined?

An article in Nature Scitable on DNA Replication and the causes of Mutation states that: When an incorrect nucleotide is added to the growing strand, replication is stalled by the fact that the ...
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99 views

Can a phosphodiester bond form between RNA and DNA?

In the initiation of DNA synthesis: the RNA segments are first synthesized by primase and then elongated by DNA polymerase (Wikipedia). What does 'elongated' mean in this context? Is it possible ...
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173 views

Why difference in degree of folding in a cell?

For a cell to maintain constant volume, input should be equal to output of substances. My question is, if the basolateral membrane, by less folding can attain the same rate of transport as of the ...
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0answers
36 views

What's the best source characterizing proteolysis cleavage sites in the phagolysosome?

I have found MEROPS and TopFIND via the survey paper Quantitative proteomics and terminomics to elucidate the role of ubiquitination and proteolysis in adaptive immunity. These look like a good start, ...
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35 views

Nucleic acid extractions

Is it fine to leave pulverized plant tissue in CTAB buffer at -80 degrees over night? will the buffer remain effective to generate good quality nucleic acids?
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63 views

Basic molecular biology of nucleic acids book for a mathematician studying DNA and RNA formally?

I am a mathematician studying DNA and RNA language from the perspective of Formal Language Theory. Note that I am aware of these posts: best book for a comprehensive introduction to biology for a ...
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37 views

non-coding RNA modelling in silico

I've been trying to model a non-coding RNA molecule which binds to a RNA binding protein. I found the DNA sequence for ncRNA from NCBI. I did not find the RNA seq of the same. Hence my doubt is, ...
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63 views

Generating all possible conformations of an Intrinsically disordered protein

I want to simulate interaction between the bHLH-LZ domain of c-Myc encoded protein and a test ligand. Since the domain is intrinsically disordered, I want to generate all possible conformations of the ...
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0answers
60 views

Where am I going wrong in a Reactive Oxygen Species Assay done in N9 cells?

I have followed the modified protocol that was given to me by my senior (who was using for his RAW 264.7 cells - Reference article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3308605/ ) for ...
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767 views

What´s the role or function of the homologous arms in a donor template in a knockout/knock edition via Crispr-cas9?

I have to make an exposition in my university about Crispr-cas9 edition and I have some questions about the method. In the knock out/knock in technique is used a plasmid containing the DNA that ...
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0answers
73 views

Can telomere length maintenance be an answer to increased life span of human beings?

Telomere shortening may prevent the development of cancer in human aged cells by limiting the number of cell divisions. However, shortening of telomeres impairs immune function and thus might also ...
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71 views

Do users of CRISPR/Cas iterate or parallelize to try multiple guide sequences?

I've read about on-target efficiency and off-target effects in use of CRISPR/Cas9, and about tools that suggest good guide sequences. I am wondering: how many guide sequences do typical CRISPR users ...
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How do the chemical components of these spices prevent fungal growth?

I am doing an EE on how spices affect fungal growth for the following spices - oregano, garlic, cinnamon, cumin and turmeric. Its been hard to find any sites that say why or how they affect fungal ...
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0answers
63 views

Has a restriction enzyme ever been tagged?

As part of an experiment that I am preparing, it would seem necessary for me to tag a restriction enzyme (HaeIII to be exact) with GFP. I began researching its domains to determine whether to tag the ...
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49 views

Lifeforms concentrations of the categories of macromolecules, and Lipids

Lifeforms are formed of large, modular, organic molecules called macromolecules, large organic molecules called Lipids, and simpler molecules such as H2O. Macromolecules are commonly grouped into the ...
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838 views

Which DNA fragments do not have expected sizes on this gel electrophoresis?

The problem is such: After performing a PCR, the vector carrying the PCR fragment with two restriction enzymes (Nhe1 and Asc1). The DNA samples were then separated using agrose gel electrophoresis ...
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271 views

How does lactic acidosis lead to pain?

I come from Physics, not biology. My understanding is that without sufficient oxygen present, the Krebs cycle terminates in lactic acid formation for the body to later continue the reaction when ...
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0answers
265 views

PCR that worked previously is now only showing primer dimers and a smear on gel

PCR amplification of a promoter sequence for gel extraction worked beautifully using Phusion HF enzyme with GC (higher error but less picky) buffer. However, DNA concentration from the gel extraction ...
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64 views

Gel Electrophoresis

we add Etbr within the agarose gel but we do not add Etbr directly in native PAGE ?when we make agarose gel, we add Etbr before its solidification but we do not add Etbr when the native PAGE gel is in ...
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62 views

What is the difference between cell, membrane and animal based assay?

I am reading a review about MRP1, discussing it's ability to extrude different compounds from cell interior. When describing the different experiments conducted to observe the MRP1's reaction to ...
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0answers
268 views

Why is there a size limit on inserts that a plasmid can accept?

Throughout my undergraduate education I have been taught that plasmids can't carry very large inserts, but I have never been told why. Any insight would be greatly appreciated.
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47 views

Is there a good easy protocol for extracting proteins (enzymes) from fungal mycelium?

I quantify the enzyme (polygalacturanase) activity by DNSA method. To determine endo-polygalacturonase activity I'm searching for a good easy enzyme extracting method. Any suggestions for a suitable ...