19

Antibiotics are used in very different ways in cell culture and in livestock farming. As you note, in farming, antibiotics are used to manage infection in unsanitary conditions and also to increase animal growth. Farming is essentially an inherently non-sterile environment and so there's not really any good way to keep microbes from spreading and ...


14

This question has been directly addressed by the paper The Mechanism of Proton Exclusion in the Aquaporin-1 Water Channel. I think it's a pretty good one too! I paste the abstract below: Aquaporins are efficient, yet strictly selective water channels. Remarkably, proton permeation is fully blocked, in contrast to most other water-filled pores which are ...


11

There are no formal definitions accepted in science for ambiguous phrases such “protein expression”. If you wish to know what a particular author who uses such a shorthand phrase means you need to examine the context. If you wish to write scientific reports that are comprehensible to others you must express yourself precisely, defining any shorthand phrases ...


11

tl;dr Cells are 3D and the cytoskeleton does not exist within the nucleus. There are several things you have to be aware of when looking at such pictures. Remember, you are looking at a 3D object which is not homogeneous and uniform in depth. Shape of a plated HeLa cells You are looking at HeLa cells. When plated like in your case, they adhere to the plate ...


10

There's Trichoplax adhaerens, a Placozoa, made of a few thousand cells. Then there is Dicyema japonicum, a simple mesozoan, made up of 9 to 41 cells. Arguably, the simplest multicellular organism is the algae Tetrabaena socialis, whose body consists of 4 cells. Then, there's the parasitic Myxozoa which have 7 cells.


9

A plasmid is a length of circular or linear double stranded DNA that exists independent of chromosomal DNA with a cell (i.e. extra-chromosomal DNA) and often confers a selective advantage to an organism such as antibiotic resistance. Plasmids have been identified in archaea, prokaryotes, and eukaryotes and allow horizontal gene transfer within a population, ...


8

I would strongly recommend looking in more detail into available resources for SD and Kozak sequences, wikipedia basically answers these questions and has plenty of further reading if you desire to explore these questions. At the same time, remember that these are statistical processes involving thousands of molecules, rather than deterministic processes ...


8

The Thermo Fisher definition is more explicitly accurate, although one could argue that the term "production" in the NCI definition implies regulation and post-translational modification (PTMs) as well. Either way, protein expression definitely includes regulation. Typically, when you measure protein expression, such as via Western blot, you are ...


7

This nematode always has either 959 or 1031 cells. https://en.wikipedia.org/wiki/Caenorhabditis_elegans


7

The skin is highly vascularized up to the epidermis, with dense vessels right at the top of the dermis (your picture omits these, but you will find them in better diagrams like this one). The epidermis itself gets substantial oxygenation from the outside air (see Stücker et al, for example), though the very outermost layers are not metabolically active (&...


7

It's also worth noting that the ~15-60 most superficial layers of keratinocytes (epidermal epithelial cells) are not metabolically active (i.e., "dead") and therefore do not need to receive nutrients/gasses or eliminate wastes. Therefore, exchange with blood is not needed beyond 10-15 layers of "living" epithelial cells in the deeper ...


7

The answer to Question 1 is: The ribonucleases responsible for digesting removed intron RNA do not recognize the miRNA as such. They are unable to digest it because (or to the extent that) it assumes a double-stranded structure, as they are specific for single-stranded RNA. The answer to Question 2 is briefly: By the same mechanism as the many microRNAs ...


7

The spike proteins expressed by cells that take up mRNA or ChAdOx vaccines are modified so they cannot induce membrane fusion. However, the research article you refer to indicates that circulating spike protein damages endothelial cells simply by binding ACE2, which suggests vaccine derived spike protein could still cause this kind of damage if it enters the ...


6

Quantitative in the context of biology is similar to chemistry, and means "how much of something there is" - for example, how much of a particular protein is produced under what conditions. Now, you might think this is a simple problem, just measure the protein/RNA/DNA and find out. However, it isn't quite as simple as that. Even if the best ...


5

There are proteins (in truth, small peptides) released by neurons, but these are not the most typical or canonical type so I don't know where you got that information. Wikipedia has a list. Most are amino acids or derived from amino acids. They are transported into vesicles and then released when these vesicles fuse with the plasma membrane. ...


5

The mitochondrial genome has a nonzero mutation rate, though estimates differ according to method. Estimates are approximately 10^-8 per bp per year on average, and the mt genome is ~20,000 bp. So we can do some math and expect that many (or most) people experience heteroplasmy, which is to say that they carry various different mitochondria (in the same ...


5

In earlier days, biological classification systems were often described as artifical or natural, with natural systems reflecting the 'real' relationships among living beings, and artificial ones allowing classification only for some limited purpose (Gilmour, 1937). Natural systems were supposed to be based on a large number of characters, with a focus on ...


5

Well, the nucleus does not divide per se. Remember, the nuclear membrane dissolves during mitosis. It starts reforming after metaphase. Here is a review detailing the process and the mechanisms which are known. By extension, the Endoplasmic reticulum gets portioned as it is derived from the nuclear membrane. Organelles also rely on the cytoskeleton and ...


5

I am asking this question to understand whether the cells which are used to create spike proteins are attacked by the immune system. Yes, that is the aim of RNA vaccinations! But don't worry, that's a good thing, as can be concluded from this review-paper, that emphasizes the advantage of RNA vaccinations to invoke cellular immune response: Although ...


5

Freeze-thaw cycles are often suspected of causing degradation in organic molecules 1,2. My first guess would be that your fluorophore is breaking down due to those repeated cycles. Alternatively, you might be getting precipitation of a calcium compound from the buffer you are freezing that your colleague is not. Standard laboratory practice is to make ...


5

Adding a third viewpoint, I'm primarily an electrophysiologist in neuroscience. In my corner of the world, I have to say we can be a bit sloppy about terminology from molecular biology. There might be more precise meanings intended in other areas, but when someone writes "protein expression" I typically translate this roughly to "we measured ...


5

I have read that the general definition for puncta is a small, distinct point. That's correct. From my understanding, puncta are dots. However, I was wondering whether puncta is a synonym for clusters of a protein In the context of fluorescence microscopy, a punctum (plural puncta) does not specifically refer to the aggregation of proteins. Any small, ...


5

The first amino acids For how life arose from no life, the Miller-Urey Experiment demonstrates how in primordial Earth conditions, a spark in the atmosphere (analogous to lightning) could have initiated synthesis of the many of the same amino acids (and amines) life uses today. My understanding was that the spark broke some bonds between the gases (and water ...


4

Even though the DNA sequence may be 90+% similar between two species, individual amino acids can make a huge difference in the interaction between two proteins. In this case, the most relevant proteins are the coronavirus spike protein and the ACE2 enzyme expressed on the surface of target cells. Even in the limited amount of time SARS-CoV-2 has existed and ...


4

The answer to the first part of your question is: diffusion. After transcription and some processing, the eukaryotic mRNA is exported to the cytoplasm. Here it floats around until it meets a ribosome. Binding of ribosome to mRNA is facilitated by proteins called initiation factors (IFs) and the 5' cap of mRNA$^1$. The second part of your question basically ...


4

The M.DNA mutates about 1% in a million years, and because our Mt-Eve is 150,000 years old, our mitochondria are 0.15% different, or 99.85% the same globally, and 99.95% the same in Eurasia. The variation of mitochondrial DNA between different people can be used to estimate the time back to a common ancestor, because mitochondrial DNA accumulates mutations ...


4

Species from Gonium genus are typically 4-16 celled. Gonium pectorale is 16 celled. Arakaki, Yoko et al. “The simplest integrated multicellular organism unveiled.”, vol. 8,12, e81641. 11 Dec. 2013, doi:10.1371/journal.pone.0081641 Also, there is four celled Basichlamys sacculifera. See this picture for reference


4

In order to assemble your TAG oligos by PCR you will need to redesign your primers so they are complementary to the TAG oligos as DNA polymerases work by adding nucleotides to the 3' end of a DNA strand. Your design would look like this : Now with this design you won't be able to assemble everything together as TAG-3 complementarity to primer 2 only ...


4

GSK3 is interesting because as a kinase, it is itself regulated by its phosphorylation status (particularly by Akt in neurons). Therefore, more protein does not necessarily mean more activity. For example from E13.5 to E15.5 GSK3 levels do not change but activity steadily increases. Hence if you increase GSK3 levels in neurons, it may not mean that ...


4

One of the advantages you already stated that depending on protein of interest if it's already expressed in CHO cell line, researchers use that. Apart from that, this question is more of a general type. I will try my best to logically put down the things. You are right, it's more appropriate to study proteins using cultured neurons. But, there are many ...


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