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- Видео 107
- Просмотров 371 117
Professor Drew Collop
Канада
Добавлен 25 май 2020
Science & Math Education
Видео
Euglena Wet Mount
Просмотров 3187 месяцев назад
Euglena wet mount on an Nikon E200 compound microscope.
Paramecium Wet Mount
Просмотров 2197 месяцев назад
Paramecium hanging out at the edge of a cover slip under a Nikon E200 compound microscope.
Milk Product Analysis - Benedict's Test for Carbohydrates
Просмотров 8 тыс.2 года назад
Benedict's Test is used to identify a reducing Carbohydrate. 1 mL of Benedict's Reagent [Sodium citrate, Sodium carbonate & Copper (II) sulfate] was added to 0.5 mL of each sample. Samples were then heated for 2 min in boiling water, followed by cooling in an ice water bath. Monosaccharides will be oxidized in the reaction, while the Copper (II) sulfate will be reduced to copper (I) oxide, prod...
Milk Product Analysis - Barfoed's Test for Monosaccharides
Просмотров 1,5 тыс.2 года назад
Barfoed's Test is used to identify a Monosaccharide. 1 mL of Barfoed's Reagent, copper (II) acetate in acetic acid, was added to 0.5 mL of each sample. Samples were then heated for 2 min in boiling water, followed by cooling in an ice water bath. Monosaccharides will be oxidized in the reaction, while the copper (II) acetate will be reduced to copper (I) oxide, producing a red precipitate that ...
Milk Product Analysis - Iodine Test for Polysaccharides
Просмотров 2,7 тыс.2 года назад
The Iodine Test is used to identify a Polysaccharides. 2 drop of Iodine was added to 0.5 mL of each sample. The Iodine interacts with the different structures of the Polysaccharide to create a colour change. Starch Iodine = Blue-Black colour Glycogen Iodine = Brown-Red colour Negative Control = Distilled Water Positive Control = 1 % (w/v) Starch Positive Control = 1 % (w/v) Glycogen Unknowns Te...
Milk Product Analysis - Biruet Test for Proteins
Просмотров 2,7 тыс.2 года назад
Biuret Test is used to identify Proteins. 50 uL of each sample was added to a multi-welled ceramic plate. 250 uL of Biuret Reagent was added to each well. More Purple = More Protein Negative Control = Distilled Water Positive Control = 10 mg/mL BSA (Bovine Serum Albumin) Unknowns Tested = 12 Alphabetical list of Samples: 0% Skim Milk, 2% Milk, 2% Lactose-free Milk, 2% Milk ( Protein), 5% Light ...
Milk Product Analysis - Sudan Red Test for Lipids
Просмотров 4,2 тыс.2 года назад
Sudan Red Test is used to identify Lipids 1 drop of each sample was added to Whatmen filter paper and allowed to dry. The filter paper was then submerged in a 0.1% Sudan Red IV solution dissolved in 95% ethanol, for a 5 min duration. The filter paper was removed from the Sudan Red solution and washed in a solution of 95% ethanol. Once washed the filter paper was left a air dry. Take note that S...
Milk Product Analysis - Visual Assessment
Просмотров 1,8 тыс.2 года назад
Various milks and milk products were purchased from the local grocery store for the purpose of laboratory analysis. The levels of proteins, carbohydrates and lipids will be assessed using a variety of tests. Sudan Red Test = Lipids Biuret Test = Proteins Iodine Test = Polysaccharides Barfoed's Test = Monosaccharides Benedict's Test = Carbohydrates Alphabetical list of Samples: 0% Skim Milk, 2% ...
Sudan Red Test for Lipids
Просмотров 2,5 тыс.2 года назад
The Sudan Test is used to identify a Lipids. 1 drop of each sample was applied to filter paper and dried. The filter paper was incubated for 5 min in 0.5% Sudan Red IV solutions dissolved in 95% ethanol. After incubation, the filter was washed with 95% ethanol and air dried. The Sudan Red IV is hydrophobic, so it will bind to any lipids in the sample, staining them red. Negative Control = Disti...
Seliwanoff's Test for Ketoses 2.0
Просмотров 4,1 тыс.2 года назад
Seliwanoff's Test is used to identify a Ketose. 5 mL of Seliwanoff's Reagent (Resorcinol & Hydrochloric acid) was added to 0.2 mL of each sample. Samples were then heated for 5 min in boiling water, followed by cooling in an ice water bath. Ketoses dehydrate more rapidly then Aldoses. The Ketose biproduct will react with the Resorcinol to produce a cherry-red colour change. The Aldose biproduct...
Bial's Test for Pentoses 2.0
Просмотров 8 тыс.2 года назад
Bial's Test is used to identify a Pentose. 2 mL of Bial's Reagent (Orcinol, Hydrochloric acid & Ferric chloride) was added to 0.5 mL of each sample. Samples were then heated for 3 min in boiling water, followed by cooling in an ice water bath. Pentoses will be dehydrated furfural in the reaction, which will react with the Orcinol to produce a blue-green colour change. Hexoses will be dehyrdated...
Barfoed's Test for Monosaccharides 2.0
Просмотров 6 тыс.2 года назад
Barfoed's Test is used to identify a Monosaccharide. 1 mL of Barfoed's Reagent, copper (II) acetate in acetic acid, was added to 1 mL of each sample. Samples were then heated for 2 min in boiling water, followed by cooling in an ice water bath. Monosaccharides will be oxidized in the reaction, while the copper (II) acetate will be reduced to copper (I) oxide, producing a red precipitate that wi...
Iodine Test for Polysaccharides 2.0
Просмотров 5 тыс.2 года назад
The Iodine Test is used to identify a Polysaccharides. 2 drop of Iodine was added to 0.5 mL of each sample. The Iodine interacts with the different structures of the Polysaccharide to create a colour change. Starch Iodine = Blue-Black colour Glycogen Iodine = Brown-Red colour Negative Control = Distilled Water Positive Control = 1 % (w/v) Glycogen Positive Control = 1 % (w/v) Starch Unknowns Te...
Molisch's Test for Carbohydrates 2.0
Просмотров 13 тыс.2 года назад
Molisch's Test is used to identify a Carbohydrate. 5 drop of Molisch Reagent (alpha-naphthol) was added to 2 mL of each sample. 2 mL of Sulfuric Acid was gently added to each test tube to layer the 2 solutions. It is important not to mix the 2 solutions as the chemical reaction will occur at the interface. The Sulfuric Acid converted the Carbohydrate into an aldehyde, which will then react with...
Primary Culture of Chicken Embryos - Step 4: Tissue Disaggregation
Просмотров 6 тыс.2 года назад
Primary Culture of Chicken Embryos - Step 4: Tissue Disaggregation
Primary Culture of Chicken Embryos - Step 3: Dissection
Просмотров 4,5 тыс.2 года назад
Primary Culture of Chicken Embryos - Step 3: Dissection
Primary Culture of Chicken Embryos - Step 2: Embryo Extraction
Просмотров 27 тыс.2 года назад
Primary Culture of Chicken Embryos - Step 2: Embryo Extraction
Primary Culture of Chicken Embryos - Step 1: Preparation
Просмотров 7 тыс.2 года назад
Primary Culture of Chicken Embryos - Step 1: Preparation
Tissue Culture Virtual Lab Introduction - Twitch Live Recording - January 18, 2022 - PM Session
Просмотров 1,6 тыс.2 года назад
Tissue Culture Virtual Lab Introduction - Twitch Live Recording - January 18, 2022 - PM Session
BSA Protein Standard Curve - Bradford Assay
Просмотров 13 тыс.3 года назад
BSA Protein Standard Curve - Bradford Assay
Counting BHK Cells using a Hemocytometer
Просмотров 2,4 тыс.3 года назад
Counting BHK Cells using a Hemocytometer
Counting BHK Cells using a Countess II FL Automated Cell Counter
Просмотров 9 тыс.3 года назад
Counting BHK Cells using a Countess II FL Automated Cell Counter
Counting BHK Cells using a Coulter Counter
Просмотров 6 тыс.3 года назад
Counting BHK Cells using a Coulter Counter
Preparing Typsin - EDTA in PBS with Filter Sterilization for Tissue Culture
Просмотров 3,5 тыс.3 года назад
Preparing Typsin - EDTA in PBS with Filter Sterilization for Tissue Culture
Setting up the Biosafety Cabinet for Tissue Culture
Просмотров 1,7 тыс.3 года назад
Setting up the Biosafety Cabinet for Tissue Culture
Thanks for excellent video, what the code or brand of trypan blue that fit the machine, please?. Or not especific trypan blue?
There is no specific brand we use. We have use commercial products and made it up from powder. With either version, watch out for particles in the trypan blue. I find they will always appear given enough time. These particles can through off the reading from the Countess.
Thanks a lot for replying
Hi, just a question. Can this process be applied to any bacteria?
I am not a microbiologist, so I cannot definitely say it will work on any bacteria. There are alternative protocols that do exist. The purpose of going through each of the steps was to explain the reason we use each of these techniques. The great thing about science, is that it is always evolving. Once I discover a better technique, I switch to it after I have tested it myself. As a result, the way I run protocols in the lab is completely different today than it was years ago. One caveat is if you are working in industry. If you have a protocol approved for production, it cannot be changed with out going through the approval process again. So it is very important to have the best protocol before submission.
How much is it?
How much is what? The Coulter Counter?
Can you do a video of growing normal edible egg from scratch in the lab. Like ivf you take the egg from the hen, but you growing the egg in the lab without fertilizing it.
If the egg is not fertilized there will be nothing to grow. That is what an edible egg is, an unfertilized one.
@@ProfessorDrewCollop yes that's what I want. Edible eggs. Can you teach one how to grow it. 😇😇😇
This would be a question to ask an egg farmer.
@@ProfessorDrewCollop I know, but I thought scientist now have a way to grow edible eggs that is not fertilized. Guess it's my imagination, I was just so interested in most of your videos. That's why asked if it's possible to have a edible egg in a lab without a hen. But since it's not possible, it's fine. Thank for responding back, I really appreciate.
There is a process to grow edible meat in the lab now, without killing animals. Search for "Clean Meat" or "Cultured Meat" to get more inform. A process to replace the creation of an edible egg is not cost effective. Hens are cheap and not worth the effort.
What if the counter shows cell number or concentration per mL but total volume of cells in the tube is 0.5 mL ? Your cell count won’t be per 0.5mL ?
Concentration is irrelevant to the volume of your solution. The volume is only important if you are trying to determine the amount of the solute in your solution. As an example, you could have 0.5 mL of a 1000 cell/mL sample. It does not matter that it is only 0.5 mL, the concentration will still be 1000 cells/mL. As the concentration is a fraction, it can be used as a conversion factor to determine how many cells are in your 0.5 mL sample. Mathematically, it would be 0.5 mL X 1000 cells/mL. The mL units cancel leaving you with 0.5 x 1000 cells = 500 cells. Therefore you have a 0.5 mL sample, with 500 cells in it, with a concentration of 1000 cells/mL. Hope this helps.
Thank you for the clarification. Indeed was helpful
i have got to drink that
I would not advise you drink it after the Biuret solution has been added. It is highly basic and contains copper sulfate and potassium sodium tartrate.
How does this method compare to miniprep, eg alkaline lysis? Thank you!
The alkaline lysis technique is optimized for purification of plasmid DNA from bacteria. The alkaline environment keeps the DNA denatured. Bacterial DNA is supercoiled, so even when it is denature, the strands remain in close proximity to each other. The genomic DNA is bound to other macromolecules (proteins & lipids) and will precipitate out of solution during neutralization of the alkaline environment. Many of the kits you buy come with a filtration tube. This will filter out precipitated DNA and allow the plasmid DNA to run through the filter and into the lower collection tube after centrifugation.
thanks for your informative video! is it ok if I did not use a bunsen burner since I did not have access to one?
The Bunsen burner is there to heat the air in the neck of the flask. Hot air rises, so the air in the flask will flow up and out, helping to prevent contaminates from floating down in to your flask. If you don't have one, you might just have some contamination issues, but hopefully you will get many sterile plates.
there is no voice over the video, hard to understand what's being done. It is like kids playing with a toy. No use.
You might want to check your audio, as there is voice over for 50% of the video. At the half way mark I state that I am just going to be running the samples for larger number of wavelengths and I stop the voice over at that point, as it would be superfluous to continue speaking.
@@ProfessorDrewCollop Yes; indeed. Could you please share the plots of the final output, on x-y axis? Also, in practical terms, what characteristics can it measure in wastewater?
Sorry, I cannot add the final graph to this video, as this is an activity I get my students to perform after watching the video. If you really wanted it, you could graph it yourself. Plot wavelength (nm) as your independent variable (horizonal axis) and Absorbance (no units) as your dependent variable (vertical axis). The Spectrophotometer measures absorbance of different wavelengths of light by a sample. As a Biologist, I do not work with waste water. I suppose you could analyze the turbidity of the water as a function of how many particles are in it. We have some Chemists and Chemical Engineers, within our department, that work with waste water. If you are really interested, I could put you in touch with them. The Spectrophotometer works best for a single known chemical, with a known wavelength of maximum absorbance.
Thank you so much for your video!
Thanks for the video. Its very informative
Is there any simple method to test beta glucan
Sorry, but I do not know of one off the top of my head.
idk why i love watching this lol, it’s fascinating!!
That was helpful
I am currently doing a master's degree in the animal breeding department and I am also an agricultural engineer/zootechnician. And I am about to complete my master's degree by receiving a significant project scholarship in my country, which aims to manipulate the gender of chicks by injecting herbal and artificial materials with the in ovo injection method. I have provided long-term support to many projects using feed and animal materials on poultry. I am the first generation in my family to pursue higher education and I am looking for a PhD education with a scholarship. Due to my increasing interest in laboratory studies, I have also completed the laboratory veterinary health department and am in the internship phase. I am looking for an internship in a laboratory in the field of poultry nutrition or breeding for the summer term. I have a laboratory animals certificate and a B1 level English certificate. I followed some of your works on RUclips with interest and reached you. I live in Turkey and I do not want to leave the field in which I work with interest due to financial difficulties. I would be grateful if you could guide me. Best regards
Sounds like you are passionate with what you do. That is so very important. Are you referring to the manipulation of the sex of the chicks? Gender is a social construct. Sounds like a very interesting project. What type of chemicals modify the sex of the chicks. They only gestate for 3 weeks. You must need to inject the eggs very early. How to you ensure sterility. I am unsure as to what kind of guidance you are looking for. I do not take PhD students, if that is what you are looking for. Happy to answer any more questions you might have.
good day professor, why is the boiling necessary for the reduction of sugars to take place, what causes the color change in the tubes, and what are the reactions called in this test? i am currently researching for our chem project and there are some things we havent understood properly due to our own professor's poor teaching so i apologise for the lack of knowledge
I am sure there must be ample resources to explain the reaction if you were to Google it. In short, the heat usually needed to open up the carbon ring in the sugars. In Bial's test, the sugar is first dehydrated (loses water molecules) to create a new compound. Pentoses create furfural, while hexoses create hydroxyfurfural. These products will react with Bial's reagent, turns it from a yellow solution to a coloured solution. Furfural will turn blue-green. Hydroxyfurfural will turn brown. The chemicals in Bial's reagent include orcinol, ferric chloride and hydrochloric acid.
Hi Sir, I would like to ask this will contaminate with RNA?
If you are concerned about RNA contamination, you can treat the sample with RNase.
It hurts to see that you lost 1 drop of precious DNA at 10:06.
Astute observation.
Sir i want to perform some experiments on a muscle .... So i took out muscle from a chicken (not from embroy like after killing it) and i kept it in normal saline as a physiological solution and after adding a pinch of glucose ...will this setup of my will work and if it does how can i make muscles contract in vitro
This experiment is performed to make cell lines. You need fresh tissue that is not contaminated. Adult tissue does not work great, as the cells are bound tightly together and the cells are not in a state of constant cell division, like in the developing embryo. You will then need to disaggregate the tissue into individual cells, if you want to make a cell line. Without a circulatory system, the solid tissue will die as a result of a lack of oxygen and other nutrients. If you want to stimulate the muscle to contract, that is a completely different experiment. You need to harvest the muscle and find the nerve that stimulates it. Then you can apply an electrical current to activate the muscle fibers. I believe I performed an experiment like this on frogs back in third year Physiology. That was a course that changed my life.
Thank you
What method would you use for bone marrow isolation from the femur of that small chicken embrio ? The femur is too small to use a needle to extract the bone marrow. What method are used ? Thanks
I have no experience attempting to extract bone marrow from a chicken embryo. Sorry, I cannot help you on this one.
how many days has the embryo ??
I assume you are asking about the age of the embryo. Once a chicken egg is fertilized the embryo will hatch about 3 weeks later. The embryos we used for primary culture in the lab are 2-weeks past fertilization. The embryo in the videos is slightly more than 2-weeks old by a day or two.
Thank you
Would there be a difference in results if yogurt and milk were to be used?
You could used different types of yogurt to in an attempt to see the relative levels of protein in them.
Hi Professor! I have a question. How did you dispose the egg contents after culturing? Do you have any references for that? Thank you.
I believe you emailed me this question already. If not, everything is autoclaved when we are done with it. In terms of references, I don't really have one. The protocols tend to evolve semester to semester as I learn new things or experiments don't work.
Hi there, thank you so much for your informative video. Would you mind sharing your protocol for BHK cells on the Countess please? Many thanks.
Are you looking for the protocol on how I load the hemocytometer, or are you interesting in my gating protocol for BHK cells?
Your gating protocol please. I have started setting my own gating protocol and have been comparing results to our manual counting method. I have no other means for comparison, and I contacted ThermoFisher but they didn't provide much support. Thank you. @@ProfessorDrewCollop
I had the same issue with ThermoFisher. I contacted them to get their gating protocol, but they offered no support. I really don't understand why they could not hired someone to go through the most popular cell lines and create protocols. Here is the protocol I am using for BHK. Not sure if it is perfect, but it works for my needs. I optimized it using a Coulter Counter and a manual hemocytometer to compare. Within the Countess appropriate range, it seems give approximately the same count numbers.
Sorry, the image would not add so here it is typed out. Count setting both checked for Auto FL Threshold and Auto Lighting Size Gating = 12 - 28 Contrast Gating = 0 - 255 Roundness Gating = 0 - 75 Let me know how it works for you. Good luck.
Thank you very much @@ProfessorDrewCollop I'll try it out asap. Many thanks!
Thanks that was very helpful
2024 here doing my assignment for microbiology on chick embryo
Thank you so much sir for making such efforts. All of your 4 videos were really helpful and of incredible knowledge. With love from India.
Happy to hear you found them useful.
@@ProfessorDrewCollop how many days it has the embryo ?
We used Fehling's reagent in class, would this be the same as Barfoed's?
I was not familiar with Fehling's reagent. I looked it up and do appear to be similar. Fehling's reagent contains a strong base; whereas, Barfoed's contains acetic acid. From what I read, with Barfoed's test, different carbohydrates react at different rates. As an example monosaccharides react quickly but disaccharides react more slowly. As a result you can more easily distinguish mono- vs di- saccharides. What has been your experience with Fehling's reagent?
Why you do that
The majority of preclinical testing is performed on cell lines. To create a cell line students learn to extract tissue and disaggregate (break it down into individual cells). In addition, if you have a cancer diagnosis, you might have a biopsy taken to analysis the disease. Cell lines can be made from your cancer tissue and oncologists can test out different chemotherapeutic drugs on the cells in the lab. This way they can eliminate the drugs that will not work on your cells and they can focus on the best treatment for you before the cancer has a chance to spread. I hope this helps explain the importance of learning this technique.
Really good video and you covered all types of disaggregations in it. One this is , try to show the complete result Thank you.❤
Are you asking me to show you an image of a successful cell line?
I appreciate your wonderful work done in best explanation. Well, what temperature should I keep for the hot pan for all such practicals?
I did not record the temperature I set the hot plate to. I probably turned it up to max temp to heat it as fast as possible.
@@ProfessorDrewCollop Alright Professor, Thank you
Thanks Prof! I know how black holes work and exothermic combustion, but I have to skip the math of it all, and I come away feeling like I never really learn the intuition sometimes, or without months or years of repeated study instead of taking no time. A review was just what I needed and I'll continue through your courses and make notes so that I can come out on top 😊
That was helpful, thanks :*
You would have first of all egg punching with the help of egg punching machine then with the help of forcep first remove the punched egg shell,then remove the membrane and then with the help of thin pointed forcep remove the embryo it will be easily removed. Then put it in the petridish its head will be separated.
I have never heard of an Egg Punching Machine. How do you maintain sterility with this device? Removing the embryo directly with forceps can be a challenge, as the chorionic membrane and the yolk sac impede this. Finally, you state that the head will already be separated. What do you mean by this? I do not believe that any device can do this for you, as the embryo is floating inside the egg and be positioned in any orientation. What is your past experience with Primary Culture?
Biurette may be good for larger concentrations, bradford is much more sensitive
You are correct. That is why I have another video featuring the Bradford assay. ruclips.net/video/Ool9Vair-O0/видео.html We usually start of with first semester students using the Biuret assay, then switch to the Bradford when they gain more experience in second semester.
Very interesting.
THANK YOU SO MUCH SIR
Hello! I have two questions Can I omit trypan blue when using a cell counter? And is the dilution factor of trypan blue automatically multiplied by the cell counter? Thank you so much
I suppose you count not add trypan blue. In this case you would only get the total number of cells and would not know the division better live an dead. The Countess does all the calculations for you, including multiplying by 2 to account for the 1/2 dilution. I think there is a feature to disable the x2 function. The screen will read "Trypan Blue Corrected" if it has x2. Alternatively, you can just divide by 2 to get the cell concentration without trypan blue. Hope this helps.
Thanks for sharing! I have another question though. Could you tell me how the hypothalamus is separated from the chicken embryo?
Unfortunately, I do no have this knowledge or skill. The brain from the chicken embryo is very small and jelly like. I am not sure if isolating the hypothalamus would even be possible at this stage of development.
thanks for the information professor
You are welcome
Thank for helping me I study pharmacy technician institute
All the best
what if I'm trying to measure the efficacy of a protease at varying pH levels. I'm conducting a biuret test for each condition, but what wavelength should I pick to measure the solution? Online many things indicate 540nm, why is this? Is it because it is most contrasting to purple ?
Hi Fabian. When using a Spectrophotometer you want to always set the wavelength to the one of maximal absorbance (Amax or λmax). This will provide you with the largest dynamic range between max and min absorbance. This will ensure the data you are collecting has the best resolution. To determine the Amax, create an Absorption Spectrum using a positive control. This value can usually be found online; however, I always determine it during an experiment to double check. The Genesys 30 Spectrophotometer can perform this automatically in just a few minutes. I hope this answers your question and sends you on the right path.
Nice explanation
Dear Professor. Have you a full protocol ( pdf file) about all these methods of cell primary culture? Please.
Hi Jose. There is a lab manual that contains these protocol; however, it is published by my College. I do not believe I can just send you a PDF version of it. I am very clear in the videos about the protocol and would be happy to answer any questions you might have, if you try to create your own protocol while watching the videos. Sorry I cannot be more help.
Thanks sir
Good afternoon professor, Thank you for the video. I just want to ask aren,t we suppose to Blank eachtime before we record %T for every standard and unknown using live display mode?
You only need to blank if you change the wavelength. If you are using the same wavelength, you just need to blank it the one time. Hope this helps.