User:Z3331330: Difference between revisions

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Teeth are formed from cells that derived from the ectoderm of the first branchial arch and the ectomesenchyme of the neural crest and also mesoderm.It is organized into 3 parts, the enamel organ, the dental papilla and the dental follicle. The enamel organ give rise to ameloblasts which produce enamel and the reduced enamel epithelium and ultimately determines the root shape of the tooth.The dental papilla contains cells that develop into odontoblasts which determines the crown shape of a tooth. Mesenchymal cells in the dental papilla are for the formation of tooth pulp. The dental follicle contribute to cementoblasts which form the cementum of the tooth, osteoblasts which give rise to the alveolar bone and fibroblasts give rise to periodontal ligamtns.  
Teeth are formed from cells that derived from the ectoderm of the first branchial arch and the ectomesenchyme of the neural crest and also mesoderm.It is organized into 3 parts, the enamel organ, the dental papilla and the dental follicle. The enamel organ give rise to ameloblasts which produce enamel and the reduced enamel epithelium and ultimately determines the root shape of the tooth.The dental papilla contains cells that develop into odontoblasts which determines the crown shape of a tooth. Mesenchymal cells in the dental papilla are for the formation of tooth pulp. The dental follicle contribute to cementoblasts which form the cementum of the tooth, osteoblasts which give rise to the alveolar bone and fibroblasts give rise to periodontal ligamtns.  
==Lab 11 assessment==
(1)Identify a recent research article (using the pubmed tags to cite) on iPS cells and summarise in a few paragraphs the main findings of the paper.
'Two-step differentiation of mast cells from induced pluripotent stem cells.'
Mast cells are responsible for the pathogenesis of many allergic diseases in the human body. There are mainly two types of mast cells and they are connective tissue type mast cells (CTMCs) and mucosal-type mast cells. This study aim to report on the generation and characterisation of connective tissue type mast cells that are derived from induced pluripotent stem cells (iPS cells) that originated from mouse. Mast cells are generated from mouse iPS cells and are characterised from several aspects including morphology, function and gene expression.
The study generated mast cells and differentiated them from mouse iPS cells from two major methods. The first one is by co-culturing the mouse iPS cells with OP9 stromal cells and the second one is the embryoid body formation method. With these two methods, they were able to produce mast cells that have characteristics similiar to CTMCs. When mouse iPS cells were generated with the OP9 stromal cells and also co-cultured with Swiss 3T3 fibroblasts, the result of the generation was that the mast cells exhibit even more of a functional phenotype. Therefore, the study provided a protocol with two step differentiation which allows the transformation of mouse iPS cells to mast cells. The two differentiation method was co-culture with OP9 stromal cells and co-culture with Swiss 3T3 fibroblasts.
The protocol provided by this study consist of mesoderm induction, mast cell specification, differentiation and maturation of mast cells from mouse iPS cells. The study also suggested a few cytokines and feeder cells that were essential for the development of iPS cells to mast cells. Interleukin-3 has been recgonised and considered to play a very important role in the differentiation of mast cells. OP9 cells may not be necessary for the specification of mast cells but it promotes the maturation of them. Swiss 3T3 fibroblasts have been proved to be essential for the maturation of the mast cells from mouse iPS cells. The successful protocol generated from the study has provided a novel method for more efficient generation of mast cells from mouse iPS cells, with the production of more mature mast cells. <ref><pubmed>23045993</pubmed></ref>




===References===
===References===
<references/>
<references/>

Revision as of 17:35, 14 October 2012

Lab Attendance

Lab 1--Z3331330 11:49, 25 July 2012 (EST) Lab 2--Z3331330 10:41, 1 August 2012 (EST) Lab 3--Z3331330 13:00, 8 August 2012 (EST) Lab 4--Z3331330 10:07, 15 August 2012 (EST) Lab 5--Z3331330 10:08, 22 August 2012 (EST) Lab 6--Z3331330 10:10, 29 August 2012 (EST) Lab 7--Z3331330 10:05, 12 September 2012 (EST) Lab 8--Z3331330 10:03, 19 September 2012 (EST) Lab 9--Z3331330 10:08, 26 September 2012 (EST) Lab 10--Z3331330 10:10, 3 October 2012 (EST) Lab 11--Z3331330 10:07, 10 October 2012 (EST)

Lab 1 Assessment

(1)Identify the origin of In Vitro Fertilization and the 2010 nobel prize winner associated with this technique and add a correctly formatted link to the Nobel page.

Many studies and experiments were conducted and they all contributed to the development of In Vitro Fertilization as it is today. Some early studies have used hamster gametes to prove the possibility of mammalian gametes being fertilized in vitro, done by Yanagimachi and Chang in1963. Chang, in 1959 has also done a study that demonstrated the normal development of a rabbit egg that was fertilized in vitro. Numerous experiments were done using different animals and species which proved the success of in vitro fertilization. Capacitation of the sperm in the uterus of the mother was a significant discovery to in vitro fertilisation. On July 25, 1978, the first successful 'test-tube' baby was born. Dr. Patrick Steptoe, a gynecologist and Dr. Robert Edwards, a physiologist, the team who pioneered the IVF were accredited for their contribution to IVF.

In 2010, Robert Edwards was awarded the 'Nobel prize in physiology or medicine' for his contribution in the development of "In Vitro Fertilization", see [1]


(2)Identify and add a PubMed reference link to a recent paper on fertilisation and describe its key findings (1-2 paragraphs).

'Genes required for the common miracle of fertilization in Caenorhabditis Elegans' [1]

Fertilization is a result of various sperm-egg interactions and together these interactions lead to gamete fusions and egg activation.This paper describes the identity of genes that are responsible for the interactions between gametes during ferilization and the function of protein products that are produced by these specific genes. The paper focuses on the fertilization process in Caenorhabditis Elegans which is a type of worm. There are two main types of molecules that are essential in fertilization and they are sperm function molecules and egg function molecules. Spe-9 gene produces a single-pass transmembrane molecules with extracellular domain that contain 10 epidermal growth factor and it is responsible for adhesion or ligand receptor functions. Its critical presence on the surface of the sperm allow the sperm to bind to the oocytes during fertilization. Other genes such as Spe-38 is also identified with similar function.

Egg function genes such as egg-1 and egg-2 genes lead to the production of type II transmembrane molecules. Loss of these gene can lead to complete hermaphrodite fertility. Sperms will not be able to enter the oocytes.The main function of these genes is to act as oocyte surface receptor for sperms during fertilization. These discoveries and results in C.elegans provide a blueprint of the genetic control involved in the process of fertilization and encouraged discoveries of similar genes that are involved in fertilization in humans.

--Mark Hill 16:30, 11 September 2012 (EST) Question 1 is answered well and I like that you have discussed earlier research. Question 1 is also answered well, though a 2008 paper is not as recent as I was seeking as an answer. You will need to fix your referencing (ref 1 is blank because it is incorrectly formatted and should only contain the PMID (not PMC number) number without text)10/10

lab 2 assessment

Degradation of ooctyes by sperm proteasomes

--Mark Hill 16:49, 11 September 2012 (EST) This should be a sub-heading.

(1)Degradation of oocytes by sperm proteasomes.png

(2) Rac-1 is a member of the Rho GTPases family of proteins. It was discovered that with the activation of the Rac-1 gene, its protein product can regulate the motility of the human endometrial stromal cells (HESCs) in reponse to the implantation of the embryo in the uterine wall. Rac-1 promotes the lamellipodial protrusion at front of the migrating cells. This protein also encourage the migration of HESCs away from the implantation site which then facilitate the invasion of trophoblast and lead to the inplantation of the embryo into the stromal compartment. [2]

--Mark Hill 16:32, 11 September 2012 (EST) Question 1 image is well named and contains all the requested information. Though the image is quite small 320 × 399 pixels and a larger version should have been sourced, also png files are quite large 125 KB, jpg are smaller). You have also misinterpreted my request as the file name should be a sub-heading on the file summary page, not here. Question 2 is also relevant to implantation. Rac proteins regulate the actin cytoskeleton and this is further explored in the 3rd year Cell Biology course. 10/10

Lab 3 assessment

(1)Identify the difference between "gestational age" and "post-fertilisation age" and explain why clinically "gestational age" is used in describing human development.

Answer: Gestational age is classified as the time elapsed from the first day of a women's last menstrual period, and the post-fertilization age is referred as the time since the fertilzation of the egg in the woman's uterus. The main difference is their starting date and gestational age is often two weeks earlier than the post-fertilization age. Clinically, gestational age is often used in describing human development because the start date of the gestational age can be clearly defined while the exact time of fertilization can be confusing. It is also essential for predicting consequences to the development of fetus from toxin exposure of infection during the gestational age.It is also important for evaluation of physical findings such as fetal growth and screening markers.

(2)Identify using histological descriptions at least 3 different types of tissues formed from somites.

3 types of tissues formed from somites: - dermatome --> Skin are formed from dermatome. There are 3 layers to skin, epidermis which contain stratified squamous cells with epidermal ridges with thick layer of keratin. Dermis layer contain a lot of the vasculature such as blood vessels and glands, there are also dense collagen and irregular elastic fibres. Usually, this layer contains a lot of type I collagen fibre. The last layer is the hypodermis layer where its mainly adipose tissue.

- myotome--> skeletal muscle are developed from myotome. Skeletal muscle has a lot of myocytes and they are long and elongated with multiple nucleus. Their nucleus are often pushed to the periphery of the cells. They also contain myosin and actin which are called the thick and thin filament which cause striation appearance of the muscle cells.

- Sclerotome--> vertebrae and rib cartilages are developed from it, where different type of bone cells are present. The extracellular matrix of bone is formed through inorganic material such as phosphate along with some organic component being collagen fibres and ground substance.


--Mark Hill 16:41, 11 September 2012 (EST) Question 1 has been clearly and correctly answered. Question 2 the somite compartments and major tissues correctly identified. The one error is the answer for dermatome suggests that the epidermis is also a component of this compartment, while it is ectodermal in origin. 9/10

Lab 4 assessment

(1)Identify the 2 invasive prenatal diagnostic techniques related to the placenta and 2 abnormalities that can be identified with these techniques.

The first invasive prenatal diagnostic techniques is called "chorionic villus sampling" and it involves a catheter passed via the vagina through the cervix and into the uterus to the placenta, under the guidance of ultrasound. There can be other approaches as well such as transvaginal and transabdominal. The catheter will then collect sample of the chorionic villus which is placental tissue. The sample will then be analyse for any chromosomal abnormalities or genetic disorders, and the karotype of the fetus will be determined.

The second technique is "Placental biopsy", it is similiar to the chorionic villus sampling, but it has a transabdominal approach to it. It can be performed at a later stage of the pregnancy. It is used to obtain a rapid result. The karyotype of the fetus can be determined and genetic disorders can be detected such as trisomy 21 and monosomy X.


(2)Identify a paper that uses cord stem cells therapeutically and write a brief (2-3 paragraph) description of the paper's findings.

"Transplantation of microencapsulated umbilical-cord-bloodderived hepatic-like cells for treatment of hepatic failure" [2]

The paper aim to investigate intraperitoneal transplantation of microencapsulated hepatic-like cells from human umbilical cord blood for treatment of hepatic failure in rats. There are a few candidates for this experiment but human umbilical cord blood (UCB) cells were thought to be the best as they have some advantages that other cells do not have. The frequencies of UCB hematopoietic stem or progenitor cells is much higher than those from bone marrow and peripheral blood. The paper also mentioned that there are three ways of inducing the UCB cells into hepatocytes-like cells and they are Co-culture with injured liver cell, growth factor-assisted and MNC transplantation.

In the experiment, CD34 cells are isolated from the UCB cells and through the combination of fibroblast growth factor and hepatocyte growth factor, the CD34 cells are induced to hepatocytes-like cells. It was found that in the cultured cells, the level of human albumin, alpha-fetoprotein and GATA-4 mRNA and albumin positive cells have increased significantly suggesting the transformation of the CD34 cells into hepatic-like cells. The cultured system with growth factors have the ability to convert these UCB cells into hepatocytes phenotype and it is confirmed through PCR and immunohistochemcial staining. Then these hepatic-like cells are encapsulated and transplanted into the abdominal cavity of rats with acute hepatic failure. The transplantation occurs 48 hours after the onset of an acute hepatic failure.The microencapsulation of the cells provide a possibility to overcome the immuno-rejection from the AHF rats.

The result obtained from this experiment was that CD34 cells from the UCB cells can be converted into hepatic-like cells under suitable conditions with appropriate growth factors. The transplantation of these encapsulated hepatic-like cells have resulted in decreased mortality of the AHF rats. But these hepatic-like cells can only offer short term metabolic effect to these AHF rats and cannot interrupt or repair the damaged hepatocytes. Therefore the conclusion of this paper suggests the possibility of UCB cells used in conversion to hepatic-like cells that can temporarily alleviate the symptoms of Acute hepatic failure in rats bur not regenerating healthy hepatocytes. [3]


--Mark Hill 16:46, 11 September 2012 (EST) Question 1 You have clearly identified 2 invasive techniques diagnostic techniques. I would have liked specific disorders for the first technique, as you have for the second technique. Question 2 this is an excellent description of the paper and technique. You have used the UCB acronym correctly (citing in full the first time), though you still have problems in formatting your reference links, which only require the PMID number to link correctly. 10/10

Lab 7 assessment

(1) Provide a one sentence definition of a muscle satellite cell (b) In one paragraph, briefly discuss two examples of when satellite cells are activated ?

It is a mononuclear stem cell that are found in mature skeletal muscle fibres and promote their growth, repair and regeneration, they are usually situated between sarcolemma and basement membrane of muscle fibres.

Satellite cells are activated after muscle strains such as trauma, where myogenic regulatory factors will be expressed and they are similar to those produced by muscle precursor cells during muscle development. These cells proliferate and fuse with each other to form myotubes and slowly mature into myofibres. They can also fuse with damaged segments of muscle fibres. These cells can also give rise to new satellite cells. Heavy exercise can induce muscle hypertrophy which also encourage the growth and proliferation of these muscle satellite cells.


(2)In one brief paragraph, describe what happens to skeletal muscle fibre type and size when the innervating motor nerve sustains long term damage such as in spinal cord injury?

In situations of long term motor nerve damage, since skeletal muscles are activated by these motor nerves, when they are damaged, the muscles will often lose their function and movement. There can be a complete loss of function or only a part of, depending on the severity of the damage to the nerve. When the muscle lose their initiation, they can present symptoms such as muscle twitching, cramping and muscle can become stiff due to the lack of movement. Muscles paralysed by spinal cord injury are usually atrophic, possesses lower tension generating capacity and is less fatigue resistant compared to normal muscles. Upper motor neuron paralysed muscles lose the normal type I (slow) and II (fast) fibre and become predominantly composed of type II (fast glycolytic) fibres. A transitional period can be seen ranging from 1 to 20 months after the injury where there is usually drop in the proportion of slow muscle fibres and a rise in the development of fast fibres.


Lab 8 assessment

Vision

I really liked the eye image at the top of the project page, it automatically drags my attention towards the page and it clearly shows what the project is going to be focused on. The introduction was good, its not too long but provide sufficient information about the project and as reader, we know what we can expect from the project page. The image used there is very good as well but maybe more labelling and explanation can be included.

Images from the textbook, Atlas of the development of men, both on the development of lens and the formation of optic vesicle, they are really good. I understand that the page is not complete yet, but just looking at these images, a lot of explanation and labelling need to be put in to ensure that readers know what is going on and actually learn from those images. The development of the optic nerve is good. Information provided is clear and precise. The whole process of the development was explained well and used simple terms so that it is very easy to follow and understand but maybe the images need to be labelled more? I saw that this section of the project, only 1-2 references is used? Maybe try to expand the research and include more information from different sources. I really liked the way that most of the images are hand-drawn, this really shows that you understand the process yourself and able to interpret all the knowledge you gathered from resources and produce something that is easy to understand and can actually teach readers about vision development.

There is a glossary at the end of the page which includes all the scientific terms, maybe expand this section a little bit more. Some scientific words are not included such as mesenchyme, as a science student, maybe we will understand these words but for the general public, they may not. That's why it is essential to have a glossary. I thought having an image gallery was a good idea, in that way, people can concentrate on only the image aspect of the project without all the text in between, allowing a different approach in looking at this project. Referencing of the project overall was good, except there is one citing error, no.13? But this should be quite easy to fix. In terms of variety of resources used, i thought was quite narrow, with the majority resources being websites and lab material from the course. Maybe use more journal articles and reviews to expand the depth of the information presented. The structure and the lay out of the page is very clear with consistent headings and sub-headings, which makes the page very easy to read and follow.

Overall, the project page is looking good.There are just some minor parts to be completed and maybe a little bit more research needs to be done. :) hope this helps. --Z3331330 18:35, 23 September 2012 (EST)


Somatosensory

The introduction is very detailed and precise, and it really prepares the readers for what is going to be covered within the project. I thought it was a good introduction but the referencing needs to be fixed up because it looks really different too all the other parts of the project. I do not think that style of in-text citation is needed for the purpose of this project. The histories of discoveries will look better if it is in dot-points, it would be so much easier to read.

In the central somatosensory differentiation section, you mentioned that there are three components, but to me, only the primary somatosensory cortex has been extensively researched, i think more research should be done on the other two components. There is an imbalance of information between the three components. Also, I can see that only 2 references have been used in this entire section, maybe this is why there is an imbalance of information. Using a large variety of resources will definitely expand your knowledge and enable you to put in more information in this section. I thought the hand-drawn image was impressive but the colour is a bit vague and hard to see. A larger version of the image should be uploaded so that it is easier to see.

The "making connection" section has very good description on the physiology and the signalling process of CNS but I do not really understand the stages? Are they the stage events that are involved in embryonic development? Some more detailed explanation is needed here, and maybe some images will help? The touch section has some good information but again only 2 references have been used which shows the need for further research. Images should be put in here because right now it is very crowded with text. Also, the same problem keeps occurring throughout the project, I feel like there are lots of information about the function of different components of the somatosensory system but not how they are developed. Make sure you do not go off track. There are some weird referencing in the hot/cold section which needs fixing up. There are nothing in the glossary, scientific terms and definition should be put here because not everyone will understand the terms used within the project page. The structure of the project was good though, very clear and simple which makes the page very easy to follow.

Overall, the page is looking good but maybe more research should be done and more images should be put in to balance with the large amount of text. Also, keeping the information related to the research topic will be a huge aspect to focus on. Hope this helps :)


Taste

The introduction is very detailed but did not mention anything about the development of the taste. But I thought the mechanisms behind sweet and salty tastes are very interesting. Maybe do the same for the other 3 tastes? The image of the basic 5 tastes is a bit small, maybe upload a bigger version of the image. Also, the image is lacking some reference, copyright information and a student image template.

The type II receptor section is pretty good and descriptive but it does not really relate to the development of the taste. The taste map is a very eye-catchy image and it would be really useful if it had all the needed information such as the copyright notice. The timeline of the gustatory system is very well-presented and easy to read. I understand the project is not completed yet, therefore more images are still to be put in. Only 2 references have been used in the timeline section, maybe try to research more and use different resources. There are some citing error but it should be quite easy to fix.

Histories of discoveries section is very detailed and easy to read but the referencing needs to be fixed. The adult tongue and taste bud section is very clear and precise and contain a lot of useful information but it does not really relate to the research topic, should beware of going off-track. The hand-drawn diagram of the taste bud is impressive and easy to understand but again lacking in some referencing information such as who drew it. The abnormalities section is good and well-researched and it is interesting to know about which gene or receptors will effect the development of taste and sensation. Maybe the abnormalities section can be included into the current research section because abnormalities are repeated in the current research section below. There are detailed definitions of terms in the glossary which is good because it really helps the reader to understand more about the research topic.

Overall, the page is looking good. The main thing that needs to be fixed will be the images that are already on the page, they need the correct and essential information with them when uploaded on the page or else, they will get deleted and there will be no images on the page and the nice balance of images and text now will be gone. There seem to be a lot of anatomy and biology of the taste system but not a lot of information about their development. Although there is a timeline of development but i think more information is needed. Referencing is pretty good with only one or two minor citing error but it should be easy to fix. Structure of the page is clear and simple with headings and sub-headings being consistent, making the page easy to read and follow. Hope this helps :)


Olfaction

The introduction is quite small but very precise, indicating the function and the components of the olfactory system but maybe include one or two sentences in the introduction telling readers that it is actually about the development of the olfactory system, not just the function and components of it. After all, introduction is meant to show others what your project is about. The hand-drawn image there is very nice but maybe more information need to be provided other than just labelling parts of it. Along with the image, there are the important informations such as the copyright notice which is good to see.

The history of discoveries section is very well-researched but it will be easier to read if it was in a table. The timeline, i thought was very good because there are a lot of useful information about the development of olfaction which relates to the research topic. The developmental process is explained in quite simple terms but i notice some of the scientific terms in the timeline are not explained in the glossary, this makes it a little bit hard to understand the whole process. It is very interesting that a youtube link has been included in the structure section, this is really a good peer teaching but make sure you referenced the video correctly to avoid plagiarism. The section on Kallman's syndrome is quite interesting but the structure of that section is a bit messy, maybe try clarifying and tidy it up a lit. But i can see that a lot of research effort has been put into it which is good and the variety of resources used in the section is very broad. More images should be put here because right now, there is just a huge block of text in the section. Images will balance out the heavy text load and attract readers more. The current research section contains a lot of useful information and it relates to the research topic well. Again, images should be put here because right now, there are just small blocks of text in the section without any images, this maybe a little bit boring for readers.

Overall, the project looks well-researched and relates pretty well to the research topic. The balance of the images and text still needs to be fixed but in terms of the text and information on the page, i think it is pretty sufficient and in-depth especially the timeline of development and current research section. There are some terms in the glossary which is good but maybe more terms should be added. The structure of the page is good, very easy to follow. There are a few external links which is always good to put there for anyone that are interested by the topic and want some further information about it. Referencing is good, there is only one minor citing error (no.7), but it should be easy to fix. Hope this helps :)


Hearing

Good use of image, it attracts my attention straight away and it is very relaxing to look at a funny image before reading the text. Introduction is precise and to point, clearly identifying the purpose of the project and gives a general overview of what the readers will see or learn from the project. The timeline for history is good, but maybe indicate what kind of history is it? The adult anatomy and histology section is good but the heading should be "adult ear anatomy and histology"? I like it how the ear is divided into outer ear, middle ear and inner ear and then it is further divided into components that are included in these 3 different parts of the ear. This makes the structure of the ear very easy to understand and we can locate the different structure of the ear much easily. The image used in this section is very good with clearly labelled structures, the image also contained all the important information and referenced correctly but you forgot to include the student image template.

The development section is well-researched and contain a lot of information. More images should be put in to balance out the heavy text load in the section but the information provided is very in-depth and precise. The developmental process is explained in simple terms but i noticed that there is an imbalance in terms of research and information between middle ear and the other two. Maybe more research should be done on the middle ear. The summary of the inner idea was a good idea because it clearly points out the main points that readers should know, should consider do something similar for both the outer and middle ear.

The abnormal hearing section is well-researched and interesting. It is very nice to know about the association between gene mutation and its influence on hearing development. Maybe some images should be put here to balance out the text a bit. The table of genetic syndrome is very nice, maybe you can consider putting the gene mutations into table as well. The environmental section is nice and well-researched but maybe images should be put here because right now it is pretty boring just going through all the text. And there are just some weird reference under each infections but i think this can be fixed soon. Structural malformation of the ear table is nice as well, clearly showing all the important information. It will look even better when all the images are put in.

Overall, i thought the project is really good. Contained a lot of useful information and a lot of research effort has been put in, all the information are related to the research topic. The tables work really well and the structure of the page is easy to follow. Referencing is generally good but maybe get rid of some of the random citations in sections. More images should be put in to balance out the heavy text but I thought it was a very well-researched project. Hope this helps :)

Lab 9 assessment

(1)Identify and write a brief description of the findings of a recent research paper on development of one of the endocrine organs covered in today's practical.

'Stam2 expression pattern during embryo development.'

Signal transduction adaptor molecules 1 and 2 (STAM1 and STAM2). They are both involved in the endosomal sorting of the cargo proteins for trafficking towards the lysosome. STAM2 is activated by tyrosine phosphorylation and can also be stimulated by various cytokines and growth factors. It is involved in the regulation of endocytosis and also regulation of intracellular signal transduction for DNA synthesis through JAK2 and JAK3 tyrosine kinases.

In the paper, a mouse line have been created to enable the expression of STAM2 to be observed by X-gal histochemistry. At around embryonic day 16.5, it is evident that STAM2 is expressed in the heart, testes, olfactory bulbs, trigeminal and dorsal root ganglia, pituitary and medulla of the adrenal glands. Around embryonic day 18.5, the expression of STAM2 become much stronger, especially in areas of testes, ovaries, lungs, kidneys, urogenital sinus, pituitary and adrenal glands. Near the end of gestation, STAM2 expression is confined to regions such as nervous tissue, and endocrine organs like pituitary and adrenal glands and they are already highly secretory active at this stage of embryonic development. This paper demonstrates a very strong correlation between the development of the adrenal glands and the expression of STAM2. [4]


(2)Identify the embryonic layers and tissues that contribute to the developing teeth.

Teeth are formed from cells that derived from the ectoderm of the first branchial arch and the ectomesenchyme of the neural crest and also mesoderm.It is organized into 3 parts, the enamel organ, the dental papilla and the dental follicle. The enamel organ give rise to ameloblasts which produce enamel and the reduced enamel epithelium and ultimately determines the root shape of the tooth.The dental papilla contains cells that develop into odontoblasts which determines the crown shape of a tooth. Mesenchymal cells in the dental papilla are for the formation of tooth pulp. The dental follicle contribute to cementoblasts which form the cementum of the tooth, osteoblasts which give rise to the alveolar bone and fibroblasts give rise to periodontal ligamtns.


Lab 11 assessment

(1)Identify a recent research article (using the pubmed tags to cite) on iPS cells and summarise in a few paragraphs the main findings of the paper.

'Two-step differentiation of mast cells from induced pluripotent stem cells.'

Mast cells are responsible for the pathogenesis of many allergic diseases in the human body. There are mainly two types of mast cells and they are connective tissue type mast cells (CTMCs) and mucosal-type mast cells. This study aim to report on the generation and characterisation of connective tissue type mast cells that are derived from induced pluripotent stem cells (iPS cells) that originated from mouse. Mast cells are generated from mouse iPS cells and are characterised from several aspects including morphology, function and gene expression.

The study generated mast cells and differentiated them from mouse iPS cells from two major methods. The first one is by co-culturing the mouse iPS cells with OP9 stromal cells and the second one is the embryoid body formation method. With these two methods, they were able to produce mast cells that have characteristics similiar to CTMCs. When mouse iPS cells were generated with the OP9 stromal cells and also co-cultured with Swiss 3T3 fibroblasts, the result of the generation was that the mast cells exhibit even more of a functional phenotype. Therefore, the study provided a protocol with two step differentiation which allows the transformation of mouse iPS cells to mast cells. The two differentiation method was co-culture with OP9 stromal cells and co-culture with Swiss 3T3 fibroblasts.

The protocol provided by this study consist of mesoderm induction, mast cell specification, differentiation and maturation of mast cells from mouse iPS cells. The study also suggested a few cytokines and feeder cells that were essential for the development of iPS cells to mast cells. Interleukin-3 has been recgonised and considered to play a very important role in the differentiation of mast cells. OP9 cells may not be necessary for the specification of mast cells but it promotes the maturation of them. Swiss 3T3 fibroblasts have been proved to be essential for the maturation of the mast cells from mouse iPS cells. The successful protocol generated from the study has provided a novel method for more efficient generation of mast cells from mouse iPS cells, with the production of more mature mast cells. [5]


References

  1. <pubmed>18649278</pubmed>
  2. <pubmed>PMC2562412</pubmed>
  3. <pubmed>PMC3051145</pubmed>
  4. <pubmed>22143071</pubmed>
  5. <pubmed>23045993</pubmed>