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Figure 2. Inferred life cycle and high degree of organellar complexity of the last common ancestor of all extant eukaryotes. Origin of the cell nucleus, mitosis and sex: roles of intracellular coevolution Thomas Cavalier-Smith http://www.biology-direct.com/content/5/1/7
© 2010 Cavalier-Smith; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The use of confocal microscopy in observing melanin and the skin
The human skin is a complex organ in the way that it protects the rest of the body from light and UV penetration. Although its has been determined that “skin optics respect the rules of absorption, reflection and scattering” (Corcuff, P et al 2001), the skin still has features that may prevent direct penetration of light. These include
• The stratified, layered nature of the epidermis
• Biochemical composition of both the epidermis and dermis
• Melanin within the epidermis and haemoglobin from blood in the dermis.
For these reasons, in vivo observation of the skin in its physiology and responses to stimuli has always been somewhat of a challenge. What Corcuff, P et al experimented with was a method of observing the skin of the forearm before sun exposure and for a month afterward using confocal microscopy techniques. Observations were made in regards to melanasome (melanin-containing organelle) caps within basal keratinocytes (skin cells in the deep epidermis). The use of in vivo confocal microscopy also “affords new insight to the role of melanin and its gradual migration after sun exposure”
In vivo confocal microscopy involved reflected singals being used to create an image. Contrast was improved due to absorption and scattering (minimal loss of photons). Another feature that was regarded was realtime imaging to prevent blurring from motion caused by blood pulses and involuntary movement.
• Skin optics revisited by in vivo confocal microscopy: Melanin and sun exposure
PIERRE CORCUFF, CIdLINE CHAUSSEPIED, GENEVIEVE MADRY, and CHRISTOPHE HADJUR, L'Ordal
Journal of Cosmetic Science, 52, 91-102 (March/April 2001)
--Mark Hill (talk) 11:29, 11 April 2013 (EST) You have identified a research article using in vivo confocal imaging of the skin and this meets the criteria for the microscopy. The paper though is from 2001 (12 years ago) and I do not think this meets the "recent research article" criteria. Furthermore you have not used the Pubmed formatting as described in the in-class tutorial and as shown below, see also Project Referencing. Both these factors affected your final mark.
1) Fragmentation and partitioning of the Golgi apparatus during mitosis in HeLa cells
HeLa cells are a type of human cell used in scientific research obtained from cervical cancer cells in 1951. These cells were used to observe the activity of the Golgi apparatus when they divide. It has been concluded that animal cells contain only one copy of the Golgi apparatus and they are unable to be synthesised de novo. The Golgi must divide when the cell divides and involves breaking down into fragments. By using osmium to stain the Golgi, Lococq and Warren were able to demonstrate the division of the organelle through twisting and turning in a ribbon form.
Lucocq JM, Warren G (1987) Fragmentation and partitioning of the Golgi apparatus during mitosis in HeLa cells. The EMBO Jounal 6(11)
2) Active ADP-ribosylation Factor-1 (ARF1) is required for Mitotic Golgi Fragmentation.
Although it has been established that animal cell Golgi apparatuses undergo division and disassembly during mitosis, the mechanism for the way this occurs is still not clear. Xiang Y et. al. investigated how ARF1 may dictate the division of the Golgi. ARF1 is a GTPase that is necessary for the forming of vesicles from the Golgi and is associated with Golgi vesicles created in vitro as well as in mitotic cells. When the Golgi was treated with ARF1, it was converted to vesicles. However depletion of ARF1 meant the Golgi failed to fragment.
Xiang Y et. al. (2007) Active ADP-ribosylation Factor-1 (ARF1) is required for Mitotic Golgi Fragmentation. Journal Of Biological Chemistry 282(30)
3) The Golgi-associated protein GRASP65 regulates spindle dynamics and is essential for cell division
It is found that that the protein known as GRASP65 (a Golgi-associated protein) is significant in the in Golgi fragmentation during mitosis. GRASP65 is required for the stacking of Golgi cisternae in vitro and is phospohrylated during mitosis to cause unstacking during mitosis. The study showed that depletion of GRASP65 did not affect the stacking of cisternae however it did afect the organisation of the mitotic spindle. This ultimately lead to cell death.
Sutterlin C, Polishchuk R, Pecot M, Malhotra V (2005) The Golgi-associated protein GRASP65 regulates spindle dynamics and is essential for cell division. Molecular Biology of the Cell Vol 16
4) The Golgi and Endoplasmic reticulum remain independent during mitosis in HeLa cells
The Golgi apparatus must undergo partitioning and dissasembly prior to mitosis. And although it may not require molecular machinery to dissasemble/ reassemble, it requires a number of specific cell-cycle regulated activities. The same can be said about the Endoplasmic reticulum which is a large tubular network that involves the nuclear membrane. In this study, Jesch SA et. al. conducted a number of assays to observe wether the Golgi apparatus and ER are dependent or independent of one another during mitosis
Jesch SA, Linstedt AD (1998) The Golgi and Endoplasmic reticulum remain independent during mitosis in HeLa cells. Molecular Biology of the Cell 9(3).
--Mark Hill (talk) 12:12, 3 May 2013 (EST) I cannot see appropriate information associated with this image from EMBO J that allows you to reuse here. Unless you provide this information I will be deleting this image.
Integrin α1 Antibody (A-9): sc-271034
-Isotype - IgG (made of 4 peptide chains - 2 light, 2 heavy)
-Raised in mice, used within mice
-Provided at 200µg/ml
-Recommended for detection of Integrin α1 of human and rat origin by Western Blot, IP, IF and ELISA
Group 1 Peer Review
• Good introduction – Sums up what will be on the page well. Informative without being too detailed
• Some sentences were a tad long and were a little confusing to read. Separating some of the longer sentences into two shorter ones would make this intro even better
• A simple picture in the introduction would break up the text nicely
• Pleasing to the eye – Nice colours and succinct info drew my attention and made me want to read into it.
• Obviously, some more information needs to be added to the last 3 rows.
Entry into M phase
• The intro to this section needs to be a little more informative, to assume the readers know nothing about cell biology. What is a G2 phase? What is M phase? Why shouldn’t replicated DNA be damaged and why are key regulators required for this transition?
• Cyclins – Good information, informative and succinct.
• CDK – Once again, good info and succinct. It might be good to add what CDK stands for and why it is called that.
• Pictures are good. Relevant, eye catching and simple.
• The second picture should be a ‘thumb’, much like the first one. The other pictures of the page should be thumbs too so that you can add a little information to what the picture is.
• Overall, the information in this section is lacking some citation.
Metaphase to anaphase
• Im confused by the text in brackets here. Is this an error?
• An introduction would benefit this section well, explaining what metaphase and anaphase are and why the complex and checkpoint are relevant to this part.
• Good information. A picture could help break up the text.
• I like the definition that started this section. Simple yet effective.
• The ‘mitogens’ section is very well written. It was an enjoyable read, and was structured nicely. A picture here could be nice. And just a slight spelling error in the first paragraph, ‘Mitogens effect cell division by overcoming the intracellular…’ should read ‘mitogens AFFECT cell division’.
• PDGF history – This section was well written too. Overall, a good section. A few more citations here wouldn’t hurt.
• A good idea – Listing diseases that can occur involving cell division and putting it in table form is not something I would’ve thought of. Very creative, very relevant. I will be looking forward to seeing this table once it is completed.
• It might make the table even better to add a ‘treatment’ column. But once the table is complete, it may not need it. Your call. Current/future research
• Current research requires more detail
• Future research was good. With a bit more citation, it will be perfect.