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Create a 3 page essay paper that discusses Cell Biology.Download file to see previous pages... They found out that when antibodies of GRASPs were introduced, daughter cells resulting from mitosis had

Create a 3 page essay paper that discusses Cell Biology.

Download file to see previous pages...

They found out that when antibodies of GRASPs were introduced, daughter cells resulting from mitosis had improper stacking of cisternae membranes.

Nonetheless, the findings have been inconclusive due to other studies using equally logical and accepted techniques. The studies conducted by other scientists employing gene knockout (removal of gene responsible for GRASP production) and siRNA depletion on animal cells, such as that of Behnia et al (2007), have shown that proper stacking occurred even in the absence of GRASPs. General protein secretion was also unencumbered. Furthermore, the absence of GRASPs in plants has not prevented them from acquiring proper stacking of the cisternia membranes.

It is in the confusion regarding the true physiological function of the GRASPs that Kutzen and his colleagues conducted their study. They sought an explanation on why GRASPs exists by determining and establishing its role in cellular development.

The authors present a new perspective on the physiological role of GRASPs. They contend that these proteins are not needed for conventional protein secretion, growth (i.e. stacking) and viability of vegetative cells. Their importance lies in making sure that AcbA, a protein that initiates spore differentiation, are secreted. Since AcbA lacks a signal sequence for its transport to the site where terminal differentiation occurs, GRASPs present an unconventional mechanism that facilitates the secretion and transportation of AcbA. Since spore differentiation ultimately results to fruiting bodies containing mature spores, GRASPs can be thought of as necessary for the reproductive mechanism of the cell and not the stacking of the membranes.

3.0 Major Findings

Thru the use of cells of Dictyostelium, a type of mold, the authors found that GRASPs are not necessary for insuring cell growth and viability. This was the result of comparing the Golgi structure of cells containing GRASP and those without thru the use of immunoflourescence microscopy. The structure, even the stacking of the Golgi membranes, was similar for both cases.

In proving their hypothesis, the authors studied the prespore cell type of the mold. With molds that have GRASPs as the control and those without as the experimental variable, they were able to determine that the viability of the mature spores in the control was 100% as compared to the 25% of those negative for GRASPs. Digging deeper, the authors were able to determine that the decrease in viability was the result of the insignificant production of SDF-2, a major peptide factor necessary for proper spore formation.

According to the Anjard and Loomis (2005), SDF-2 is generated in the cleaving of AcbA. The cleaving of the protein AcbA initiates a loopback process that ultimately results to a successful sporulation event. The question now that faced the authors was to determine how GRASPs affected the production of AcbA. After having conducted Western blot analysis on moulds which did not have GRASPs, they found that AcbA was still as abundant as that in normal conditions.

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