Edwin Croucher
Cellular physiology midterm
Paper #3
1:A) The focus of this paper is the function of the endoplasmic reticulum in protein transport in the axons and dendrites of neurons. The paper is asking that since neurons differ greatly from the other type of cells in the body what kind of differences are there in the ER of neurons, particularly when it comes to protein transport? (Ramirez & Couve, 2010)
B) Cellular biology is scientific study of cells; their anatomy and physiology, and that of their organelles. It focuses on how cells interact with their environment, their life cycle and processes, cell division and death. This paper relates to the study of cellular biology in that it is studying the anatomy and physiology of neurons and in particular the endoplasmic reticulum and protein transport (wikipedia).
C) The physiological processes this paper focuses on are; non-canonical pathway of protein trafficking in dendrites via the ER due to the special morphology of the neuron (Ramirez &
Couve, 2010). Another process the paper focuses on is how the ER contributes to neuron function and dysfunction (Ramirez & Couve, 2010).
D) The authors did not imply very many cell biology techniques as this was a review paper. This means that they just look at others techniques and wrote about the significance they contributed to the area of study. Some of the techniques looked at were; Electron micrograph 3-D reconstruction of neurons, Photon images of neurons transfected with cytoplasmic red fluorescent, Mean excitatory post synaptic current in dendrites with and without ER spines.
E,F&G) The take home message of this paper is that the ER structure, dynamics and functions in dendrites and axons needs to be studied in greater detail. Currently not enough about nonneuronal ER is known to truly even begin to understand why neuronal ER is different. It appears that in neuronal cells the (figure 1) ER forms a spine like structure in some dendrites which could be the reason the ER is heavily involved in protein trafficking in neurons versus not being so involved in non-neuronal cells. In non neuronal proteins are usually transported from the ER to the Golgi and then thru vesicles(canonical) to other parts of the cells(figure 2). However in neuronal cells it appears that proteins are also transported to their destination via the ER (noncanonical). An analysis of excitatory postsynaptic current in dendrite (figure 3) with ER in their spines versus those without show that dendrites with ER spines are more involved in calcium ion releasing events in neurons. This could give insight into neuron function and dysfunction under normal and pathological condition (Ramirez & Couve, 2010). It would be nice to see what circumstances make proteins travel via vesicles versus ER.

2: A) The focus of this paper is a review of the major highlights of ten years of research on the growth of lettuce ( Lactuca sativa ) under hydroponic conditions performed at Cornell University.
The question this paper asks is if hydroponics could be an economically viable, source of vegetable production in upstate New York?
B) This paper relates to cell biology in that the researchers studied how to optimize (for the purpose of human consumption) every part of lettuce life cycle, from nutrient absorption in cells located in roots(figure 2,3) to light levels versus carbon dioxide concentration to maximize photosynthesis(figure 1,6,7,8) (Both).
C) The physiological processes that the researchers had to understand were all of the different system of lettuce to optimize growth rates without causing them to exceed their resource levels and causing tip burn. This is caused by calcium not being able to be transported quickly enough into the rapidly growing tips of the shoots. Nutrients, nutrient transport systems, optimal light exposure, soluble oxygen soil concentration, and carbon dioxide enrichment all needed to be accounted for and monitored when undergoing this experiment.
D) The author did not make readily available any of the cellular biology techniques as this paper just highlights the productivity of the experiment. Unless making graphs is a technique, he used a lot of graphs. I would have liked to see them employ some assay methods to show metabolism rates in the two types of hydroponics performed during the study to see if there were major differences between the deep flow system and nutrient film technique.
E,F) This paper was focused on determining if greenhouse hydroponics were an economically viable option in the production of lettuce in upstate New York. Due to the presence of winter and decreased sunlight in upstate NY (11 of the top 100 least sunny places in the U.S. are in New
York. http://www.city-data.com/top2/c475.html
) the growing season is remarkably short, to increase the productivity indoor growing facilities could be economically viable. At the peak productivity the 750 square meter facility produced 945 heads of lettuce a day. Figure 1 shows the amount of natural light available on average during the year based on the Julian date for
Ithaca, NY. This shows demonstrates the need for supplemental lighting and temperature control in this region. Figure 2 shows how the researchers determined the optimal light exposure levels by exposing trials to different amounts of light. Figure 3 displays the water levels needed to avoid tipburn based on light exposure. The researchers determined that 400 mL per gram of dry mass was required to avoid tipburn in plants exposed to under 17 mol-m^(-2)-d(^-1) of light.
Figure 4 shows that the final mass of the lettuce correlated with the total accumulated light level since seeding. This makes sense as plants generally grow larger with more light. Figure 5 shows the correlation between leaf area and mass of the shoot. Again this makes sense as the bigger things are the more they tend to weigh. Figure 6 shows that increased carbon dioxide levels can reduce the amount of light necessary to reach the target growth size. This is great a CO2 is

abundant and cheap, and energy to power light is generally expensive, so during the winter months when there is less ambient light crop producers can save money on electric by providing crops with more CO2. Figure 7 simply shows the growth rate as a function of time versus mass.
Figure 8 shows the theoretical growth versus the actual growth of lettuce. It appears to me that the results correlated well with the model (Both).
G) I chose this article as I am interested in pursuing research in hydroponics and this appears to be a huge study (ten years’ worth). What is even better about this paper is that the research was done in the state I live in and where I will be conducting the research. Hopefully I will be able to look at this research while designing my own experimental model.
3: A) Vital Staining :
Basic description: Staining is a technique that is used to make biological tissue more visible, or to highlight contrast between different types of tissues, cells, and organelles. The term Vital
Staining implies that the cells are (or were at the time of the staining) alive. These stains can be viewed with by microscopy or in some cases by the naked eye. The technique involves spraying or injecting target areas with dye. The contrasting colors make identifying cell structures and tissue much easier. This can assist surgeons in removal of tissue, or help identify pre-cancerous and cancerous cells. It can also be used to show different structures when used for microscopy.
Purpose of technique: Vital staining is common practice in ocular surgeries, oncology and gastroenterology (Rodrigues, et al., 2009). The staining process quickly illustrates areas that could be problematic for the health of the individual. In ocular surgery it is often uses to distinguish cataracts. In gastroenterology it is able to help identity legions that could be precancerous in the mouth, and esophagus.
Origins of Vital Staining:
Staining as a useful identifier has been around since the 1800’s. The name of the person to begin utilizing the method is lost to antiquity and discrepancy. The protocol for staining is fairly individualized depending on what is being stained. For example different dysfunctions in eyes require different dyes to highlight optimally (Rodrigues, et al.,
2009).
Recent research: In oncology Vital staining with iodine solution has been used to distinguish between normal mucosa and oral epithelium that is malignant or dysplastic (Xiao, Kurita,
Shimane, Nakanishi, & Koike, 2012). This is paper goes into the mechanism on how iodine enters the tissue.

Fig. 1. Squamous cell carcinoma of the tongue. (A) Clinical appearance before vital staining. (B)
Appearance after application of iodine, which produces a brown-black stain on normal, nonkeratinised mucosa, but not on malignant mucosa. This clearly shows the intraepithelial extent of the lesion. The epithelial lesion was resected with a border of more than 5 mm of normal tissue around the unstained area (dotted line). (Kurita, Kamata, Li, Nakanishi, Shimane, & Koike,
2012)
In gastroenterology, vital staining is being used to diagnose superficial esophageal lesions using a methylene blue dye and lugol’s iodine (Peng, Long, Wu, Zhao, Chen, & Li, 2011). They determine a more effective method of vital staining to assist in the detection and diagnosis of early esophageal squamous cells.

Figure 1. Duodenoscopic images of normal mucosa and mucosal atrophy by videoendoscopic inspection alone and after vital dye staining with methylene blue 1%. A and B , Normal without

and with dye staining. C and D , Mosaic pattern without and with staining. E and F , Scalloped folds without and with staining. G , Reduction in the number of duodenal folds (note the mucosal nodularity in distal duodenum). H , Underlying vascular pattern. (Niveloni, Fiorini, Dezi, &
Pedreira, 1998)
In ocular surgeries vital staining is a critical tool. A wide array of stains and techniques for delivery of the stains are pivitol in treatment of various disorders (Rodrigues, et al., 2009). http://www.visioncareeducation.com/archive/om/images/OM_Suppl_May_A01_Fig03.jpg

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