Home Methods Results Discussion
Introduction
More and more grocery stores are starting to carry organic produce. This is a manifestation of the underlying sentiment in American society that organic produce is safer and more nutritious than conventional. Organic goods are foods that are produced without the use of synthetic chemicals or additives in a manner that maintains the integrity of the local environment. Recent research has provided substantial support for the advantage of organic over conventional foodstuff specifically in regards to the chemical content the produce. On comparison organic produce contains a significantly greater concentration of beneficial chemicals, like zinc and iron, and less of the harmful chemicals, like lead and mercury. (Loyd 2005) Despite a consortium of similar evidence substantiating the nutritional superiority of organic to conventional food, there is controversy about the safety of eating organic produce. Food born pathogens, especially those found in fecal matter are a concern for critics of organic industry. (OCA 2004) In light of such controversy, it seems relevant to determine the difference in the expression of others components organic and conventional systems.
Ribulose bisphosphate carboxylase (EC:4.1.1.39) (RuBisCO) is the most abundant protein in plants and has been well studied in spinach. It is an integral enzyme in the Calvin cycle as it is responsible for the capture of CO2. (Taylor 1997) Of the two subunits that make up Rubisco, the function of the larger subunit is coded by the chloroplastic genome while the small subunit is encoded in the nuclear genome. In this experiment we will be looking at the expression of large subunit. The figure below gives a schematic of the large subunit. It was obtained from http://pfam.wustl.edu/cgi-bin/getdesc?name=RuBisCO_large.
The purpose of our study was to investigate the differences in levels of Rubisco between the organic and conventional varieties of store bought spinach (see Pictures below). The two types of packaging were tested to monitor the differences in preservation of the total protein content and therefore Rubisco content. It has thought that microbiological and enzymatic deterioration might be affected by the permeability of the containers they are stored in (Pandrangi 2004). Additionally, we wanted to see if the brand of spinach affected the amount of Rubisco present. Our hypothesis was that the small company distributing organic produce only (Fresh Express) would have a greater content of Rubisco than the large corporation, Dole. Also, we believed the spinach packed in less permeable containers would have a greater content of Rubisco than the more permeable. Lastly, we believe that all the organic spinach types would have a greater content of Rubisco than the conventional ones.