Wednesday, December 7, 2016

Detection of the Hepatitis A Virus

Detection of the Hepatitis A Virus
By Samantha Lin
            Hepatitis A is one of the five hepatitis viruses that infect the liver. These viruses are a major health problem since it can affect millions of people around the world. Although there is a vaccine that prevents the virus, transmission is still possible especially in countries without access to the vaccine. Out of the five hepatitis viruses, Hepatitis A accounts for half the total number of human hepatitis infections diagnosed worldwide. Although there is no specific treatment after contracting the virus, there are ways of detection to help prevent it. Each year, there are approximately 30,000 to 50,000 cases of Hepatitis A in the United States. So what are the main sources and how do we prevent this virus?
Contaminated Produce
            Hepatitis A virus is transmitted through the ingestion of contaminated food as well as through the fecal-oral route. Common foods associated with the virus are contaminated drinking water, raw or undercooked shellfish from contaminated water, and raw produce. Green vegetables are the most common produce (spinach, green onions, and lettuce) that are contaminated with Hepatitis A virus. These produce are exported and grown in large volumes and are commonly eaten raw in ready-to-eat salads. The virus can enter the produce in a variety of locations including the roots from the soil, as well as the leaves. Since the virus is commonly found in contaminated water, washing these vegetables can be a source of contamination. Since the produce is grown in such large numbers, further contamination could occur during processing. Contamination could occur in the soil where they grow, in the handling process, and when washing the vegetables. These vegetables are often consumed raw, which makes consumers susceptible to the Hepatitis A virus.
            Washing your hands seems like a simple mundane task, but it is an effective method to prevent the spread of the virus. Since the virus can often be spread through food handlers, sanitation of hands, as well as the food plant is important. Hepatitis A has no specific treatment and recovery can take several months. There are both mild and severe symptoms which includes fever, diarrhea, and jaundice. To prevent exposure to the virus, sanitation is very important. Especially when traveling to areas where hepatitis A is common, avoid food from street vendors. Foods that are eaten raw should be avoided since they may have been washed in contaminated water. Food can also be cooked properly on your own to ensure proper sanitation method.
            In terms of detection, the Nested Real-Time Polymerase Chain Reaction (NRT-PCR) can be used to find presence of the virus. Since Hepatitis A can cause outbreaks, a rapid detection is necessary. NRT-PCR is a highly sensitive and specific method that combines multiple PCR methods. It uses a TaqMan probe for detection that allows for good specificity and reproducibility in the detection. The probe is basically a fluorescent light that looks specifically for a gene during Polymerase Chain Reaction (PCR). As the name suggests, the Polymerase Chain Reaction consists of multiple cycles.
Purpose of TaqMan Probe Photo Credit: Manit Arya
TaqMan Probe
The photo shows how the TaqMan probe is used to detect the target Hepatitis A virus. The probe contains a reporter dye on one end, and a quencher on the other. The reporter and quencher which are shown as the star and circle are used together in order to emit a fluorescence when the virus is detected. The reporter is a fluorescent molecule that monitors the PCR. As the virus is detected, the PCR accumulates and the fluorescence increases. When the quencher is close to the reporter (TaqMan probe is intact), it suppresses the fluorescence. However, when the virus is detected and the probe is broke apart and separates the reporter and quencher. This then gives of a fluorescent light. The data can be seen with a computer and can show positive or negative for the detection of the virus.

            With the help of this detection method, the number of Hepatitis A cases is gradually declining. Along with the vaccine, detection methods like this have allowed us to find the Hepatitis A virus in the vegetables before distribution. This helps in surveillance and reduces the number of outbreaks. The use of nested real-time PCR is a rapid method that has proven to work with the Hepatitis A virus. Using this new technology, it can be applied to other pathogens in order to minimize other diseases. This method can detect the virus and therefore be able to help prevent outbreaks. I can’t wait to see what impact this method has. 

Friday, December 2, 2016

Renewable plastic made from Mother Nature

Renewable plastic made from Mother Nature
By Brenda Hernandez

Plastic Pollution
Currently, the average American throws away approximately 185 pounds of plastic every year…that is enough to circle the earth four times. Keep in mind that the circumference of the earth is 24,901 miles- yikes! Plastic constitutes approximately 90% off all the trash floating on the ocean’s surface, which can kill marine mammals. Frequently found on the ocean are plastic water bottles, possibly because Americans dispose of 35 billion plastic water bottles yearly. Half of the plastic used, only gets used once, and only 5% of the plastic that gets thrown away is recovered. The main way of recovering plastic is recycling. 

So why recycle?
Recycling reduces the amount of waste sent to landfills and incinerators. It also prevents pollution by reducing the need to collect new raw materials and conserves natural resources such as timber, water, and minerals. Recycling reduces greenhouse gas emissions that contribute to global climate change and helps sustain the environment for future generations, all while saving energy.

In 2014, California became the first state to ban the sale of plastic single-use bags. San Francisco became the first jurisdiction in California to ban single-use plastic bags, in 2007. Last year, Los Angeles, the largest city in California and second largest in the United States, banned single-use plastic bags and placed a 10-cent charge on paper bags. When it comes to shopping bags and water bottles, it is advised to reuse. Although it may be easier to recycle and reuse plastic shopping bags and water bottles, it is harder to reuse and recycle food packaging. The plastic used for food packaging has several purposes. Most importantly, it protects food products from distribution damage, contains the food, and provides consumers with ingredient and nutrition information.
Really, the overall goal of food packaging is to contain food in a cost-effective way that satisfies industry requirements and consumer desires, maintains food safety, and minimizes environmental impact. So what are some innovative ways to do all of the above? Renewable plastic!

So what is renewable plastic?!
A novel way to make plastic from carbon dioxide and inedible plant material, such as agricultural waste and grasses has been discovered. Researchers say the new technology could provide a low-carbon alternative to plastic bottles and other items currently made from petroleum. The current goal is to replace petroleum-derived products with plastic made from CO2. Scientists from Stanford believe that by changing the formula for plastic by using Earth-friendly materials to create plastic, the goal will be feasible. Many plastic products today are made from a polymer called polyethylene terephthalate (PET), also known as polyester. PET is made from two components, terephthalic acid and ethylene glycol, which are derived from refined petroleum and natural gas. Manufacturing PET produces significant amounts of CO2, a greenhouse gas that contributes to global warming. A promising alternative to PET called polyethylene furandicarboxylate (PEF). PEF is made from ethylene glycol and a compound called 2-5-Furandicarboxylic acid (FDCA). PEF is an attractive replacement for PET because FDCA can be sourced from biomass instead of petroleum. Despite the many desirable attributes of PEF, the plastics industry has yet to find a low-cost way to manufacture it at scale. One approach is to convert fructose into FDCA from corn syrup. A better alternative is to make FDCA from inedible biomass, like grasses or waste material left over after harvest, such as furfural, a compound made from agricultural waste. However, making FDCA from furfural and CO2 typically requires hazardous chemicals (carbonate) that are expensive and energy-intensive to make. By combining carbonate with CO2 and furoic acid, a molten salt is formed which becomes the starting material for FDCA. The next step, transforming FDCA into PEF plastic, is a straightforward process that has been worked out by other researchers.
Chemistry can unlock the promise of PEF that has yet to be realized. This is just the first step. Some work still needs to be done to see if it is viable at scale and to quantify the carbon footprint. But as of now PEF has the potential to significantly reduce greenhouse emissions as it is made entirely from vegetable raw materials and CO2. Not only is PEF considered to be the packaging material of the future, particularly for food and beverages, but PEF can also be recycled or converted back to atmospheric CO2 by incineration. Eventually, that CO2 will be taken up by grass, weeds and other renewable plants, which can then be used to make more PEF. Lastly, PEF promises a greater level of impermeability to carbon dioxide and oxygen, thus ensuring a longer shelf life of packaged products. Overall, by providing a low-carbon and petroleum alternative to plastic packaging, PEF is looking like a promising replacement for polyethylene terephthalate due to the potential of reducing greenhouse emissions by a drastic measure. PEF will proved package modernization for consumer convenience, along with a makeover healthy to the environment- a double win!

Dianne Depra. Researchers Develop Renewable Plastic From Carbon Dioxide And Plants. 2016. Available from:

Clare Goldsberry. 2015. Innovations and Trends in Plastic Food Packaging. Available from:

Stanford University. Science Daily. Renewable plastic made from carbon dioxide and plants. 2016. Available from: