kat's biology blog

Kat de Villa SBI 3U1-04

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Factors Affecting Plant Growth

Biosolids are nutrient-rich organic material that are processed from our own human waste. The treatment plants which make the material use a polymer to precipitate the suspended solids in the wastewater. The water is then drained and the rest of the product is used as fertilizer. While incredibly gross, biosolids may prove to be a stepping stone towards a better environment. 

PROS

Prevents pollution. Before biosolids were used, raw waste used to be dumped into rivers, lakes, and streams. 

Method of recycling. It saves landfill space. 

Excellent source of nutrients.

Improves crop production.

Reduces the need for chemical and commercial fertilizers.

Can be used for mine reclamation. 

Promotes timber growth. 

CONS

Potential health hazards. Many regulations have to be set in place in order to apply biosolids to land. 

Odour.

Contains nitrogen. A pollutant found in any fertilizer. 

Pathogens (disease causing organisms).

Toxic pollutants. 

Nutrient flows through urban environment. 

Biosolids Microbes Pose Manageable Risk To Workers

ScienceDaily (Oct. 27, 2008) — Class B biosolids are sewage sludges that have been treated to contain fewer than 2.0 x 106 fecal coliforms/dry gram. The USEPA estimates that 6.3 million tonnes of Class B biosolids are generated in the United States each year, and that by 2010, the amount generated per year will increase to 7.4 million tonnes.

Biosolids produced during municipal sewage treatment are most commonly applied to land as a fertilizer at agricultural sites throughout the United States. Class B biosolids, which are the principal type of biosolids applied to land, contain a variety of enteric pathogens.

Land application of biosolids has received national attention due to the potential for off-site transport of disease-causing microorganisms through soil, water, and air. Workers face greater exposure to bioaerosols from biosolids than those not associated with the operation. A new study investigated levels of microorganisms in air immediately downwind of land application operations and estimated occupational risks from aerosolized microorganisms.

The authors report that risks of aerosol-borne infection for biosolids workers are generally low, at less than 1 or 2% per year. Overall, occupational exposure to bioaerosols from biosolids appears to be less risky than similar exposures among wastewater treatment workers.

In all, more than 300 air samples were collected downwind of biosolids application sites at various locations within the United States. Coliform bacteria, coliphages, and heterotrophic plate count (HPC) bacteria were enumerated from air and biosolids at each site. Concentrations of coliforms relative to Salmonella and concentrations of coliphage relative to enteroviruses in biosolids were used, in conjunction with levels of coliforms and coliphages measured in air during this study, to estimate exposure to Salmonella and enteroviruses in air.

The HPC bacteria were ubiquitous in air near land application sites whether or not biosolids were being applied, and concentrations were positively correlated to windspeed. Coliform bacteria were detected only when biosolids were being applied to land or loaded into land applicators. Risks from aerosolized microorganisms at biosolids land application sites appear to be lower than those at wastewater treatment plants, based on previously reported literature.

At a first glance, this article appears to be against the use of biosolids. The title "Biosolids Microbes Pose Manageable Risk to Workers" seems very negative, which is surprising because most sources on the internet are plenty in favour of this method. But as you read on it becomes clear that the article sides with the majority of researchers. 

It delves into the studies done to review the health concerns that come with biosolids, which are mostly the involved risks of pathogens such as Coliform bacteria, coliphages, and HPC bacteria. The article reports that the chances of infection for those working closely with biosolids are generally very low; low being one to two per cent. It also states that these bacteria were found everywhere, whether or not biosolids were used in the area, and that the severity of the concentration depended more on windspeeds than the actual presence of our natural fertilizers. 

The source of this article appears credible. It was found on ScienceDaily but was reposted from the SSSA (Soil Science Society of America). The SSSA is an international group of more than 6 000 scientists across the United States. The current president of the society, Dr. Gary Pierzynski, is the Interim-Dean College of Agriculture at Kansas State University and the rest of the officers are also university professors or have obtained their PhDs. 

SOURCES

http://www.biosolids.com.au/what-are-biosolids.php

Australian & New Zealand Biosolids Partnership. "What are biosolids?" 2009. Web. 5 Jun 2012. 

http://www.cwwa.ca/faqbiosolids_e.asp

Canadian Water and Wastewater Association. "Frequently Asked Questions." 2012. Web. 5 Jun. 2012. 

http://www.sciencedaily.com/releases/2008/10/081027140821.htm

Soil Science Society of America. "Biosolids Microbes Pose Manageable Risk To Workers." ScienceDaily, 27 Oct. 2008. Web. 5 Jun. 2012.

http://lancaster.unl.edu/enviro/biosolids/whatare1.shtml

Ogg, Barb. University of Nebraska-Lincoln. "Biosolids?? What are Biosolids?" 2012. Web. 5 Jun. 2012

http://www.sciencedaily.com/releases/2008/10/081027140821.htm

Soil Science Society of America. "Biosolids Microbes Pose Manageable Risk To Workers." ScienceDaily, 27 Oct. 2008. Web. 5 Jun. 2012.

Biosolids.

[kdvllaunits-blog]

Gene Therapy

Designer babies have become a hugely controversial topic in the science world during the past few years. It is a colloquial term used by the media which refers to children who's genes have been modified or selected for desirable characters. Typically, these methods are used for cosmetic purposes. This form of genetic engineering, however, when addressed under a broader category such as gene therapy, can also have a medicinal advantage. In the same way that genes can be inserted or changed so that the child will have a specific eye colour, their whole genetic makeup can be altered in order to eliminate the risks of some diseases. 

One such article which demonstrates the benefits of this method is this:

Photo: Science Photo Library/Scanpix

Gene Therapy for Ears

ScienceDaily (Dec. 19, 2011) — Normal hearing depends on the presence of healthy hair cells in the inner ear. Gene therapy has the potential to slow the loss of hair cells and promote the growth of hair cells that have already been damaged.

In gene therapy, genetic material -- DNA or RNA -- is transported by a carrier to cells to provide instructions for and replace damaged genes. The carrier must protect its genetic package and help it make its way through the membranes that protect cells and their surroundings. The carrier should also be able to transport the genetic material right to the cells that need help.

For the first time ever, chitosan nanoparticles have been used as a carrier for gene therapy in the ear. Chitosan is produced from shrimp shells.

"Gene therapy may someday be an alterna­tive to using surgery to implant CI, cochlear implants, in the deaf and hard of hearing," says Sabina Strand, at NTNU's Department of Biotechnology.

Basic research promising

Strand studies the use of chitosan in gene therapy, and conducted this basic research, now ended, in cooperation with the Karolinska Institutet in Sweden. Here, researchers attempted to use chitosan as a carrier to deliver drugs and genes to the inner ear in guinea pigs. Chitosan was able to deliver drugs through the membrane that covers the tiny gap between the middle ear and inner ear. Chitosan was also able to deliver genes to the hair cells. Whether or not the results from guinea pigs can be transferred to human ears remains uncertain.

"However, chitosan is non-toxic and is not harmful to cells. Chitosan is therefore better than other carriers and has characteristics that mean it could potentially be used with patients," says Strand.

Tidy packages

Chitosan is produced from powdered shrimp shells. Acid removes salts, minerals and calcium carbonate. Strong alkalis and heat remove proteins. What remains is chitosan.

Extremely small nanoparticles in the range of 50-200 nm (nanometres) are formed spon­taneously when the positively charged chitosan and negatively charged genes are mixed. Chitosan does a good job packaging up DNA and RNA's relatively large molecules.

Tailored therapy

In the body, chitosan attaches itself to molecules, cells and membranes. When the nanoparticles have passed through a membrane, chitosan packages up the gene molecules so they return to their normal size again. Chitosan also creates gaps between cells, which facilitate the absorption of medicine.

Different forms of gene therapy require nanoparticles with different properties. The properties of nanoparticles are controlled by the way in which researchers tailor the chitosan structure, its molecular size and 3D architecture. But whether or not researchers will find the perfect mix of medicines for our ears and hair cells remains to be seen -- and heard.

The Norwegian University of Science and Technology (NTNU). "Gene therapy for ears."ScienceDaily, 19 Dec. 2011. Web. 15 Jan. 2012.

Gene therapy is using genes as medicine to treat diseases (especially hereditary ones). The process is as follows:

A proper vector or carrier is found which can hold the required healing genes and carry them successfully to the correct cells in the body

Genes are inserted into the vector. 

From here, there are two ways to transfer the new genes: ex vivo or in vivo. Ex vivo means the new gene has been put into cells which have been removed from the patient's body, therefore it is grown in the laboratory before it is returned to the patient. In vivo is the direct insertion of the vector into the body. 

This article, in short, addresses an advancement in genetic engineering that could potentially use gene therapy as an alternative to surgically implanting hearing aids to those with ear problems. Since healthy hearing requires healthy hair cells in the inner ear, the simple solution would be to insert genes that encourage hair growth and slow down the hair loss process. The major obstacle in the past, however, was finding the ideal vector. 

Fortunately, the breakthrough reported in this piece states that a carrier was finally discovered. The answer to the problem was chitosan nanoparticles; though its success still has yet to be proven in humans, it has worked on guinea pig test subjects. 

The article is definitely very accurate with its facts and information. Everything matches with the previous research I've done about designer babies, gene therapy and the like. The ability to hear really does depend on the state of the hair cells in one's ear and the proof given that gene therapy can help regenerate them has clear logic. 

The source of the piece appears to be credible, after all, the item was found on ScienceDaily.com; a very highly reviewed and trusted site for the latest scientific updates. I'm sure that the whole article has been reviewed and screened to make sure that its content is true. Not only that, but the source comes from the Norwegian University of Science and Technology. A quote was also used by the Project Manager of the Department of Biotechnology of the institute, Sabina P. Strand, and she supported this discovery. 

Clearly, the bias of this article is all in favour of this advancement. Although it was more of a report more than anything else, there was still very little about the negative aspects of this discovery. There was no mention of the disadvantages. The whole piece appeared to hold a very hopeful stance about the use of chitosan nanoparticles in gene therapy for the deaf and hard of hearing.