Question

10. a.Many recent studies have shown a relationship between heavy metal tolerance and antibiotic resistance. Find one primary source (scientific research article) on this topic that has been published since 2010 and provide a copy of the abstract and DOI (Digital Object identifier). The paper can originate in any country and test any potential interactions in agricultural manure, wastewater, aquaculture, beach safety. (4 marks) List the main conclusions of the research team from the abstract only (2 marks) b. Explain the message of the graphic below in your own words. How does a bacteria cell equipped with a resistance plasmid respond to an environment that contains both antibiotics and metals all the time 22 marks) Co-resistance The object shown at 11 o'clock on the cell is an efflux pump. Co-regulation means that the cell controls the machinery necessary for both kinds of resistance genes plasmids at the same time because they are on the same plasmid (It is not possible to duplicate one gene and not the other when a plasmid is copied). Plasmid Co-regulation Co-expression Arti Co-expression means that the responses special enzymes etc) are produced by the cell's ribosomes at the same time. Review the 1311 lectures on Metals, Bacterial Genetics and Antibiotics if necessary,

Answer 1

QUESTION 10 (a)

Ans :The bacterial strain Bacillus sp. possessing the properties such as heavy metal tolerance and antibiotic resistance were isolated and studied.The isolated strain showed amylase and protease positive ,spore forming,Gram positive bacilli and exhibited growth in wide range of substrates,temperature(30-40 degree C)and pH(6-11).Based on the 16Sr DNA molecular technique,it was found that the isolate was Bacillus sp. and has a mega plasmid.Moreover it was found to grow in presence of a wide range of metals namely nickel,cadmium,chromium and cobalt and also it was found that the isolate was resistance to a wide range of antibiotics namely kanamycin,Ampicillin and Methicillin.

When Plasmid isolation and curing was carried onto the bacterial strain it was found that the heavymetal tolerance and antibiotic resistance properties of the isolated strain have been lost.

It is thought that a correlation exists between metal tolerance and antibiotic resistance in bacteria because of the likelihood that resistance genes to both (antibiotics and heavy metals )may be located closely together on the same plasmid in bacteria.

This result confirms a relationship between antibiotic and heavy metal resistance with plasmid.

10 (b)

Ans :From the above graphic, it can be depicted that the bacterial cell consist of plasmid which possess genes resistance to antibiotics and heavy metals.

The antibiotic resistant gene and the heavy metal tolerance gene are present close to each other in the plasmid.

The antibiotic resistant genes and heavy metal tolerance genes present on the bacterial plasmid are expressed or regulated at the same time by a common regulator when the bacterial cell encounters the antibiotics and heavymetals present in the environment.

Definition of key terms :

a)Cross-resistance:where one resistance system confers resistance to both an antibiotic and a metal

b)Co-resistance:where resistances to antibiotics and metals are physically co-located on the same genetic element

c)Co-regulation / Co-expression : where expression of resistance systems to metals and antibiotics are controlled by a common regulator.