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18 Oct 2018

Considering that there are pathogenic and non-pathogenic strains of bacterial species (E. coli for example), and reflecting on the 5 traits of virulence, describe how non-pathogenic strains could become pathogenic (i.e. what is likely to change). Note, you will needed to discuss both likely changes in the organism as well as any in the host. Appropriate examples will provide clarity to your answer.

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Irving HeathcoteLv2

21 Oct 2018

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2.Conclusion:

What have you learned from your study?

Interpret your data/ results:

Do your results support of disprove your hypothesis?

Compare and contrast your result with those of previous research.

Significance of the results: âBig Pictureâ

What is the global impact of your results?

What questions remain unanswered?

What kinds of experiments can come out of your study?

i have lab for biology and i need help with the Lab Report

the lab name is Bacterial Transformation Lab

1. Introduction:

Introduce the background and the nature of the problem your experiment is investigating.

Summarize the current knowledge of your subject.

Use examples of other research that have examined the same or a similar topic as your experiments.

Ending your introduction:

State your hypothesis

State your predictions

Give a brief statement about how you tested your hypothesis.

please help me with it is important for my lab class tomorrow

that is the lab i put the info please help me for the intro and for number 2 please be clear please

i would be happy if you help me it is due tommorrow i realy need your help on the intro and number 2 please be clear and show clear work hope you do it because it is due tomorrow

Bacterial Transformation Lab

Genetic engineering is one of the newest applications of basic knowledge in biology. It involves the isolation of specific genes from one organism and the insertion of those genes into a second organism of the same, or even different, species. Remember that a gene is a piece of DNA which codes for a product, usually a protein, which gives an organism a particular trait. The development of these techniques has generated considerable excitement and answered many questions, but it has also raised questions. Many scientists and others see genetic engineering as offering opportunities to make life better, for example, by exploring how genes are regulated, by curing diseases of genetic origin, by adding desirable traits to agricultural crops such as the ability to fix nitrogen in corn and pest resistance in cotton, and by genetically altering bacteria with genes enabling them to digest oil spills.

For almost 100 years, it has been possible to isolate DNA from cells, but only in the last 40 years or so has its function been understood. Your textbook discusses the work of such investigators as Fred Griffith and Oswald Avery, who demonstrated that if DNA was isolated from a pneumonia-causing strain of bacteria and added to cultures of nonvirulent bacteria, the recipient cells were transformed into virulent types that caused pneumonia. These transformation experiments were the first to show that genes could be artificially transferred in the laboratory. Since the time of those experiments (Avery's work was done in the 1940s), our knowledge of gene structure, function and control has increased astronomically. The application of this knowledge has created the field of genetic engineering.

Modern genetic engineering techniques depend on three critical factors:

A suitable host organism in which to insert the foreign gene;

A vector to carry foreign genes into the host; and

A means of isolating the host cells that have taken up the foreign gene.

The host organism

The most commonly used host organism is the gut bacterium Escherichia coli (E. coli). Its chromosome is a single large circular DNA molecule, called the genomic DNA, containing about 4 x 10⁶ base pairs. Not every cell will take up foreign DNA when exposed to it, but E. coli grows rapidly, dividing in less than 20 minutes, so that a single cell can give rise to a billion genetically identical descendants in a matter of 10 hours. Thus, a few transformed cells can provide a large number of offspring within a day. The strain we are using is K-12.

The vector

A vector is a DNA molecule used as a vehicle to carry genes from one organism to another. This DNA molecule can be modified by gene-splicing techniques using restriction enzymes and ligases so that it carries the genes of interest (essentially a cut-and-paste operation). Sometimes viruses are used as vectors, but for E. coli, plasmids are often used. A plasmid is a small circular DNA molecule containing 1000 to 200,000 base pairs. Plasmids exist naturally in many strains of E. coli and other bacteria. Plasmids replicate as the cell grows, independent of replication of the genomic DNA. These plasmids are transmitted to each of the product cells during cell division. Plasmids carrying genetic information that is beneficial to the host cell are maintained in a given population by natural selection. Plasmids frequently carry genes that confer antibiotic resistance, an obvious benefit.

When E. coli cells are exposed to plasmids or any other foreign DNA, some of the cells, called competent cells, will take up the DNA. We can induce cells to become competent by treating them with divalent cations, such as Ca⁺⁺, followed by a brief exposure to high temperature, called a heat shock treatment. Exactly how this treatment causes cells to become competent is not understood, but it is described as making the membranes "leaky" so that large DNA molecules (like plasmids), which would not normally pass through the cell membrane, can enter the cell. This treatment does not make all cells competent, but it greatly increases the number of competent cells. Once in a cell, the plasmids replicate and are passed to the product cells during cell division.

The selective medium

The last requirement for genetic engineering is a means of isolating host cells that have taken up the gene of interest. The techniques used depend on the growth requirements of the host organism. For example, each species of bacteria has particular nutrient requirements. The composition of the growth medium (agar or broth) can be modified to allow growth of only certain bacteria -- for example, by adding or removing nutrients or other chemicals from the medium mixture. This modified medium is called a selective medium, because it selects for the growth of only some species. By introducing an antibiotic such as ampicillin into the medium in which the bacteria are grown, you will select for growth of only those bacteria carrying the antibiotic-resistance gene on newly acquired plasmids. In a matter of days, billions of antibiotic-resistant cells, all with the plasmid, can be grown.

Genetic engineers use a modification of this technique to insert a foreign gene into E. coli. In simplified terms, the plasmid (already carrying an ampicillin resistance gene) is modified by inserting the gene of interest. The gene of interest has been isolated from another source; for example, the gene for human insulin has been isolated from the human genome. The modified plasmid, carrying the inserted gene, is then mixed with competent E. coli and the bacteria are placed in a medium containing ampicillin. Only those cells that have the plasmid will grow in the medium, and they are also the cells carrying the insulin gene (in their plasmids). These selected cells can now be used to manufacture insulin, which can be used for insulin therapy by diabetics.

The genes

In the following experiment, you will insert a plasmid into E. coli. The plasmid you will use carries the gene bla, which codes for a protein (beta-lactamase) that is secreted by the bacteria, inactivating the ampicillin in the agar and allowing for bacterial growth. The plasmid also carries an indicator gene. The indicator gene we are using was isolated from a bioluminescent jellyfish, Aequorea victoria. It codes for Green Fluorescent Protein (GFP).

The GFP gene has been modified to include a regulator system that can be used to control the expression of the gene. Gene expression in all organisms is carefully regulated to allow for adaptation to differing conditions and to prevent wasteful overproduction of unneeded proteins. The genes involved in the breakdown of different food sources are good examples of highly regulated genes. For example, the sugar arabinose is both an energy source and a carbon source for bacteria. The bacterial genes that make digestive enzymes to break down arabinose for food are not expressed when arabinose is not in the environment. But, when arabinose is present, these genes are turned on. When the arabinose runs out, the genes are turned off.

Arabinose initiates transcription of these genes by promoting the binding of RNA polymerase. In the genetically engineered pGLO DNA, some of the genes involved in the breakdown of arabinose have been replaced by the jellyfish gene GFP. When bacteria with this plasmid are grown in the presence of arabinose, the GFP gene is turned on and the bacteria glow green in UV light. When arabinose is absent form the growth medium, the GFP gene remains turned off and the colonies appear white. This is an example of the central molecular framework of biology in action: DNA ? RNA ? protein ? trait.

In summary, you will render E. coli cells competent to take up plasmid DNA. The plasmid carries two identifiable phenotypic markers:

The beta-lactamase or bla gene codes for resistance to the antibiotic ampicillin. We will use this to select for bacteria that have taken up the plasmid.

The pGLO gene codes for Green Fluorescent Protein (GFP), which is switched âONâ if arabinose is present.

Safety Procedure

For your own safety and the safety of others, it is essential that you follow all instructions about handling bacteria and disposal of materials. When you finish work for the day, swab your table with disinfectant. WASH YOUR HANDS thoroughly with soap before leaving the lab for any reason, and at the end of the day after you have cleaned your table. Report any spills to your instructor.

List of Materials

Prepared agar plates (2 LB, 2 LB/amp, 1 LB/amp/ara)

Transformation solution (50 mM CaCl₂, pH 7.4)

LB broth

1 pack of inoculation loops

Sterile transfer pipets

1 foam microtube holder w/ tubes

E. coli starter plate

1 red biohazard bag for loop disposal (common use â Loops/pipets only - NO PAPER!!!)

beigefox320

1. Discuss and decide upon characteristics that define each of the following broad groups

(domains, kingdoms) of organisms in order to attempt to define these major groups of life

on the planet. Although many characteristics may overlap from one group to the next,

attempt to define some traits that could be used to definitively (exclusively) place an

organism into a specific group. Finally, for each, what would the small subunit ribosomal

rRNA gene sequence tell us?

Viruses

Bacteria

Archaea

Protists (algae, protozoa)

Fungi

Animals

Plants

2. For the previous groups, which include representatives of ones that live as part of the

âhuman ecosystemâ? Provide some examples of each and where they can be found,

including both those that are part of our normal microbiota (i.e., not pathogens) and some

that are.

3. Considering the above and what weâve covered about these groups of organisms,

identify some structures/processes that hypothetically could be used to inhibit or kill

different types of pathogens without (hypothetically, at least) harming the human host.

4. Consider the microbial world. Which has a greater impact or importance â pathogens,

or benign microbes? Explain, giving examples.

5. A number of antibiotics target the bacterial 70S ribosome, exploiting structural

differences from the 80S ribosome found in humans and other eukaryotes. Although

effective at killing bacteria, these drugs can still have some toxicity to humans. In the

context of the endosymbiotic theory of evolution, provide a hypothesis as to why this

might be.

viridianeel412

Question:

Organisms living in Antarctica are thought to be particularly susceptible to change in climatic conditions. How might future climate changes affect the distribution of Antarctic organisms?

Describe the current Antarctic climate and factors that are likely to affect environmental change. Make predictions about future changes to the environment and how this might impact the distribution of organisms in the region.

Below has the format that it could be answered.

below the template, it has exampler template with different topic.

------ template

What do you think is the answer to the question? / What is your perspective on the topic? This is your stance or thesis.

Why do you think this? Give at least three supporting reasons (main points)

-
-
-

Use your stance and supporting points to build your plan. For each main point give a brief explanation, some evidence and/or examples you will use to support it. Provide references where appropriate.

I. Introduction

Possible ideas for the introduction:

(What does the reader need to know to understand the essay? Write as a statement rather than a question or keyword)

Proposed thesis statement:

II. Body - The number of body paragraphs will vary from essay to essay, you choose how many you need.

- Topic sentence:

(Include the main point making it clear how it supports your stance)

Explanations /Evidence/ Examples (include references with each fact (author, date)):

Write as a statement of fact not as a question, heading or keyword

- Topic sentence (include the topic and how it supports your stance):

Explanations /Evidence/ Examples (include references (author, date)):

Write as a statement of fact not as a question, heading or keyword

-Topic sentence (include the topic or how it supports your stance):

Explanations /Evidence/ Examples (include references (author, date)):

Write as a statement rather than a question or keyword

III. Conclusion:

(What are the broad implications of the essay?)

DRAFT WRITING

Introduction and first body paragraph

------- exampler template with different topic

I. Introduction

Possible ideas for the introduction

Climate change

Process of OA

Somehow lead to SO

Thesis Statement : All organisms living bathed in an acidic environment will incur a metabolic cost as a result of the energy expended to maintain functioning cell chemistry this results in reduced growth and reproductive outputs. As a consequence population numbers will drop with a flow on reduction in overall ecosystem biomass and diversity.

II. Body

Main Point: OA has a metabolic cost for all marine organisms and affects growth, reproduction and nutrient value as a food source.[CA2]

Examples/Details/Explanations (include references (author, date)) :

Most pronounced in small organisms but is variable and dependant on pH

e.g. krill, gill & haemolymph regulation issues (Flores et al, 2012) ;

e.g. phytoplankton, reduced nutritional value;

e.g. shell forming organisms dissolution of CaCO₃ shells e.g. pteropods

Main Point: The metabolic cost on the individual results in lower numbers of individuals in a population.

Examples/Details/Explanations (include references (author, date)):

This cost results in reduced fertilisation, extended larval development time, deformities

e.g. seastar (Gonzalez-Bernat et al, 2014) detail effects at different pH levels;

e.g. urchin (Sewell et al 2014)

Main Point: A reduction in biomass of any one species has flow on effects up and down the food chain and could be especially pronounced in the unique Southern Ocean ecosystem.

Examples/Details/Explanations (include references (author, date)):

SO characterised by high nutrient low productivity, âwasp-waistâ structure and short food chains

e.g. phytoplankton as primary producers

e.g. krill as important food source

e.g. pteropods as nutrient cyclers

Main Point: Reduced food availability will likely alter interspecific interactions and may result in some species being driven to extinction.

Examples/Details/Explanations (include references (author, date)):

a. competition will increase as a result of less food e.g. between larger birds and mammals as a flow on from loss of krill

b. shell forming species will be at greater risk of predation due to weaker shells

c. e.g. seastars as keystone species maintaining diversity

III. Conclusion

Effects at organism level will impact on total biomass of that species and those that depend on it for food, therefore the overall productivity and biomass of the SO ecosystem will be reduced and loss of species diversity is expected.

Other Ideas to Conclude:

Effects growth and reproduction and is especially costly for shell forming organisms.

Will see changes as a result of effects on organisms with key functions within the SO ecosystem.

Ideas to leave the reader with (clincher):

Global significance of effects of OA on SO (something related to carbon sink and sequestering of Carbon) or perhaps reminding reader that OA is only one consequence of climate change and that organisms will also be at risk from rising sea temps, melting ice, and invasive species.

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