Method to prepare Banana Agar medium.

[Tripthi B]

Preparation of Banana Agar medium

 

Requirements (100ml of the medium) –

1.       One ripe yellow banana.

2.       2 grams of agar

3.       Yeast pellets

4.       Distilled water

5.      4 Glass bottles (200ml)

6.      150ml beaker

7.      Funnel

8.      Mortar and pestle

9.      Hot pan

10.   Autoclave

11.   Cotton

12.   Protective gloves

13.   Glass rod

14.   Spatula

 

Procedure –

-          Weigh exactly 40 grams of the banana and make a  fine paste using mortar and pestle

-          Now pour the paste into the beaker. Use distilled water to remove the paste which is stuck on the surface of the mortar. (Use only meagre quantity of distilled water)

-          Now add Distilled water in the beaker till the level reaches 98ml.

-          Turn on the hot pan and heat the beaker for 4 minutes till the contents are lukewarm.

-          Once it is lukewarm, add agar and start stirring immediately.

               [Note :- Stir constantly to avoid formation of lumps of Agar in the solution.]

-           Wait till the solution starts boiling. Then, using gloves pour out 25ml of the solution into each bottle using a glass funnel. Plug them with cotton and set it to autoclave at 120°C for 20 minutes.

-           After autoclaving, allow the medium to cool and solidify by keeping it at room temperature for one hour.

-           Now add 2 yeast pellets in each bottle and tilt the bottles to check if the medium is completely solidified. If yes, you medium is now ready for transfer!

 

[MC Arunan]

Dear all,

First:

Could you guys who are part of this research program, immediately write a line of comment  by clicking Reply All button, on what Tripthi has written, here?

 

 This will tell us how many people of the neuroius are currently part of this conversation. Even if some one is not able to come and participate in research at the HBCSE, TIFR< Mankhurd because of some logistical problem, but would like to be part of this course of Collaborative Undergraduate Research, may please chip in with his/her comments.

 

Second:

I would like people in the group not start a new mail, evry time when you correspond on this project; but should continue writing on this mail by clicking Reply All button, so that there is continuity of our conversation/discussion.

 

Third:

If any one has serious problem in accesing emails regularly, please pass a word on that here or to Kshiteej.

 

Fourth and most mportant:

Whenever you write something to any one,lease write an introduction to what you write and why you write. For e.g. why is Tripthi giving the Banana Agar preparation method, here now? What is the context? From where did she get this method of preparation?

 

All this will help in our teaching-learning program. I am sure, if you are patient enough and follow certain pattern of communication like, to be considerate about all others whom you are addressing your mail, we all will become true 'ustads' in biology research, with in a very short time. You wouldn't know what has happened to you!!!! You will become a different person!

 

Our attempt is to make ourself different from what we started with!

 

Looking forward to comments.

 

 Cheers!

Arunan

[Kshiteej Sode]

On Tue, Apr 12, 2011 at 11:22 PM, Tripthi B <trip...@gmail.com> wrote:

Dear Sir etal,

Below are my comments in bold.

Preparation of Banana Agar medium

Banana Agar Medium is an affordable and easy-to-prepare medium which can be used to culture Drosophila Melanogaster (commonly known as fruit flies) .The ingredients are easily available and the recipe is easier. And as far as we have observed, the flies thrive well in the medium.

Requirements (100ml of the medium) –

1.       One ripe yellow banana.

2.       2 grams of agar (We use agar agar of the bacto company but one can use the agar agar powder provided by their lab. )

3.       Yeast pellets(Baker's Yeast is easily available in the market. I used the Baker's delight company)

4.       Distilled water

5.      4 Glass bottles (200ml) (For this we used the Aarey Lassi bottles found in any aarey milk booth in mumbai.)

6.      150ml beaker (This is wrong . We use the 1000ml beaker. A bigger beaker makes it easier to stir the medium)

7.      Funnel ( Recommended to use a funner with a bigger mouth. Although banana medium flows easily, it takes a lot of time to flow through a smaller orifice and many a times it hardens while travelling through the funnel, therefore blocking it.)

8.      Mortar and pestle

9.      Hot pan (Bunsen Burner also could work)

10.   Autoclave

11.   Cotton (Non Absorbent. We do not want it wet after autoclaving.)

12.   Protective gloves

13.   Glass rod

14.   Spatula

                15. Tissue Paper

 

 

Procedure –

-          Weigh exactly 40 grams of the banana and make a  fine paste using mortar and pestle

-          Now pour the paste into the beaker. Use distilled water to remove the paste which is stuck on the surface of the mortar. (Use only meagre quantity of distilled water).

-          Now add Distilled water in the beaker till the level reaches 98ml.

-          Turn on the hot pan and heat the beaker for 4 minutes(that is 4 minutes after the hotpan has heated up not as soon as you turn it on. Also 4 minutes on the bunsen burner is good enough) till the contents are lukewarm.

-          Once it is lukewarm, add agar and start stirring immediately.

               [Note :- Stir constantly to avoid formation of lumps of Agar in the solution.Lumps will be like big beads of solidified agar.You will have to break them down in case you notice any , using a spatula or a glass rod. These lumps reduce the amount of available agar if not broken down.]

-           Wait till the solution starts boiling. Then, using gloves pour out 25ml of the solution into each bottle using a glass funnel. Plug them with cotton (which will be shaped into a plug) and set it to autoclave at 120°C for 20 minutes.

-           After autoclaving, allow the medium to cool and solidify by keeping it at room temperature for one hour.(Do not transfer the flies immediately as they will die. Even after the medium has cooled let it dry. Hence the one hour. Otherwise the flies will get stuck to the medium and die. After that wrap some tissue around the spatula and wipe the insides of the bottle with it.)

-           Now add 2 yeast pellets in each bottle and tilt the bottles to check if the medium is completely solidified. If yes, you medium is now ready for transfer!(Yeast ferments the medium releasing alcohol, which makes the females to get gravid.)

 

 

[MC Arunan]

Dear all,

 I am waiting for others like Keith to comment as well. In fact, Tripthi and Kshiteej should have more discussions through this forum. Since Kshiteej attempts to correct on wgat Tripthi wrote Tripthi should comment.

Further, Kshiteej should also critically evaluate his comments again along with Trpthi's write up again. I am tempted to make some comments. But i shall wait till Tripthi and Kshiteej settles among themselves.

But at the same time we do not have much time to spend in settling this issue.

So, I will ask them one question on the agar: why are you not putting banana and the necessary amount of agar and mix them first before making up the volume to 100 mLand cook it?

 

Arunan 

[Keith Costa]

On Fri, Apr 15, 2011 at 10:53 PM, Kshiteej Sode <kshite...@gmail.com> wrote:

On Tue, Apr 12, 2011 at 11:22 PM, Tripthi B <trip...@gmail.com> wrote:

Dear Sir etal,

Below are my comments in red.

Preparation of Banana Agar medium

Banana Agar Medium is an affordable and easy-to-prepare medium which can be used to culture Drosophila Melanogaster (commonly known as fruit flies) .The ingredients are easily available and the recipe is easier. And as far as we have observed, the flies thrive well in the medium.

Requirements (100ml of the medium) –

1.       One ripe yellow banana.(which type of ripe yellow banana are we using in particular? please specify)

2.       2 grams of agar (We use agar agar of the bacto company but one can use the agar agar powder provided by their lab. )

3.       Yeast pellets(Baker's Yeast is easily available in the market. I used the Baker's delight company)

4.       Distilled water

5.      4 Glass bottles (200ml) (For this we used the Aarey Lassi bottles found in any aarey milk booth in mumbai.)

6.      150ml beaker (This is wrong . We use the 1000ml beaker. A bigger beaker makes it easier to stir the medium)

7.      Funnel ( Recommended to use a funner with a bigger mouth. Although banana medium flows easily, it takes a lot of time to flow through a smaller orifice and many a times it hardens while travelling through the funnel, therefore blocking it.)

8.      Mortar and pestle

9.      Hot pan (Bunsen Burner also could work) (why don't we directly mix the medium and autoclave it? why use a hot pan to heat it first?)

10.   Autoclave

11.   Cotton (Non Absorbent. We do not want it wet after autoclaving.)

12.   Protective gloves

13.   Glass rod

14.   Spatula

                15. Tissue Paper

 

 

Procedure –

-          Weigh exactly 40 grams of the banana and make a  fine paste using mortar and pestle

-          Now pour the paste into the beaker. Use distilled water to remove the paste which is stuck on the surface of the mortar. (Use only meagre quantity of distilled water).

-          Now add Distilled water in the beaker till the level reaches 98ml.(how will i know exactly when it reaches 98ml? there is no such graduation on the beaker?)

-          Turn on the hot pan and heat the beaker for 4 minutes(that is 4 minutes after the hotpan has heated up not as soon as you turn it on. Also 4 minutes on the bunsen burner is good enough) till the contents are lukewarm (How warm is this "lukewarm" exactly? It could vary from person to person. Could you specify?).

-          Once it is lukewarm, add agar and start stirring immediately.

               [Note :- Stir constantly to avoid formation of lumps of Agar in the solution.Lumps will be like big beads of solidified agar.You will have to break them down in case you notice any , using a spatula or a glass rod. These lumps reduce the amount of available agar if not broken down.]

-           Wait till the solution starts boiling. Then, using gloves pour out 25ml of the solution into each bottle using a glass funnel. Plug them with cotton (which will be shaped into a plug) (How exactly do you make these plugs?). and set it to autoclave at 120°C for 20 minutes.

-           After autoclaving, allow the medium to cool and solidify by keeping it at room temperature for one hour.(Do not transfer the flies immediately as they will die. Even after the medium has cooled let it dry. Hence the one hour. Otherwise the flies will get stuck to the medium and die. After that wrap some tissue around the spatula and wipe the insides of the bottle with it.)

[MC Arunan]

Dear all,
1. Why should the fly come to a ripe banana and not to an unripe banana?

2. And how does it decide that it is ripe enough?

3. What type of cognitive process the fruit fly will have to 'understand the biochemistry of ripening'.
4. What understanding do we have on the biochemistry of ripening of banana?

Hope , some of you, if not all, will give some idea on these, to start a discussion.
Cheers!
Arunan

[Kshiteej Sode]

Sir etal,

Below are my comments in blue.

 

1. Why should the fly come to a ripe banana and not to an unripe banana?

 

• It is possible that flies prefer sweet taste of the ripe banana rather than the plain taste of the unripe banana since the ripe banana has more sugar content.

•  

• Also connected to this, the rise in the sugar lever could lead to a rise in the water level inside the banana ( as with most fruits) , which maybe suitable conditions for the fly to feed on.

•  Also a fly wants to lay its eggs in a place in which its larvae could have an ample supply of food to grow and change into adults, therefore a medium with more sugar would be ideal.
  

2. And how does it decide that it is ripe enough?

Like I had mentioned above, it is possible it judges the same basic way we do, i.e. by taste. If the banana is sweet in taste it is ripe  and if it is plain tasting or non sweet tasting it is unripe.

3. What type of cognitive process the fruit fly will have to 'understand the biochemistry of ripening'.

 Since the fly has to perceive the smell of the chemicals given out by the ripened fruit such as ethylene ( read comment on q.4) a probable cognitive process would be some form of perception such as olfaction .

Another probable process would be association, since the fly would link the particular odour or taste with the concept of an ideal feeding ground and egg laying site (ripe banana).
Therefore the fly would be acknowledging the fact that the fruit which is ripening is releasing some chemicals which were not there in its previous unripe stage, which brings changes in flavor as well as smell, and also make it a suitable place to feed and lay eggs. This would make the fly go to that particular fruit.

4. What understanding do we have on the biochemistry of ripening of banana?

 

The way bananas ripen is that there is commonly a ripening signal...a burst of ethylene production.(Ethylene is a simple hydrocarbon gas (H₂C=CH₂) that ripening fruits make and shed into the atmosphere.) Therefore we get the characteristic odour of the fruit.

Now here are some of the associations we make with ripe bananas .

a. Raw bananas are hard while ripe bananas are soft. ( This is because unripe/raw bananas contain a chemical called pectin which acts like glue between the cells in the banana and its peel , and when the ripening process is triggered something known as the  pectinase enzyme is released which breaks down the pectin therefore making the fruit softer.

b. Raw bananas are green while ripe bananas are yellow. (This is because raw bananas contain chlorophyll, which is present in all green plants, but during ripening hydrolases break down chlorophyll molecules in the banana. The green pigment of chlorophyll is destroyed and replaced by yellow, red or blue pigments. Depending on the type of banana, the result is either the golden yellow color of our favorite dessert banana, or shades of red or purple for other banana varieties.)

c.Raw bananas taste plain while ripe bananas taste sweet : This is because raw bananas contain starch which do not have a sweet taste. During ripening the amylase breaks down the starch into glucose , which gives the bananas its sweet taste.

it is a possibility that Ethylene apparently "turns on" the genes that are then transcribed and translated to make these enzymes. The enzymes then catalyze reactions to alter the characteristics of the fruit.

Please comment.

Thank you,
Kshiteej Sode

 

Hope , some of you, if not all, will give some idea on these, to start a discussion.
Cheers!
Arunan

[Tripthi B]

Hello, 

In reference to your previous male - Why the fly should come to ripe banana and not to unripe one?

As the fruit ripens, the tissue becomes softer and degrades. It is easier to break it down. Also, there are changes in the aroma (formation of acetates, alcohols and carbonyl compounds) during the metabolic pathways. These changes influence the growth of the flies. Using their sense of smell, they differentiate between different stages during the ripening of the banana.

 

Sir, I will be going to lab tomorrow to transfer the flies to A.3.0 and B.3.0 

Last Saturday, I had been to the lab. We had transferred the flies from A.0.0 and B.0.0 to A.1.0 and B.1.0 at 11am. 

30 males and 20 females in A.1.0

40 males and 30 females in B.1.0.

Thankyou.

[Kshiteej Sode]

Sir etal,

Today we observed :

NO larvae ( first or second instar ) in bottles A.0.0 and B.0.0 , both of which were 2 days and 12 hours + or - old today at 11am
NO larvae ( first or second instar ) in bottles A.1.0 and B.1.0 , both of which were 1 day and 12 hours + or - old today at 11am

We prepared standard cornmeal medium using a recipe given by Dr. Arunan to us, and accordingly made the medium (recipe and procedure attached with this email) . We then transferred the medium ( after autoclaving ) to four bottles containing 25 ml each. Since we had two bottles remaining, which were prepared on Friday the 16th of April, 2010, we transferred the flies from

bottles A.1.0 and B.1.0 to A.2.0 and B.2.0 .

Each bottle contains approximately 30 flies each, A.2.0 having 10 females and 20 males and B.2.0 having 15 females and 15 males.

Our plan for tomorrow, since Keith and myself have our results and report cards given to us. We might be late and if we have to line up for admissions as well tomorrow, we might not come ( apologies for giving such a rough idea, but we havent been given any clear idea by the college as well). In any case Tripthi will be coming to the lab, and she will be :

Transferring flies from A.3.0 and B.3.0 to A.4.0 and B.4.0 , the latter two bottles containing standard cornmeal medium prepared by the method attached with this mail.

I apologise for sending a mail so late, but I had work outside and reached late today. Please forgive me .

Thank you,
Kshiteej Sode

[MC Arunan]

Dear Kshiteej,

 

1. you have not been getting flies thriving in the Banana Agar Medium you guys prepared recently.

Can you try finding out (Analyse it!) the problem with that medium, assuming the flies are NOT non-cooperating with you guys. You also know that we got reasonably great culture with Banana Agar in the beginning, perhaps in January! Could you not check those results from the mails, if not from the log book?

Incidentally, could you replace a fresh log book for the missing one?

 

2. I am really worried about the Corn Meal Medium that you guys have made today! That is if the recipe that you send as attachment is what was followed verbatim!

For one, you have retyped the material I have given to you and I am not sure that every thing exactly the same. For one 4mL of acid in 100 Ml of medium looks a bit too much ! I may be wrong and you may be right.

But still, when you retype, there is enough possibilities of mistakes creeping in if you guys don't take adequate precautions.

 

Looking for you comment.

P.S. The Corn Meal Medium recipe material I gave you yeaterday was a part of a May Workshop of 2009, if I am not mistaken! It will be wise to chek it again either with Ankit or with the CCT group. The best is to check the Sophia MSc Thesis.

Arunan

[Kshiteej Sode]

Sir etal,

I am extremely sorry for the typo. it was 0.4 ml of propionic acid and 0.07 ml of orthophosporic acid i.e. 400microlitres of propionic acid and 70 microlitres of orthophosphoric acid. Sorry again, it was an accidental typo. And no, we didnt put 4 ml of acid in 100 ml of medium. Sorry again. The retyped word file is attached to this . Other than that, yes I have retyped the whole thing but I have also added some points which we followed in the lab like I mentioned that although a total sterile zone (eg. between burners ) is not compulsory, one should sanitize the area in which one is working. Another point I mentioned about the stirring while heating the medium.

I have replaced the log book in the lab.

• I went through the previous mails which I had written in January and February when we had a thriving cultures. There is a possibility, like you pointed the other day, that the banana agar I am preparing is not ripe enough. That could be the reason that the flies are not laying eggs ( based on the fact that we did not observe any larvae after 3 days in bottles A.0.0 and B.0.0 )
• I do have a question however. Previously (i.e. IN january and february) I just cooked the medium on a hot pan  and transferred them to the bottle. This month I have been autoclaving the medium. Now, I may be completely wrong ( please correct me if I am) but is there a possibility that the medium could be getting overcooked or burnt for cooking at such a high temparature? Just asking, I am not completely sure about this.

Tomorrow our aim would be to

• Transfer the Drosophila from A.3.0 and B.3.0 to Bottles A.4.0 and B.4.0 . All of the mentioned bottles contain 25 ml of Standard Cornmeal medium that has been prepared on the 18th of April 2011.

Also , since this mail is going out to all the members of the current neuronius group, I request those interested to please reply with the fact that they would like to continue in this group.

Thank You,
Kshiteej Sode

[MC Arunan]

Dear all,

 We shall continue the discussion on Fly's Cognition and the Banana ripening, here.

Thanks Kshiteej. But I am worried when you write things with such finality without bothering to give some reference as to from where you got this information.

My comments in green.

However, it is nice, that we have some communication started on a real biology question. Would Trpthi and Keith write there comments, here? One Sophia student, Minoshka is interested to join us in discussion. She has started some work on habituation in the snail, already, she says. May be, Kshiteej and Keith can take a leaf from her on your snail study which you have been prolonging with.

I am marking this mail to Minoshka too. 

Cheers!

Arunan

On Mon, Apr 18, 2011 at 11:09 PM, Kshiteej Sode <kshite...@gmail.com> wrote:

Sir etal,

Below are my comments in blue.

 

1. Why should the fly come to a ripe banana and not to an unripe banana?

 

• It is possible that flies prefer sweet taste of the ripe banana rather than the plain taste of the unripe banana since the ripe banana has more sugar content.

Do they have a colorimeter to estimate the sugar? The eclogical/biological explanation could be something like this: The flies are attracted by the smell of the banana that reaches it from a distance. (The smell could be some esters like acetates, alcohols or some other organic compounds like what Tripthi has mentioned in her mail.

It is an interesting question to ask whether the same chemical that triggers the ripening namely Ethylene is the odourant that invites the flies to the banana. I doubt!

However, what is the predominant smell that you get from a ripe-to-over-ripe banana? Will the same compound act as an odourant? Can we design an experiment to study and verify this?

Secondly, how do we rule out Ethylene as the odourant that attracts the fly to the ripe fruit??MCA

•  

• Also connected to this, the rise in the sugar lever could lead to a rise in the water level inside the banana ( as with most fruits) , which maybe suitable conditions for the fly to feed on.

•  Also a fly wants to lay its eggs in a place in which its larvae could have an ample supply of food to grow and change into adults, therefore a medium with more sugar would be ideal.

So, according to Kshiteej, flies are real brainy creatures that decide which brand of fruits to lay eggs on by looking at its nutritive value by reading from the label of contents!!!! Or, still better, by doing a biochemical test !!!!MCA

• 
  

2. And how does it decide that it is ripe enough?

Like I had mentioned above, it is possible it judges the same basic way we do, i.e. by taste. If the banana is sweet in taste it is ripe  and if it is plain tasting or non sweet tasting it is unripe.

 

For all you know, it may not worry whether the fruit is ripe or not but only

(a) associate the attractive taste of sugar with the smell that comes from the ripe banana and always is guided by the smell, unless it is fooled!! Can we design an experiment to prove or disprove this?

(b) It lays eggs perhaps because a particular odour triggers egg laying whether it is part of the fruit or applied to plain wet filter paper!!!Can we design an experiment to prove or disprove this?MCA

3. What type of cognitive process the fruit fly will have to 'understand the biochemistry of ripening'.

 Since the fly has to perceive the smell of the chemicals given out by the ripened fruit such as ethylene ( read comment on q.4) a probable cognitive process would be some form of perception such as olfaction . Can we design an experimnent o verify or falsify this claim?MCA

Another probable process would be association, since the fly would link the particular odour or taste with the concept of an ideal feeding ground and egg laying site (ripe banana). I am worried about Kshiteej's usage of "ideal"...ground. How do we prove whether the fly has an "ideal" concept for anything? Do we have, for that matter? Will it help us  in using such terms as "ideal"?MCA

Therefore the fly would be acknowledging the fact that the fruit which is ripening is releasing some chemicals which were not there in its previous unripe stage, which brings changes in flavor as well as smell, and also make it a suitable place to feed and lay eggs. This would make the fly go to that particular fruit.

Can't we rephrase it in fly's simple language, assuming that like most of us flies too have simple cognitive ability and simple behavioral responses. Most of us, perhaps, like Kshiteej, complicate it with high sounding language!!!! I am sure, Kshiteej himself will be able to frame it in simple verifiable or falsifiable statements.MCA

 

4. What understanding do we have on the biochemistry of ripening of banana?

 

The way bananas ripen is that there is commonly a ripening signal...a burst of ethylene production.(Ethylene is a simple hydrocarbon gas (H₂C=CH₂) that ripening fruits make and shed into the atmosphere.) Therefore we get the characteristic odour of the fruit. Do you mean the smell of banana is smell of ehylene?Please give reference.MCA

Now here are some of the associations we make with ripe bananas .

a. Raw bananas are hard while ripe bananas are soft. ( This is because unripe/raw bananas contain a chemical called pectin which acts like glue between the cells in the banana and its peel , and when the ripening process is triggered something known as the  pectinase enzyme is released which breaks down the pectin therefore making the fruit softer. Reference?

b. Raw bananas are green while ripe bananas are yellow. (This is because raw bananas contain chlorophyll, which is present in all green plants, but during ripening hydrolases break down chlorophyll molecules in the banana. The green pigment of chlorophyll is destroyed and replaced by yellow, red or blue pigments. Depending on the type of banana, the result is either the golden yellow color of our favorite dessert banana, or shades of red or purple for other banana varieties.) Reference?

c.Raw bananas taste plain while ripe bananas taste sweet : This is because raw bananas contain starch which do not have a sweet taste. During ripening the amylase breaks down the starch into glucose , which gives the bananas its sweet taste. No fructose?MCA

it is a possibility that Ethylene apparently "turns on" the genes that are then transcribed and translated to make these enzymes. The enzymes then catalyze reactions to alter the characteristics of the fruit. Ethylene is one of the plant hormones. It is nice if some one tell us which genes are triggered by ethylene during ripening.MCA

[MC Arunan]

Dear Kshiteej et al,

VVV MPORTANT.

I hope you realize the difference between 4mL and 0.4mL of an acid in a medium. The question is not just that. The question is how to build credibility of lab worker? In a scientist? For a scientist, his/her credibility is the most important. So,never allow yourself to be making loose comments for ones convenience. This,we do elsewhere and get away without much trouble, apparently. But in science and in laboratories it could be fatal!

That is the difference when you grow from a novice to a science worker!

 

I hope, we will uderstand this and keep this as most important in our life as a science student.

 

A typo is not a typo in science. It could be death of several thousand people as in Bhopal and several innocent flies and misleading several people, as in this case.

 

I wish, you take the lead and develop a series of Good Lab Practices today onwards!

 

All the best.

Arunan

[Kshiteej Sode]

sir etal,

My comments are in red

On Tue, Apr 19, 2011 at 9:17 PM, MC Arunan <mcar...@gmail.com> wrote:

Dear all,

 We shall continue the discussion on Fly's Cognition and the Banana ripening, here.

Thanks Kshiteej. But I am worried when you write things with such finality without bothering to give some reference as to from where you got this information.

My comments in green.

However, it is nice, that we have some communication started on a real biology question. Would Trpthi and Keith write there comments, here? One Sophia student, Minoshka is interested to join us in discussion. She has started some work on habituation in the snail, already, she says. May be, Kshiteej and Keith can take a leaf from her on your snail study which you have been prolonging with.

I am marking this mail to Minoshka too. 

Cheers!

Arunan

On Mon, Apr 18, 2011 at 11:09 PM, Kshiteej Sode <kshite...@gmail.com> wrote:

Sir etal,

Below are my comments in blue.

 

1. Why should the fly come to a ripe banana and not to an unripe banana?

 

• It is possible that flies prefer sweet taste of the ripe banana rather than the plain taste of the unripe banana since the ripe banana has more sugar content.

Do they have a colorimeter to estimate the sugar? The eclogical/biological explanation could be something like this: The flies are attracted by the smell of the banana that reaches it from a distance. (The smell could be some esters like acetates, alcohols or some other organic compounds like what Tripthi has mentioned in her mail.

It is an interesting question to ask whether the same chemical that triggers the ripening namely Ethylene is the odourant that invites the flies to the banana. I doubt!

However, what is the predominant smell that you get from a ripe-to-over-ripe banana? Will the same compound act as an odourant? Can we design an experiment to study and verify this?

Secondly, how do we rule out Ethylene as the odourant that attracts the fly to the ripe fruit??MCA

•  

• Also connected to this, the rise in the sugar lever could lead to a rise in the water level inside the banana ( as with most fruits) , which maybe suitable conditions for the fly to feed on.

•  Also a fly wants to lay its eggs in a place in which its larvae could have an ample supply of food to grow and change into adults, therefore a medium with more sugar would be ideal.

So, according to Kshiteej, flies are real brainy creatures that decide which brand of fruits to lay eggs on by looking at its nutritive value by reading from the label of contents!!!! Or, still better, by doing a biochemical test !!!!MCA NO , what i am trying to say is that a fly would prefer to lay eggs in a ripe banana. How it would judge that fact, is written below, which is NOT the entire explanation but a part of it since i DO NOT KNOW the entire part.

• 
  

2. And how does it decide that it is ripe enough?

Like I had mentioned above, it is possible it judges the same basic way we do, i.e. by taste. If the banana is sweet in taste it is ripe  and if it is plain tasting or non sweet tasting it is unripe.

 

For all you know, it may not worry whether the fruit is ripe or not but only

(a) associate the attractive taste of sugar with the smell that comes from the ripe banana and always is guided by the smell, unless it is fooled!! Can we design an experiment to prove or disprove this? I'm on it

(b) It lays eggs perhaps because a particular odour triggers egg laying whether it is part of the fruit or applied to plain wet filter paper!!!Can we design an experiment to prove or disprove this?MCA I'm on it

3. What type of cognitive process the fruit fly will have to 'understand the biochemistry of ripening'.

 Since the fly has to perceive the smell of the chemicals given out by the ripened fruit such as ethylene ( read comment on q.4) a probable cognitive process would be some form of perception such as olfaction . Can we design an experimnent o verify or falsify this claim?MCA

Another probable process would be association, since the fly would link the particular odour or taste with the concept of an ideal feeding ground and egg laying site (ripe banana). I am worried about Kshiteej's usage of "ideal"...ground. How do we prove whether the fly has an "ideal" concept for anything? Do we have, for that matter? Will it help us  in using such terms as "ideal"?MCA It could be possible that according to the fly, the smell of ethylene or the taste of the banana associates with the decision of whether or not it should lay eggs there. "Ideal" wasn't in the literal sense, and i apologise for using it.

Therefore the fly would be acknowledging the fact that the fruit which is ripening is releasing some chemicals which were not there in its previous unripe stage, which brings changes in flavor as well as smell, and also make it a suitable place to feed and lay eggs. This would make the fly go to that particular fruit.

Can't we rephrase it in fly's simple language, assuming that like most of us flies too have simple cognitive ability and simple behavioral responses. Most of us, perhaps, like Kshiteej, complicate it with high sounding language!!!! I am sure, Kshiteej himself will be able to frame it in simple verifiable or falsifiable statements.MCA In simple language the fly would prefer feeding on and laying eggs in the ripe banana, rather than the unripe , since the former has a sweeter taste and an odour which attracts the fly to it.

 

4. What understanding do we have on the biochemistry of ripening of banana?

 

The way bananas ripen is that there is commonly a ripening signal...a burst of ethylene production.(Ethylene is a simple hydrocarbon gas (H₂C=CH₂) that ripening fruits make and shed into the atmosphere.) Therefore we get the characteristic odour of the fruit. Do you mean the smell of banana is smell of ehylene?Please give reference.MCA No I mean that the characteristic odour of an overripe fruit is ethylene. I may be wrong on this please correct me if so.

Now here are some of the associations we make with ripe bananas .

a. Raw bananas are hard while ripe bananas are soft. ( This is because unripe/raw bananas contain a chemical called pectin which acts like glue between the cells in the banana and its peel , and when the ripening process is triggered something known as the  pectinase enzyme is released which breaks down the pectin therefore making the fruit softer. Reference? All of the information given below and here is a from a collection of different resources . Wikipedia and google
b. Raw bananas are green while ripe bananas are yellow. (This is because raw bananas contain chlorophyll, which is present in all green plants, but during ripening hydrolases break down chlorophyll molecules in the banana. The green pigment of chlorophyll is destroyed and replaced by yellow, red or blue pigments. Depending on the type of banana, the result is either the golden yellow color of our favorite dessert banana, or shades of red or purple for other banana varieties.) Reference? Wikipedia and google

c.Raw bananas taste plain while ripe bananas taste sweet : This is because raw bananas contain starch which do not have a sweet taste. During ripening the amylase breaks down the starch into glucose , which gives the bananas its sweet taste. No fructose?MCA

it is a possibility that Ethylene apparently "turns on" the genes that are then transcribed and translated to make these enzymes. The enzymes then catalyze reactions to alter the characteristics of the fruit. Ethylene is one of the plant hormones. It is nice if some one tell us which genes are triggered by ethylene during ripening.MCA http://www.actahort.org/books/398/398_17.htm

[Kshiteej Sode]

also the link that I have given for the genes triggerred by ethylene, I read it but did not fully understand. I would like you all( keith and tripthi) to read it as well and please explain to me if you do

[Kshiteej Sode]

Yes sir, I am extremely sorry for this, and it would not happen again. Thank you for pointing it out. I will keep what you said in mind

[MC Arunan]

Kshiteej,

Urgent.

 What time you guys are there at HBCSE lab on tomorrow (Wednesday)? Shama wants to come and work with you guys.

Please let me know ASAP.

I am marking this amil to Shama too.

Arunan

[Kshiteej Sode]

  We will be coming at 10.30 am sharp.

[MC Arunan]

Dear Kshiteej etal,

Shama will be reaching HBCSE at 11AM.  

Arunan

[MC Arunan]

Dear all,

Looking for comments on today's work on Drosophila and the discussion, we had at the NIUS lab, HBCSE.

 

And also the plan for Thursday, April 21st, 2011.

 

P.S. I am marking this mail to Minoshka too. So, Kshiteej's report on the snail study will be very much in order!

Cheers!

Arunan

[Tripthi B]

Hello,

We had been to lab today, me and Shama. Kshiteej and Keith were in their college for the whole day, so they couldn't come.

Also, the medium they had prepared yesterday was watery and so we couldn't transfer the flies. 

Since the lab is going to be shut tomorrow, we wont be able to go. 

 

Also, Kshiteej's net has crashed, he wont be able to reply to emails for some time.

Thank you.

The cornmeal agar medium they prepared yesterday turned out to be watery, as a result we couldn't transfer the flies. 

[MC Arunan]

Dear Tripthi and Shama,

What happened to the flies already,in the Corn Meal Medium bottles?

I thought you would be interested to know about their well being, egg laying and the larvae!

Please keep in touch. And also plan what to do on Saturday?

Arunan

[Tripthi B]

Hello,

Unfortunately, I couldn't see any eggs or  larvae in the bottles yesterday. :(

Today, we didn't go to the lab, as I mentioned earlier. 

Tomorrow, the lab being shut we wont be going. Also, Kshiteej has to go to college for admission procedure and to confirm his 2nd year subjects.

There is some kind of electricity problem near his residential area for 3 days or so, hence he cant email you. 

We will be going to the lab directly on Monday to check on the flies and also transfer them. 

Thank you.

[MC Arunan]

My dears,

 

1. That will be sure recipe how research should not be done!

Research and more so the organisms that is supposed to tell you their stories to the researcher do not wait for your convenience nor do they give an alarm call, before they are forced to quit this not-so-benign world!

 

(I will be going to HBCSE even today. You could have coordinated with me and come. Or I could do some work myself for you. if you so choose).

 

2. I am also amazed at the casualness with which you guys take the fact that the Corn Meal Medium you had attempted to prepare refuse to be solid !!!

 

3. Could we go over the methods you had followed and why it did not come up to your expectation? Please do not give up thinking and discussing even though you are not able to come to the lab.

 

4. There is enough to do even if you are not near the flies. Could Trpthi give more detail account of the current bottles she had observed when she visited the lab last with the date and time? Could others chip in and say some bit on the finding? Was Shama present with Tripthi on 21st April?

 

You may also call me up either at (Res) 022-2351 2560 or 022-2507 2224 (HBCSE)

Today, I will start from Sophias only after 3PM and expect to reach HBCSE at 4-30 ish. (Some former students are siiting to sort out a movie they made to be sent for an international competition).

 

5. Hope Minoshka's snails are as good eaters and poachers like Kshiteej's.

 

Cheers!

Arunan

[MC Arunan]

Dear all,

Please check this link and comment: http://www.youtube.com/watch?v=GYr8ZYMIkq0 

Cheers!

Arunan

[MC Arunan]

Dear all,

1.  I will request you to give a summary of what is happening in the lab

 

2. Please make a plan for  tomorrow's work . It will be wise we all agree on it.

 

3. Our earlier deadline for the thriving culture was last Thursday. Please see that we have sufficient good culture medium (both Banana Agar and Cron Meal) prepared and aslo plan to trap some local drosophila for culturing.

4. I am expecting a written report on snails from Kshiteej.

 

5.. Aashutosh will come to the lab at 11AM tomorrow. He is interested in our work. He just finished Biophysics from the Mumbai Univ.

 

Treat this as urgent.

Cheers!

Arunan

[Kshiteej Sode]

On Sun, Apr 24, 2011 at 7.24 PM, kshiteejsode@gmail.com

Dear all,

1. As of now we have bottles A.1 and B.1 and A.2 and B.2 ,containing banana agar medium, and A.3 and B.3 and A.4 and B.4 containing standard cornmeal agar medium.I will be observing these bottles tomorrow and report. I request tripthi and Shama to write their observations as of late.

2.Tomorrow we have a lot on our hands

• Firstly , we have to observe cultures bottles A.3.0 ,B.3.0, A.4.0 and B.4.0 for any eggs, first second or third instar larvae. A.4.0 abd B.4.0 have been 5 days and 12 hours + or - old and we expect eggs, larvae ( first, second and third) and probably pupae in those bottles.
  

• We will be transferring those flies into fresh cornmeal medium that Shama had prepared on saturday the 23rd ( I request her to please mail us what steps she followed to make the medium).

• We will be preparing Cornmeal and Banana agar Medium tomorrow and we will be filming it.Cornmeal will be 100 ml four bottles and banana agar will be 100ml four bottles (each bottle having 25ml each).
  

If there is anything else please reply. I'm having limited time on the cyber cafe therefore i may have forgotten something in a hurry.

I will be writing the snails report tomorrow in the lab where I can access internet for ample time. I apologize for the delay.

Thank you ,
Kshiteej

[Tripthi B]

Hello,

I last visited the lab on Thursday. Since, the medium prepared was  liquid we couldn't transfer the flies. So we again prepared cornmeal agar medium for two bottles but, even that was liquid after autoclaving! 

We prepare two more bottles of corn meal medium, but didn't autoclave them. ( Just for comparative study)
 Also, I didn't observe any larvae in the previous bottles, i.e A.4.0 and and B.4.0.

Thank you. 

[MC Arunan]

Dear Tripthi,

Thanks for your report, even though very short. Please note my comments and queries for clarifications in green below.

Hope to meet you in the Lab at 11 AM.

Arunan

 

On Sun, Apr 24, 2011 at 11:38 PM, Tripthi B <trip...@gmail.com> wrote:

Hello,

I last visited the lab on Thursday (Pl give the date for full clarityMCA). Since, the medium prepared (on which date and by whomMCA) was  liquid we couldn't transfer the flies. So we again prepared cornmeal agar medium (based on which protocol? MCA) for two bottles but, even that was liquid after autoclaving! 

 

We prepare two more bottles of corn meal medium (how much amount?MCA), but didn't autoclave them. ( Just for comparative study) Very good. But what happened to that? Did you cook it and poured into bottles for solidification? Did it solidify? MCA)

 

 Also, I didn't observe any larvae in the previous bottles, i.e A.4.0 and and B.4.0. (flies transferred into these bottles on which date?MCA)

 

What do you suggest we should do now onwards, to meet our objective?MCA

Tripthi, Please give your specific responses so that we can advance in our work. It will be nice if each one including Shama will give his/her suggestions based on our work so far. MCA

[MC Arunan]

Dear Kshiteej and Keith,
Sorry, I did not know you guys had to go early, today. Please remind me in future,  in case, I go on with my rambling and commentaries!
Affly,
 Arunan