Hey guys,

I'm a college student and I'm trying to dig up information about the
evolutionary advantage of bromelain in pineapples. Could anyone give me a
few pointers or lead me in the right direction?

Thanks!

In article ,
Lambert wrote:

I'm a college student and I'm trying to dig up information about the
evolutionary advantage of bromelain in pineapples. Could anyone give me a
few pointers or lead me in the right direction?

Do an experiment. Buy a whole fresh pineapple. Peel and eat. Reflect
that domestic pineapples have been highly selected for palatability.

Note that cooked (e.g. canned) pineapple does not have the same effect.

I know about the effects of bromelin on polypeptide chains and how it
hydrolizes proteins. Also, the canning process denatures the enzymes via
heat. Hence you don't get the tingling sensation on your tongue (the
pineapple is actually catalysing proteins on your tongue.)

I'm just wondering about why the pineapple and other fruits (papayas,
pawpaws) have evolved to have bromelin enzymes. What exactly is the
particular survival advantage of having such a trait?

"Beverly Erlebacher" wrote in message
. ..
In article ,
Lambert wrote:

I'm a college student and I'm trying to dig up information about the
evolutionary advantage of bromelain in pineapples. Could anyone give me a
few pointers or lead me in the right direction?

Do an experiment. Buy a whole fresh pineapple. Peel and eat. Reflect
that domestic pineapples have been highly selected for palatability.

Note that cooked (e.g. canned) pineapple does not have the same effect.

Lambert schreef
I know about the effects of bromelin on polypeptide chains and how it
hydrolizes proteins. Also, the canning process denatures the enzymes via
heat. Hence you don't get the tingling sensation on your tongue (the
pineapple is actually catalysing proteins on your tongue.)

I'm just wondering about why the pineapple and other fruits (papayas,
pawpaws) have evolved to have bromelin enzymes. What exactly is the
particular survival advantage of having such a trait?

+ + +

One of the avenues to explore is the direct one:
these enzymes are in the fruits
the fruits are eaten, and hopefully the seeds are spread
the plants that has the fruits that are preferred by those animals that
spread the fruits the furthest or to the most suitable locations will
survive best
etc

Another is the systematic approach
in what plant groups do these enzyms occur?
do these plant groups have similar enzyms used for something else?
etc
PvR

I've done some rough research and all I can come up with is that the enzyme
may have something to do with the plant's method to acquire nutrients. The
crown at the top of the pineapple collects decomposing material and absorbs
nutrients this way.

I thought about the enzymes being appealing for eating etc. but Bromelin
hydrolizes proteins and would be generally uncomfortable for an animal to
eat (speculation)? Certainly when humans eat pineapples their tongues can
feel itchy/raw/red etc...


"P van Rijckevorsel" wrote in message
.. .
Lambert schreef
I know about the effects of bromelin on polypeptide chains and how it
hydrolizes proteins. Also, the canning process denatures the enzymes via
heat. Hence you don't get the tingling sensation on your tongue (the
pineapple is actually catalysing proteins on your tongue.)

I'm just wondering about why the pineapple and other fruits (papayas,
pawpaws) have evolved to have bromelin enzymes. What exactly is the
particular survival advantage of having such a trait?

+ + +

One of the avenues to explore is the direct one:
these enzymes are in the fruits
the fruits are eaten, and hopefully the seeds are spread
the plants that has the fruits that are preferred by those animals that
spread the fruits the furthest or to the most suitable locations will
survive best
etc

Another is the systematic approach
in what plant groups do these enzyms occur?
do these plant groups have similar enzyms used for something else?
etc
PvR

From: "P van Rijckevorsel"

I'm just wondering about why the pineapple and other fruits (papayas,
pawpaws) have evolved to have bromelin enzymes. What exactly is the
particular survival advantage of having such a trait?

+ + +

One of the avenues to explore is the direct one:
these enzymes are in the fruits
the fruits are eaten, and hopefully the seeds are spread
the plants that has the fruits that are preferred by those animals that
spread the fruits the furthest or to the most suitable locations will
survive best
etc

Another is the systematic approach
in what plant groups do these enzyms occur?
do these plant groups have similar enzyms used for something else?
etc

I think the question sounds like, "why would a plant develop an enzyme that
digests a potential seed distributor?" Maybe the seeds are distributed by a
some organism with a salivary component that neutralizes the bromelin, and this
is a way to get specificity for a distributor.

Sean



--
Visit my photolog page; http://members.aol.com/grommit383/myhomepage
Last updated 08-04-02 with 15 pictures of the Aztec Ruins.
Address mungled. To email, please spite my face.

This is assuming that a diet consists of pineaple only
PvR

Lambert schreef
I've done some rough research and all I can come up with is that the
enzyme may have something to do with the plant's method to acquire
nutrients. The crown at the top of the pineapple collects decomposing
material and absorbs nutrients this way.

I thought about the enzymes being appealing for eating etc. but Bromelin
hydrolizes proteins and would be generally uncomfortable for an animal to
eat (speculation)? Certainly when humans eat pineapples their tongues can
feel itchy/raw/red etc...

+ + +

"P van Rijckevorsel" wrote
One of the avenues to explore is the direct one:
these enzymes are in the fruits
the fruits are eaten, and hopefully the seeds are spread
the plants that has the fruits that are preferred by those animals that
spread the fruits the furthest or to the most suitable locations will
survive best
etc

Another is the systematic approach
in what plant groups do these enzyms occur?
do these plant groups have similar enzyms used for something else?
etc
PvR
....
Lambert schreef
I know about the effects of bromelin on polypeptide chains and how it
hydrolizes proteins. Also, the canning process denatures the enzymes via
heat. Hence you don't get the tingling sensation on your tongue (the
pineapple is actually catalysing proteins on your tongue.)

I'm just wondering about why the pineapple and other fruits (papayas,
pawpaws) have evolved to have bromelin enzymes. What exactly is the
particular survival advantage of having such a trait?

Perhaps the "purpose" is insecticidal. Ananas comosus wasn't always seedless
and the enzyme might have functioned as a toxin or repellant to insect larvae that
could have damaged the fruit before the seeds could be dispersed.


"Sean Houtman" wrote in message ...
From: "P van Rijckevorsel"

I'm just wondering about why the pineapple and other fruits (papayas,
pawpaws) have evolved to have bromelin enzymes. What exactly is the
particular survival advantage of having such a trait?

+ + +

One of the avenues to explore is the direct one:
these enzymes are in the fruits
the fruits are eaten, and hopefully the seeds are spread
the plants that has the fruits that are preferred by those animals that
spread the fruits the furthest or to the most suitable locations will
survive best
etc

Another is the systematic approach
in what plant groups do these enzyms occur?
do these plant groups have similar enzyms used for something else?
etc

I think the question sounds like, "why would a plant develop an enzyme that
digests a potential seed distributor?" Maybe the seeds are distributed by a
some organism with a salivary component that neutralizes the bromelin, and this
is a way to get specificity for a distributor.

Sean



--
Visit my photolog page; http://members.aol.com/grommit383/myhomepage
Last updated 08-04-02 with 15 pictures of the Aztec Ruins.
Address mungled. To email, please spite my face.

From: "Jeff Shimonski"

Perhaps the "purpose" is insecticidal. Ananas comosus wasn't always seedless
and the enzyme might have functioned as a toxin or repellant to insect larvae
that
could have damaged the fruit before the seeds could be dispersed.

This also is a reasonable theory. It can easily be tested by examining wild
species of Ananas for fruit predation by insects through various stages of
developement.

Sean



--
Visit my photolog page; http://members.aol.com/grommit383/myhomepage
Last updated 08-04-02 with 15 pictures of the Aztec Ruins.
Address mungled. To email, please spite my face.

From: "Jeff Shimonski"

Perhaps the "purpose" is insecticidal. Ananas comosus wasn't always seedless
and the enzyme might have functioned as a toxin or repellant to insect larvae
that
could have damaged the fruit before the seeds could be dispersed.

This also is a reasonable theory. It can easily be tested by examining wild
species of Ananas for fruit predation by insects through various stages of
developement.

Sean BRBR

This may be a bit off topic, but thought I'd reply to the "Ananas comosus
wasn't always seedless," above. As far as I know, all pineapples are still
completely fertile, and will make plenty of viable seeds IF they are pollenized
by a different cultivar. They are quite self-incompatible, and are grown
commercially in single-variety plantings to force seedlessness.

Definitely some pineapples set seed, and I was incorrect in implying that all
A. comosus were infertile, but you might want to check out some of the literature
by David H. Benzing or perhaps Studies in the Bromeliaceae by Lyman B. Smith,
Contributions from the Reed Herbarium No. 28, 1977 under Ananas pp. 56
"Berry sterile in cultivated forms"


"MMMavocado" wrote in message ...
From: "Jeff Shimonski"

Perhaps the "purpose" is insecticidal. Ananas comosus wasn't always seedless
and the enzyme might have functioned as a toxin or repellant to insect larvae
that
could have damaged the fruit before the seeds could be dispersed.

This also is a reasonable theory. It can easily be tested by examining wild
species of Ananas for fruit predation by insects through various stages of
developement.

Sean BRBR

This may be a bit off topic, but thought I'd reply to the "Ananas comosus
wasn't always seedless," above. As far as I know, all pineapples are still
completely fertile, and will make plenty of viable seeds IF they are pollenized
by a different cultivar. They are quite self-incompatible, and are grown
commercially in single-variety plantings to force seedlessness.

Lambert schreef
I've done some rough research and all I can come up with is that the
enzyme may have something to do with the plant's method to acquire
nutrients. The crown at the top of the pineapple collects decomposing
material and absorbs nutrients this way.

I thought about the enzymes being appealing for eating etc. but Bromelin
hydrolizes proteins and would be generally uncomfortable for an animal to
eat (speculation)? Certainly when humans eat pineapples their tongues can
feel itchy/raw/red etc...

+ + +
A key question is the concentration of such enzymes in the fruits of
the wild progenitors. The present properties of pineapples have been set by
selection in cultivation.
PvR

Also does anyone happen to know the evolutionary history of the pineapple?


"Lambert" wrote in message
u...
Hey guys,

I'm a college student and I'm trying to dig up information about the
evolutionary advantage of bromelain in pineapples. Could anyone give me a
few pointers or lead me in the right direction?

Thanks!

Lambert schreef
Also does anyone happen to know the evolutionary history of the pineapple?

----- Original Message -----
From: P van Rijckevorsel
Sent: Wednesday, April 23, 2003 10:37 AM

+ + +
A key question is the concentration of such enzymes in the fruits of
the wild progenitors. The present properties of pineapples have been set
by selection in cultivation.
PvR

Addendum: the pineapple likely is a hybrid
PvR

You sound like a horticulturist when you dismiss a plant as being a hybrid.
They always confuse cultivars with hybrids.

If Ananas comosus is a hybrid, what are the parent species?

There are more than one species in the genus Ananas, so you have a few to
choose from!




P van Rijckevorsel wrote in message
.. .
Lambert schreef
Also does anyone happen to know the evolutionary history of the
pineapple?

----- Original Message -----
From: P van Rijckevorsel
Sent: Wednesday, April 23, 2003 10:37 AM

+ + +
A key question is the concentration of such enzymes in the fruits of
the wild progenitors. The present properties of pineapples have been set
by selection in cultivation.
PvR

Addendum: the pineapple likely is a hybrid
PvR