Subject: Pectinatella magnifica
Date: Thu, 14 Aug 1997 18:54:12 -0500 (EST)
From: BACKUS.BYRON@epamail.epa.gov
To: DMiller@ziplink.net
I was in Massachusetts
in 1977 (coincidentally, I was
attending the
International Bryozoology Association
conference held
at Woods Hole) and, in the course of some of
our explorations,
we came across a pond containing a number
of large colonies
of P. magnifica, much as you describe - so
this is certainly
not a new phenomenon in Massachusetts.
It may be that
in some years colonies of this species are
relatively small
or few and far between - but in other
years, for unknown
reasons (perhaps a good food supply,
perhaps relatively
little disturbance) there is a build-up
of many large
colonies (and they can, under optimum
circumstances,
get as large as a bushel basket!). Most of
the mass is
a secreted gelatinous material; the actual
living colony
is fairly close to the surface, and this is
also where you
find the statoblasts. A number of other
organisms (particularly
nematodes, insect larvae etc.) may
burrow into
the gelatinous mass. It is possible that the
living colony
(which consists of relatively small feeding
zooids) will
die off, leaving the gelatinous mass with
statoblasts
(the gelatinous mass disintegrates within a few
days).
For what it is
worth, I believe that the so-called
freshwater "bryozoans"
or phylactolaemates are not really
bryozoans at
all, but are freshwater phoronids, and the
statoblasts
(which you have described) are derived from the
so-called "fat
body" of phoronids. Most of my work on these
organisms has
been on their chromosomes (the chromosome
number for P.
magnifica is 18).
The statoblasts
are for reproduction; each statoblast is
capable of producing
a new massive colony. Since
statoblasts
are produced asexually, each of these new
colonies will
be genetically identical to the parent colony.
The statoblasts
produced at this time of year will probably
not germinate,
however, until next spring.
Pectinatella
magnifica can be a nuisance, as the large
gelatinous colonies
can clog up water intake pipes. However,
as previously
indicated, insect larvae and other organisms
may burrow into
the gelatinous material, and it may have
some food value
for them. I think it is possible that other
organisms may
eat the colonies too - I believe a raccoon ate
a specimen I
collected several years ago.
If you have any
additional questions, or observations, feel
free to get
in touch. This is actually such an obscure
field, that
I find it amazing that a number of people have
gotten in touch
with me over the Internet!
Byron T. Backus
703-305-7043(W)
301-984-9164(H)
Subject: Pectinatella magnifica
Date: Fri, 15 Aug 1997 13:50:53 -0500 (EST)
From: Byron Backus <BACKUS.BYRON@epamail.epa.gov>
To: DMiller@ziplink.net
I am not aware
of any health hazard associated with
Pectinatella
magnifica (other than the possibility of
someone slipping
on a colony). I have handled colonies with
my bare hands,
and have never had any signs of irritation.
If you take
a colony and put it in a bucket, it will start
to smell after
a few hours, and it may be that this is
indicative of
some sort of bacterial decay process, but, as
far as I know,
there is no potential for infection.
The individual
zooids that make up a P. magnifica colony are
filter feeders,
so it is possible that the large number of
colonies are
making a significant contribution to clearing
the water.
Most of the phylactolaemates
are either small and
inconspicuous
organisms, or have a "mossy" appearance. P.
magnifica and
Asajirella gelatinosa (formerly known as
Pectinatella
gelatinosa) are capable of forming large
gelatinous colonies
(sometimes, possibly under less than
optimum conditions,
they form small colonies - about the
size of a fingernail).
Asajirella gelatinosa is found in
Japan and other
areas of Asia, although I am aware that it
has also been
collected in Panama. I have worked with
budding statoblasts
of Asajirella gelatinosa (the
statoblasts
were sent to me by a Japanese scientist) and
obtained chromosome
spreads. I was informed a few years ago
that Asajirella
gelatinosa has been largely displaced from
Lake Tatara-numa
(the source of his material) by
Pectinatella
magnifica. Incidentally, P. magnifica and A.
gelatinosa are
not that closely related - the massive
gelatinous growth
form in both species is apparently an
example of convergent
or independent evolution.
Another species
that you might look for (and I also observed
it in Massachusetts)
is Cristatella mucedo. The colonies
are gelatinous,
but considerably smaller than those of P.
magnifica.
They tend to be elongate, perhaps 1-2 inches
long (but they
can get longer - to 6 or 8 inches) and
perhaps 1/3
to 3/4 inch thick. They look like submerged
caterpillars.
Usually, a number of colonies of C. mucedo
are found together
in close proximity. The statoblast is
somewhat like
that of P. magnifica, but with more spines,
and it tends
to be somewhat smaller and more circular. The
statoblast of
P. magnifica tends to have a saddle-shape when
seen in profile,
while that of C. mucedo is flatter.
The person who
is probably the expert on Massachusetts
phylactolaemates
is Doug Smith, at the University of
Massachusetts
at Amherst, Dept. of Zoology. He has
collected a
number of different species from the streams and
lakes of Massachusetts,
and wrote a book a few years ago
describing the
different species and the localities from which
he had collected
them.
I will add here
that A. gelatinosa and a closely-related
species (to
A. gelatinosa), Lophopodella carteri, have been
shown to contain
a substance (or substances) which are toxic
to fish.
This material is released when the colony is
damaged.
If the colony is not damaged, then the fish and
phylactolaemate
can co-exist. The toxin damages the gill
tissue, and
is apparently not toxic to mammalian species.
However, I am
not aware of any research along these lines
which has been
conducted with P. magnifica. Incidentally,
Doug Smith has
collected Lophopodella carteri in
Massachusetts
(colonies tend to be greenish-gray in color,
about the size
of a pea, and, when they are found, usually
are present
in great numbers).
Byron T. Backus
703-305-7043(W)
301-984-9164(H)
Subject: Re[2]: Pectinatella magnifica
Date: Mon, 29 Sep 1997 10:33:06 -0500 (EST)
From: BACKUS.BYRON@epamail.epa.gov
To: Dick and Jill Miller <DMiller@gis.net>
I recently received
a query as to the composition of the
jelly-like substance
of Pectinatella magnifica, and the
person indicated
that this information was not on the
website, so
here is the information that I have managed to
obtain:
The following
is from The Invertebrates, vol. 5, by L.H.
Hyman (1959):
"The jelly of Pectinatella (Kraepelin, 1887)
consists of
99.7% water; the mass left by pressing out as
much water as
possible was composed of 89.23% water, 0.88%
ash (salts),
6% protein, 1.25% chitin and 2.64% other
organic material.
The presence of chitin was checked out by
crystallizing
out glucosamine. Similar results were obtained
by Morse (1930),
who also crystallized glucosamine; he found
that a mass
of jelly weighing 1200 g when fresh dried to 5
g."
The short article
by Withrow Morse on the composition of
Pectinatella
magnifica appears in Science, in the issue of
March 7, 1930,
p. 265 (Vol. LXXI), and includes the
following:
"...the jelly-like
secretion is not of the order of collagen
but of true
protein... Protein reactions were typical of
such proteins
as ovalbumin, serum albumin etc. The biuret
reaction was
positive and typical, that is, like that of
white of egg
and not like that of gelatin or peptone."
"The following
amino-acids were demonstrated: tyrosin,
tryptophane,
cystin. In a cold extract of the dried material
all three were
positive, but the reactions were intensifed
after acid hydrolysis.
This was especially true of cystin.
The protein
was heat coagulable."
"Of the inorganic
substances, sodium chloride was
demonstrable.
Phosphorus was negative before hydrolysis, and
after boiling
with equal volumes of sulphuric and nitric
acids, none
was demonstrable. Calcium is present in copious
amounts, as
one would suspect from the calcareous nature of
the body and
statoblasts."
"Characteristic
of these organisms is the supporting
structure composed
of chitin. In the specimen, examined
chemically,
glucosamine (galactosamine?) was readily
demonstrable
after hydrolysis."
The only problem
I have with the above is the statement:
"...as one would
suspect from the calcareous nature of the
body and statoblasts."
I believe that Morse did not
actually analyze
these, but relied on information from other
sources.
-Byron