From: PO4::"BatesS@GFC.DFO.CA" "Stephen Bates" 14-FEB-1996 11:13:32.55 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance Fellow Diatomists, The description of Richard Gordon's twisted Bacillaria paradoxa frustules prompted me to write this. For several years, we have been puzzled by deformed cells of the pennate diatoms Pseudo-nitzschia multiseries and P. pungens growing in culture. After 1-2 years of being in culture, our strains (cultures isolated from either one cell or one chain) eventually take on a bizarre "handle bar" shape. This starts out as "bumps" or "swellings" on the outer frustule, then progresses to the more twisted shape of the entire frustule. Once a deformed cell is present, it becomes a template for all subsequent daughter cells, thus eventually propagating the same shape throughout the entire culture. It is possible that several deformed shapes may be found in the same culture. We have observed such deformities in cultures originally isolated from coastal waters of Prince Edward Island (Canada), northern Nova Scotia (Canada), Massachusetts Bay (USA), and the Gulf of Mexico. I have only seen three references relating to this phenomenon in the literature. Takano, H. and K. Kikuchi (1985, Anomalous cells of Nitzschia pungens Grunow found in eutrophic marine waters. Diatom 1: 18 20) documented "swellings" (of the type we see) on Nitzschia pungens cells growing in nature. Photomicrographs of the type of deformed cells I am referring to are also found in Subba Rao, D.V. and G. Wohlgeschaffen (1990, Morphological variants of Nitzschia pungens Grunow f. multiseries Hasle. Bot. Mar. 33: 545 550), who describe them as "lobate" (their Figs. 5-8, 14, 15). The authors state that this cell shape (along with other unusual forms) was found in significant numbers in natural populations from coastal waters of eastern Prince Edward Island. However, in the thousands of cells observed by workers here, we have never seen any such deformed cells in field samples from the same location. Additional photomicrographs of lobate cells from cultures are found in Subba Rao, D.V., F. Partensky, G. Wohlgeschaffen, and W.K.W. Li. (1991, Flow cytometry and microscopy of gametogenesis in Nitzschia pungens, a toxic, bloom forming, marine diatom. J. Phycol. 27: 21 26) (their Fig. 1B,C). In contrast to what the authors argue, I have found no evidence that this particular shape of cell has anything to do with any part of a sexual cycle. In fact, I have never yet observed sexual reproduction, auxospore formation, etc., in any of our Pseudo-nitzschia cultures, despite having mixed different strains together and growing them under different conditions of light, temperature and nutrients. The cell size continues to diminish, cell division slows, and the culture eventually (after another 1-2 years) dies out completely. This remains yet another mystery of these fascinating cells. Being able to trigger sexual reproduction would let us maintain our cultures for a longer period (and at a more ecologically- realistic cell size), perhaps also preventing the formation of deformed cells. I would be interested to know if anyone has observed this type of anomalous shape in pennate diatoms, either in nature, culture, or the literature. Thanks, Steve Stephen S. Bates (Research Scientist - Phytoplankton) Department of Fisheries and Oceans Gulf Fisheries Centre, P.O. Box 5030 Moncton, New Brunswick, Canada E1G 1Z3 Phone: 1-506-851-3982; Fax: 1-506-851-2079; E-mail: batess@gfc.dfo.ca From: PO4::"kingston@USGS.GOV" "John Kingston" 14-FEB-1996 11:57:56.93 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance Of possible interest: Round, F.E.1992. A re-investigation of some fragilarioid diatoms in the = Provasoli/Guillard culture collection. Diatom Research 7(2): 303-311. Feldt, L.E., E.F. Stoermer, and C.L. Schelske.1973. Occurrence of = morphologically abnormal Synedra populations in Lake Superior = phytoplankton. Proc. 16th Conf. Great Lakes Res. 1973: 34-39. Internat. = Assoc. Great Lakes Res. --John From: PO2::"stoermer@UMICH.EDU" "Gene Stoermer" 14-FEB-1996 12:04:24.79 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance On Wed, 14 Feb 1996, John Kingston wrote: > Of possible interest: > > Round, F.E.1992. A re-investigation of some fragilarioid diatoms in the Provasoli/Guillard culture collection. Diatom Research 7(2): 303-311. > > Feldt, L.E., E.F. Stoermer, and C.L. Schelske.1973. Occurrence of morphologically abnormal Synedra populations in Lake Superior phytoplankton. Proc. 16th Conf. Great Lakes Res. 1973: 34-39. Internat. Assoc. Great Lakes Res. > > --John > Just an add-on to John's note. The strange Synedra population in Lake Superior has maintained itself for more than 20 years - at least it was there the last time we looked. ***************************************************************** Eugene Stoermer, University of Michigan Internet e-mail address: stoermer@umich.edu Voice Phone: 313-764-5238 Fax: 313-747-2748 ***************************************************************** From: PO2::"roesslep@TCPLINK.NREL.GOV" 14-FEB-1996 12:07:02.10 To: Multiple recipients of list DIATOM-L CC: Subj: Re[2]: cytoplasmic inheritance Steve (and other interested folks), A number of years ago, I published a short note describing abrupt size reduction of cultured Synedra cells (Phycologia 27:294-297 [1988]). For what it's worth, I noticed that the progenitors of the shortened cells had slightly aberrant morphologies (i.e., small bumps and such). I doubt there's a real connection here, but thought I'd let you know about it. Paul Roessler paulr@nrel.gov From: PO3::"czdiatom@LCAC1.LORAS.EDU" "Dave Czarnecki" 14-FEB-1996 13:48:27.25 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance Guess I'd better get some of this stuff published, eh? In cultured clonal strains of several diatoms, anomalous forms are perpetuated more than not. I have particularly good evidence for this type of "inheritance" in *Rhoplaodia gibba* which in overcrowded populations develops all sorts of shape anomalies, one assignable to var. *ventricosa*, another assignable to *R. gibberula*,another strongly and quite symmetrically bilobed, another looking much like a "button mushroom", etc. Similarly in three different strains of *Synedra cyclopum*, I have evidence of all sorts of strange shapes in offspring, some remarkably similar to Round's anomalous (?) *Synedra*. I surmise that the continuation of such anomalous forms is the result of two co-occuring phenomenona: (1) wall (outline) formation in daughter cells is highly interactive and dependent on the parental (epivalve) shape; (2) MacDonald-Pfitzer reduction intensifies the anomalous deviation with each division. This in no way should invoke Lamarckian inheritance since it is strictly a mitotic phenomenon propagated via the constraints of a hard wall. My problem has been keeping the strains alive long enough to allow them to undergo their sexual phase and presumably resume their normal morphology. I did not attempt to "de-frustule" them to a naked protoplast to see if they would resume normal morphology in lieu of a sexual event, but I have been able to do so with rather 'atypical' morphs of *Surirella peisonis* and *Campylodiscus clypeus* [Anna-Marie Schmid apparently has done this several times as well, although she has not published on that technique as far as I know]. As to Gene's observance of continued occurrence of apparently such a deformed morph in the Great lakes, I'm guessing that entity has yet to re-set via a sexual process or asexual correction by having the protoplast leave its frustule. I would also suggest that such entities as *Synedra cyclopum* var. *incisa* and *Fragilaria vaucheriae* f. *contorta* as well as others of similarly strange valve outlines, are also the result of the above processes. While it is interesting that they appear to survive for for some time in nature, where generally one would expect selective pressures to be unfavorable (as opposed to culture conditions where selective pressures are comparably minimized), I would be quite reticent to invoke a genetically-based cause. From an ecological perspective though, rather than lump these anomalies under one taxon (as Drouet & Daily did with many bluegreens), it would seem appropriate and valuable to assign to them the *forma* rank, should there appear to be an ecologically based induction mechanism responsible for the initial anomaly (e.g.,low levels of silicon, temp., etc.). **************************************************************************** * David B. Czarnecki Tel: (319) 588-7231 * * Curator, FW ALGAE CULTURE COLLECTION Fax: (319) 588-7964 * * Department of Biology Fax: (319) 588-7292 * * Loras College * * P.O. Box 178 E-mail: * * Dubuque, Iowa 52004-0178 U.S.A. czdiatom@lcac1.loras.edu * **************************************************************************** From: PO2::"pharg@gsosun1.gso.uri.edu" "Paul Hargraves" 14-FEB-1996 13:55:23.50 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance: weird cells Several of the Pseudo-nitzschia species I have in culture (fraudulenta, multiseries, pseudodelicatissima, pungens) have done the same thing . Over the years I've also seen it in Nitzschia, Amphora, Bacillaria, Asterionellopsis, Navicula, and a few others. All anecdotal, just observed in passing; no suggestion of auxosporulation. Never seen such among natural populations, atleast in the marine plankton. I've often wondered whether some of these teratologies are a consequence of in vitro crowding of rapidly dividing cells in the bottom of tubes & flasks: pressure on the silicalemma in the mash, etc. - a good M.S. thesis for someone - to compare morphology in stationary vs. roller bottle cultures of planktonic pennates. Paul Hargraves From: PO2::"umriedin@NEIU.EDU" "Melanie Riedinger" 14-FEB-1996 14:11:04.16 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance: weird cells We've found teratological forms in natural populations in Ecuador, in both Andean and Amazonian systems. Indentations are quite common (Cocconeis, Eunotia, Fragilaria, Navicula) or distended portions (i.e. Tabellaria -inflated center or end). Melanie Riedinger From: PO2::"stoermer@UMICH.EDU" "Gene Stoermer" 14-FEB-1996 14:52:50.26 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance Strange shapes in diatoms have been observed almost every since people started making microscopes out of glass beads. It has been my experience that almost any culture will occasionally develop monstrosities (particularly benthic species). Such grossly deformed cells are less commonly found in nature, although they do occur in some limited environments. My favorite examples are temporary pools formed by tire or animal tracks, which develop large populations of Navicula, Nitzschia, etc. Quite often one will find deformed clones in such situations. It has been my assumption that these sorts of deformations result from mechanical damage incurred by crowding during division, which is then perpetuated in a clone by templating the mother cell. Many years ago, Rick Drum published a little paper in the Iowa Academy of Sciences which shows this in Surirella. At the time we talked about doing a complete literature survey on deformed diatoms. If memory serves correctly, we came up with ca. 150 references (prior to 1960!) before we got discouraged. In my experience, the majority of pennate diatom clones that have been maintained in culture for more than a few transfers are morphologically abnormal to some degree. One must wonder about their physiology - one of the reasons we usually re-isolate. A somewhat more interesting example is the fact that grossly deformed fossil diatoms (triradiate araphid pennates, elliptical centrics, etc.) seem to be associated with certain ages and formations. If someone can explain that, we may have something interesting! ***************************************************************** Eugene Stoermer, University of Michigan Internet e-mail address: stoermer@umich.edu Voice Phone: 313-764-5238 Fax: 313-747-2748 ***************************************************************** From: PO2::"frithjof@PI.NET" "F.A.S. Sterrenburg" 14-FEB-1996 14:56:42.96 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance The cytoplasmic inheritance question cropped up in the course of discussions on another subject. I there mentioned a phenomenon which might be of general interest also, so here goes: 1) Gyrosigma valves can show a typical "kink" in the concave section of the valve contour, Sterrenburg, Diatom Res. 6/2. 2) This occurs in (so far) at least half a dozen species and also in Pleurosigma, Sterrenburg, Diat. Res 7/1. 3) The mechanism is a general one, in all these species the deformation is of an identical nature. 4) The mechanism is also highly regular: the location of the kinks is about halfway down the valve, INVARIABLY on the convex side and INVARIABLY apically symmetric. It's not a question of "contact malformation", therefore, as has been suggested for other deformations in the literature. No other form of kinks has been described in Gyros and Pleuros. 5) The phenomenon occurs in wild populations and can be particularly frequent in cultures (I have seen many kinky valves in Dave Czarnecki's single-cell isolate Gyro cultures). 6) These kinks led to the choice of the specific epithet by W. Smith in the case of Gyrosigma distortum, but (Sterrenburg, Proc. Acad. Nat. Sci. Philadelphia, 145) even there they are unspecific as the type material contains "non-kinky" valves. I have seen large wild populations of G. distortum where the vast majority of specimens are "non-kinky". Graham Underwood just sent me a nice slide of UK material where the absence of kinks might turn people away from G. distortum - but they conform to the type. Thus G. distortum is NOT identifiable by a kink ("beaks" in the literature). The kink looks like a deformation induced by the presence of a sort of "constricting cuff" during valve morphogenesis. Originally I saw the kinks in early specimens of the vegetative range and believed that this might occur at the zygote stage, or immediately afterwards. I have now seen minute specimens too, but only in cultures. It should be stressed that I do not posit that this phenomenon is cytoplasmically inherited in the sense that it would be of a mitochondrial origin. It might be "cytoplasmic" in the sense that the vegetative reproductive mechanism of diatoms would enforce it upon the next generations, but I am not sure that this is indeed the case in nature. From the tiny kinky specimens in Czarnecki's cultures, I would conclude that they stay that way, but in nature, the kinky ones are never that small. Are they selected out by environmental pressure, or are they able to straighten themselves out, one wonders - phase of nudism? For reference: the database consists of tens of thousands of specimens also in live populations (my own ditch has Gyros by the hundredweight throughout the year) and I have NEVER seen a conjugation yet, nor nudism. From: PO4::"kingston@USGS.GOV" "John Kingston" 14-FEB-1996 15:26:07.98 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance To contrast to all the mention of pennate and benthic species showing = great abnormality, as mentioned by many contributors today, one of = weirdest culture-abnormalities that Gene Stoermer and I saw in our SEM = adventures at Great Lakes Research Division in the early 70s were = cultures of Stephanodiscus binderanus with multiple rows of marginal = spines, necessarily coming up onto the valve face. I cannot remember = now whether they had multiple accompanying rows of submarginal strutted = processes (maybe we can find the photographs), but they were centric = monstrosities. Perhaps these were cultures we had from Susan Kilham, but = I cannot quite remember that either. While I do not recall seeing dents = in centric diatoms, these multiple features on valves were very = striking, and something that I have not seen in nature in any = Thalassiosiraceae species.=20 --John From: PO3::"frithjof@PI.NET" "F.A.S. Sterrenburg" 14-FEB-1996 18:12:07.95 To: Multiple recipients of list DIATOM-L CC: Subj: cytoplasmic inheritance As an aside: I wonder whether the propagation of things like "dents" down the vegetative line may be called inheritance? Or should that be limited to the (chromosomal/mitochondrial) transmission mode? From: PO4::"Reinhard.Pienitz@CEN.ULAVAL.CA" 14-FEB-1996 19:38:08.03 To: Multiple recipients of list DIATOM-L CC: Subj: ...no subject... With respect to examples of grossly deformed fossil diatoms (biraphid pennates with missing or displaced raphe branches, odd striae; deformed centrics, etc.) given by Gene Stoermer, I found such strange shapes in diatoms most frequently in sediments associated with marine-lacustrine transitions in 'isolation basins' (osmotic stress may have played an important role in these environments?). Reinhard Pienitz From: PO2::"agm@GEO.ED.AC.UK" 15-FEB-1996 07:59:02.51 To: Multiple recipients of list DIATOM-L CC: Subj: Deformed diatoms I studied Palaeogene diatoms from the North Sea Basin for my Ph.D., and often came across stratigraphically significant horizons of deformed diatom frustules. These appear to be asssociated with lowstand conditions, often in laminated sediments which at one horizon (the Palaeocene/Eocene boundary) are intercalated with volcanic ash. It is postulated that the North Sea during the period in question was essentially isolated from the North Atlantic by the Artois sill and the Greenland-Scotland Ridge, creating a "super lake". Across the basin, in northern Denmark is a very famous diatomite deposit (now called the Fur formation, previously "Moler"- early diatomists were familiar with its ornate, well preserved diatoms), and diatoms from here are often teratologically distorted (especially Trinacria species). This situation appears to be a good example of a marine to lacustrine transition, with diatoms undergoing osmotic stress. Has anybody else encountered horizons of deformed diatoms from strata known to have been deposited under stressed conditions? Alex Mitlehner Department of Geography Edinburgh University Edinburgh EH8 9XP UK From: PO2::"H.deWolf@RGD.NL" "Hein de Wolf" 16-FEB-1996 02:25:39.35 To: Multiple recipients of list DIATOM-L CC: Subj: teratological forms In samples from Holocene estuarine sediments in the vicinity of Amsterdam, deformed valves from Biddulphia rhombus fo. trigona are found. Norman Hendey told me that he also had found these valves in the Thames estuary in recent materials. Of course, an estuary is a good environment for stressing conditions. On the other hand, after the closure of the Zuiderzee, van der Werff found Actinoptychus undulatus abundant in very tiny individuals at a very low salt content. Are these very small valves also teratological forms ? Hein de Wolf Geological Survey of the Netherlands From: PO2::"Reed.Scherer@NATGEOG.UU.SE" "Reed Scherer" 16-FEB-1996 06:42:52.84 To: Multiple recipients of list DIATOM-L CC: Subj: Re: twisted cells Following on Richard Gordon and Steve Bates' remarks on inherited morpholoogic characteristics such as twisted valves, I can contribute observations on fossil Sceptroneis species. Diverse Sceptroneis dominated the northern Norwegian-Greenland Sea during the Oligocene. Several elongate species were very common and during the interval ~27 - 33 million years ago (mid- to late early Oligocene) these species exhibited a pronounced twisting. Their descendents, several million years later, had flat valves. Any thoughts? Reed Scherer Uppsala, Sweden From: PO2::"fass@mailhost.pi.net" "F.A.S. Sterrenburg" 18-FEB-1996 06:24:04.31 To: Multiple recipients of list DIATOM-L CC: Subj: Cytoplasmic inheritance Two notes concerning the cytoplasmic inheritance/anomalous forms discussions: 1) Reed Scherer mentions anomalous forms of Sceptroneis, whose descendants appear to have corrected the anomalies some 30 million years later. Can we be sure these are indeed the descendants? Over such a long period entirely "fresh" populations could have become established. Also, whilst sexual procreation appears to be infrequent in diatoms (at intervals of several years, as is also suggested by the contributions to this discussion), it surely must have occurred in such a long period. Thus, in so many millennia the anomalous population may either have died out and been supplanted by new normal ones, or the anomalous descendants may have escaped by going through a sexual phase. 2) Hein de Wolf mentions the minute forms of Actinoptychus described by Van der Werff after the former Zuyderzee was closed off and became progressively less saline. In my opinion, these are not truly "teratological forms" but find a more logical explanation if we propose that they were in a cul-de-sac. Continuation of the vegetative road was still possible up to a low salinity, but conjugation was out. In the wild, I have seen such populations consisting of inordinately small cells for several species. May I make an attempt at summarising what I believe to have understood from the discussions so far? - In the first place, teratological forms. Perhaps that term should be reserved for true monsters such as valves with major raphe deformities or even absence of one half or both halves of the raphe e.g. Sterrenburg 1973: Extreme malformation and the notion of species. Microscopy 32, 314-318. I am not sure that these are relevant to cytoplasmic inheritance: * are such monsters at all capable of procreation? ** are teratologies like missing raphes of cytoplasmic origin? - Secondly, valve deformations like twists, bends or impressed valve contour are frequent in many genera. When these are explainable as "contact effects" (mechanical deformation of the silicalemma), I wonder whether they really come under the cytoplasmic inheritance discussion: they are stochastic and the cause is exogenous rather than cytoplasmic. - Not so the kinks I described in Gyrosigma. These are not due to exogenous contact effects and are certainly not stochastic but highly regular. - The vegetative way of procreation seems to complicate the issue because of the template effect (Stoermer). One wonders again, however: can enforcement by the template (which strictly speaking is an exogenous mechanism too!) come under the heading of "inheritance"? Whatever the mechanisms of inheritance would want to express, they simply can't escape the "Terror of the Template"... - The inflations of the valve - also frequent, it appears - would appear to be of ecological origin. In this case, however, the descendants might theoretically get themselves straightened out by correcting for the inflation. Assuming that the genomic instruction would include "parallel sides" (in a Synedra, for instance), is that overridden by the interactive valve morphogenesis phenomenon? David Mann, please: is the latter obligatory? - The "multiple rows of spines (and possibly strutted processes)" of Stoermer/Kingston are the best "anomalies" I've seen described. These are surely not under the Terror of the Template? But do they not appear to be genomic rather than cytoplasmic? Multiple strutted processes might even have tempted an observer who had not seen the original population to introduce a new genus ... - The question of cytoplasmic - in the sense of mitochondrial - inheritance seems to be open still. ****** From: PO2::"hduthie@SCIBORG.UWATERLOO.CA" "Hamish Duthie" 19-FEB-1996 12:29:03.84 To: Multiple recipients of list DIATOM-L CC: Subj: More on teratological forms With reference to the recent discussion on abnormal valves, some of you may have read a recent paper by Jingrong Yang and myself (Hydrobiologia 269/270: 57-66, 1993) where we described abnormalities to Stephanodiscus niagarae and S. parvus in Hamilton Harbour, Lake Ontario, and which we tentatively attributed to heavy metal (Cu, Cd, Zn) pollution. The frequency of abnormal valves in counts from dated sediment samples varied (in the case of S. niagarae) from 12% in 1911, to an astonishing 88% in 1979 when pollution was at its worst. We are planning fine resolution stratigraphic analysis of diatoms and metals in surficial sediment cores to assess the effectiveness of the ongoing remedial action plan (RAP) cleanup in the harbour, and we are also planning experimental culture work to test our assumption that heavy metals are to blame. Does anyone know of similar work on heavy metals and freshwater diatoms? Has anyone else ever attempted to use % abnormal valves in sample counts as a paleo index of heavy metal pollution history? (P.S. I am looking for a suitable grad student, or possibly even a postdoctoral, to work on this project.) ******* Prof. Hamish C. Duthie Department of Biology, University of Waterloo Waterloo, Ontario N2L 3G1 CANADA Phone: 519-888-4567 Fax: 519-746-0614 E-Mail: hduthie@sciborg.uwaterloo.ca From: PO2::"pharg@gsosun1.gso.uri.edu" "Paul Hargraves" 14-FEB-1996 13:55:23.50 To: Multiple recipients of list DIATOM-L CC: Subj: Re: cytoplasmic inheritance: weird cells Several of the Pseudo-nitzschia species I have in culture (fraudulenta, multiseries, pseudodelicatissima, pungens) have done the same thing . Over the years I've also seen it in Nitzschia, Amphora, Bacillaria, Asterionellopsis, Navicula, and a few others. All anecdotal, just observed in passing; no suggestion of auxosporulation. Never seen such among natural populations, atleast in the marine plankton. I've often wondered whether some of these teratologies are a consequence of in vitro crowding of rapidly dividing cells in the bottom of tubes & flasks: pressure on the silicalemma in the mash, etc. - a good M.S. thesis for someone - to compare morphology in stationary vs. roller bottle cultures of planktonic pennates. Paul Hargraves From: PO2::"Annemarie.Schmid@SBG.AC.AT" "Annemarie Schmid" 29-FEB-1996 12:36:59.33 To: Multiple recipients of list DIATOM-L CC: Subj: Re: More on Heavy metals and on teratological forms >Date: Fri, 23 Feb 1996 10:58:29 +0100 >To: DIATOM-L@iubvm.listserv.indiana.edu >From: Annemarie.Schmid@sbg.ac.at >Subject: Re: More on Heavy metals and on teratological forms > >>Date: Thu, 22 Feb 1996 11:33:27 +0100 >>To: Hamish Duthie >>From: Annemarie.Schmid@sbg.ac.at >>Subject: Re: More on teratological forms >> >>Hello from Salzburg, I am Anna Maria Schmid, just recently linked into this distinguished society. > >>1) as to your question on heavy metal studies: >>M.A. Smith (1983) The effect of heavy metals on the cytoplasmic fine structure of Skletonema costatum (Bacillariophyta). Protoplasma 116, 14-23 >>Sicko-Goad, L & EF Stoermer (1979) A morphometric study of lead and copper effects in Diatoma tenue var. elongatum. J. Phycol.15, 316-321 > >In a joint study with P.E.Hargraves, he found heavy metals in the "wing" of P.sol , as did G Novarino in the Stalk of Achnanthes. >>Schmid AM & PE Hargraves (1995) Planktoniella sol - morphological and X-ray analysis of the "wing". In: MJ Sullivan &P. Kociolek (eds). A century of diatom research in North America. Koeltz Scientific books, USA, 111-123 >Novarino G (1993) Presence of minerals in the mucilage stalk of the diatom Achnanthes longipes. Diatom Research 8, 199-202 > >>2) as to explanation for teratological forms: >>Pickett-Heaps J, Schmid AM, Edgar L (1990) The cell biology of diatom valve formation. In: (Round & Chapmann, eds)Progress in phycological Research, Vol.7, 1-168; Biopress Ltd. > >Among the notes on teratological forms coming over the internet-highways, to me the most interesting was that of Paul Roessler, who observed that the progenitors of abrubtly shortend cells had slightly aberrant morphologies. >I had started 20 years ago to study Centronella reichelti, a tripolar, fragilarioid form. It was originally described by VOIGT from the Pluss-See near Ploen in 1903. About 10 Years ago I received a living sample of the plankton of this lake from Barbara Hickel-Meyer and took 7 clones of Centronella into culture and studied recovery. Because of many other activities, which seemed more pleasing (skiing, travelling, looking at large marine diatoms...) I managed just 2 months ago to finish this study: The only way (aside from possible sex already at the tripolar stage, what I believe to be not realistic) for the tripolar Centronella to become bipolar, is first to shed one arm, becoming a kinked, bipolar form, and then one arm is step by step reduced, leaving one short arm, which looks completely different, but is definitely a chainforming Fragilaria. The intermediate forms are all kind of weird and funny teratologies. This paper is now in press in Nova Hedwigia, Birthday volume dedicated to Ursula Geissler. If you can't wait that long to hear about it, please take the opportunity to come to our 10th German Diatomists Meeting (which meanwhile covers diatomfriends from whole Europe) in March 21st-24th, in Salzburg University. We would be pleased to welcome you here in Mozart Town, snowy mountains, nice scenery........ > >>Hope this is of some help! Best wishes, AMS >> >>At 12:11 19.02.1996 -0500, you wrote: >>>With reference to the recent discussion on abnormal valves, some of you may >>>have read a recent paper by Jingrong Yang and myself (Hydrobiologia >>>269/270: 57-66, 1993) where we described abnormalities to Stephanodiscus >>>niagarae and S. parvus in Hamilton Harbour, Lake Ontario, and which we >>>tentatively attributed to heavy metal (Cu, Cd, Zn) pollution. The frequency >>>of abnormal valves in counts from dated sediment samples varied (in the case >>>of S. niagarae) from 12% in 1911, to an astonishing 88% in 1979 when >>>pollution was at its worst. >>> >>>We are planning fine resolution stratigraphic analysis of diatoms and metals >>>in surficial sediment cores to assess the effectiveness of the ongoing >>>remedial action plan (RAP) cleanup in the harbour, and we are also planning >>>experimental culture work to test our assumption that heavy metals are to >>>blame. >>> >>>Does anyone know of similar work on heavy metals and freshwater diatoms? >>>Has anyone else ever attempted to use % abnormal valves in sample counts as >>>a paleo index of heavy metal pollution history? >>> >>>(P.S. I am looking for a suitable grad student, or possibly even a >>>postdoctoral, to work on this project.) >>>******* >>>Prof. Hamish C. Duthie >>>Department of Biology, University of Waterloo >>>Waterloo, Ontario N2L 3G1 >>>CANADA >>> >>>Phone: 519-888-4567 Fax: 519-746-0614 >>>E-Mail: hduthie@sciborg.uwaterloo.ca >>> >> >