Reproduction in amoeba

[dougalbod]

Hi All

 

Does anybody know of the mechanism of, or any evidence of, sexual reproduction in amoeba?

 

ta

 

Dougal

[CharonY]

There are organisms that in their unicellular lifestyle are sometimes called amoebae, like e.g slime molds that form macrocysts. But amoebae in the stringent sense generally do not proliferate sexually.

Edited October 13, 2009 by CharonY

[Animalia01]

The single-celled amoeba uses the method of asexual reproduction; it divides in half by a process called fission, producing two smaller daughter cells. After a period of feeding and growth, these two daughter cells will themselves divide in half.

[dougalbod]

I realise that amaoba reproduce asexually! However I've heard about some research that suggests that they do exchange genetic material but nobody seems to know how. I was wondering if anybody had further information??

[dr.syntax]

I realise that amaoba reproduce asexually! However I've heard about some research that suggests that they do exchange genetic material but nobody seems to know how. I was wondering if anybody had further information??

 

REPLY: Bacteria [ also asexual organisms ] have three known methods of exchanging partial DNA material. Perhaps amoebae have developed some simullar methods. I`ll give you a website that describes these processes : http://www.slic2.wsu.edu:82/hurlbert/micro101/pages/chap9.html . I am not saying this is what amoebae do,only offering it as a possibility. ...Dr.Syntax

[CharonY]

It appears there is some confusion here. Exchange of genetic material is not reproduction as no offspring is created. What you are thinking of is horizontal gene transfer. Amoeba may be able to conjugate, but to be honest I do not know how common this may be.

However, the genome of Entamoeba histolytica for instance showed extensive horizontal gene transfer from bacteria, quite possible from those that have been consumed.

[dr.syntax]

It appears there is some confusion here. Exchange of genetic material is not reproduction as no offspring is created. What you are thinking of is horizontal gene transfer. Amoeba may be able to conjugate, but to be honest I do not know how common this may be.

However, the genome of Entamoeba histolytica for instance showed extensive horizontal gene transfer from bacteria, quite possible from those that have been consumed.

 

REPLY:I guess you are technically correct about that, but one of those bacteriums now has a new set of genes and when the time comes for it to undergo mitosis it`s daughter cells will now carry an altered genome ever after. I never said amoebae had this ability, only offered it as a suggestion that seemed quite possible because many bacteria are known to have this ability to exchange DNA in these 3 different manners. It is not sexual reproduction and yet genetic information is exchanged. Most people are not aware of it so it makes for an interesting read if nothing else. The original poster was not getting any answers that answered the question asked. I felt this at least offered some sort of answer. In fact,after rereading the question it`s a very good answer. I see no other posters offering any sort of answer as to what he was asking about. I think my answer is a very good one and may be exactly

what he was searching for. ...Dr.Syntax

Edited October 16, 2009 by dr.syntax

[CharonY]

I was replying to the OP.

it`s daughter cells will now carry an altered genome ever after.

This is not what is happening (usually). Once the genetic information has entered the genome it will copied over to the daughter cell. This also includes plasmids (or more likely a few copies of the plasmid end up in the daughter cell during cell division).

[GDG]

Hi All

 

Does anybody know of the mechanism of, or any evidence of, sexual reproduction in amoeba?

 

ta

 

Dougal

 

See

• H. Urushihara, "Cultivation, spore production, and mating" Methods Mol Bio (2006) 346:113-24, which mentions sexual reproduction in Dictyostelium (the slime mold amoeba); and
  
• H. Urushihara et al., "Genes involved in Dictyostelium discoideum sexual reproduction" Eur J Cell Biol (2006) 85:961-68.
  

[dougalbod]

REPLY: Bacteria [ also asexual organisms ] have three known methods of exchanging partial DNA material. Perhaps amoebae have developed some simullar methods. I`ll give you a website that describes these processes : http://www.slic2.wsu.edu:82/hurlbert/micro101/pages/chap9.html . I am not saying this is what amoebae do,only offering it as a possibility. ...Dr.Syntax

 

Hi Dr.Syntax, thanks for trying to help but...

I get 'access denied' for this website....

 

Dougal

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Merged post follows:

Consecutive posts merged

See

• H. Urushihara, "Cultivation, spore production, and mating" Methods Mol Bio (2006) 346:113-24, which mentions sexual reproduction in Dictyostelium (the slime mold amoeba); and
  
• H. Urushihara et al., "Genes involved in Dictyostelium discoideum sexual reproduction" Eur J Cell Biol (2006) 85:961-68.
  

 

 

THanks GDG, I've only had a chance to look at one of these so far, but it looks interesting.

The information I've been able to put together suggests that amoeba are normally haploid, but form a diploid zygote - presumably by nuclear fusion - but details on this seem sparse.

I've also got intersted in slime moulds, but I'll start a new topic when I work out what I need to ask about them:-)

 

 

Dougal

[CharonY]

I've also got intersted in slime moulds, but I'll start a new topic when I work out what I need to ask about them

 

Dictyostelium is a slime mold. It also belongs to the amoebozoa. The ones that are more commonly called amoeba (e.g. the Enatamoeba and Amoeba) belong to the Tubulinea, whereas slime molds belong to the Mycetozoa. The latter are the ones that form macrocysts, which represents a form of sexual reproduction (as indicated by GDG).

I am pretty sure this has not been shown in the non-social amoeba.

[GDG]

Here are a few more references:

• T.A. Iudna et al., "Cell biology and life cycle of the testate amoeba Corythion delamarei" Tsitologiia (2000) 42(7):613-23 (finding that C. delamarei undergoes sexual reproduction); and
  
• P. Pernin et al., "Genetic structure of natural populations of the free-living amoeba, Naegleria lovaniensis. Evidence for sexual reproduction", Heredity (1992) 68:173-81 (finding evidence for sexual reproduction in N. lovaniensis)
  

Don't know if they're considered social or not. You are correct that most of the literature states (or assumes) asexual reproduction for most amoeba.

[CharonY]

Yeah nomenclature is quite a bit messed up with regards to amoeaba. Essentially it is a catch-all name for anything that does not appear to have a rigid structure. Naegleria for instance are (as pointed out) called amoeba, but they belong to a completely different phylum (Percolozoa, I think).

But my knowledge is pretty dated and I may find myself wrong in a number of details.