Sex Cells in Parasites Are Doing Their Own Thing

Researchers at the University of Bristol have actually found how microorganisms accountable for human African sleeping illness produce sex cells.

In these single-celled parasites, referred to as trypanosomes, each reproductive cell divides off in turn from the adult germline cell, which is accountable for handing down genes. Conventional germline cells divide two times to produce all 4 sex cells – or gametes – all at once. In human beings, 4 sperms are produced from a single germline cell. So, these unusual parasite cells are doing their own thing instead of staying with the biology rulebook.

Trypanosome cell biology has actually currently exposed a number of curious functions. They have 2 special intracellular structures – the kinetoplast, a network of circular DNA and the glycosome, a membrane-enclosed organelle which contains the glycolytic enzymes. They don’t follow the main dogma that DNA is consistently transcribed into RNA, however will return and modify a few of the RNA records after they’ve been made.

Trypanosome cell throughout meiosis producing the very first gamete. Credit: Dr Lori Peacock

Professor Wendy Gibson of the University of Bristol’s School of Biological Sciences led the research study. She stated “We’ve got used to trypanosomes doing things their own way, but of course what we think of as normal cell biology is based on very few so-called model organisms like yeast and mice. There’s a whole world of weird and wonderful single-celled organisms — protozoa — out there that we don’t know much about! Trypanosomes have got more attention because they’re such important pathogens — both of humans and their livestock.”

Same image with superimposed pictures of DNA-containing nuclei and kinetoplasts in blue. Credit: Dr Lori Peacock

Biologists believe that sexual recreation developed really early on, after the very first complex cells appeared a number of billion years back. The sex cells are produced by an unique type of cellular division called meiosis that minimizes the variety of chromosomes by half, so that gametes have just one total set of chromosomes rather of 2. The chromosome sets from 2 gametes integrate throughout sexual recreation, producing brand-new mixes of genes in the offspring. In the case of disease-causing microorganisms like the trypanosome, sex can possibly cause a great deal of hazardous genes being integrated in one stress. Thus, research study on sexual recreation assists researchers comprehend how brand-new stress of disease-causing microorganisms develop and how attributes such as drug resistance get spread out in between various stress.

Reference: “Sequential production of gametes during meiosis in trypanosomes” by Lori Peacock, Chris Kay, Chloe Farren, Mick Bailey, Mark Carrington and Wendy Gibson, 11 May 2021, Communications Biology.
DOI: 10.1038/s42003-021-02058-5

The research study was performed by scientists from Bristol’s School of Biological Sciences and School of Veterinary Sciences in partnership with the University of Cambridge.