Predicting Acropora millepora Genetic Tolerance Towards Bleaching

 

Anthropogenic climate change is creating warmer temperatures in the oceans and for certain coral reefs when temperatures remain above a sustainable level for extended periods of time, coral bleaching occurs. This study used genomic-wide patterns of variation to predict bleaching responses across a distribution for coral conservation. Coral reefs consist of a symbiotic relationship between the coral itself and intracellular photosynthetic dinoflagellates that provide energy for the coral. During coral bleaching the coral becomes intolerant to the heat and the dinoflagellates of the Symbiodiaceae family are expelled from the coral and if the coral does not take these dinoflagellates back in after an extended period of time the coral dies. This study looked at Acropora millepora, a common reef-building coral, that is widely distributed across the Indo-Pacific Ocean that potentially can have significant genetic diversity between populations that are better adapted to warming sea temperatures. There were 237 samples of chromosomal data taken from 12 different reefs in the central Great Barrier Reef. Heat tolerance in coral is not fully understood if it is polygenic or influenced by some common large-effect loci. The only loci found in this genomic-wide association was a long-term balancing selection in heat-shock and it is called sacsin. Sacsin is a co-chaperone for the heat tolerance protein Hsp70 and this helps the coral adjust to warmer temperatures over a long period of time; however, recently due to anthropogenic impacts the changes in temperature have been fast and short-term periods. This locus is found in the genus of corals Acropora and Pocillipora and the sequence of sacsin has been maintained with little to no variation across millions of generations, so any variation detected in this gene will suggest adaptation for the balancing selection for increasing heat. There was little haplotype diversity across the chromosomal scale for genomic-wide association due to the broadcast spawning mode of reproduction in A. millepora. This indicates that coral bleaching responses are not due a common locus across a genome, which supports that the phenotype of coral bleaching is polygenic and individual coral populations responses to warmer temperatures can be predicted instead of across a whole genome.

https://www.science.org/doi/pdf/10.1126/science.aba4674?casa_token=d0li8PfomAAAAAAA:miMxO9bXbcN24--RzDA7jImRn7OvnUzPXHcm2JtGWQNKY7IAtA9m86EwfTKuZd7LksEObveIzMfp4Mk

https://oceanservice.noaa.gov/facts/coral_bleach.html

https://www.nature.com/scitable/topicpage/polygenic-inheritance-and-gene-mapping-915/

How to Set Up Protozoan Mating Swarm, Bacteria Style

At the University of California, Berkeley, scientists were researching Salpinogoeca rosetta cells when they suddenly began to form mass mating swarms after exposure to an aphrodisiac produced by a bacteria. The bacteria in question that created the aphrodisiac was Vibrio fischeri. The bacterium creates chonodroitin sulfate (CS) lyase, in which is then released as a chemical signal that causes the cells to quickly aggregate and begin cell and nuclear fusion while duplicating and recombining their genetic material. 

According to researchers, Nicole King and Ariel Woznica, this discovery has led to researchers to believe the possibility that environmental bacteria or bacterial symbionts can influence mating in animals as well. Part of the research at Berkeley was exploring the origins of multicelluarlarity. The research was mostly conducted on choanoflagellates such as the S. rosetta cells. Generally, researchers would monitor shared characteristics and behaviors that was common for evolution in animals. Based on the research, scientists have discovered symbiotic and pathogenic relationships between bacteria and multi-cellular animals. This relationship has been dated to even prehistoric times.

With this research, choanoflagelletes can serve as an excellent model organism in order to discover more information regarding the origins of multicelluarlity. By using these organisms, it can have an advantageous adaptation and uses in medicine. Supposedly, researchers can use choanoflagelletes as a means of mass drug production for cures by instilling the gene for the drug. By using bacteria to induce the cells to mass mating, it can cause a rapid supply of drugs based on a natural process within bacteria. This can certainly be very useful in the field of medicine.   

Progress Made on Vaccine for River Blindness

Onchocerciasis, most commonly known as river blindness, is an eye and skin infection that is predominant in sub-Saharan Africa. Blackflies live and breed on their river banks and streams, and they typically bite humans to transmit the tiny parasitic worm responsible for river blindness, Onchocerca volvulus. The worms reproduce inside the body, and their offspring migrate to the skin, where they cause intense itching and rashes, and to the eye where they cause ocular symptoms and, ultimately, blindness. A complete cure requires decades of treatment, and it can get complicated if Loa loa, another parasitic worm infection, is also involved. The World Health Organization (WHO) estimates that river blindness currently affects an approximate 18 million people worldwide. Researchers are concerned that the recent widespread use of the anti-parasitic medication ivermectin may cause the worms to eventually develop resistance to the drug.

The research initiative, The Onchocerciasis Vaccine for Africa (TOVA), was launched as a result of the London Declaration on Neglected Tropical Diseases, which called for tools to eliminate river blindness from Africa.

In the newly published research, the scientists describe sequencing the complete genome of O. volvulus worms gathered from Ecuador, Uganda and West Africa and reconstructing the genetic makeup of Wolbachia, the symbiotic bacteria that lives within the worms. The researcher identified genes that coded for common proteins and molecular reactions essential to infection. The authors noted the significance of their study towards developing potential new treatments for diseases associated with parasitic worm infections, specifically, river blindness.

The research, published this week in Nature Microbiology, was conducted in part by scientists of the National Institute of Allergy and Infectious Diseases (NIAID).  Their work has revealed insights into the workings of the parasite, and they’re now working towards designing better treatments.  Ideally, they're expecting to develop a preventive vaccine.  So far, they've identified 16 different proteins that could be used towards developing potential new medications to combat the disease.  The researchers state that their findings will support future basic and translational onchocerciasis research.

It's amazing that the genome sequencing of the worm and of its symbiotic bacteria are being utilized as a tool for the development of a vaccine.  A lot can be learned about the biological makeup of a species simply by analyzing their full genome.  This can allow us to see the problem from a fundamental perspective, or even to strategize a different approach.  Optimistically, a successful vaccine will be developed from these studies, and it'd be awesome to see the disease fully eradicated.