Description and Significance
Caldivirga maquilingensis was first isolated from a hot spring located in the Philippines. This hot spring, known as 'Mud Spring', is found in Mt. Maquiling, Laguna. The Mud Spring is an extremely hot and acidic environment. Therefore, the archaea is an hyperthermoacidophile. In laboratory growth, it was determined that C. maquilingensis grew best at 85°C and at a pH range of 3.7-4.2.
The appearance of C. maquilingensis ranges slightly. Most are rod-shaped and are either completely straight or have a slight curve shape. Although the width of the microbe ranges widely, the average size is 0.4-0.7 micrometers.
Identification of new hyperthermophilic archaea would definitely increase the biodiversity of microorganisms. Not much research has been done on C. maquilingensis. However, if more studies are conducted on this archaea, increased understanding of its metabolic activity and genome sequences could potentially help characterize other related species. C. maquilingensis can thereby improve our knowledge of emerging field of research such as other modes of DNA repair, transcription and translation regulation, and origins of life (Itoh, et al.).
It has been found that Caldivirga maquilingensis consists of 2,048 genes and 37 pseudogenes. With the 2048 genes, 2,000 are protein genes and the rest are RNA genes. The circular genome has a size of 2,077,567 base pairs. There were four strains of this microbial species - strains ATCC 700844, DSMZ 13496, JCM 10307, and IC-167 (Itoh, et al.).
Cell Structure, Metabolism and Life Cycle
Caldivirga maquilingensis was found to have a distinct rod shape that could be straight or slightly curved, with lengths varying between 3-20 micrometers. The widths of these cells were consistantly found to be 0.4-0.7 micrometers in diatmeter. Occasionally, observations of globular bodies were found at either one or both ends of the cell. Another distinct feature of this anaerobic organism is that it was found to have a high amount of tetraether core lipids and trace amounts of diether core lipids. These features are utilized by this microorganism to help it thrive within its very hot and very acidic environment.
This heterotrophic archaea was found to have increased growth in the presence of carbon sources such as glycogen, gelatin, beef extract, peptone, tryptone and yeast extract. However, no growth was observed when there was an absence of an electron acceptor. The addition of sulfur, thiosulfate and sulfate to its envrionment to act as electron acceptors helped to induce and support growth. As C. maquilingensis grows, it produces sulfide as a byproduct (Itoh, et al.).
Ecology and Pathogenesis
Caldivirga maquilingensis was found in the acidic hot mud springs near the base of Mt. Maquiling. The spring is extremely acidic with a pH range from 2.3-6.4. The temperature range for the spring ranged from 60-92°C. So far, there has been no evidence of a symbiosis between C. maquilingensis and other bacterial or archaeal species, but it was found that Thermoproteus spp. also reside within the same hot spring environment in the Phillipines, which may have some kind of symbiotic relationship that is still unknown. As of right now, there has been no evidence of C. maquilingensis to have any pathogenicity towards any other microbes or humans (Itoh, et al.).
More research needs to be done to determine if C. maquilingensis has any important impacts on the environment or for humans in general. As C. maquilingensis is a member of the archaea kingdom, studying its behavior in such an acidic, hot environment could give rise to the evolution of life on Earth, as early Earth conditions may have been similar to the mud spring where this archaea is located.
Currently there is one main article regarding C. maquilingensis solely. In that paper there were other details missing regarding the life cycle and reproduction of this archaea. Future studies could look into those details as well as determining whether or not C. maquilingensis is symbiotic with any other bacteria or archaea in the hot spring. Another interesting idea to research would be whether or not C. maquilingensis is found in any other hot springs off of the same volcano.
 BacMap: Bacterial Genome Atlas: Caldivirga maquilingensis.
 Dworkin, M. et al, eds. (2006). The Prokaryotes: Archeae. Bacteria: Firmicutes, Actinomycetes. (3rd ed). New York: Springer. Print.
 Itoh, T., Suzuki, K., Sanchez, P.C. and Nakasel, T. (1999). Caldivirga maquilingensis gen. nov., sp. nov., a new genus of rod-shaped crenarchaeote isolated from a hot spring in the Philippines. International Journal of Systematic Bacteriology; 49, p 1157-1163.
Page authored by Katelyn Prieskorn, Elgin Paul Quebral, Mitchel Reed, and Grace Rodriguez, students of Prof. Jay Lennon at Michigan State University.
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