The organism I chose to do my micro-biography on was Nitrospira multiformis. I chose this organism because it’s method of respiration sounded interesting to me. Unlike humans, nitrifying bacteria can utilize ammonia as an electron acceptor rather than oxygen. I find things like this interesting, because it is nice to know of the different ways that organisms can thrive in their environments that seem strange to us, but that work well for them. This organisms also has novel interactions with humans and other parts of the biosphere in that it helps in the nitrogen cycle.
N. multiformis is an organism that is part of the bacterial domain and its phylum is that of betaproteobacteria. Betaproteobacteria is one of the phyla that is known for containing similar types of chemolithrotrophic organisms. The genus and class of N. multiformis is Nitrospira; the family to which this microorganism belongs is Nitrosomonadaceae and the order is Nitrosomonadales. Organisms of this order are known for being ammonia-oxidizing bacteria.
This organism has many habitats and though it is often associated with being a soil-dwelling microbe it is also been found in a variety of other wet environments such as sea water and water in lakes and rivers (Kozlowski et al., 2016). One paper mentioned that various nitrifying microbes actually have a symbiotic relationship with sea sponges. In this paper, ammonia oxidizing archaea and nitrite oxidizing bacteria, including some from Nitrospira were found to live inside a species of sea sponge (Feng et al., 2015). It is not confirmed if N.
multiformis has done this as of yet, but if it did, it would probably replace the ammonia oxidizing archaea and assume their role. N. multiformis has been known to be found in biofilms quite often.
N. multiformis, when first discovered in 1971, was isolated from a soil environment. This soil environment happened to be near Paramaribo which was in Surinam. Sand filters involved in clean water production have been found to be homes for microbes of this kind. Because there are many inorganic sources of electrons, this type of environment is one that serves well for the chemolithotrophic microbes including Nitrospira. Comparative populations of Sand-filter . The image above shows the populations of microorganisms on various points on a sand filter that is involved in the treatment of waste-water. The outer region is the upward region of the filter and the middle circle is the lower region.
As betaproteobacteria, all organisms in the Nitrospira genus have a gram negative cell wall, having a lipopolysaccharide layer and a cell membrane with a periplasmic space in between. It has also been noted that the organisms of the Nitrospira genus tend to have a large periplasmic space. N. multiformis cells that are not in a biofilm have been known to have a peritrichous arrangement of flagella. When discovered, N. multiformis was described as having a “lobular”, or ellipsoid, shape.
Many of the ammonia oxidizing bacteria, including N. multiformis prefer to have a decent supply of oxygen as well as ammonia. Although, as stated before, this species and many of those like it have been notable for being able to survive in multiple forms of location, a common feature between the various papers that I researched was that these sorts of microbes have often been found at plants for the treatment of waste water as well as other artificial bodies of water. As far as the pH of the environment, N. multiformis has a preference for slightly basic environments, because this increases the availability of ammonia as opposed to ammonium.
N. multiformis is a chemolithotroph and is able to gain energy via the oxidation of ammonia. They have a TCA cycle and an electron transportation system that involves NADH and ubiquinone pools. The Nitrospira genus is known for being one of the ammonia-oxidizing bacteria. This is often abbreviated as “AOB.” There are also organisms called ammonia-oxidizing archaea. This is abbreviated as “AOA.” Both of these terms are seen often in papers relating to the microbes involved in nitrification. Some organisms are nitrite oxidizing bacteria, which can oxidize nitrite and convert it into nitrate. These are abbreviated as “NOB” in many papers. N. multiformis is, in certain cases where oxygen is lacking in its environment, capable of reducing nitrite into N2O. It is not a nitrite oxidizing bacteria, however.
The two types of oxidizing bacteria, the nitrite oxidizers and the ammonia oxidizers form an interesting relationship in they function like one chemical assembly line. The ammonia oxidizers take ammonia and convert it into nitrite and the nitrite oxidizers convert nitrite to nitrate. In this, they help each other and also help to keep the Nitrogen cycle moving. Among its ammonia-oxidizing relatives, N. multiformis is unique in that it has been shown to have a utilization of hydrogenase as part of its metabolic reactions. It is possible that the hydrogenase is used to help fuel reduction in the transportation of electrons in the metabolic system of N. multiformis. When N. multiformis is culture in the lad it is done so on a nutrient medium and at the temperature of 28 degrees Celsius. This is done in a dark location.
The chromosome of N. multiformis has 3,234,309 base pairs in it. It has one chromosome which is circular and also comes equipped with 3 plasmids. Some strains of N. multiformis have been cultured for various research purposes and there are also strains of other Nitrospira species produced for research purposes. A common strain of N. multiformis that is used is ATCC 25196T.
N. multiformis, as well as similar nitrifying microbes, are beneficial to humans and other life-forms because they help in the nitrogen cycle, an imporant, sustaining cycle in our biosphere. It can help in bioremediation potentially because it, other ammonia oxidizing bacteria and nitrite oxidizing bacteria together can help remove nitrogenous pollutants. Biotechnologically speaking, they can be used to clean artificial bodies of water when used in biological filters.
Some research has been done in order to determine the quorum sensing process and mechanisms done by various genuses of ammonia oxidizing bacteria including those of the Nitrospira genus. The genes that N. multiformis utilizes for its quorum sensing process have been discovered and it has been found that this species makes use of the Acyl-Homoserine Lactone molecule for this purpose.
This microorganism was initially discovered in 1971 and misidentified as being part of the Nitosolobus genus, due to its morphology. One of the most recent papers on it had to do with this organism’s ecological impact. This paper involved researched creating a filter in an artificial body of water that used various organisms in order to filter out various pollutants including nitrogen-related pollutants. For this reason, various Nitrospira species were part of the population involved in the biological filtration of this body of water.
N. multiformis is one of the many microorganisms in our biosphere which will be worthy of much study. In the case of N. multiformis, part of this worthiness comes from its potential utility for bioremediatory purposes, including those above in artificial bodies of water. These kinds of organisms are important also because they are involved in the cycle of nitrogen in the environment (Kozlowski et al., 2016). When there is an increase in our knowledge of microorganisms such as these, so too, is an increase in our knowledge of our biosphere.