Subdoligranulum didolesgii
1. Classification
a. Higher order taxa
i. Domain: Bacteria, Phylum: Bacillota, Class: Clostridia, Order: Eubacteriales, family: Oscillospiraceae, Genus: Subdoligranulum
b. Species
Subdoligranulum Didolesgii [1]
2. Description and significance
Subdoligranulum didolesgii, a Gram-negative anaerobic bacterium is a human gut bacterium that was recently studied in the context of rheumatoid arthritis (RA), a chronic autoimmune condition impacting millions globally [2][3][4]. Named after the Cherokee word for arthritis or rheumatism, S. didolesgii is of interest in the development of RA-related autoimmunity [5]. Emerging evidence suggests that RA may initiate in mucosal tissues, potentially due to infectious agents or immune reactions to antigens, including those produced by S. didolesgii [5][6]. Previously, studies had shown that Subdoligranulum species? are associated with health benefits such as improved metabolic markers and gut integrity, making them a potential target for therapeutic interventions in metabolic disorders [7][8]. However, new research indicates that S.didolesgii can influence the immune system and inflammatory responses [2][9][10].
3. Genome structure
The genome of Subdoligranulum sp. Isolate_7 sample (which was later coined S. didolesgii) is 1.7 billion DNA base pairs [11][2] and has a GC content of the genus Subdoligranulum is known to be 52%, indicating that S. didolesgii also has similar GC content, as being one of its species [12]. S. didolesgii is one of the unclassified species from the genus Subdoligranulum, which is known to be a genus of firmicute in the family Oscillospiraceae [1]. However, S. didolesgii it is also closely linked to both the Ruminococcaceae and Lachnospiraceae families. It suggests a potential resemblance in genome structure to taxa from either family. S. didolesgii’s similarilty to the Ruminococcacae and Lachnospiraceae may be due to their engagement in lateral gene transfer or infection by bacteriophages which leads to the expression of distinct proteins and gain of functions that could lead to host immunomodulation [2].
4. Cell structure
S. didolesgii (Subdoligranulum didolesgii) is a non-spore-forming and Gram-negative staining bacterium [7]. Species in the genus Subdoligranulum tend to exhibit the shape of coccoid-droplet and are highly pleomorphic, along with being non-motile [12]. However, it is uncertain whether S.didolesgii also has the cocci-shaped cell. Since experiments on S.didolesgii species are still ongoing, additional aspects of its the cell structure are yet to be determined.
5. Metabolic processes
Subdoligranulum can hydrolyse esculin but not starch. As a strictly anaerobic organism, S. didolesgii produces butyric and lactic acids with limited acetic and succinct acids as the major end products of glucose metabolism [7][12]. According to the AN-MicroLogTM system, S.didolesgii can utilize a wide range of carbohydrate substrates, which includes N-acetyl-dglucosamine, N-acetyl-d-mannosamine, amygdalin, arbutin, d-cellobiose, dextrin, d-fructose, etc [12]. The API Rapid ID 32A kit does detect activities of α-galactosidase, β-galactosidase, βglucosidase, β-glucuronidase, arginine arylamidase, leucine arylamidase and histidine arylamidase, but only weak or negative activity for α-glucosidase [12]. According to the API ZYM test system, S. variabile has similar positive reactions for α-galactosidase, β-galactosidase, β-glucosidase, β-glucuronidase, but a weak reaction for α-glucosidase [12].
