Where is mycobacterium smegmatis found

The volume of the periplasm was calculated by subtracting the cytoplasmic volume from the whole cell volume. The total number of ribosomes in each cell and the number of ribosomes per 0. In addition, 3D reconstruction of Cell 3 was tried with Amira 6. With this preparation protocol, ultrastructures of cell were preserved with extremely high-quality, where not only membrane structures, but also every single ribosome can be examined and enumerated separately.

In addition, ice-embedded whole-mount CryoTEM examination was performed Figure 1B to obtain cell profiles in the most intact condition. Cell lengths of the seven cells ranged from 2. Figure 1. Images of ultrathin section and cryo-transmission electron microscopy TEM of M.

A Two M. Figure 2. One of the representative images of serial ultrathin sections in seven M. Table 1. One-dimensional data of 7 M.

Cell diameter measured at OM and PM in serial ultrathin sections ranged from 0. In cell diameter, seven cells showed similar values to each other. On the contrary, cell diameter measured in CryoTEM examination ranged from 0. The aspect ratio of these seven cells was 6. These data were compared with those of M. In comparison of cell diameter, both average OM 0.

Furthermore, average whole cell diameter of M. In cell length, whereas, there was no significant difference between the three species in the serial ultrathin sections, average length of M. In aspect ratio, average aspect ratio of M. In addition, M. In Ziehl-Neelsen staining, M. Difference in acid-fastness between M. Two-dimensional cell properties were measured.

In seven M. Both surface areas of M. There were no significant differences in comparison of surface areas between M. Table 2. Two-dimensional data of 7 M.

Three-dimensional cell properties of seven M. Average whole cell volume was 0. This value was significantly larger than that of M. Average cytoplasmic volume was 0. This value was also significantly larger than that of M. The OM, PM, and periplasm volume in average were 0. Finally, there were no significant differences in all cell volume categories between M. It is suggested that M. Table 3. Three-dimensional data of 7 M. The M. Three-dimensional reconstitutions for seven M.

Figure 3. The 3D reconstruction of Cell 3 with visualization of cell profile and cytoplasmic distribution of ribosomes. Cytoplasmic ribosome number was enumerated on each serial ultrathin section for seven cells.

On the contrary, ribosome density per 0. As shown in Figure 3 , ribosomes were evenly distributed throughout the cytoplasmic space in 3D reconstruction. The average total ribosome number of M. In addition, average ribosome density of M. Table 4. Total ribosome number and cytoplasmic ribosome density of 7 M.

Table 5. Comparison of total ribosome number and cytoplasmic density in structome-analyzed microorganisms. As shown in Table S1 , the cell diameters of M. In addition, cell lengths of M. In comparison with E. As discussed in previous literature, cell division of M. This phenomenon is much more obvious in M.

Asymmetric cell divisions in M. In a single cell time-lapse observation, Aldridge et al. Then, cells with older growth poles elongate faster than cells with younger growth poles. In addition, the birth length of cells increases as the growth pole matures. Taken together, these data suggest that as the growth pole matures, cells elongate faster and are larger Aldridge et al.

Furthermore, Vijay et al. The authors confirmed the phenomena by TEM examination. Our data confirm these reports. On the contrary, the length of E. This result indicates that E. It revealed that the machinery of cell division in mycobacteria completely differs from that of E. This is the first report on the surface area of the M.

These values are approximately twice of those of M. This suggests that if M. In the circumstance, the gene s from M. There were no significant differences between M. Average whole cell and cytoplasmic volume of M. These values are approximately three times larger than those of M.

Based on these results, if in vivo or in vitro experiments are performed using M. In the cell volume analysis in serial ultrathin sections, there were no significant differences between M. Compared with the M.

These evidences suggest that single M. Structome analysis data have been already reported in six species, including two yeast species and four bacterial species Table 5 Yamaguchi, ; Yamaguchi et al. Because total ribosome number per cell can differ from cell to cell according to the volume of cytoplasm with a large standard deviation, even if the cells would belong to the same strain, the value is not appropriate to be used in comparison between species or strains.

On the contrary, it has been revealed that ribosome density per unit volume of cytoplasm is specific to the species or the strain with an extremely small standard deviation Table 5 Yamaguchi, ; Yamaguchi et al. Average total cytoplasmic ribosome number of M. This value was significantly more than Myojin spiral bacteria and M.

However, average cytoplasmic ribosome density of M. It is then surprising that there was only a small difference in average cytoplasmic ribosome density between M. These results supported that M. Figure 4. Correlation curve between ribosome density per 0. Correlation curve was drawn based on known doubling time and ribosome densities per 0.

Number in parenthesis indicates ribosome density per 0. Underlined doubling time min in species with unknown doubling time, Myojin spiral bacteria, Myojin amorphous bacteria, E. Srivastava et al. Authors used M. When ribosomes of M. The evidence supports our data that the cytoplasmic ribosome density of M.

However, Srivastava et al. This value means 1. It is intriguing that this huge number of ribosomes may be acceptable in experimental conditions. On the contrary, it has been demonstrated that M.

Compared with E. As mentioned in our previous paper, there is a close correlation between ribosome density and doubling time min Yamada et al. According to data obtained from this study, the correlation chart was revised as shown in Figure 4 based on the known doubling time data in E. On the contrary, in M. Liu et al. The data cannot be compared with our data because our samples were prepared through rapid-freezing and freeze-substitution, and ribosome density was calculated by direct enumeration of cytoplasmic ribosome number and volume of cytoplasm in serial ultrathin sectioning spanning a cell from one end to the other end.

Furthermore, Zhu and Dai reviewed the correlation of protein synthesis rate and ribosome content with growth rate in E. However, because these ribosome quantifications were described as ribosome content derived from a population of microorganisms, and not ribosome density obtained from direct enumeration through TEM examination of serial ultrathin sections in a single cell, quantifications were much less accurate than our structome analysis.

It is revealed that although M. Most recently, genus Mycobacterium has been divided into an emended genus Mycobacterium and four novel genera, Mycolicibacterium gen. Non pathogenic M. Single M. The more the antigens that can be contained in their cell surface, the more the host cell response that can be elicited. This means that M. Therefore, it is not appropriate to use M. This means usage of M.

We propose that data obtained from the experiments with M. HY and MY performed experiments. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Authors wish to thank Y. Kayama and N. Kai Terabase Inc. Aldridge, B. Asymmetry and aging of mycobacterial cells lead to variable growth and antibiotic susceptibility. Science , — Angara, R.

An IclR like protein from mycobacteria regulates leuCD operon and induces dormancy-like growth arrest in Mycobacterium smegmatis.

Tuberculosis , 83— Bakshi, S. Superresolution imaging of ribosomes and RNA polymerase in live Escherichia coli cells. Bashiri, G. Production of recombinant proteins in Mycobacterium smegmatis for structural and functional studies.

Protein Sci. Bhatt, A. Jr The genome was sequenced in November 29, by the J. Craig Venter Institute 9. Mycobacterium smegmatis is a Gram-positive bacteria, characterized by an inner cell membrane and a thick cell wall.

The Gram-positive bacteria is further classified as one with a high GC content and therefore a low AT content. This quality is used as a crude measure of similarity of different species of bacteria.

Although this bacteria is Gram-positive, it has some unique qualities that are divergent from most Gram-positive bacteria. Its cell wall contains mycolic acids, long, branched fatty acids that are normally present in scid-fast bacteria. The acids prevent proper gram staining that would normally identify the cell as a gram positive cell because they create a waxy coating so the crystal violet has difficulty entering the cell, therefore making it seem gram-negative.

The cell wall is also abnormal because it is irregularly thick for a gram-positive bacteria and its hydrophobicity reduces desiccation. This feature in addition to its slow cell growth in comparison to most other bacteria attribute to Mycobacterium smegmatis' low response to antibiotics. Although Mycobacterium smegmatis contains the similar structural features of Mycobacterium tuberculosis , the former grows much quicker in comparison to the latter Mycobacterium smegmatis is an aerobic organism.

Mycobacerium smegmatis may donate its final electrons in aerobic respiration to oxygen using one of three terminal oxidases. In aerobic respiration, the bacteria undergo oxidative phosphorylation to yield the highest amount of energy.

Since Mycobacteria are obligate aerobes, oxygen is required for aerobic respiration. Mycobacterium smegmatis doesn't undergo anaerobic respiration, however certain virulent Mycobacteria undergo anaerobic respiration only during infection.

Mycobacterium smegmatis may survive on chemolithotrophic growth on carbon monoxide as its inorganic carbon source during aerobic respiration.

The bacteria may also use methanol for its sole source carbon and energy. In addition, Mycobacterium smegmatis requires a unique fatty acid biosynthesis to produce the mycolic acids that are present on the cell wall. Mycobacterium smegmatis has no motility and no formation of endospores 3, 13, Biofilms of Mycobacterium smegmatis may use stigmasterol as a carbon source from plants. The bacteria will metabolize the compound to a potent androgen, androstenedione.

If Mycobacterium smegmatis is around a large body of water, which is where it usually exists, then the bacteria will secrete androstenedione. The androgen in the water causes female mosquito fish to form male anatomical sex organs Not much else could be found about the contribution to the environment. This organism is classified as saprophytic and therefore relatively safe. Mycobacterium smegmatis doesn't normally reside in any animals, and doesn't cause dangerous or even any infections.

There have only been a few threats, which have seem to come out in only extreme cases, however there hasn't been any documented virulence of Mycobacterium smegmatis in over 15 years.

There are many other species under this genus are pathogenic. Obligate pathogens such as Mycobacterium tuberculosis, Mycobacterium bovis, and Mycobacterium leprea are highly pathogenic in animals. These species can cause tuberculosis and leprosy, debilitating diseases that may lead to death or disfigurement.

These pathogens can only survive inside the host organism. There is also the classification of potential pathogens in this genus, such as Mycobacterium avium , which may survive outside of the host environment and cause virulence once it is contracted by the host. However, there has been 1 case where the bacteria has killed a human after infection. In this case, an Italian child was infected by Mycobacterium smegmatis and died at the age of 8. After genetic analysis of the child, it was determined that four nucleotides were inserted, causing a frameshift and a nonsense mutation.

The stop codon allowed for a premature stop of translation and essential proteins weren't made. Although this showed potential pathogenic properties of Mycobacterium smegmatis , this case required that the child have two mutant alleles in his genome for the bacteria to be particularly virulent. Therefore in most cases, Mycobacterium smegmatis is generally safe and not pathogenic 5. Mycobacterium smegmatis has been used to produce Xylitol. Xylitol is an important sugar that is used as a substitute for commercial dietary sugars to prevent tooth decay and reduce plaque.

It is also absorbed more slowly in the bloodstream, so it prevents the negative affects of high blood sugar levels. This is used as a dietary alternative for diabetics. It also has potential treatments for osteoporosis and ear and upper respiratory infections. The D-xylulose sugar produced by Mycobacterium smegmatis is combined with the D-xylose sugar produced by D-xylose isomerase of immobilized Mycobacterium smegmatis to produce the beneficial Xylitol 6.

Mycobacterium smegmatis is also used to transform L-ribulose into L-arabinose with the enzyme L-arabinose isomerase. Mycobacterium smegmatis produces L-arabinose during carbohydrate metabolism. L-arabinose is used by biotech companies to produce chiral drugs. Researchers use L-arabinose as a component for many tissue culture medium.

It is also used by food producers for the Maillard reaction to make bread, beer, dried or condensed milk, etc. Fahey's lab at UCSD studies the methods of mycothiol biosynthesis that produces thiols necessary for Mycobacterium to live and grow. The lab is trying to determine the missing and unknown enzymes and substrates that are present in the biosynthesis pathway and if they are essential.

There are currently three steps that have been determined by this lab. The Fahey lab aims to determine the unknown substrate to determine the full mycothiol biosynthesis pathway, and to determine some inhibitors of this pathway to prevent Mycobacterium smegmatis growth. Since Mycobacterium smegmatis has the same mechanism to create its cell wall as Mycobacterium tuberculosis , this can translate into treatments tuberculosis.

Mycobacterium smegmatis uses a terminal oxidase to donate electrons to the final electron acceptor oxygen in oxidative phosphorylation during aerobic respiration. These terminal oxidases have been identified as using both a cytochrome c aa3 type oxidase and a quinol bd type oxidase.

When bd type oxidase gene is knocked out so cytochrome c aa3 type oxidase is the only functional oxidase, the latter didn't attain normal levels of expression of the oxidase.

In addition, the oxidase concentration for the knockout didn't reduce during log phase, while the wild type without the knockout had decreased oxidase concentration 3.