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Ultrastructural study on the morphological changes in indigenous bacteria of mucous layer and chyme throughout the rat intestine.

Mantani Y, Ito E, Nishida M, Yuasa H, Masuda N, Qi WM, Kawano J, Yokoyama T, Hoshi N, Kitagawa H - J. Vet. Med. Sci. (2015)

Bottom Line: The vacuoles were more frequently found in bacteria of ileal chyme than in those of ileal mucous layer and were found in a large majority of bacteria in both the mucous layer and chyme throughout the large intestine.Lysis or detachment of the cell wall in the indigenous bacteria was more frequently found in the large intestine than in the ileum, whereas bacterial remnants, such as cell walls, were distributed almost evenly throughout the intestine.In an experimental control of long-time-cultured Staphylococcus epidermidis on agar, similar vacuoles were also found, but cell-wall degeneration was never observed.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan.

ABSTRACT
Indigenous bacteria in the alimentary tract are exposed to various bactericidal peptides and digestive enzymes, but the viability status and morphological changes of indigenous bacteria are unclear. Therefore, the present study aimed to ultrastructurally clarify the degeneration and viability status of indigenous bacteria in the rat intestine. The majority of indigenous bacteria in the ileal mucous layer possessed intact cytoplasm, but the cytoplasm of a few bacteria contained vacuoles. The vacuoles were more frequently found in bacteria of ileal chyme than in those of ileal mucous layer and were found in a large majority of bacteria in both the mucous layer and chyme throughout the large intestine. In the dividing bacteria of the mucous layer and chyme throughout the intestine, the ratio of area occupied by vacuoles was almost always less than 10%. Lysis or detachment of the cell wall in the indigenous bacteria was more frequently found in the large intestine than in the ileum, whereas bacterial remnants, such as cell walls, were distributed almost evenly throughout the intestine. In an experimental control of long-time-cultured Staphylococcus epidermidis on agar, similar vacuoles were also found, but cell-wall degeneration was never observed. From these findings, indigenous bacteria in the mucous layer were ultrastructurally confirmed to be the source of indigenous bacteria in the chyme. Furthermore, the results suggested that indigenous bacteria were more severely degenerated toward the large intestine and were probably degraded in the intestine.

No MeSH data available.


Related in: MedlinePlus

a) Low-magnification image of bacterial colony of S. epidermidis.The colony is vertically sliced at the maximum diameter. M, marginal portion. C,central portion. Bar=50 µm. b, c) Most of S.epidermidis cultured for 1 day have a typical structure of bacteria withhomogeneous and highly electron-dense cytoplasmic matrix and nucleoid body(arrowheads). Cell-dividing bacteria are plentiful in the marginal portions (b,arrows), but are few in the central portion (c, arrow). d, e) Cell debris (arrows) andvacuolated bacteria (arrowheads) are visible in the central (e) and marginal portions(d) of a bacterial colony cultured for 45 days. Bar=1 µm.
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fig_006: a) Low-magnification image of bacterial colony of S. epidermidis.The colony is vertically sliced at the maximum diameter. M, marginal portion. C,central portion. Bar=50 µm. b, c) Most of S.epidermidis cultured for 1 day have a typical structure of bacteria withhomogeneous and highly electron-dense cytoplasmic matrix and nucleoid body(arrowheads). Cell-dividing bacteria are plentiful in the marginal portions (b,arrows), but are few in the central portion (c, arrow). d, e) Cell debris (arrows) andvacuolated bacteria (arrowheads) are visible in the central (e) and marginal portions(d) of a bacterial colony cultured for 45 days. Bar=1 µm.

Mentions: Degeneration pattern of cultured S. epidermidis: Most of S.epidermidis cultured for 1 day possessed cytoplasm divided into two parts:cytoplasmic matrix with homogeneous electron density and nucleoid body with low electrondensity. Cell division of S. epidermidis cultured for 1 day was morefrequently found in the marginal portions than in the central portions of bacterialcolonies. Cell debris was restricted to the central portions of a bacterial colony culturedfor 1 day. Vacuoles were very rarely found in any portions of a bacterial colonycultured for 1 day. In S. epidermidis cultured for 45 days, there were fewbacteria with intact cytoplasmic matrices, whereas cell debris, such as cell wall remnants,and bacteria possessing vacuoles with low electron density in their cytoplasm wereoccasionally found in all portions of the colony. Cell debris and vacuolated bacteria weremore frequently found in the colony cultured for 45 days than that cultured for 1 day,whereas cell division was less frequent in the colony cultured for 45 days than in thatcultured for 1 day (Fig. 6Fig. 6.


Ultrastructural study on the morphological changes in indigenous bacteria of mucous layer and chyme throughout the rat intestine.

Mantani Y, Ito E, Nishida M, Yuasa H, Masuda N, Qi WM, Kawano J, Yokoyama T, Hoshi N, Kitagawa H - J. Vet. Med. Sci. (2015)

a) Low-magnification image of bacterial colony of S. epidermidis.The colony is vertically sliced at the maximum diameter. M, marginal portion. C,central portion. Bar=50 µm. b, c) Most of S.epidermidis cultured for 1 day have a typical structure of bacteria withhomogeneous and highly electron-dense cytoplasmic matrix and nucleoid body(arrowheads). Cell-dividing bacteria are plentiful in the marginal portions (b,arrows), but are few in the central portion (c, arrow). d, e) Cell debris (arrows) andvacuolated bacteria (arrowheads) are visible in the central (e) and marginal portions(d) of a bacterial colony cultured for 45 days. Bar=1 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591154&req=5

fig_006: a) Low-magnification image of bacterial colony of S. epidermidis.The colony is vertically sliced at the maximum diameter. M, marginal portion. C,central portion. Bar=50 µm. b, c) Most of S.epidermidis cultured for 1 day have a typical structure of bacteria withhomogeneous and highly electron-dense cytoplasmic matrix and nucleoid body(arrowheads). Cell-dividing bacteria are plentiful in the marginal portions (b,arrows), but are few in the central portion (c, arrow). d, e) Cell debris (arrows) andvacuolated bacteria (arrowheads) are visible in the central (e) and marginal portions(d) of a bacterial colony cultured for 45 days. Bar=1 µm.
Mentions: Degeneration pattern of cultured S. epidermidis: Most of S.epidermidis cultured for 1 day possessed cytoplasm divided into two parts:cytoplasmic matrix with homogeneous electron density and nucleoid body with low electrondensity. Cell division of S. epidermidis cultured for 1 day was morefrequently found in the marginal portions than in the central portions of bacterialcolonies. Cell debris was restricted to the central portions of a bacterial colony culturedfor 1 day. Vacuoles were very rarely found in any portions of a bacterial colonycultured for 1 day. In S. epidermidis cultured for 45 days, there were fewbacteria with intact cytoplasmic matrices, whereas cell debris, such as cell wall remnants,and bacteria possessing vacuoles with low electron density in their cytoplasm wereoccasionally found in all portions of the colony. Cell debris and vacuolated bacteria weremore frequently found in the colony cultured for 45 days than that cultured for 1 day,whereas cell division was less frequent in the colony cultured for 45 days than in thatcultured for 1 day (Fig. 6Fig. 6.

Bottom Line: The vacuoles were more frequently found in bacteria of ileal chyme than in those of ileal mucous layer and were found in a large majority of bacteria in both the mucous layer and chyme throughout the large intestine.Lysis or detachment of the cell wall in the indigenous bacteria was more frequently found in the large intestine than in the ileum, whereas bacterial remnants, such as cell walls, were distributed almost evenly throughout the intestine.In an experimental control of long-time-cultured Staphylococcus epidermidis on agar, similar vacuoles were also found, but cell-wall degeneration was never observed.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan.

ABSTRACT
Indigenous bacteria in the alimentary tract are exposed to various bactericidal peptides and digestive enzymes, but the viability status and morphological changes of indigenous bacteria are unclear. Therefore, the present study aimed to ultrastructurally clarify the degeneration and viability status of indigenous bacteria in the rat intestine. The majority of indigenous bacteria in the ileal mucous layer possessed intact cytoplasm, but the cytoplasm of a few bacteria contained vacuoles. The vacuoles were more frequently found in bacteria of ileal chyme than in those of ileal mucous layer and were found in a large majority of bacteria in both the mucous layer and chyme throughout the large intestine. In the dividing bacteria of the mucous layer and chyme throughout the intestine, the ratio of area occupied by vacuoles was almost always less than 10%. Lysis or detachment of the cell wall in the indigenous bacteria was more frequently found in the large intestine than in the ileum, whereas bacterial remnants, such as cell walls, were distributed almost evenly throughout the intestine. In an experimental control of long-time-cultured Staphylococcus epidermidis on agar, similar vacuoles were also found, but cell-wall degeneration was never observed. From these findings, indigenous bacteria in the mucous layer were ultrastructurally confirmed to be the source of indigenous bacteria in the chyme. Furthermore, the results suggested that indigenous bacteria were more severely degenerated toward the large intestine and were probably degraded in the intestine.

No MeSH data available.


Related in: MedlinePlus