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Query: UMLS:C1832526 (PCC)
 5,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have attempted to observe the native shape of DNA in rapidly frozen whole cyanobacterial cells through 5-bromo-2-deoxyuridine (BrdU) incorporation and visualization with a Hilbert differential contrast transmission electron microscopy (HDC TEM). The incorporation of BrdU into the DNA of Synechococcus elongatus PCC 7942 was confirmed with fluorescently labelled anti-BrdU antibodies and through EDX analysis of ultra-thin sections. HDC TEM observed cells that had incorporated BrdU into their DNA exhibited electron dense areas at the location corresponding to fluorescently labelled BrdU. Since various strings and strands were observed in high contrast with the HDC TEM, we conclude that the method promises to allow us to identify and understand bulk structural changes of the in vivo DNA and the nucleoid through observation at high resolution.
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PMID:Visualization of BrdU-labelled DNA in cyanobacterial cells by Hilbert differential contrast transmission electron microscopy. 1939 40

Although most cyanobacterial cells contain prominent polyphosphate bodies in the central cytoplasmic area enclosed by the peripheral thylakoid membranes, their roles are not fully understood. Storing phosphate for nucleotide production might be one of their important roles in survival of the cells. As a step towards identifying a possible contribution of the polyphosphate bodies to DNA synthesis, the relationship between polyphosphate bodies and DNA throughout cell division cycle of Synechococcus elongatus PCC 7942 cells cultured under light/dark cycles was investigated with light and electron microscopy. During the dark period, the average size of polyphosphate bodies increased gradually without significant change in their number and distribution. However, during the light period, the number of polyphosphate bodies increased, while the size of each polyphosphate body decreased and cells elongated until the end of the light period, when most cells divided. The ratio of the content of polyphosphate bodies to cell length increased gradually during the dark period and decreased during the light period. Hoechst 33342-stained DNA appeared diffuse during the dark period, but in the light period it became condensed and eventually formed a wavy, rope-like structure prior to cell division. Close association between fibres containing DNA and polyphosphate bodies was demonstrated by TEM using DNA-specific staining and BrdU labelling. These regular coordinated changes of polyphosphate bodies and DNA shape during the cell division cycle, together with their intimate interaction, imply a role of polyphosphate bodies in supplying material for DNA.
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PMID:Observation of polyphosphate bodies and DNA during the cell division cycle of Synechococcus elongatus PCC 7942. 2357 45

Synechocystis sp. PCC 6803 strains overexpressing pha genes were constructed and characterized for poly-3-hydroxybutyrate (PHB) production. These pha overexpressing strains showed slightly reduced growth rates. Under N-deprived condition, the strains overexpressing (OE) phaAB, phaEC and phaABEC showed significantly higher PHB contents than the wild type. The maximum PHB content, a 2.6-fold increase producing 26% PHB (dcw), was observed in OE phaAB cells grown for 9days in N-deprived medium. Under this condition, these OE phaAB cells increased PHB production to 35% PHB (dcw) upon addition of 0.4% (w/v) acetate. Higher PHB granules in OE phaAB cells were clearly visualized by both Nile red staining and TEM imaging. All OE strains under N-deficient condition had increased glgX transcript levels. Overall results demonstrate an enhanced PHB production in Synechocystis cells overexpressing pha genes, particularly phaA and phaB, when grown in N-deprived medium containing 0.4% (w/v) acetate.
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PMID:Enhancement of poly-3-hydroxybutyrate production in Synechocystis sp. PCC 6803 by overexpression of its native biosynthetic genes. 2721 77

To visualize the fine structure of compacted DNA in Synechococcus elongatus PCC 7942, which appears at a specific time in the regular light/dark cycle prior to cell division, Chrom EM (Ou et al., 2017) with some modifications was applied. After staining DNA with DRAQ5, the cells were fixed and irradiated by red laser in the presence of DAB, and subsequently fixed with OsO4. A system with He-Ne laser (633 nm) was set up for efficient irradiation of the bacterial cells in aqueous solution. The compacted DNA was visualized by TEM, in ultrathin sections as electron dense staining by osmium black.
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PMID:TEM observation of compacted DNA of Synechococcus elongatus PCC 7942 using DRAQ5 labelling with DAB photooxidation and osmium black. 3298 72