Multiple rRNA operons are essential for efficient cell growth and sporulation as well as outgrowth in Bacillus subtilis

Yano, Koichi; Wada, Tetsuya; Suzuki, Shota; Tagami, Kazumi; Matsumoto, Takashi; Shiwa, Yuh; Ishige, Taichiro; Kawaguchi, Yasuhiro; Masuda, Kenta; Akanuma, Genki; Nanamiya, Hideaki; Niki, Hironori; Yoshikawa, Hideki; Kawamura, Fujio

doi:10.1099/mic.0.067025-0

Cited by 59 publications

(71 citation statements)

References 37 publications

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“…In contrast, we observed that B. subtilis encapsulated in mPEG-PDLLA are capable of proliferating in an exponential fashion with an estimated doubling time of approximately 25 minutes. This is in close agreement with the minimum doubling time of 21 minutes reported for B. subtilis under optimal growth conditions (Yano et al 2013). …”

Section: Discussionsupporting

confidence: 91%

High throughput microencapsulation of Bacillus subtilis in semi-permeable biodegradable polymersomes for selenium remediation

Barlow

Gozzi

Kelley

et al. 2016

Appl Microbiol Biotechnol

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Encapsulating bacteria within constrained microenvironments can promote the manifestation of specialized behaviors. Using double-emulsion droplet-generating microfluidic synthesis, live Bacillus subtilis were encapsulated in a semi-permeable membrane comprised of poly(ethylene glycol)-b-poly(D,L-lactic acid). This mPEG-PDLLA membrane was sufficiently permeable to permit exponential bacterial growth, metabolite-induced gene expression, and rapid biofilm growth. The biodegradable microparticles retained structural integrity for several days, and could be successfully degraded with time or sustained bacterial activity. Microencapsulated B. subtilis successfully captured and contained sodium selenite added outside the polymersomes, converting the selenite into elemental selenium nanoparticles that were selectively retained inside the polymer membrane. This remediation of selenium using polymersomes has high potential for reducing the toxicity of environmental selenium contamination, as well as allowing selenium to be harvested from areas not amenable to conventional waste or water treatment.

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Section: Discussionsupporting

confidence: 91%

High throughput microencapsulation of Bacillus subtilis in semi-permeable biodegradable polymersomes for selenium remediation

Barlow

Gozzi

Kelley

et al. 2016

Appl Microbiol Biotechnol

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“…6A). The decrease in the number of rrn operons correlated with the reduction in the amount of ribosomes as well as the reduction in the growth rate (61,62). These results suggest that the Mg 2ϩ content in the cell is influenced by the amount of ribosomes present, especially 70S ribosomes and polysomes.…”

Section: Resultsmentioning

confidence: 62%

“…When the 50S and 30S subunits were included with the 70S ribosomes and polysomes, the total areas of the peaks were 89%, 77%, and 80% of the wild-type area in the ⌬rplA, ⌬rplW, and ⌬rpmH mutants, respectively. Previously, we have constructed mutants that harbor one to nine copies of the rrn operon in their genome (the wild type contains 10 copies) and confirmed that the number of ribosomes is reduced in these mutants, especially in those that harbor only one or two rrn operons (61,62). In the present study, we determined the cellular Mg 2ϩ content in these mutants and found that the Mg 2ϩ content decreased as the number of rrn operons decreased (Fig.…”

Section: Resultsmentioning

confidence: 87%

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Defect in the Formation of 70S Ribosomes Caused by Lack of Ribosomal Protein L34 Can Be Suppressed by Magnesium

et al. 2014

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dTo elucidate the biological functions of the ribosomal protein L34, which is encoded by the rpmH gene, the rpmH deletion mutant of Bacillus subtilis and two suppressor mutants were characterized. Although the ⌬rpmH mutant exhibited a severe slowgrowth phenotype, additional mutations in the yhdP or mgtE gene restored the growth rate of the ⌬rpmH strain. Either the disruption of yhdP, which is thought to be involved in the efflux of Mg 2؉ , or overexpression of mgtE, which plays a major role in the import of Mg 2؉ , could suppress defects in both the formation of the 70S ribosome and growth caused by the absence of L34. Interestingly, the Mg 2؉ content was lower in the ⌬rpmH cells than in the wild type, and the Mg 2؉ content in the ⌬rpmH cells was restored by either the disruption of yhdP or overexpression of mgtE. In vitro experiments on subunit association demonstrated that 50S subunits that lacked L34 could form 70S ribosomes only at a high concentration of Mg 2؉ . These results showed that L34 is required for efficient 70S ribosome formation and that L34 function can be restored partially by Mg 2؉ . In addition, the Mg 2؉ content was consistently lower in mutants that contained significantly reduced amounts of the 70S ribosome, such as the ⌬rplA (L1) and ⌬rplW (L23) strains and mutant strains with a reduced number of copies of the rrn operon. Thus, the results indicated that the cellular Mg 2؉ content is influenced by the amount of 70S ribosomes.T he eubacterial ribosome (70S), which plays a central role in protein synthesis, is composed of a small (30S) subunit and a large (50S) subunit. The small subunit is comprised of the 16S rRNA and more than 20 proteins, whereas the large subunit is comprised of the 23S and 5S rRNAs and more than 30 proteins (1, 2). The molecular mechanisms of translation have been elucidated in detail by the convergence of various approaches, including crystal structure analysis (3-8). The individual functions of several ribosomal proteins have also been elucidated by biochemical and genetic analyses, including reconstitution and mutational analysis. For example, ribosomal protein L2 plays important roles in the assembly of the ribosomal subunits, binding of the tRNA to the A and P sites, peptidyltransferase activity, and formation of the peptide bond (9-13). However, in general, disruption of the genes that encode the ribosomal proteins has been avoided as a means of identifying protein function, because these genes, which are highly conserved in bacteria, have been considered essential for cell proliferation (14). Nonetheless, recently, it was found that 22 of the 54 Escherichia coli genes for ribosomal proteins could be deleted on an individual basis (15,16). We have also shown that out of the 57 ribosomal-protein-encoding genes that have been annotated in the Gram-positive bacterium Bacillus subtilis, at least 22 genes are not individually essential for cell proliferation (17). The rpmH gene encoding ribosomal protein L34, which is a component of the large subunit, is one of the...

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“…Condon et al (1995) used Escherichia coli with multiple rRNA operons inactivated by antibiotic cassettes to demonstrate that the number of rRNA operons in the genome affects cell proliferation rate. Yano et al (2013) found that the existence of multiple rRNA operons underlies the high growth rate of Bacillus subtilis . Another study reported that the copy number of rRNA operons on the genomes is correlated with growth rate of the prokaryotes under optimal culture condition (Vieira-Silva and Rocha, 2010; Roller et al, 2016).…”

Section: Resultsmentioning

confidence: 99%

Expression and Function of Different Guanine-Plus-Cytosine Content 16S rRNA Genes in Haloarcula hispanica at Different Temperatures

2017

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The halophilic archaeon Haloarcula hispanica harbors three ribosomal RNA (rRNA) operons (rrnA, rrnB, and rrnC) that contain the 16S rRNA genes rrsA, rrsB, and rrsC, respectively. Although rrsB and rrsC (rrsBC) have almost identical sequences, the rrsA and rrsBC sequences differ by 5.4%, and they differ by 2.5% with respect to guanine-plus-cytosine content (PGC). The strong correlation between the typical growth temperatures of archaea and PGC of their 16S rRNA genes suggests that H. hispanica may harbor different 16S rRNA genes having different PGC to maintain rapid growth in a wide range of temperatures. We therefore performed reverse transcription-coupled quantitative PCR to assess expression levels of rrsA (PGC, 58.9%) and rrsBC (PGC, 56.4–56.5%) at various temperatures. The expression ratio of rrsA to rrsBC increased with culture temperature. Mutants with complete deletions of one or two of the three rRNA operons were constructed and their growth rates at different temperatures compared to that of the wild-type. The growth characteristics of the rRNA operon single-mutant strains were indistinguishable from the wild-type. The rRNA operon double-mutant strains maintained the same temperature range as wild-type but displayed reduced growth rates. In particular, the double-mutant strains grew much slower than wild-type at low temperature related to minimum growth temperature of the wild-type. On the other hand, at physiologically high temperatures the wild-type and the double-mutant strain which harbors only rrnA with high-PGC rrsA grew significantly faster than the double-mutant strain which harbors only rrnC with low-PGC rrsC. These findings suggest the importance of 16S rRNAs transcribed from rrsA with high-PGC in maintaining rapid growth of this halophilic archaeon at raised growth temperatures.

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Multiple rRNA operons are essential for efficient cell growth and sporulation as well as outgrowth in Bacillus subtilis

Cited by 59 publications

References 37 publications

High throughput microencapsulation of Bacillus subtilis in semi-permeable biodegradable polymersomes for selenium remediation

High throughput microencapsulation of Bacillus subtilis in semi-permeable biodegradable polymersomes for selenium remediation

Defect in the Formation of 70S Ribosomes Caused by Lack of Ribosomal Protein L34 Can Be Suppressed by Magnesium

Expression and Function of Different Guanine-Plus-Cytosine Content 16S rRNA Genes in Haloarcula hispanica at Different Temperatures

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