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1
Laursen, Brian Søgaard, Hans Peter Sørensen, Kim Kusk Mortensen, and Hans Uffe Sperling-Petersen. "Initiation of Protein Synthesis in Bacteria." Microbiology and Molecular Biology Reviews 69, no. 1 (March 2005): 101–23. http://dx.doi.org/10.1128/mmbr.69.1.101-123.2005.
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SUMMARY Valuable information on translation initiation is available from biochemical data and recently solved structures. We present a detailed description of current knowledge about the structure, function, and interactions of the individual components involved in bacterial translation initiation. The first section describes the ribosomal features relevant to the initiation process. Subsequent sections describe the structure, function, and interactions of the mRNA, the initiator tRNA, and the initiation factors IF1, IF2, and IF3. Finally, we provide an overview of mechanisms of regulation of the translation initiation event. Translation occurs on ribonucleoprotein complexes called ribosomes. The ribosome is composed of a large subunit and a small subunit that hold the activities of peptidyltransfer and decode the triplet code of the mRNA, respectively. Translation initiation is promoted by IF1, IF2, and IF3, which mediate base pairing of the initiator tRNA anticodon to the mRNA initiation codon located in the ribosomal P-site. The mechanism of translation initiation differs for canonical and leaderless mRNAs, since the latter is dependent on the relative level of the initiation factors. Regulation of translation occurs primarily in the initiation phase. Secondary structures at the mRNA ribosomal binding site (RBS) inhibit translation initiation. The accessibility of the RBS is regulated by temperature and binding of small metabolites, proteins, or antisense RNAs. The future challenge is to obtain atomic-resolution structures of complete initiation complexes in order to understand the mechanism of translation initiation in molecular detail.
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Kwaik, Yousef Abu. "Induced Expression of the Legionella pneumophila Gene Encoding a 20-Kilodalton Protein during Intracellular Infection." Infection and Immunity 66, no. 1 (January 1, 1998): 203–12. http://dx.doi.org/10.1128/iai.66.1.203-212.1998.
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ABSTRACT The eukaryotic protein synthesis inhibitor cycloheximid has been used by many investigators to selectively radiolabel intracellular bacteria. Although cycloheximide has no direct effect on bacterial gene expression, there are concerns that long-term inhibition of the host cell protein synthesis may have secondary effects on bacterial gene expression. Therefore, prior to further identification and cloning of the macrophage-induced (MI) genes of Legionella pneumophila, the effects of cycloheximide on L. pneumophila-infected U937 cells were evaluated by transmission electron microscopy. Inhibition of protein synthesis of the host cell for 6 h had no major effect on the ultrastructure of the host cell, on the formation of rough endoplasmic reticulum-surrounded replicative phagosome, or on initiation of intracellular bacterial replication. In contrast, by 15 h of cycloheximide treatment, there was profound deterioration in the host cell as well as in the phagosome. To examine protein synthesis by L. pneumophila during the intracellular infection, U937 macrophage-like cells were infected with L. pneumophila, and intracellular bacteria were radiolabeled during a 2-h cycloheximide treatment or following 12 h of cycloheximide treatment. Comparison by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the protein profile of radiolabeled in vitro-grown L. pneumophila to that of intracellularly radiolabeled bacteria showed that 23 proteins were induced in response to the intracellular environment during 2 h of inhibition of host cell protein biosynthesis. Twelve MI proteins ofL. pneumophila were artifactually induced due to prolonged inhibition of the host cell protein synthesis. The gene encoding a 20-kDa MI protein was cloned by a reverse genetics technique. Sequence analysis showed that the cloned gene encoded a protein that was 80% similar to the enzyme inorganic pyrophosphatase. Studies of promoter fusion to a promoterless lacZ gene showed that compared to in vitro-grown bacteria, expression of the pyrophosphatase gene (ppa) was induced fourfold throughout the intracellular infection. There was no detectable induction in transcription of the ppa promoter during exposure to stress stimuli in vitro. The ppa gene of L. pneumophila is the first example of a regulated ppagene which is selectively induced during intracellular infection and which may reflect enhanced capabilities of macromolecular biosynthesis by intracellular L. pneumophila. The data indicate caution in the long-term use of inhibition of host cell protein synthesis to selectively examine gene expression by intracellular bacteria.
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Dethlefsen, Les, and Thomas M. Schmidt. "Performance of the Translational Apparatus Varies with the Ecological Strategies of Bacteria." Journal of Bacteriology 189, no. 8 (February 2, 2007): 3237–45. http://dx.doi.org/10.1128/jb.01686-06.
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ABSTRACT Protein synthesis is the predominant activity of growing bacteria; the protein synthesis system accounts for more than one-half the cell's dry mass and consumes most of the cell's energy during rapid growth. Translation has been studied extensively using model organisms, and the translational apparatus is qualitatively similar in terms of structure and function across all known forms of life. However, little is known about variation between organisms in translational performance. Using measurements of macromolecular content in a phylogenetically diverse collection of bacteria with contrasting ecological strategies, we found that the translational power (the rate of protein synthesis normalized to the mass of the protein synthesis system) is three- to fourfold higher among bacteria that respond rapidly to nutrient availability than among bacteria that respond slowly. An analysis of codon use in completely sequenced bacterial genomes confirmed that the selective forces acting on translation vary with the ecological strategy. We propose that differences in translational power result from ecologically based variation among microbes in the relative importance of two competing benefits: reducing the biomass invested in the protein synthesis system and reducing the energetic expense of protein synthesis.
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Simon, M., and F. Azam. "Protein content and protein synthesis rates of planktonic marine bacteria." Marine Ecology Progress Series 51 (1989): 201–13. http://dx.doi.org/10.3354/meps051201.
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Nally, Jarlath E., John F. Timoney, and Brian Stevenson. "Temperature-Regulated Protein Synthesis by Leptospira interrogans." Infection and Immunity 69, no. 1 (January 1, 2001): 400–404. http://dx.doi.org/10.1128/iai.69.1.400-404.2001.
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ABSTRACT Leptospira interrogans is an important mammalian pathogen. Transmission from an environmental source requires adaptations to a range of new environmental conditions in the organs and tissues of the infected host. Since many pathogenic bacteria utilize temperature to discern their environment and regulate the synthesis of appropriate proteins, we investigated the effects of temperature on protein synthesis in L. interrogans. Bacteria were grown for several days after culture temperatures were shifted from 30 to 37°C. Triton X-114 cellular fractionation identified several proteins of the cytoplasm, periplasm, and outer membrane for which synthesis was dependent on the culture temperature. Synthesis of a cytoplasmic protein of 20 kDa was switched off at 37°C, whereas synthesis of a 66-kDa periplasmic protein was increased at the higher temperature. Increased synthesis of a 25-kDa outer membrane protein was observed when the organisms were shifted from 30 to 37°C. A 36-kDa protein synthesized at 30 but not at 37°C was identified as LipL36, an outer membrane lipoprotein. In contrast, expression of another lipoprotein, LipL41, was the same at either temperature. Immunoblotting with convalescent equine sera revealed that some proteins exhibiting thermoregulation of synthesis elicited antibody responses during infection. Our results show that sera from horses which aborted as a result of naturally acquired infection withL. interrogans serovar pomona type kennewicki recognize periplasmic and outer membrane proteins which are differentially synthesized in response to temperature and which therefore may be important in the host-pathogen interaction during infection.
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Wei, Hong Tao, Zhong Wen Lv, Xue Mei Han, and Guo Li Zhang. "High Expression and Preliminary Purification of Human β-Defensin-2 Fusion Protein." Advanced Materials Research 781-784 (September 2013): 1076–79. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.1076.
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This study was undertaken to achieve high expression and preliminary purification of human β-defensin-2 fusion protein to lay a solid foundation for production of human β-defensin-2 using genetic engineering. A prokaryotic expression vector for human β-defensin-2 fusion protein was generated using in vitro gene synthesis before transformation into BL21 (l DE3) plysS TrX-B host bacteria. High expression of TrX-A-HBD-2 fusion protein was induced with IPTG in the bacteria exposed to various expression conditions. The fusion protein then underwent preliminary purification. The protein of interest was released from the genetically engineered bacteria after freezing and thawing. The expression of the target protein accounted for 16.12% of the total bacterial proteins. Fractional precipitation with saturated ammonium sulfate and metal chelate affinity chromatography yielded human β-defensin-2 peptide fusion protein, with a relative purity of 80.53%.Human β-defensin-2 fusion protein could be highly expressed in a soluble form, with a relatively high purity
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Banta, Amy B., Jeremy H. Wei, and Paula V. Welander. "A distinct pathway for tetrahymanol synthesis in bacteria." Proceedings of the National Academy of Sciences 112, no. 44 (October 19, 2015): 13478–83. http://dx.doi.org/10.1073/pnas.1511482112.
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Tetrahymanol is a polycyclic triterpenoid lipid first discovered in the ciliate Tetrahymena pyriformis whose potential diagenetic product, gammacerane, is often used as a biomarker for water column stratification in ancient ecosystems. Bacteria are also a potential source of tetrahymanol, but neither the distribution of this lipid in extant bacteria nor the significance of bacterial tetrahymanol synthesis for interpreting gammacerane biosignatures is known. Here we couple comparative genomics with genetic and lipid analyses to link a protein of unknown function to tetrahymanol synthesis in bacteria. This tetrahymanol synthase (Ths) is found in a variety of bacterial genomes, including aerobic methanotrophs, nitrite-oxidizers, and sulfate-reducers, and in a subset of aquatic and terrestrial metagenomes. Thus, the potential to produce tetrahymanol is more widespread in the bacterial domain than previously thought. However, Ths is not encoded in any eukaryotic genomes, nor is it homologous to eukaryotic squalene-tetrahymanol cyclase, which catalyzes the cyclization of squalene directly to tetrahymanol. Rather, heterologous expression studies suggest that bacteria couple the cyclization of squalene to a hopene molecule by squalene-hopene cyclase with a subsequent Ths-dependent ring expansion to form tetrahymanol. Thus, bacteria and eukaryotes have evolved distinct biochemical mechanisms for producing tetrahymanol.
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Woolstenhulme, C. J., S. Parajuli, D. W. Healey, D. P. Valverde, E. N. Petersen, A. L. Starosta, N. R. Guydosh, W. E. Johnson, D. N. Wilson, and A. R. Buskirk. "Nascent peptides that block protein synthesis in bacteria." Proceedings of the National Academy of Sciences 110, no. 10 (February 19, 2013): E878—E887. http://dx.doi.org/10.1073/pnas.1219536110.
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Bürk, Jonas, Benjamin Weiche, Meike Wenk, Diana Boy, Sigrun Nestel, Bernd Heimrich, and Hans-Georg Koch. "Depletion of the Signal Recognition Particle Receptor Inactivates Ribosomes in Escherichia coli." Journal of Bacteriology 191, no. 22 (September 11, 2009): 7017–26. http://dx.doi.org/10.1128/jb.00208-09.
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ABSTRACT The signal recognition particle (SRP)-dependent cotranslational targeting of proteins to the cytoplasmic membrane in bacteria or the endoplasmic reticulum membrane in eukaryotes is an essential process in most living organisms. Eukaryotic cells have been shown to respond to an impairment of the SRP pathway by (i) repressing ribosome biogenesis, resulting in decreased protein synthesis, and (ii) by increasing the expression of protein quality control mechanisms, such as chaperones and proteases. In the current study, we have analyzed how bacteria like Escherichia coli respond to a gradual depletion of FtsY, the bacterial SRP receptor. Our analyses using cell-free transcription/translation systems showed that FtsY depletion inhibits the translation of both SRP-dependent and SRP-independent proteins. This synthesis defect is the result of a multifaceted response that includes the upregulation of the ribosome-inactivating protein ribosome modulation factor (RMF). Although the consequences of these responses in E. coli are very similar to some of the effects also observed in eukaryotic cells, one striking difference is that E. coli obviously does not reduce the rate of protein synthesis by downregulating ribosome biogenesis. Instead, the upregulation of RMF leads to a direct and reversible inhibition of translation.
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Errington, Jeffery, Richard A. Daniel, and Dirk-Jan Scheffers. "Cytokinesis in Bacteria." Microbiology and Molecular Biology Reviews 67, no. 1 (March 2003): 52–65. http://dx.doi.org/10.1128/mmbr.67.1.52-65.2003.
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SUMMARY Work on two diverse rod-shaped bacteria, Escherichia coli and Bacillus subtilis, has defined a set of about 10 conserved proteins that are important for cell division in a wide range of eubacteria. These proteins are directed to the division site by the combination of two negative regulatory systems. Nucleoid occlusion is a poorly understood mechanism whereby the nucleoid prevents division in the cylindrical part of the cell, until chromosome segregation has occurred near midcell. The Min proteins prevent division in the nucleoid-free spaces near the cell poles in a manner that is beginning to be understood in cytological and biochemical terms. The hierarchy whereby the essential division proteins assemble at the midcell division site has been worked out for both E. coli and B. subtilis. They can be divided into essentially three classes depending on their position in the hierarchy and, to a certain extent, their subcellular localization. FtsZ is a cytosolic tubulin-like protein that polymerizes into an oligomeric structure that forms the initial ring at midcell. FtsA is another cytosolic protein that is related to actin, but its precise function is unclear. The cytoplasmic proteins are linked to the membrane by putative membrane anchor proteins, such as ZipA of E. coli and possibly EzrA of B. subtilis, which have a single membrane span but a cytoplasmic C-terminal domain. The remaining proteins are either integral membrane proteins or transmembrane proteins with their major domains outside the cell. The functions of most of these proteins are unclear with the exception of at least one penicillin-binding protein, which catalyzes a key step in cell wall synthesis in the division septum.
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Ryjenkov, Dmitri A., Marina Tarutina, Oleg V. Moskvin, and Mark Gomelsky. "Cyclic Diguanylate Is a Ubiquitous Signaling Molecule in Bacteria: Insights into Biochemistry of the GGDEF Protein Domain." Journal of Bacteriology 187, no. 5 (March 1, 2005): 1792–98. http://dx.doi.org/10.1128/jb.187.5.1792-1798.2005.
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ABSTRACT Proteins containing GGDEF domains are encoded in the majority of sequenced bacterial genomes. In several species, these proteins have been implicated in biosynthesis of exopolysaccharides, formation of biofilms, establishment of a sessile lifestyle, surface motility, and regulation of gene expression. However, biochemical activities of only a few GGDEF domain proteins have been tested. These proteins were shown to be involved in either synthesis or hydrolysis of cyclic-bis(3′→5′) dimeric GMP (c-di-GMP) or in hydrolysis of cyclic AMP. To investigate specificity of the GGDEF domains in Bacteria, six GGDEF domain-encoding genes from randomly chosen representatives of diverse branches of the bacterial phylogenetic tree, i.e., Thermotoga, Deinococcus-Thermus, Cyanobacteria, spirochetes, and α and γ divisions of the Proteobacteria, were cloned and overexpressed. All recombinant proteins were purified and found to possess diguanylate cyclase (DGC) activity involved in c-di-GMP synthesis. The individual GGDEF domains from two proteins were overexpressed, purified, and shown to possess a low level of DGC activity. The oligomeric states of full-length proteins and individual GGDEF domains were similar. This suggests that GGDEF domains are sufficient to encode DGC activity; however, enzymatic activity is highly regulated by the adjacent sensory protein domains. It is shown that DGC activity of the GGDEF domain protein Rrp1 from Borrelia burgdorferi is strictly dependent on phosphorylation status of its input receiver domain. This study establishes that majority of GGDEF domain proteins are c-di-GMP specific, that c-di-GMP synthesis is a wide-spread phenomenon in Bacteria, and that it is highly regulated.
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Scheffers, Dirk-Jan, and Mariana G. Pinho. "Bacterial Cell Wall Synthesis: New Insights from Localization Studies." Microbiology and Molecular Biology Reviews 69, no. 4 (December 2005): 585–607. http://dx.doi.org/10.1128/mmbr.69.4.585-607.2005.
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SUMMARY In order to maintain shape and withstand intracellular pressure, most bacteria are surrounded by a cell wall that consists mainly of the cross-linked polymer peptidoglycan (PG). The importance of PG for the maintenance of bacterial cell shape is underscored by the fact that, for various bacteria, several mutations affecting PG synthesis are associated with cell shape defects. In recent years, the application of fluorescence microscopy to the field of PG synthesis has led to an enormous increase in data on the relationship between cell wall synthesis and bacterial cell shape. First, a novel staining method enabled the visualization of PG precursor incorporation in live cells. Second, penicillin-binding proteins (PBPs), which mediate the final stages of PG synthesis, have been localized in various model organisms by means of immunofluorescence microscopy or green fluorescent protein fusions. In this review, we integrate the knowledge on the last stages of PG synthesis obtained in previous studies with the new data available on localization of PG synthesis and PBPs, in both rod-shaped and coccoid cells. We discuss a model in which, at least for a subset of PBPs, the presence of substrate is a major factor in determining PBP localization.
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Landini, P., E. Corti, B. P. Goldstein, and M. Denaro. "Mechanism of action of purpuromycin." Biochemical Journal 284, no. 1 (May 15, 1992): 47–52. http://dx.doi.org/10.1042/bj2840047.
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Purpuromycin, an antibiotic active against both fungi and bacteria, shows different modes of action against these two kinds of micro-organisms; in Candida albicans it inhibits RNA synthesis, whereas in Bacillus subtilis protein synthesis is primarily affected, with DNA and RNA synthesis blocked at higher concentrations of the drug. In bacterial cell-free protein-synthesis systems, purpuromycin did not inhibit synthesis from endogenous mRNA (elongation of peptides initiated within the intact cell) but inhibited MS2-phase RNA-dependent protein synthesis (which requires initiation) by 50% at 0.1 mg/l. Poly(U)-directed polyphenylalanine synthesis was 50% inhibited by 20 mg of purpuromycin/l when added to a complete system; however, when purpuromycin was preincubated with ribosomes dissociated into 30 S and 50 S subunits, the concentration for 50% inhibition fell to 0.1 mg/l. By contrast, in a C. albicans cell-free system poly(U)-directed polyphenylalanine synthesis was partially inhibited only at 200 mg/l. Purpuromycin also inhibited polynucleotide synthesis in vitro in reactions using Escherichia coli or wheat-germ RNA polymerases or E. coli DNA polymerase I. We suggest that in bacteria the primary target of purpuromycin is on ribosomes and that its action precedes the elongation step of protein synthesis. The effect on nucleic acid synthesis in both fungi and bacteria may be due to interaction of purpuromycin with DNA.
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Laskowska, Ewa, and Dorota Kuczyńska-Wiśnik. "New insight into the mechanisms protecting bacteria during desiccation." Current Genetics 66, no. 2 (September 26, 2019): 313–18. http://dx.doi.org/10.1007/s00294-019-01036-z.
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Abstract Desiccation is a common stress that bacteria face in the natural environment, and thus, they have developed a variety of protective mechanisms to mitigate the damage caused by water loss. The formation of biofilms and the accumulation of trehalose and sporulation are well-known strategies used by bacteria to survive desiccation. Other mechanisms, including intrinsically disordered proteins and the anti-glycation defence, have been mainly studied in eukaryotic cells, and their role in bacteria remains unclear. We have recently shown that the impairment of trehalose synthesis results in higher glucose availability, leading to the accumulation of acetyl phosphate and enhanced protein acetylation, which in turn stimulates protein aggregation. In the absence of trehalose synthesis, excess glucose may stimulate non-enzymatic glycosylation and the formation of advanced glycation end products (AGEs) bound to proteins. Therefore, we propose that trehalose may prevent protein damage, not only as a chemical chaperone but also as a metabolite that indirectly counteracts detrimental protein acetylation and glycation.
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Christner, Brent C. "Incorporation of DNA and Protein Precursors into Macromolecules by Bacteria at −15oC." Applied and Environmental Microbiology 68, no. 12 (December 2002): 6435–38. http://dx.doi.org/10.1128/aem.68.12.6435-6438.2002.
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ABSTRACT DNA and protein precursors were incorporated into trichloroacetic acid-precipitated material by bacterial cell suspensions during incubation for 50 to 100 days at −15oC. Incorporation did not occur at −70oC and was inhibited by antibiotics. The results demonstrate that bacteria can perform macromolecular synthesis under conditions that mimic entrapment in glacial ice.
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Zhang, Jie, Ying Zhang, Bin Song Wang, and Maria Shishova. "Biosynthesis Silver Nanoparticles Using Bacillus Amyloliquefaciens Zxw01 and Research on Synthesis Mechanism." Materials Science Forum 852 (April 2016): 437–42. http://dx.doi.org/10.4028/www.scientific.net/msf.852.437.
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This research reported on synthesis of silver nanoparticles using Bacillus amyloliquefaciens zxw01 culture mixed with silver nitrate. The nanoparticles were characterized by UV-vis spectrum, X-ray diffraction (XRD), Transmission electron microscopy (TEM) and high-resolution transmission electron microscope (HRTEM).In addition, we discussed synthesis mechanism by comparing the protein files of the bacteria before and after mixed with silver nitrate and proteins attached to silver nanoparticles. Our results indicated that silver nanoparticles biosynthesized by Bacillus amyloliquefaciens zxw01 were equally distributed with size between 5 nm to 30 nm and face-centred cubic structure; results of SDS-PAGE suggested that after mixed with silver nitrate, the bacteria differentially expressed and produced a new protein with weight of 33 kDa. Furthermore, analysis of proteins attached to silver nanoparticles indicated that protein with weight of 33 kDa was related to the synthesis of silver nanoparticles.
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Aizouq, Mohammed, Helga Peisker, Katharina Gutbrod, Michael Melzer, Georg Hölzl, and Peter Dörmann. "Triacylglycerol and phytyl ester synthesis inSynechocystissp. PCC6803." Proceedings of the National Academy of Sciences 117, no. 11 (March 2, 2020): 6216–22. http://dx.doi.org/10.1073/pnas.1915930117.
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Cyanobacteria are unicellular prokaryotic algae that perform oxygenic photosynthesis, similar to plants. The cells harbor thylakoid membranes composed of lipids related to those of chloroplasts in plants to accommodate the complexes of photosynthesis. The occurrence of storage lipids, including triacylglycerol or wax esters, which are found in plants, animals, and some bacteria, nevertheless remained unclear in cyanobacteria. We show here that the cyanobacteriumSynechocystissp. PCC6803 accumulates both triacylglycerol and wax esters (fatty acid phytyl esters). Phytyl esters accumulate in higher levels under abiotic stress conditions. The analysis of an insertional mutant revealed that the acyltransferase slr2103, with sequence similarity to plant esterase/lipase/thioesterase (ELT) proteins, is essential for triacylglycerol and phytyl ester synthesis inSynechocystis. The recombinant slr2103 enzyme showed acyltransferase activity with phytol and diacylglycerol, thus producing phytyl esters and triacylglycerol. Acyl-CoA thioesters were the preferred acyl donors, while acyl-ACP (acyl carrier protein), free fatty acids, or galactolipid-bound fatty acids were poor substrates. The slr2103 protein sequence is unrelated to acyltransferases from bacteria (AtfA) or plants (DGAT1, DGAT2, PDAT), and therefore establishes an independent group of bacterial acyltransferases involved in triacylglycerol and wax ester synthesis. The identification of the geneslr2103responsible for triacylglycerol synthesis in cyanobacteria opens the possibility of using prokaryotic photosynthetic cells in biotechnological applications.
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Orelle, Cédric, Skylar Carlson, Bindiya Kaushal, Mashal M. Almutairi, Haipeng Liu, Anna Ochabowicz, Selwyn Quan, et al. "Tools for Characterizing Bacterial Protein Synthesis Inhibitors." Antimicrobial Agents and Chemotherapy 57, no. 12 (September 16, 2013): 5994–6004. http://dx.doi.org/10.1128/aac.01673-13.
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ABSTRACTMany antibiotics inhibit the growth of sensitive bacteria by interfering with ribosome function. However, discovery of new protein synthesis inhibitors is curbed by the lack of facile techniques capable of readily identifying antibiotic target sites and modes of action. Furthermore, the frequent rediscovery of known antibiotic scaffolds, especially in natural product extracts, is time-consuming and expensive and diverts resources that could be used toward the isolation of novel lead molecules. In order to avoid these pitfalls and improve the process of dereplication of chemically complex extracts, we designed a two-pronged approach for thecharacterization ofinhibitors ofproteinsynthesis (ChIPS) that is suitable for the rapid identification of the site and mode of action on the bacterial ribosome. First, we engineered antibiotic-hypersensitiveEscherichia colistrains that contain only one rRNA operon. These strains are used for the rapid isolation of resistance mutants in which rRNA mutations identify the site of the antibiotic action. Second, we show that patterns of drug-induced ribosome stalling on mRNA, monitored by primer extension, can be used to elucidate the mode of antibiotic action. These analyses can be performed within a few days and provide a rapid and efficient approach for identifying the site and mode of action of translation inhibitors targeting the bacterial ribosome. Both techniques were validated using a bacterial strain whose culture extract, composed of unknown metabolites, exhibited protein synthesis inhibitory activity; we were able to rapidly detect the presence of the antibiotic chloramphenicol.
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Mustafa, M. Golam, M. Ayub Al Mamun, and A. K. M. Khorshed Alam. "Study on ascitic fluid protein level in cirrhotic patients with spontaneous bacterial peritonitis." Bangladesh Medical Research Council Bulletin 35, no. 2 (August 11, 2009): 41–43. http://dx.doi.org/10.3329/bmrcb.v35i2.3023.
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Complement 3 is an important component of ascitic fluid total protein, which offers local defence against infection of the ascitic fluid. Hepatic synthesis of complement 3 as well as other proteins and their concentrations in ascitic fluid is significantly reduced in patients with advanced cirrhosis. The level of protein in ascitic fluid in cirrhotic patients with spontaneous bacterial peritonitis was compared with that in patients without spontaneous bacterial peritonitis. Ascitic fluid protein level in spontaneous bacterial peritonitis (n=15) was 1.1 ± 0.3 g/dL whereas it was 1.5 ± 0.5 g/dL in patients without spontaneous bacterial peritonitis (n=15). In conclusion, this study suggests that, ascitic fluid protein level is significantly (p=0.008) reduced in cirrhotic patients who develop spontaneous bacterial peritonitis.Keywords: Ascitic fluid; Bacteria; Cirrhosis; PeritonitisOnline: 11 August 2009DOI: 10.3329/bmrcb.v35i2.3023Bangladesh Med Res Counc Bull 2009; 35: 41-43
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Shan, Libo, Hye-sook Oh, Jianfu Chen, Ming Guo, Jianmin Zhou, James R. Alfano, Alan Collmer, Xu Jia, and Xiaoyan Tang. "The HopPtoF Locus of Pseudomonas syringae pv. tomato DC3000 Encodes a Type III Chaperone and a Cognate Effector." Molecular Plant-Microbe Interactions® 17, no. 5 (May 2004): 447–55. http://dx.doi.org/10.1094/mpmi.2004.17.5.447.
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Type III secretion systes are highly conserved among gram-negative plant and animal pathogenic bacteria. Through the type III secretion system, bacteria inject a number of virulence proteins into the host cells. Analysis of the whole genome sequence of Pseudomonas syringae pv. tomato DC3000 strain identified a locus, named HopPtoF, that is homologous to the avirulence gene locus avrPphF in P. syringae pv. phaseolicola. The HopPtoF locus harbors two genes, ShcFPto and HopFPto, that are preceded by a single hrp box promoter. We present evidence here to show that ShcFPto and HopFPto encode a type III chaperone and a cognate effector, respectively. ShcFPto interacts with and stabilizes the HopFPto protein in the bacterial cell. Translation of HopFPto starts at a rare initiation codon ATA that limits the synthesis of the HopFPto protein to a low level in bacterial cells.
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Nau, Roland, and Helmut Eiffert. "Modulation of Release of Proinflammatory Bacterial Compounds by Antibacterials: Potential Impact on Course of Inflammation and Outcome in Sepsis and Meningitis." Clinical Microbiology Reviews 15, no. 1 (January 2002): 95–110. http://dx.doi.org/10.1128/cmr.15.1.95-110.2002.
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SUMMARY Several bacterial components (endotoxin, teichoic and lipoteichoic acids, peptidoglycan, DNA, and others) can induce or enhance inflammation and may be directly toxic for eukaryotic cells. Bactericidal antibiotics which inhibit bacterial protein synthesis release smaller quantities of proinflammatory/toxic bacterial compounds than Β-lactams and other cell wall-active drugs. Among the Β-lactams, compounds binding to penicillin-binding protein 2 (PBP-2) release smaller amounts of bacterial substances than antibacterials inhibiting PBP-3. Generally, high antibiotic concentrations (more than 10 times the MIC) induce the release of fewer bacterial proinflammatory/toxic compounds than concentrations close to the MIC. In several in vitro and in vivo systems, bacteria treated with protein synthesis inhibitors or Β-lactams inhibiting PBP-2 induce less inflammation than bacteria treated with PBP-3-active Β-lactams. In mouse models of Escherichia coli peritonitis sepsis and of Streptococcus pneumoniae meningitis, lower release of proinflammatory bacterial compounds was associated with reduced mortality. In conclusion, sufficient evidence for the validity of the concept of modulating the release of proinflammatory bacterial compounds by antibacterials has been accumulated in vitro and in animal experiments to justify clinical trials in sepsis and meningitis. A properly conducted study addressing the potential benefit of bacterial protein synthesis inhibitors versus Β-lactam antibiotics will require both strict selection and inclusion of a large number of patients. The benefit of this approach should be greatest in patients with a high bacterial load.
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Muchová, Katarína, Zuzana Chromiková, and Imrich Barák. "Linking the Peptidoglycan Synthesis Protein Complex with Asymmetric Cell Division during Bacillus subtilis Sporulation." International Journal of Molecular Sciences 21, no. 12 (June 25, 2020): 4513. http://dx.doi.org/10.3390/ijms21124513.
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Peptidoglycan is generally considered one of the main determinants of cell shape in bacteria. In rod-shaped bacteria, cell elongation requires peptidoglycan synthesis to lengthen the cell wall. In addition, peptidoglycan is synthesized at the division septum during cell division. Sporulation of Bacillus subtilis begins with an asymmetric cell division. Formation of the sporulation septum requires almost the same set of proteins as the vegetative septum; however, these two septa are significantly different. In addition to their differences in localization, the sporulation septum is thinner and it contains SpoIIE, a crucial sporulation specific protein. Here we show that peptidoglycan biosynthesis is linked to the cell division machinery during sporulation septum formation. We detected a direct interaction between SpoIIE and GpsB and found that both proteins co-localize during the early stages of asymmetric septum formation. We propose that SpoIIE is part of a multi-protein complex which includes GpsB, other division proteins and peptidoglycan synthesis proteins, and could provide a link between the peptidoglycan synthesis machinery and the complex morphological changes required for forespore formation during B. subtilis sporulation.
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Trösch, Raphael, and Felix Willmund. "The conserved theme of ribosome hibernation: from bacteria to chloroplasts of plants." Biological Chemistry 400, no. 7 (June 26, 2019): 879–93. http://dx.doi.org/10.1515/hsz-2018-0436.
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Abstract Cells are highly adaptive systems that respond and adapt to changing environmental conditions such as temperature fluctuations or altered nutrient availability. Such acclimation processes involve reprogramming of the cellular gene expression profile, tuning of protein synthesis, remodeling of metabolic pathways and morphological changes of the cell shape. Nutrient starvation can lead to limited energy supply and consequently, remodeling of protein synthesis is one of the key steps of regulation since the translation of the genetic code into functional polypeptides may consume up to 40% of a cell’s energy during proliferation. In eukaryotic cells, downregulation of protein synthesis during stress is mainly mediated by modification of the translation initiation factors. Prokaryotic cells suppress protein synthesis by the active formation of dimeric so-called ‘hibernating’ 100S ribosome complexes. Such a transition involves a number of proteins which are found in various forms in prokaryotes but also in chloroplasts of plants. Here, we review the current understanding of these hibernation factors and elaborate conserved principles which are shared between species.
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Santos, Ana L., Vanessa Oliveira, Inês Baptista, Isabel Henriques, Newton C. M. Gomes, Adelaide Almeida, António Correia, and Angela Cunha. "Effects of UV-B Radiation on the Structural and Physiological Diversity of Bacterioneuston and Bacterioplankton." Applied and Environmental Microbiology 78, no. 6 (January 13, 2012): 2066–69. http://dx.doi.org/10.1128/aem.06344-11.
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ABSTRACTThe effects of UV radiation (UVR) on estuarine bacterioneuston and bacterioplankton were assessed in microcosm experiments. Bacterial abundance and DNA synthesis were more affected in bacterioplankton. Protein synthesis was more inhibited in bacterioneuston. Community analysis indicated that UVR has the potential to select resistant bacteria (e.g.,Gammaproteobacteria), particularly abundant in bacterioneuston.
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Eschenlauer, S. C. P., N. R. McEwan, R. Onodera, R. J. Wallace, and C. J. Newbold. "Cloning and properties of a lysozyme from the rumen ciliate protozoan, Entodinium caudatum." Proceedings of the British Society of Animal Science 2000 (2000): 55. http://dx.doi.org/10.1017/s1752756200000569.
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The breakdown of bacterial protein in the rumen leads to a nutritionally wasteful cycle of protein breakdown and re-synthesis, decreasing the flow of microbial protein from the rumen to the small intestine (Williams and Coleman, 1992). Engulfment and subsequent digestion by ciliate protozoa was demonstrated to be the most important cause of bacterial lysis in mixed ruminal micro-organisms incubated in vitro (Wallace and McPherson, 1987). Despite their importance, little is known about the enzymes responsible for the digestion of bacteria in rumen ciliates. The objective of this study was to clone and characterise a lysozyme from Entodinium caudatum, a common rumen protozoan important in the ingestion and breakdown of rumen bacteria (Williams and Coleman, 1992).
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Pribat, Anne, Linda Jeanguenin, Aurora Lara-Núñez, Michael J. Ziemak, John E. Hyde, Valérie de Crécy-Lagard, and Andrew D. Hanson. "6-Pyruvoyltetrahydropterin Synthase Paralogs Replace the Folate Synthesis Enzyme Dihydroneopterin Aldolase in Diverse Bacteria." Journal of Bacteriology 191, no. 13 (April 24, 2009): 4158–65. http://dx.doi.org/10.1128/jb.00416-09.
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ABSTRACT Dihydroneopterin aldolase (FolB) catalyzes conversion of dihydroneopterin to 6-hydroxymethyldihydropterin (HMDHP) in the classical folate biosynthesis pathway. However, folB genes are missing from the genomes of certain bacteria from the phyla Chloroflexi, Acidobacteria, Firmicutes, Planctomycetes, and Spirochaetes. Almost all of these folB-deficient genomes contain an unusual paralog of the tetrahydrobiopterin synthesis enzyme 6-pyruvoyltetrahydropterin synthase (PTPS) in which a glutamate residue replaces or accompanies the catalytic cysteine. A similar PTPS paralog from the malaria parasite Plasmodium falciparum is known to form HMDHP from dihydroneopterin triphosphate in vitro and has been proposed to provide a bypass to the FolB step in vivo. Bacterial genes encoding PTPS-like proteins with active-site glutamate, cysteine, or both residues were accordingly tested together with the P. falciparum gene for complementation of the Escherichia coli folB mutation. The P. falciparum sequence and bacterial sequences with glutamate or glutamate plus cysteine were active; those with cysteine alone were not. These results demonstrate that PTPS paralogs with an active-site glutamate (designated PTPS-III proteins) can functionally replace FolB in vivo. Recombinant bacterial PTPS-III proteins, like the P. falciparum enzyme, mediated conversion of dihydroneopterin triphosphate to HMDHP, but other PTPS proteins did not. Neither PTPS-III nor other PTPS proteins exhibited significant dihydroneopterin aldolase activity. Phylogenetic analysis indicated that PTPS-III proteins may have arisen independently in various PTPS lineages. Consistent with this possibility, merely introducing a glutamate residue into the active site of a PTPS protein conferred incipient activity in the growth complementation assay, and replacing glutamate with alanine in a PTPS-III protein abolished complementation.
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Feliciano, Joana R., António M. M. Seixas, Tiago Pita, and Jorge H. Leitão. "Comparative Genomics and Evolutionary Analysis of RNA-Binding Proteins of Burkholderia cenocepacia J2315 and Other Members of the B. cepacia Complex." Genes 11, no. 2 (February 21, 2020): 231. http://dx.doi.org/10.3390/genes11020231.
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RNA-binding proteins (RBPs) are important regulators of cellular functions, playing critical roles on the survival of bacteria and in the case of pathogens, on their interaction with the host. RBPs are involved in transcriptional, post-transcriptional, and translational processes. However, except for model organisms like Escherichia coli, there is little information about the identification or characterization of RBPs in other bacteria, namely in members of the Burkholderia cepacia complex (Bcc). Bcc is a group of bacterial species associated with a poor clinical prognosis in cystic fibrosis patients. These species have some of the largest bacterial genomes, and except for the presence of two-distinct Hfq-like proteins, their RBP repertoire has not been analyzed so far. Using in silico approaches, we identified 186 conventional putative RBPs in Burkholderia cenocepacia J2315, an epidemic and multidrug resistant pathogen of cystic fibrosis patients. Here we describe the comparative genomics and phylogenetic analysis of RBPs present in multiple copies and predicted to play a role in transcription, protein synthesis, and RNA decay in Bcc bacteria. In addition to the two different Hfq chaperones, five cold shock proteins phylogenetically close to E. coli CspD protein and three distinct RhlE-like helicases could be found in the B. cenocepacia J2315 genome. No RhlB, SrmB, or DeaD helicases could be found in the genomes of these bacteria. These results, together with the multiple copies of other proteins generally involved in RNA degradation, suggest the existence, in B. cenocepacia and in other Bcc bacteria, of some extra and unexplored functions for the mentioned RBPs, as well as of alternative mechanisms involved in RNA regulation and metabolism in these bacteria.
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Giedraitienė, Agnė, Astra Vitkauskienė, Rima Naginienė, and Alvydas Pavilonis. "Antibiotic Resistance Mechanisms of Clinically Important Bacteria." Medicina 47, no. 3 (March 22, 2011): 19. http://dx.doi.org/10.3390/medicina47030019.
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Bacterial resistance to antimicrobial drugs is an increasing health and economic problem. Bacteria may be innate resistant or acquire resistance to one or few classes of antimicrobial agents. Acquired resistance arises from: (i) mutations in cell genes (chromosomal mutation) leading to cross-resistance, (ii) gene transfer from one microorganism to other by plasmids (conjugation or transformation), transposons (conjugation), integrons and bacteriophages (transduction). After a bacterium gains resistance genes to protect itself from various antimicrobial agents, bacteria can use several biochemical types of resistance mechanisms: antibiotic inactivation (interference with cell wall synthesis, e.g., β-lactams and glycopeptide), target modification (inhibition of protein synthesis, e.g., macrolides and tetracyclines; interference with nucleic acid synthesis, e.g., fluoroquinolones and rifampin), altered permeability (changes in outer membrane, e.g., aminoglycosides; new membrane transporters, e.g., chloramphenicol), and “bypass” metabolic pathway (inhibition of metabolic pathway, e.g., trimethoprim-sulfamethoxazole).
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Arakaki, Atsushi, Daiki Kikuchi, Masayoshi Tanaka, Ayana Yamagishi, Takuto Yoda, and Tadashi Matsunaga. "Comparative Subcellular Localization Analysis of Magnetosome Proteins Reveals a Unique Localization Behavior of Mms6 Protein onto Magnetite Crystals." Journal of Bacteriology 198, no. 20 (August 1, 2016): 2794–802. http://dx.doi.org/10.1128/jb.00280-16.
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ABSTRACTThe magnetosome is an organelle specialized for inorganic magnetite crystal synthesis in magnetotactic bacteria. The complex mechanism of magnetosome formation is regulated by magnetosome proteins in a stepwise manner. Protein localization is a key step for magnetosome development; however, a global study of magnetosome protein localization remains to be conducted. Here, we comparatively analyzed the subcellular localization of a series of green fluorescent protein (GFP)-tagged magnetosome proteins. The protein localizations were categorized into 5 groups (short-length linear, middle-length linear, long-length linear, cell membrane, and intracellular dispersing), which were related to the protein functions. Mms6, which regulates magnetite crystal growth, localized along magnetosome chain structures under magnetite-forming (microaerobic) conditions but was dispersed in the cell under nonforming (aerobic) conditions. Correlative fluorescence and electron microscopy analyses revealed that Mms6 preferentially localized to magnetosomes enclosing magnetite crystals. We suggest that a highly organized spatial regulation mechanism controls magnetosome protein localization during magnetosome formation in magnetotactic bacteria.IMPORTANCEMagnetotactic bacteria synthesize magnetite (Fe3O4) nanocrystals in a prokaryotic organelle called the magnetosome. This organelle is formed using various magnetosome proteins in multiple steps, including vesicle formation, magnetosome alignment, and magnetite crystal formation, to provide compartmentalized nanospaces for the regulation of iron concentrations and redox conditions, enabling the synthesis of a morphologically controlled magnetite crystal. Thus, to rationalize the complex organelle development, the localization of magnetosome proteins is considered to be highly regulated; however, the mechanisms remain largely unknown. Here, we performed comparative localization analysis of magnetosome proteins that revealed the presence of a spatial regulation mechanism within the linear structure of magnetosomes. This discovery provides evidence of a highly regulated protein localization mechanism for this bacterial organelle development.
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Wintermeyer, W., F. Peske, M. Beringer, K. B. Gromadski, A. Savelsbergh, and M. V. Rodnina. "Mechanisms of elongation on the ribosome: dynamics of a macromolecular machine." Biochemical Society Transactions 32, no. 5 (October 26, 2004): 733–37. http://dx.doi.org/10.1042/bst0320733.
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Protein synthesis in the cell is performed on ribosomes, large ribonucleoprotein particles, which in bacteria consist of three RNA molecules and over 50 proteins. This review summarizes recent progress in understanding the mechanisms of the elongation phase of protein synthesis. Results from rapid kinetic analysis of elongation reactions are discussed in the light of recent structural data.
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Pei, Jianwu, Joshua E. Turse, Qingmin Wu, and Thomas A. Ficht. "Brucella abortus Rough Mutants Induce Macrophage Oncosis That Requires Bacterial Protein Synthesis and Direct Interaction with the Macrophage." Infection and Immunity 74, no. 5 (May 2006): 2667–75. http://dx.doi.org/10.1128/iai.74.5.2667-2675.2006.
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ABSTRACT Previous studies suggest that smooth Brucella organisms inhibit macrophage apoptosis. In contrast, necrotic cell death of macrophages infected with rough Brucella organisms in vitro has been reported, which may in part explain the failure of some rough organisms to thrive. To characterize these potential macrophage killing mechanisms, J774.A1 murine macrophages were infected with Brucella abortus S2308-derived rough mutant CA180. Electron microscopic analysis and polyethylene glycol protection assays revealed that the cells were killed as a result of necrosis and oncosis. This killing was shown to be unaffected by treatment with carbenicillin, an inhibitor of bacterial cell wall biosynthesis and, indirectly, replication. In contrast, chloramphenicol treatment of macrophages infected at multiplicities of infection exceeding 10,000 prevented cell death, despite internalization of large numbers of bacteria. Similarly, heat-killed and gentamicin-killed CA180 did not induce cytopathic effects in the macrophage. These results suggested that killing of infected host cells requires active bacterial protein synthesis. Cytochalasin D treatment revealed that internalization of the bacteria was necessary to initiate killing. Transwell experiments demonstrated that cell death is not mediated by a diffusible product, including tumor necrosis factor alpha and nitric oxide, but does require direct contact between host and pathogen. Furthermore, macrophages preinfected with B. abortus S2308 or pretreated with B. abortus O polysaccharide did not prevent rough CA180-induced cell death. In conclusion, Brucella rough mutant infection induces necrotic and oncotic macrophage cell death that requires bacterial protein synthesis and direct interaction of bacteria with the target cells.
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Golonka, Rachel, Beng San Yeoh, and Matam Vijay-Kumar. "The Iron Tug-of-War between Bacterial Siderophores and Innate Immunity." Journal of Innate Immunity 11, no. 3 (2019): 249–62. http://dx.doi.org/10.1159/000494627.
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Iron is necessary for the survival of almost all aerobic organisms. In the mammalian host, iron is a required cofactor for the assembly of functional iron-sulfur (Fe-S) cluster proteins, heme-binding proteins and ribonucleotide reductases that regulate various functions, including heme synthesis, oxygen transport and DNA synthesis. However, the bioavailability of iron is low due to its insolubility under aerobic conditions. Moreover, the host coordinates a nutritional immune response to restrict the accessibility of iron against potential pathogens. To counter nutritional immunity, most commensal and pathogenic bacteria synthesize and secrete small iron chelators termed siderophores. Siderophores have potent affinity for iron, which allows them to seize the essential metal from the host iron-binding proteins. To safeguard against iron thievery, the host relies upon the innate immune protein, lipocalin 2 (Lcn2), which could sequester catecholate-type siderophores and thus impede bacterial growth. However, certain bacteria are capable of outmaneuvering the host by either producing “stealth” siderophores or by expressing competitive antagonists that bind Lcn2 in lieu of siderophores. In this review, we summarize the mechanisms underlying the complex iron tug-of-war between host and bacteria with an emphasis on how host innate immunity responds to siderophores.
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Nastri, Horacio G., and Israel D. Algranati. "Protein synthesis in polyamine-deficient bacteria during amino-acid starvation." Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression 949, no. 1 (January 1988): 65–70. http://dx.doi.org/10.1016/0167-4781(88)90055-3.
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Goussard, Sylvie, Catherine Grillot-Courvalin, and Patrice Courvalin. "Eukaryotic Promoters Can Direct Protein Synthesis in Gram-Negative Bacteria." Journal of Molecular Microbiology and Biotechnology 6, no. 3-4 (2003): 211–18. http://dx.doi.org/10.1159/000077252.
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Swaney, Steve M., Hiroyuki Aoki, M. Clelia Ganoza, and Dean L. Shinabarger. "The Oxazolidinone Linezolid Inhibits Initiation of Protein Synthesis in Bacteria." Antimicrobial Agents and Chemotherapy 42, no. 12 (December 1, 1998): 3251–55. http://dx.doi.org/10.1128/aac.42.12.3251.
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ABSTRACT The oxazolidinones represent a new class of antimicrobial agents which are active against multidrug-resistant staphylococci, streptococci, and enterococci. Previous studies have demonstrated that oxazolidinones inhibit bacterial translation in vitro at a step preceding elongation but after the charging ofN-formylmethionine to the initiator tRNA molecule. The event that occurs between these two steps is termed initiation. Initiation of protein synthesis requires the simultaneous presence of N-formylmethionine-tRNA, the 30S ribosomal subunit, mRNA, GTP, and the initiation factors IF1, IF2, and IF3. An initiation complex assay measuring the binding of [3H]N-formylmethionyl-tRNA to ribosomes in response to mRNA binding was used in order to investigate the mechanism of oxazolidinone action. Linezolid inhibited initiation complex formation with either the 30S or the 70S ribosomal subunits fromEscherichia coli. In addition, complex formation withStaphylococcus aureus 70S tight-couple ribosomes was inhibited by linezolid. Linezolid did not inhibit the independent binding of either mRNA or N-formylmethionyl-tRNA toE. coli 30S ribosomal subunits, nor did it prevent the formation of the IF2–N-formylmethionyl-tRNA binary complex. The results demonstrate that oxazolidinones inhibit the formation of the initiation complex in bacterial translation systems by preventing formation of theN-formylmethionyl-tRNA–ribosome–mRNA ternary complex.
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von Hippel, P. H., and F. R. Fairfield. "Thermodynamic aspects of the regulation of protein synthesis in bacteria." Pure and Applied Chemistry 57, no. 1 (January 1, 1985): 45–56. http://dx.doi.org/10.1351/pac198557010045.
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McIntosh, Kerri B., and Peta C. Bonham-Smith. "Ribosomal protein gene regulation: what about plants?" Canadian Journal of Botany 84, no. 3 (March 2006): 342–62. http://dx.doi.org/10.1139/b06-014.
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The ribosome is an intricate ribonucleoprotein complex with a multitude of protein constituents present in equimolar amounts. Coordination of the synthesis of these ribosomal proteins (r-proteins) presents a major challenge to the cell. Although most r-proteins are highly conserved, the mechanisms by which r-protein gene expression is regulated often differ widely among species. While the primary regulatory mechanisms coordinating r-protein synthesis in bacteria, yeast, and animals have been identified, the mechanisms governing the coordination of plant r-protein expression remain largely unexplored. In addition, plants are unique among eukaryotes in carrying multiple (often more than two) functional genes encoding each r-protein, which substantially complicates coordinate expression. A survey of the current knowledge regarding coordinated systems of r-protein gene expression in different model organisms suggests that vertebrate r-protein gene regulation provides a valuable comparison for plants.
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Battesti, Aurélia, and Emmanuelle Bouveret. "Bacteria Possessing Two RelA/SpoT-Like Proteins Have Evolved a Specific Stringent Response Involving the Acyl Carrier Protein-SpoT Interaction." Journal of Bacteriology 191, no. 2 (November 7, 2008): 616–24. http://dx.doi.org/10.1128/jb.01195-08.
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ABSTRACT Bacteria respond to nutritional stress by producing (p)ppGpp, which triggers a stringent response resulting in growth arrest and expression of resistance genes. In Escherichia coli, RelA produces (p)ppGpp upon amino acid starvation by detecting stalled ribosomes. The SpoT enzyme responds to various other types of starvation by unknown mechanisms. We previously described an interaction between SpoT and the central cofactor of lipid synthesis, acyl carrier protein (ACP), which is involved in detecting starvation signals in lipid metabolism and triggering SpoT-dependent (p)ppGpp accumulation. However, most bacteria possess a unique protein homologous to RelA/SpoT (Rsh) that is able to synthesize and degrade (p)ppGpp and is therefore more closely related to SpoT function. In this study, we asked if the ACP-SpoT interaction is specific for bacteria containing two RelA and SpoT enzymes or if it is a general feature that is conserved in Rsh enzymes. By testing various combinations of SpoT, RelA, and Rsh enzymes and ACPs of E. coli, Pseudomonas aeruginosa, Bacillus subtilis and Streptococcus pneumoniae, we found that the interaction between (p)ppGpp synthases and ACP seemed to be restricted to SpoT proteins of bacteria containing the two RelA and SpoT proteins and to ACP proteins encoded by genes located in fatty acid synthesis operons. When Rsh enzymes from B. subtilis and S. pneumoniae are produced in E. coli, the behavior of these enzymes is different from the behavior of both RelA and SpoT proteins with respect to (p)ppGpp synthesis. This suggests that bacteria have evolved several different modes of (p)ppGpp regulation in order to respond to nutrient starvation.
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Russo, Daniela M., Alan Williams, Anne Edwards, Diana M. Posadas, Christine Finnie, Marcelo Dankert, J. Allan Downie, and Angeles Zorreguieta. "Proteins Exported via the PrsD-PrsE Type I Secretion System and the Acidic Exopolysaccharide Are Involved in Biofilm Formation by Rhizobium leguminosarum." Journal of Bacteriology 188, no. 12 (June 15, 2006): 4474–86. http://dx.doi.org/10.1128/jb.00246-06.
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ABSTRACT The type I protein secretion system of Rhizobium leguminosarum bv. viciae encoded by the prsD and prsE genes is responsible for secretion of the exopolysaccharide (EPS)-glycanases PlyA and PlyB. The formation of a ring of biofilm on the surface of the glass in shaken cultures by both the prsD and prsE secretion mutants was greatly affected. Confocal laser scanning microscopy analysis of green-fluorescent-protein-labeled bacteria showed that during growth in minimal medium, R. leguminosarum wild type developed microcolonies, which progress to a characteristic three-dimensional biofilm structure. However, the prsD and prsE secretion mutants were able to form only an immature biofilm structure. A mutant disrupted in the EPS-glycanase plyB gene showed altered timing of biofilm formation, and its structure was atypical. A mutation in an essential gene for EPS synthesis (pssA) or deletion of several other pss genes involved in EPS synthesis completely abolished the ability of R. leguminosarum to develop a biofilm. Extracellular complementation studies of mixed bacterial cultures confirmed the role of the EPS and the modulation of the biofilm structure by the PrsD-PrsE secreted proteins. Protein analysis identified several additional proteins secreted by the PrsD-PrsE secretion system, and N-terminal sequencing revealed peptides homologous to the N termini of proteins from the Rap family (Rhizobium adhering proteins), which could have roles in cellular adhesion in R. leguminosarum. We propose a model for R. leguminosarum in which synthesis of the EPS leads the formation of a biofilm and several PrsD-PrsE secreted proteins are involved in different aspects of biofilm maturation, such as modulation of the EPS length or mediating attachment between bacteria.
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Gedela, Ravi, Naga Sai Babu Makke, and Dinesh Karra. "A Metagenomics Analysis on B-Carotene Synthesis in Neurospora Crassa." International Journal of Applied Sciences and Biotechnology 3, no. 3 (September 25, 2015): 490–503. http://dx.doi.org/10.3126/ijasbt.v3i3.13306.
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We have studied insilico on evolutionary uniqueness of phytoene synthase, which is one of the regulatory enzymes of ?-carotene synthesis in Neurospora crassa. This study reveals multiple sequence alignments showed high sequences with similarity within a species of bacteria, fungi and higher plants. This results designate interestingly between species of bacteria-fungi, fungi-plant, and among the species of bacteria-fungi-plant, showed tremendously less sequence with similarity, except bacteria-plant (high sequence with similarity) respectively. In Phylogenetics tree analysis showed within species of bacteria, fungi and plant 91%, 92% and 99% homology. Whereas in between species of bacteria-fungi, bacteria-plant, fungi-plant, and among the species bacteria-fungi-plant showed 99%, 96%, 100%, and 91%-99% homology respectively. N. crassa phytoene synthase enzyme encode (Isoprenoid Biosynthesis enzymes, Class 1) protein size 610aa, Cyanobacteria phytoene encode (Isoprenoid Biosynthesis enzymes, Class 1) protein size 310aa, and Oryza sativa Indica phytoene synthase 1 (chloroplast), (Isoprenoid Biosynthesis enzymes, Class 1) encode protein size 421aa (e- value 0.0, 0.0 and 0.0; identity 100%, 100% and 100%; Max.score:1238, 644 and 870) respectively. We studied insilico on basis of an evolutionary Endosymbiotic theory; a bacterium is the ancestors to eukaryotes. Int J Appl Sci Biotechnol, Vol 3(3): 490-503
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Wu, Yan, Guang Ting Han, Ying Gong, Yuan Ming Zhang, Yan Zhi Xia, Chang Qing Yue, and Da Wei Wu. "Antibacterial Property and Mechanism of Copper Alginate Fiber." Advanced Materials Research 152-153 (October 2010): 1351–55. http://dx.doi.org/10.4028/www.scientific.net/amr.152-153.1351.
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To apply copper alginate fibers in medical as a new alginate fiber, copper alginate fibers were researched and evaluated against Escherichia coli (E.coli) and Staphylococcus aureus (S.aureus), using antibacterial zone and flash shaking method to analyze anti-bacterial mechanism by the scanning electron microscopy (SEM). The results showed that copper alginate fibers had antibacterial effects, the antibacterial rate against E.coli and S.aureus were 97.4% and 66.2%, respectively; SEM images indicated that bacteria obviously changed after contacting with fibers, the main reason was that copper ion had a damaging effect on pericellular and cell wall. Furthermore, bacterial osmotic pressure was changed and protein synthesis were impeded, and then the normal metabolism of bacteria was destroyed, and finally, bacteria died.
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Sánchez, E., J. Teixidó, R. Guerrero, and R. Amils. "Hypersensitivity of Rhodobacter sphaeroides ribosomes to protein synthesis inhibitors: structural and functional implications." Canadian Journal of Microbiology 40, no. 9 (September 1, 1994): 699–704. http://dx.doi.org/10.1139/m94-111.
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The elongation cycle of protein synthesis systems of purple nonsulfur photosynthetic bacteria Rhodobacter sphaeroides, grown both phototrophically and chemotrophically, was studied using 33 inhibitors with different chemical structures and functional and domain specificities. No functional differences between phototrophic and chemotrophic ribosomal systems were detected. Rhodobacter sphaeroides ribosomes exhibited strong hypersensitivity to nine functional inhibitors when compared with Escherichia coli ribosomes. Most of the R. sphaeroides ribosomal hypersensitivities corresponded to peptidyltransferase inhibitors, implying that this important functional neighborhood must be somehow different in the two organisms.Key words: protein synthesis inhibitors, ribosomal function, peptidyltransferase, photosynthetic bacteria.
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Bulitta, Jürgen B., Neang S. Ly, Cornelia B. Landersdorfer, Nicholin A. Wanigaratne, Tony Velkov, Rajbharan Yadav, Antonio Oliver, et al. "Two Mechanisms of Killing of Pseudomonas aeruginosa by Tobramycin Assessed at Multiple Inocula via Mechanism-Based Modeling." Antimicrobial Agents and Chemotherapy 59, no. 4 (February 2, 2015): 2315–27. http://dx.doi.org/10.1128/aac.04099-14.
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ABSTRACTBacterial resistance is among the most serious threats to human health globally, and many bacterial isolates have emerged that are resistant to all antibiotics in monotherapy. Aminoglycosides are often used in combination therapies against severe infections by multidrug-resistant bacteria. However, models quantifying different antibacterial effects of aminoglycosides are lacking. While the mode of aminoglycoside action on protein synthesis has often been studied, their disruptive action on the outer membrane of Gram-negative bacteria remains poorly characterized. Here, we developed a novel quantitative model for these two mechanisms of aminoglycoside action, phenotypic tolerance at high bacterial densities, and adaptive bacterial resistance in response to an aminoglycoside (tobramycin) against threePseudomonas aeruginosastrains. At low-intermediate tobramycin concentrations (<4 mg/liter), bacterial killing due to the effect on protein synthesis was most important, whereas disruption of the outer membrane was the predominant killing mechanism at higher tobramycin concentrations (≥8 mg/liter). The extent of killing was comparable across all inocula; however, the rate of bacterial killing and growth was substantially lower at the 108.9CFU/ml inoculum than that at the lower inocula. At 1 to 4 mg/liter tobramycin for strain PAO1-RH, there was a 0.5- to 6-h lag time of killing that was modeled via the time to synthesize hypothetical lethal protein(s). Disruption of the outer bacterial membrane by tobramycin may be critical to enhance the target site penetration of antibiotics used in synergistic combinations with aminoglycosides and thereby combat multidrug-resistant bacteria. The two mechanisms of aminoglycoside action and the new quantitative model hold great promise to rationally design novel, synergistic aminoglycoside combination dosage regimens.
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Wang, Shuzhen, Zhiliang Li, Shiming Li, Rong Di, Chi-Tang Ho, and Guliang Yang. "Ribosome-inactivating proteins (RIPs) and their important health promoting property." RSC Advances 6, no. 52 (2016): 46794–805. http://dx.doi.org/10.1039/c6ra02946a.
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Ribosome-inactivating proteins (RIPs), widely present in plants, certain fungi and bacteria, can inhibit protein synthesis by removing one or more specific adenine residues from the large subunit of ribosomal RNAs (rRNAs).
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Vannakambadi, Ganesh, Magnus Höök, Pietro Speziale, and Jose Rivera. "Fibrinogen-binding proteins of Gram-positive bacteria." Thrombosis and Haemostasis 98, no. 09 (2007): 503–11. http://dx.doi.org/10.1160/th07-03-0233.
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SummaryFibrinogen (Fg), the major clotting protein in blood plasma, plays key roles in blood coagulation and thrombosis. In addition, this 340 kD glycoprotein is a stress inducible protein; its synthesis is dramatically upregulated during inflammation or under exposure to stress such systemic infections.This regulation of Fg expression indicates that Fg also participates in the host defense system against infections. In fact, a number of reported studies have demonstrated the involvement of both the intrinsic and extrinsic pathways of coagulation; the thrombotic and the fibrinolytic systems in the pathophysiology of infectious diseases. It is, therefore, perhaps not surprising that many pathogenic bacteria can interact with Fg and manipulate its biology.This review focuses on the major Fg-binding proteins (Fgbps) from Gram-positive bacteria with an emphasis on those that are known to have an effect on coagulation and thrombosis
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Tam, Connie K. P., Christina Morris, and Jim Hackett. "The Salmonella enterica Serovar Typhi Type IVB Self-Association Pili Are Detached from the Bacterial Cell by the PilV Minor Pilus Proteins." Infection and Immunity 74, no. 9 (September 2006): 5414–18. http://dx.doi.org/10.1128/iai.00172-06.
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ABSTRACT Salmonella enterica serovar Typhi and some strains (Vi+) of serovar Dublin use type IVB pili to facilitate bacterial self-association, but only when the PilV proteins (potential minor pilus proteins) are not synthesized. Pilus-mediated self-association may be important in the pathogenesis of enteric fever. We have shown previously that the extent of DNA supercoiling controls the rate of Rci-catalyzed inversion of a DNA fragment which includes the C-terminal portions of the PilV proteins. This inversion therefore controls PilV synthesis as a high inversion rate prohibits transcription of pilV-encoding DNA. Here, we describe the manner in which PilV protein expression inhibits bacterial self-association and present data which suggest that incorporation of one or a few PilV protein molecules into a growing pilus, comprised of PilS subunits, causes the pilus to detach at the bacterial membrane. The bacteria are then unable to self-associate. We suggest that this phenomenon may be relevant to the pathogenesis of typhoid fever.
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Burrows, Lori L., Robert V. Urbanic, and Joseph S. Lam. "Functional Conservation of the Polysaccharide Biosynthetic Protein WbpM and Its Homologues in Pseudomonas aeruginosa and Other Medically Significant Bacteria." Infection and Immunity 68, no. 2 (February 1, 2000): 931–36. http://dx.doi.org/10.1128/iai.68.2.931-936.2000.
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ABSTRACT WbpM is a highly conserved protein involved in synthesis of the O antigens of Pseudomonas aeruginosa. Homologues of this protein have been identified in a large number of bacteria, and they can be divided into two subfamilies: subfamily 1, including WbpM, contains large proteins (∼600 amino acids), while subfamily 2, typified by HP0840 (FlaA1) of Helicobacter pylori, contains smaller proteins (∼350 amino acids) homologous to the C termini of proteins in subfamily 1. Analysis of knockout mutants ofwbpM in P. aeruginosa serotypes O3, O10, O15, and O17 showed that although all 20 serotypes of P. aeruginosa possess wbpM, it is not universally required for O-antigen biosynthesis. Homologous genes fromBordetella pertussis (wlbL),Staphylococcus aureus (cap8D), and H. pylori (flaA1) complemented a P. aeruginosa O5 wbpM mutant to various degrees. These conserved proteins may represent interesting targets for the design of inhibitors of bacterial exopolysaccharide biosynthesis.
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Reesor, Meredith Joy, Isaac Joseph King, and Jeffrey Copeland. "Development of a Tetracycline Resistant Strain of E. coli Sensitive to Ultraviolet Radiation." Journal of Student Research 3, no. 1 (April 21, 2014): 63–68. http://dx.doi.org/10.47611/jsr.v3i1.159.
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Multidrug resistance bacteria pose a significant threat to human health and the efforts of the medical community. Given our reliance on antibiotics for therapeutic treatment of bacterial infections it is imperative to understand the mechanism by which bacteria develop antibiotic resistance. In the present report we develop a strain of Escherichia coli capable of resisting high levels of tetracycline and other protein synthesis inhibitors. Furthermore the tetracycline resistant strain is approximately 1/3rd in length and is sensitive to UV radiation.
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Sidarta, Margareth, Dongdong Li, Lars Hederstedt, and Ewa Bukowska-Faniband. "Forespore Targeting of SpoVD inBacillus subtilisIs Mediated by the N-Terminal Part of the Protein." Journal of Bacteriology 200, no. 13 (April 16, 2018): e00163-18. http://dx.doi.org/10.1128/jb.00163-18.
Full textAbstract:
ABSTRACTSpoVD and PBP4b are structurally very similar high-molecular-weight, class B penicillin-binding proteins produced early during sporulation inBacillus subtilis. SpoVD is known to be essential for endospore cortex synthesis and thereby the production of heat-resistant spores. The role of PBP4b is still enigmatic. Both proteins are synthesized in the cytoplasm of the mother cell. PBP4b remains in the cytoplasmic membrane of the mother cell, whereas SpoVD accumulates in the forespore outer membrane. By the use of SpoVD/PBP4b chimeras with swapped protein domains, we show that the N-terminal part of SpoVD, containing the single transmembrane region, determines the forespore targeting of the protein.IMPORTANCEBeta-lactam-type antibiotics target penicillin-binding proteins (PBPs), which function in cell wall peptidoglycan synthesis. Bacteria of a subset of genera, includingBacillusandClostridiumspecies, can form endospores. The extreme resistance of endospores against harsh physicochemical conditions is of concern in clinical microbiology and the food industry. Endospore cortex layer biogenesis constitutes an experimental model system for research on peptidoglycan synthesis. The differentiation of a vegetative bacterial cell into an endospore involves the formation of a forespore within the cytoplasm of the sporulating cell. A number of proteins, including some PBPs, accumulate in the forespore. An understanding of the molecular mechanisms behind such subcellular targeting of proteins in bacterial cells can, for example, lead to a means of blocking the process of sporulation.
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BUKHOLM, GEIR, METTE BERGH, and MIKLOS DEGRÉ. "Interferon-Induced Protein Synthesis Inhibits Endocytosis of Bacteria in Epithelial Cells." Journal of Interferon Research 7, no. 4 (August 1987): 409–17. http://dx.doi.org/10.1089/jir.1987.7.409.
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