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Shadrin VS, Machulin AV, Dorofeeva LV, Chernyshov SV, Mikoulinskaia GV. Lysis of cells of diverse bacteria by l,d-peptidases of Escherichia coli bacteriophages RB43, RB49 and T5. J Appl Microbiol 2020; 130:1902-1912. [PMID: 33107183 DOI: 10.1111/jam.14910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/07/2020] [Accepted: 10/22/2020] [Indexed: 01/03/2023]
Abstract
AIMS The objective of this work was to study the antibacterial specificity and antibacterial effect of endolysins isolated from colibacteriophages RB43, RB49 and T5-as manifested on the exponential and stationary cell cultures of diverse bacteria depending on the growth stage, structure of peptidoglycan (PG) and antibiotic resistance. METHODS AND RESULTS Enzyme activity was assayed by the spectrophotometric method. Antimicrobial activity was estimated by the number of colony forming units (CFUs), with the results represented as logarithmic units. Morphological examination of bacterial cells was conducted using phase-contrast and scanning electron microscopy. The enzymes EndoT5, endolysin of bacteriophage T5, EndoRB43, endolysin of bacteriophage RB43 and EndoRB49, endolysin of bacteriophage RB49 turned out to be much less bacteriospecific than the corresponding Escherichia coli phages; they lysed bacteria of the genera Bacillus, Cellulomonas and Sporosarcina, whose PGs had different structures (A1γ, A4α and A4β) and chemical modifications (amidation). The specific lytic activity of phage enzymes was independent of the antibiotic resistance of bacterial cells and was higher when the cells were in the exponential, rather than stationary, growth phase. The analysis of morphological changes showed that the intermediate stage of the endolysin-induced lysis of bacterial cells was the formation of spheroplasts and protoplasts. CONCLUSIONS Endolysins of colibacteriophages RB49, RB43 and T5 have a wide spectrum of antibacterial action, which includes a number of diverse micro-organisms with different PG structures. SIGNIFICANCE AND IMPACT OF THE STUDY This is a study of the bacterial selectivity of enzymes degrading bacterial cell wall in relation to the chemical structure of PG. It is shown that endolysins of bacteriophages RB49 and RB43 efficiently lyse cell wall of Gram-positive bacteria of the genus Bacillus and Gram-negative bacteria of the genus Pseudomonas (including an antibiotic-resistant strain). The number of bacterial cells is reduced by 3-6 orders of magnitude, which indicates good prospects for using these enzymes in biotechnology.
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Affiliation(s)
- V S Shadrin
- Branch of Shemyakin & Ovchinnikov's Institute of Bioorganic Chemistry RAS, Pushchino, Russia
| | - A V Machulin
- Skryabin's Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Federal Research Center 'Pushchino Scientific Center for Biological Research of the, Russian Academy of Sciences', Pushchino, Russia
| | - L V Dorofeeva
- Skryabin's Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Federal Research Center 'Pushchino Scientific Center for Biological Research of the, Russian Academy of Sciences', Pushchino, Russia
| | - S V Chernyshov
- Branch of Shemyakin & Ovchinnikov's Institute of Bioorganic Chemistry RAS, Pushchino, Russia
| | - G V Mikoulinskaia
- Branch of Shemyakin & Ovchinnikov's Institute of Bioorganic Chemistry RAS, Pushchino, Russia
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Bennett AM, Shippy DC, Eakley N, Okwumabua O, Fadl AA. Functional characterization of glucosamine-6-phosphate synthase (GlmS) in Salmonella enterica serovar Enteritidis. Arch Microbiol 2016; 198:541-9. [PMID: 27017337 DOI: 10.1007/s00203-016-1212-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/28/2016] [Accepted: 03/14/2016] [Indexed: 11/27/2022]
Abstract
Salmonella is a threat to public health due to consumption of contaminated food. Screening of a transposon library identified a unique mutant that was growth and host cell binding deficient. The objective of this study was to determine the functional role of glucosamine-6-phosphate synthase (GlmS) in the biology and pathogenesis of Salmonella. To examine this, we created a glmS mutant (ΔglmS) of Salmonella and examined the effect on cell envelope integrity, growth, metabolism, and pathogenesis. Our data indicated ΔglmS was defective in growth unless media were supplemented with D-glucosamine (D-GlcN). Examination of the bacterial cell envelope revealed that ΔglmS was highly sensitive to detergents, hydrophobic antibiotics, and bile salts compared to the wild type (WT). A release assay indicated that ΔglmS secreted higher amounts of β-lactamase than the WT in culture supernatant fractions. Furthermore, ΔglmS was attenuated in cell culture models of Salmonella infection. Taken together, this study determined an important role for GlmS in the pathogenesis and biology of Salmonella.
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Affiliation(s)
- Alexis M Bennett
- Department of Animal Sciences, University of Wisconsin-Madison, 1675 Observatory Drive, Madison, WI, 53706, USA
| | - Daniel C Shippy
- Department of Animal Sciences, University of Wisconsin-Madison, 1675 Observatory Drive, Madison, WI, 53706, USA
| | - Nicholas Eakley
- Department of Animal Sciences, University of Wisconsin-Madison, 1675 Observatory Drive, Madison, WI, 53706, USA
| | - Ogi Okwumabua
- Wisconsin Veterinary Diagnostic Laboratory, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Amin A Fadl
- Department of Animal Sciences, University of Wisconsin-Madison, 1675 Observatory Drive, Madison, WI, 53706, USA.
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Reconciling in vivo and in silico key biological parameters of Pseudomonas putida KT2440 during growth on glucose under carbon-limited condition. BMC Biotechnol 2013; 13:93. [PMID: 24168623 PMCID: PMC3829105 DOI: 10.1186/1472-6750-13-93] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 10/24/2013] [Indexed: 11/10/2022] Open
Abstract
Background Genome scale metabolic reconstructions are developed to efficiently engineer biocatalysts and bioprocesses based on a rational approach. However, in most reconstructions, due to the lack of appropriate measurements, experimentally determined growth parameters are simply taken from literature including other organisms, which reduces the usefulness and suitability of these models. Pseudomonas putida KT2440 is an outstanding biocatalyst given its versatile metabolism, its ability to generate sufficient energy and turnover of NADH and NAD. To apply this strain optimally in industrial production, a previously developed genome-scale metabolic model (iJP815) was experimentally assessed and streamlined to enable accurate predictions of the outcome of metabolic engineering approaches. Results To substantially improve the accuracy of the genome scale model (iJP815), continuous bioreactor cultures on a mineral medium with glucose as a sole carbon source were carried out at different dilution rates, which covered pulling analysis of the macromolecular composition of the biomass. Besides, the maximum biomass yield (on substrate) of 0.397 gDCW · gglc-1, the maintenance coefficient of 0.037 gglc · gDCW-1 · h-1 and the maximum specific growth rate of 0.59 h-1 were determined. Only the DNA fraction increased with the specific growth rate. This resulted in reliable estimation for the Growth-Associated Maintenance (GAM) of 85 mmolATP · gDCW-1 and the Non Growth-Associated Maintenance (NGAM) of 3.96 mmolATP · gDCW-1 · h-1. Both values were found significantly different from previous assignment as a consequence of a lower yield and higher maintenance coefficient than originally assumed. Contrasting already published 13C flux measurements and the improved model allowed for constraining the solution space, by eliminating futile cycles. Furthermore, the model predictions were compared with transcriptomic data at overall good consistency, which helped to identify missing links. Conclusions By careful interpretation of growth stoichiometry and kinetics when grown in the presence of glucose, this work reports on an accurate genome scale metabolic model of Pseudomonas putida, providing a solid basis for its use in designing superior strains for biocatalysis. By consideration of substrate specific variation in stoichiometry and kinetics, it can be extended to other substrates and new mutants.
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Kuroda A, Sugimoto Y, Funahashi T, Sekiguchi J. Genetic structure, isolation and characterization of a Bacillus licheniformis cell wall hydrolase. MOLECULAR & GENERAL GENETICS : MGG 1992; 234:129-37. [PMID: 1495475 DOI: 10.1007/bf00272354] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A DNA fragment containing the gene for a cell wall hydrolase of Bacillus licheniformis was cloned into Escherichia coli. Sequencing of the fragment showed the presence of an open reading frame which encodes a polypeptide of 253 amino acids with a molecular mass of 27,513. The gene was designated as cwlM, for cell wall lysis. The deduced amino acid sequence indicated that there is a repeated sequence consisting of 33 amino acid residues in the C-terminal region. Deletion of the C-terminal region did not lead to any loss of cell wall lytic activity. The gene product purified from E. coli cells harboring a cwlM-bearing plasmid exhibited a M(r) value of 29 kDa on SDS-polyacrylamide gels, and characterization of the specific substrate bond cleaved by CWLM indicated that the enzyme is an N-acetylmuramoyl-L-alanine amidase (EC 3.5.1.28). The enzyme hydrolyzed the cell wall of Micrococcus luteus more efficiently than those of B. licheniformis and B. subtilis, but the truncated CWLM (lacking the C-terminal region) had lost this preference. CWLM prepared from B. subtilis cells harboring a plasmid containing cwlM had a similar M(r) value to that from E. coli. Amino acid sequence homologies between CWLM and other amidases, and their protein structures are discussed.
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Affiliation(s)
- A Kuroda
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan
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Margot P, Roten CA, Karamata D. N-acetylmuramoyl-L-alanine amidase assay based on specific radioactive labeling of muropeptide L-alanine: quantitation of the enzyme activity in the autolysin deficient Bacillus subtilis 168, flaD strain. Anal Biochem 1991; 198:15-8. [PMID: 1686374 DOI: 10.1016/0003-2697(91)90499-j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A sensitive and highly reproducible assay for N-acetylmuramoyl-L-alanine amidase (EC 3.5.1.28) was devised, based on specific and homogeneous L-[14C]alanine labeling of the substrate, the peptidoglycan. The method involves partial purification of both the enzyme and the substrate and monitoring the muropeptide cleavage by coupling fluorodinitrobenzene to freed L-alanine NH2 groups. After acid hydrolysis of the substrate, the resulting DNP-L-alanine and L-alanine are separated by TLC, and radioactive counts in relevant spots are determined. Application of the method to the autolysin-endowed strain and an autolysis-deficient flaD-bearing mutant has revealed (i) that the N-acetylmuramoyl-L-alanine amidase behaves like an endoenzyme with an apparent Kcat(s-1) of 40, and (ii) that the residual enzyme activity in the flaD bearing strain amounts to 2.5 (+/- 0.1)% of that of the parent strain.
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Affiliation(s)
- P Margot
- Institut de Génétique et de Biologie Microbiennes, Lausanne, Switzerland
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Tang SS, Labbé RG. Mode of action of Clostridium perfringens initiation protein (spore-lytic enzyme). ANNALES DE L'INSTITUT PASTEUR. MICROBIOLOGY 1987; 138:597-608. [PMID: 2900019 DOI: 10.1016/0769-2609(87)90138-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The extracellular initiation protein (IP; spore germination enzyme) produced by Clostridium perfringens was further purified and characterized. IP hydrolysed spore cortical fragments with the release of free amino groups. End group analysis of hydrolysed fragments indicated the presence of N-terminal alanine but no reducing sugars. Molecular weight analysis of IP- and lysozyme-treated fluorescamine-labelled cortical fragments indicated that IP acts only on peptidoglycan chains containing cross-linked peptide subunits. IP failed to hydrolyse a number of nitrophenyl-conjugated glucopyranosides and galactopyranosides. The results indicate that IP is an N-acetylmuramyl-L-alanine amidase.
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Affiliation(s)
- S S Tang
- Department of Food Science, University of Massachusetts, Amherst 01003
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Tsuchido T, Hiraoka T, Takano M, Shibasaki I. Involvement of autolysin in cellular lysis of Bacillus subtilis induced by short- and medium-chain fatty acids. J Bacteriol 1985; 162:42-6. [PMID: 2858469 PMCID: PMC218949 DOI: 10.1128/jb.162.1.42-46.1985] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The addition of saturated C6, C8, C10, and C12 fatty acids appeared to lyse actively growing cells of Bacillus subtilis 168, as judged by a decrease in the optical density of the culture. Of these fatty acids, dodecanoic acid was the most effective, with 50% lysis occurring in about 30 min at a concentration of 0.5 mM. These conditions also decreased the amount of peptidoglycan estimated by the incorporated radioactivity of N-acetyl-D-[1-14C]glucosamine. At concentrations above 1 mM, however, bacterial lysis was not extensive. Dodecanoic acid did not affect autolysis of the cell wall. The lytic action of dodecanoic acid was greatly diminished in cells in which protein synthesis was inhibited and in an autolytic enzyme-deficient mutant. The results suggest that fatty acid-induced lysis of B. subtilis 168 is due to the induction of autolysis by an autolytic enzyme rather than massive solubilization of the cell membrane by the detergent-like action of the fatty acids.
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Cheung HY, Freese E. Monovalent cations enable cell wall turnover of the turnover-deficient lyt-15 mutant of Bacillus subtilis. J Bacteriol 1985; 161:1222-5. [PMID: 3918987 PMCID: PMC215031 DOI: 10.1128/jb.161.3.1222-1225.1985] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A lyt-15 mutant reported to be unable to turn over the cell wall exhibited the same rate of wall turnover as the standard strain if the medium contained 0.2 M NaCl, which did not affect growth. Cell wall autolysis was also optimal at 0.2 M NaCl.
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Labbe RG, Tang SS, Franceschini TJ. Partial purification and characterization of an initiation protein for germination from Clostridium perfringens spores. Biochim Biophys Acta Gen Subj 1981. [DOI: 10.1016/0304-4165(81)90111-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Beveridge TJ. Ultrastructure, chemistry, and function of the bacterial wall. INTERNATIONAL REVIEW OF CYTOLOGY 1981; 72:229-317. [PMID: 6166584 DOI: 10.1016/s0074-7696(08)61198-5] [Citation(s) in RCA: 327] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
The penicilllin-binding proteins (PBPs) of several gram-positive and gram-negative bacteria have been examined. The results indicate that: (i) PBPs are membrane proteins with molecular weights ranging from 40,000 to 120,000. When extracted with Triton X-100 from sonicated cells, they appear to fall into two patterns: one found in rods and the other in spheres. A major difference is in the low-molecular-weight component, which is usually the major PBP in bacilli but a minor one in cocci. (ii) There is a wide variation in both the number and the amount of PBPs in different bacteria, and taxonomically related bacteria tend to have similar PBP patterns. These patterns often correlate with the affinity of PBPs for penicillin and other beta-lactam antibiotics. (iii) The low-molecular-weight component usually releases penicillin spontaneously with a half-life of 10 min or less. Most, but not all, PBPs release bound penicillin in the presence of neutral hydroxylamine (0.2 to 0.8 M).
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Abstract
Autolytic enzymes were found to be required for flagellar morphogenesis in Bacillus subtilis 168 and Bacillus licheniformis 6346. Two previously characterized, poorly lytic, chain-forming mutants of B. subtilis 168, strains FJ3 (temperature conditional) and FJ6, each 90 to 95% deficient in the production of N-acetylmuramyl-L-alanine amidase and endo-beta-N-acetylglucosaminidase, were observed to be nonmotile at 35 degrees C in a variety of liquid and semisolid meida. In contrast, cells of the isogenic wild-type strain were motile and fully separated. Electron microscopy revealed the complete absence of flagella on the mutant cells. Similar observations were made with another poorly lytic strain of B. subtilis 168 (Nil5) and with two poorly lytic, phosphoglucomutase-deficient mutants of B. licheniformis 6346 (MH-3, MH-5). In minimal media lacking galactose (restrictive conditions), the B. licheniformis mutants failed to form flagella, or had serious abnormalities in flagellar morphogenesis and motility. Under permissive conditions, mutants FJ3 (grown at 17 degrees C) and MH-5 (grown with addend galactose) showed increased autolytic activities, grew in the dechained form, and regained their capacities to synthesize functional flagella. Examination of several classes of spontaneous revertants derived from the various mutant strains further demonstrated a close relationship between autolysin acttivity and flagellation in the two Bacillus spp.
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Monodane T, Matsushima Y, Hirachi Y, Kotani S. Cell wall autolysis in log phase cells of Micrococcus lysodeikticus (luteus). Microbiol Immunol 1978; 22:57-66. [PMID: 27703 DOI: 10.1111/j.1348-0421.1978.tb00349.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Log phase cells of Micrococcus lysodeikticus (luteus) IFO 3333 autolyzed when incubated at 37 C in 0.01 M sodium-phosphate buffer pH 7.5. The enzyme involved in the autolysis was recovered mainly in an aqueous phase from cytoplasmic membranes and cytoplasmic materials treated with n-butanol, and proved to be an N-acetylmuramyl-L-alanine amidase. The autolysis of log phase cells suspended in autolyzing buffer was depressed by the addition of trypsin to the buffer.
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Pieniazek D, Piechowska M, Venema G. Characteristics of a complex formed by a nonintegrated fraction of transforming DNA and Bacillus subtilis recipient cell constituents. MOLECULAR & GENERAL GENETICS : MGG 1977; 156:251-61. [PMID: 414068 DOI: 10.1007/bf00267179] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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DeCastro-Costa MR, Landman OE. Inhibitory protein controls the reversion of protoplasts and L forms of Bacillus subtilis to the walled state. J Bacteriol 1977; 129:678-89. [PMID: 402356 PMCID: PMC234997 DOI: 10.1128/jb.129.2.678-689.1977] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
When the cell wall of Bacillus subtilis is removed by lysozyme and the resultant protoplasts are plated on hypertonic soft agar medium, each protoplast forms an L colony. L bodies from such L colonies again plate as L-colony-forming units (CFU). However, if protoplasts or L bodies are "conditioned" by 1 h of incubation in 0.4% casein hydrolysate medium and then incubated in 25% gelatin medium for 1 h, 60 to 100% of the formerly naked cells give rist to bacillary colonies. The present experiments largely explain the mechanism responsible for the "heritable" persistence of the wall-less state in B. subtilis. It is shown that protoplasts produce a reversion inhibitory factor (RIF) which blocks reversion when the cell concentration exceeds 5 x 105 CFU/ml. This inhibitor is nondialyzable and sensitive to trypsin, heat, and detergent. Efficient reversion at 2 x 107 CFU/ml is obtained if the protoplasts are treated with trypsin after conditioning and chloramphenicol is incorporated into the gelatin reversion medium. In the presence of 500 mug of trypsin per ml, the requirement for gelatin is sharply reduced, and reversion occurs rapidly in liquid medium containing only 10% gelatin. Trypsin also stimulates reversion in L colonies growing on soft agar. Latent RIF is activated by beta-mercaptoethanol. This reagent blocks reversion of protoplast suspensions at densities of 5 x 105 CFU/ml. Comparison of the autolytic behavior of B. subtilis and of the RIF revealed that several or the properties of the two activities coincide: both are inhibited by high concentrations of gelatin, both are activated by beta-mercaptoethanol, and both have high affinity for cell wall. Going on the assumption that RIF is autolysin, models for protoplast reversion is suggested by the finding that mutants with altered teichoic acid show altered reversion behavior.
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Robson RL, Baddiley J. Role of teichuronic acid in Bacillus licheniformis: defective autolysis due to deficiency of teichuronic acid in a novobiocin-resistant mutant. J Bacteriol 1977; 129:1051-8. [PMID: 838676 PMCID: PMC235045 DOI: 10.1128/jb.129.2.1051-1058.1977] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
nov-12, a novobiocin-resistant mutant of Bacillus licheniformis ATCC 9945, grows as long chains of cells, a characteristic of autolytic-deficient (Lyt-) mutants. Isolated walls from nov-12 autolyzed at a rate equal to 5% of that displayed by wild-type walls, thus confirming the Lyt- phenotype. Protein-free nov-12 walls displayed marked resistance to, and also failure to bind, added autolysin solubilized from wild-type walls. Comparison of isolated cell walls revealed a deficiency in teichuronic acid in the mutant. Lesser differences were observed in walls of this strain, including a reduction in galactose, an increase in the proportion of peptidoglycan, and small quantitative differences in peptidoglycan composition though the proportions of protein and teichoic acid were similar in walls of both strains. Autolytic sensitivity was studied in walls in which protein, teichoic acid, and teichuronic acid were removed successively by selective extraction procedures. Autolysis of wild-type walls was unaffected by removal or protein or teichoic acid, but teichuronic acid removal rendered wild-type walls as insensitive to autolysis as mutant walls had been throughout. Therefore, in this mutant, deficiency in teichuronic acid alone leads to the Lyt- phenotype and, hence, activity and binding of autolysin(s) are dependent upon teichuronic acid but not teichoic acid. Also, the potential rate of autolysis of cell walls in this organism was correlated with the proportion of teichuronic acid in the wall. The possible significance of these findings with respect to control of autolysis and cell separation is discussed.
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Abstract
Mutants of Bacillus subtilis strain 168 have been isolated that are at least 90 to 95% deficient in the autolytic enzymes N-acetylmuramyl-L-alanine amidase and endo-beta-N-acetylglucosaminidase. These mutants grow at normal rates as very long chains of unseparated cells. The length of the chains is directly related to the growth rates. They are nonmotile and have no flagella, but otherwise appear to have normal cell morphology. Their walls are fully sysceptible to enzymes formed by the wild type and have the same chemical composition as the latter. Cell wall preparations from the mutants lyse at about 10% of the rate of those from the isogenic wild type, with the correspondingly small liberation of both the amino groups of alanine at pH 8.0 and of reducing groups at pH 5.6. Likewise, Microcococcus luteus walls at pH 5.6 and B. subtilis walls at pH 8 are lysed only very slowly by LiCl extracts made from the mutants as compared with rates obtained with wild-type extracts. Thus, the activity of both autolytic enzymes in the mutants is depressed. The frequencies of transformation, the isolation of revertants, and observations with a temperature-sensitive mutant all point to the likelihood that the pleiotropic, phenotypic properties of the strains are due to a single mutation. The mutants did not produce more protease or amylase than did the wild type. They sporulate and the spores germinate normally. The addition of antibiotics to exponentially growing cultures prevents wall synthesis but leads to less lysis than is obtained with the wild type. The bacteriophage PBSX can be induced in the mutants by treatment with mitomycin C.
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Joseph R, Shockman GD. Autolytic formation of protoplasts (autoplasts) of Streptococcus faecalis; location of active and latent autolysin. J Bacteriol 1976; 127:1482-93. [PMID: 821932 PMCID: PMC232944 DOI: 10.1128/jb.127.3.1482-1493.1976] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Over 80% of the active and porteinase-activatable, latent forms of the autolytic N-acetylmuramide glycanhydrolase of Streptococcus faecalis ATCC 9790 were released to the supernatant buffer during the autolytic formation of protoplasts (autoplasts) in the presence of absence of trypsin. Autolysin activity was not found in association with released mesosomal vesicles and had little affinity for binding to membranes or to the outer surface of the wall. Isolated walls were able to bind over four times as much autolysin activity as that present on wall exponential-phase cells. Using a rapid technique for wall isolation, evidence was obtained that the latent form (as well as the active form) was wall bound in intact cells. In addition, isotope labeling and ultrastructural studies were able to show that latent autolysin was concentrated in the newer, septally associated portion of the wall.
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Guinand M, Michel G, Balassa G. Lytic enzymes in sporulating Bacillus subtilis. Biochem Biophys Res Commun 1976; 68:1287-93. [PMID: 817719 DOI: 10.1016/0006-291x(76)90336-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Elliott TS, Ward JB, Wyrick PB, Rogers HJ. Ultrastructural study of the reversion of protoplasts of Bacillus licheniformis to bacilli. J Bacteriol 1975; 124:905-17. [PMID: 1184577 PMCID: PMC235982 DOI: 10.1128/jb.124.2.905-917.1975] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The reversion of protoplasts of Bacillus licheniformis 6346 His- on a medium containing 2.5% agar has been studied in sectioned material after reaction with a ferritin-conjugated antibody specific to the peptidoglycan isolated from the walls of the bacilli. Freeze etching has also been used. Fibrils of material reacting with the antibody have been detected emerging from isolated areas of the protoplasts after 3 h of incubation. This material gradually covers the cell and can eventually (at 6 h) be seen in freeze-etched preparations as a fringe of up to 400 nm around the cells and covering the surfaces with particles that can be removed by lysozyme. At later stages the wall begins to take on a compact, well-defined appearance that can be seen in sections; however, the cells are still grossly deformed. A transitory emergence, beyond the wall of long fibers of 6 nm in diameter, takes place after about 12 h of incubation. These fibers react with the conjugated antibody and after freeze etching show a regular banded structure. They are probably indentical with the fibers isolated elsewhere (Elliott et al., 1975) and shown to contain all the wall constituents (i.e., peptidoglycan, teichoic acid, and teichuronic acid). These fibers are not detectable in the final stages of reversion.
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Elliott TS, Ward JB, Rogers HJ. Formation of cell wall polymers by reverting protoplasts of Bacillus licheniformis. J Bacteriol 1975; 124:623-32. [PMID: 1184574 PMCID: PMC235948 DOI: 10.1128/jb.124.2.623-632.1975] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The biosynthesis of peptidoglycan and teichoic acid by reverting protoplasts of Bacillus licheniformis 6346 His-, in cubated at 35 C on medium containing 2.5% agar, is detectable after 40 min. The amount of N-acetyl-[1-14C]glucosamine incorporated into peptidoglycan and teichoic acid on continued incubation doubles at the same rate as the incorporation of [3H]tryptophan into protein. At the early stages of reversion the average glycan chain length, measured by the ratio of free reducing groups of muramic acid and glucosamine to total muramic acid present, is very short. As reversion proceeds, the average chain length increases to a value similar to the found in the wall of the parent bacillus. The extent of cross-linkage found in the peptide side chains of the peptidoglycan also increases as reversion proceeds. At the completion of reversion the wall material synthesized has similar characteristics to those of the walls of the parent bacilli, containing peptidoglycan and teichoic and teichuronic acids in about the same proportions. Soluble peptidoglycan can be isolated from the reversion medium, amounting to 30% of the total formed after 3 h of incubation and 8% after 12 h. This amount was reduced by the presence in the medium of the walls of an autolysin-deficient mutant; they were not formed at all by reverting protoplasts of the autolysin-deficient mutant itself. Analysis of the soluble material provided additional evidence for their being autolytic products rather than small unchanged molecules. When protoplasts were incubated on medium containing only 0.8% agar, 53 to 67% of the peptidoglycan formed after 3 h of incubation was soluble, and 21% after 12 h. Fibers that appeared to be sheared from the protoplasts at intermediate stages of reversion on medium containing 2.5% agar were similar in composition to the bacillary walls.
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Ward JB. Peptidoglycan synthesis in L-phase variants of Bacillus licheniformis and Bacillus subtilis. J Bacteriol 1975; 124:668-78. [PMID: 241742 PMCID: PMC235953 DOI: 10.1128/jb.124.2.668-678.1975] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Stable L-phase variants isolated from Bacillus licheniformis and Bacillus subtilis, when grown in osmotically stabilized media, do not synthesize peptidoglycan but have been found to accumulate the nucleotide precursors of this polymer. The enzymes involved in the synthesis of these precursors and the later membrane-bound stages of peptidoglycan synthesis have been investigated, and the L-phase variants have been shown to contain lesions, which provide a rational explanation for the absence of peptidoglycan and for the nature of the precursor accumulated. The majority of the L-phase variants contained a single enzymic defect, but two strains were isolated with double lesions. Five out of seven strains examined accumulated uridine 5'-diphosphate (UDP)-MurAc-L-ala-D-glu and were unable to synthesize diaminopimelic acid as a consequence of a defect in aspartate-beta-semialdehyde dehydrogenase activity. Two strains were deficient in UDP-MurAc: L-alanine ligase and accumulated UDP-MurAc. One strain accumulated the complete nucleotide precursor UDP-MurAc-L-ala-D-glu-mA2pm-D-ala-D-ala and was deficient in phospho-N-acetylmuramyl pentapeptide translocase. A second strain also had this lesion, together with defective aspartate-beta-semialdehyde dehydrogenase activity. The other enzymes of peptidoglycan synthesis were present in the L-phase variants, with activities similar to those found in the parent bacilli grown under identical conditions. Membrane preparations from certain of the L-phase variants were also capable of synthesizing the secondary polymers poly(glycerol phosphate) teichoic acid and teichuronic acid and also a polymer of N-acetylglucosamine.
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van Heijenoort J, Parquet C, Flouret B, van Heijenoort Y. Envelope-bound N-acetylmuramyl-L-alanine amidase of Escherichia coli K 12. Purification and properties of the enzyme. EUROPEAN JOURNAL OF BIOCHEMISTRY 1975; 58:611-9. [PMID: 1102308 DOI: 10.1111/j.1432-1033.1975.tb02412.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
N-Acetylmuramyl-L-alanine amidase activity was detected in Escherichia coli K 12 by usine N-acetylmuramyl-L-alanyl-gamma-D-glutamyl-(L)-meso-[3H]diaminopimelic acid as a radioactive substrate. This activity cleaves the amide bond between the residues of N-acetylmuramyl acid and L-alanine. It was readily obtained in a soluble form either by mechanical disruption of the cells or by spheroplast formation. In the latter case the release of most of the activity into the sucrose medium seems to indicate that it is either periplasmic or associated with the outer membrane of the envelope of E. coli K 12. The enzyme was purified to near homogeneity. A molecular weight of 39 000 was determined by gel filtration and confirmed by polyacrylamide gel electrophoresis. Further characterisation of this N-acetylmuramyl-L-alanine amidase activity was carried out by investigating several of its properties.
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Tynecka Z, Ward JB. Peptidoglycan synthesis in Bacillus licheniformis. The inhibition of cross-linking by benzylpenicillin and cephaloridine in vivo accompanied by the formation of soluble peptidoglycan. Biochem J 1975; 146:253-67. [PMID: 1147898 PMCID: PMC1165295 DOI: 10.1042/bj1460253] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The synthesis of peptidoglycan by an autolysin-deficient beta-lactamase-negative mutant of Bacillus licheniformis was studied in vivo in the absence of protein synthesis. Benzylpenicillin and cephaloridine inhibited the formation of cross-bridges between newly synthesized peptidoglycan and the pre-existing cell wall. This inhibition, detected by measurement of the incorporation of N-acetyl[14C]glucosamine into the glycan fraction of the cell wall, was reversed by treatment with beta-lactamase and washing. Inhibition of D-alanine carboxypeptidase by benzylpenicillin was not reversed under similar conditions. Cells in which the initial penicillin inhibition of transpeptidation had been reversed showed an increased sensitivity to a subsequent addition of the antibiotic. Chemical analysis of peptidoglycan synthesized after reversal of penicillin inhibition revealed the presence of excess of alanine resulting from the continued inhibition of D-alanine carboxypeptidase. When the cell walls were digested to yield muropeptides so that the degree of cross-linking could be measured, the product after reversal of penicillin inhibition contained fewer cross-links than did the control preparation. Cultures treated with benzylpenicillin and cephaloridine continued to synthesize uncross-linked soluble peptidoglycan, which accumulated in the medium. This soluble material was all newly synthesized peptidoglycan and did not result from autolysis of the bacteria. The average chain lengths of the glycan synthesized in vivo and released as soluble peptidoglycan in the presence of both benzylpenicillin and cephaloridine were similar to those found previously in this organism.
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Blumberg PM, Strominger JL. Interaction of penicillin with the bacterial cell: penicillin-binding proteins and penicillin-sensitive enzymes. BACTERIOLOGICAL REVIEWS 1974; 38:291-335. [PMID: 4608953 PMCID: PMC413858 DOI: 10.1128/br.38.3.291-335.1974] [Citation(s) in RCA: 183] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Chaloupka J, Krecková P. Characterization of degradation products of the cell wall released during growth and sporulation of Bacillus megaterium. Folia Microbiol (Praha) 1974; 19:292-300. [PMID: 4212988 DOI: 10.1007/bf02873221] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Ward JB. The synthesis of peptidoglycan in an autolysin-deficient mutant of Bacillus licheniformis N.C.T.C. 6346 and the effect of beta-lactam antibiotics, bacitracin and vancomycin. Biochem J 1974; 141:227-41. [PMID: 4455202 PMCID: PMC1168070 DOI: 10.1042/bj1410227] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The synthesis of peptidoglycan by cell-free membrane and membrane+wall preparations from an autolysin-deficient, beta-lactamase-negative mutant of Bacillus licheniformis N.C.T.C. 6346 was studied. The membrane preparation synthesized un-cross-linked polymer, the formation of which was not inhibited by beta-lactam antibiotics. Release of d-alanine by the action of d-alanine carboxypeptidase was inhibited variably according to the antibiotic. This inhibition was reversed by neutral hydroxylamine but not by the action of beta-lactamases or by washing. Bacitracin inhibited peptidoglycan synthesis, but not the d-alanine carboxypeptidase. Examination of peptidoglycan synthesized in the presence of excess of bacitracin showed that synthesis was not restricted to the addition of one disaccharide-pentapeptide unit at each synthetic site, an average of 2-3 disaccharide-pentapeptide units being added. Peptidoglycan synthesis was three- to four-fold more sensitive to vancomycin than was the release of d-alanine by the action of the carboxypeptidase. Incorporation of newly synthesized peptidoglycan into pre-existing cell wall was studied in membrane+wall preparations. This incorporation was catalysed by a benzylpenicillin- and cephaloridine-sensitive transpeptidase. The concentrations of these antibiotics giving 50% inhibition of incorporation were almost identical with those required to inhibit growth of the bacillus. Inhibition of the transpeptidase was reversed by treatment with beta-lactamase or by washing.
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Butters TD, Hughes RC. Solubilization and fractionation of glycoproteins and glycolipids of KB cell membranes. Biochem J 1974; 140:469-78. [PMID: 4447626 PMCID: PMC1168024 DOI: 10.1042/bj1400469] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. A fraction enriched in plasma membranes of human tumour KB cell line, a permissive cell for adenovirus type 5, was obtained. 2. Electrophoresis of the membranes in polyacrylamide gels with buffers containing sodium dodecyl sulphate showed that the membranes after reduction with 2-mercaptoethanol contained over 20 polypeptide species. Three polypeptides were glycosylated and had apparent mol.wts. of 92000, 72000 and 62000. 3. The glycoproteins and the specific receptors responsible for adenovirus adsorption to the membranes were readily extracted into solutions containing low concentrations of Triton X-100. Glycolipids and proteins were also made soluble. A membranous residue obtained after Triton X-100 extraction was enriched in several proteins that appeared to consist of polypeptides of lower molecular weight than the average of KB membrane polypeptides. 4. Sphingomyelin, cholesterol and triglycerides were similarly concentrated in the insoluble residue remaining after successive extractions of KB membranes with Triton X-100. Further, ceramide trihexoside was significantly less easily extracted from KB membranes than lactosyl ceramide. 5. The differences noted in the ease of extraction of membrane components are discussed. 6. The components of membranes made soluble by detergent extraction and containing the large part of the KB membrane glycoproteins were subjected to chromatography on Sepharose 6B and DEAE-cellulose and to isoelectric focusing in the presence of buffers containing Triton X-100. In general, the degree of separation into fractions enriched in individual glycoproteins was disappointing. Possible reasons for the poor fractionation of membrane components by chromatographic systems conveniently used for purification of proteins and glycoproteins of non-membranous origin are briefly discussed.
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Forsberg CW, Rogers HJ. Characterization of Bacillus licheniformis 6346 mutants which have altered lytic enzyme activities. J Bacteriol 1974; 118:358-68. [PMID: 4828303 PMCID: PMC246766 DOI: 10.1128/jb.118.2.358-368.1974] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Two groups of mutants altered in lytic enzyme activities have been isolated from Bacillus licheniformis 6346 MH-1 by screening clones for halo production in agar plates containing cell wall conjugated with Procion brilliant red. In the first group which produced halos during colony formation, two were shown to contain three- and eightfold more muramyl-l-alanine amidase than the parent. These strains liberated amidase and intracellular alpha-glucosidase into the culture medium during exponential growth in liquid medium. Isolated walls had a normal qualitative composition and in autolysing liberated N-terminal amino acids and reducing groups. Wall preparations from the second group of mutants which did not produce halos lysed very poorly at pH 9.5, the optimal pH for amidase activity, and poorly at pH 5.5 even though they had similar endo-N-acetylglucosaminidase activities to the parent. Two of these strains that were also deficient in phosphoglucomutase had only 3 to 5% of the membrane-bound amidase activity compared with that in the parent. Cell walls of the phosphoglucomutase-deficient mutants treated with sodium dodecyl sulfate to inactivate endogenous lytic enzymes were dissolved at 10% of the rate of those from the parent by added amidase, but their sensitivities to lysozyme were similar. Those from one mutant had 10 to 20% of the amidase-binding capacity of parent walls, whereas its isolated mucopeptide was essentially inactive in this respect. The failure of these phosphoglucomutase-deficient mutants to autolyse is likely to be due to the combined effects of both low amidase activity and resistant walls. As a result, daughter cells are unable to separate and long chains are formed during exponential growth.
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Costerton JW, Ingram JM, Cheng KJ. Structure and function of the cell envelope of gram-negative bacteria. BACTERIOLOGICAL REVIEWS 1974; 38:87-110. [PMID: 4601163 PMCID: PMC413842 DOI: 10.1128/br.38.1.87-110.1974] [Citation(s) in RCA: 203] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Costerton JW, Ingram JM, Cheng KJ. Structure and function of the cell envelope of gram-negative bacteria. BACTERIOLOGICAL REVIEWS 1974. [PMID: 4601163 DOI: 10.1128/mmbr.38.1.87-110.1974] [Citation(s) in RCA: 184] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
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Sharpe A, Blumberg PM, Strominger JL. D-alanine carboxypeptidase and cell wall cross-linking in Bacillus subtilis. J Bacteriol 1974; 117:926-7. [PMID: 4204447 PMCID: PMC285596 DOI: 10.1128/jb.117.2.926-927.1974] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Inhibition of d-alanine carboxypeptidase in Bacillus subtilis by 95% caused no measurable change in the degree of cross-linking of the peptidoglycan.
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Abstract
Detergent extracts of three blue-green bacteria (Agmenellum quadruplicatum strain BG1, Anacystis nidulans strain TX20, and Nostoc sp. strain MAC) contained enzymes capable of lysing suspensions of Micrococcus lysodeikticus. The enzyme preparation from A. quadruplicatum released soluble reducing fragments from purified peptidoglycan. The lytic activity exhibited a pH optimum between 6 and 7, was relatively heat stable, and was susceptible to attack by proteolytic enzymes. These results extend the range of bacterial types exhibiting cell lytic activity as well as confirm the existence of the lytic system commonly observed in "water blooms".
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Wyrick PB, Rogers HJ. Isolation and characterization of cell wall-defective variants of Bacillus subtilis and Bacillus licheniformis. J Bacteriol 1973; 116:456-65. [PMID: 4126820 PMCID: PMC246442 DOI: 10.1128/jb.116.1.456-465.1973] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Quantitative mass conversion of intact bacterial cells of Bacillus subtilis and B. licheniformis to L-phase variants has been effected after lysozyme treatment. After subculture of the unstable L-phase variants for several months in the presence of methicillin, stable L-phase variants were obtained which grew in the absence of the antibiotic and were then unable to revert to the classical bacterial phase under conditions which gave rise to mass reversion of the protoplasts and unstable L-variants. These stable L-phase variants, which retained many of the physiological properties of the bacterium from which they were derived, were capable of growing exponentially and multiplying in liquid medium. Their morphology and apparent modes of reproduction were consistent with that described for other L-phase variants. The morphological events, as monitored by the electron microscope, of the reversion to the intact bacterial phase of an unstable L-phase variant of B. licheniformis are described.
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Abstract
The glycan chain length of peptidoglycan was measured by reduction with NaB(3)H(4) and isolation of the resulting muramitol, indicative of the length of the chains as biosynthesized, and glucosaminol, which measured the length of the chains after rupture by endo-beta-N-acetylglucosaminidases. Measurement of the non-reducing terminal N-acetylglucosamine by Smith degradation confirmed the result.
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Abstract
Two procedures are described for the extraction of autolysins from whole cells. One method uses 5 M LiCl at 4 C. The amount of enzyme obtained by this method is six times more than that obtained by autolysis of cell walls and fourteen times more than that obtained by extracting cell walls with LiCl. With the other method, cells are extracted with 2% Triton X-100. This is less efficient than the LiCl method but yields about one-half the amount of enzyme obtained by cell wall autolysis and about the same amount as obtained by extracting cell walls with salt. Both procedures yield autolysin with multiple pH optima. Autolysins can be extracted from several bacterial species by either the LiCl or the detergent method. The data suggest that these techniques have sufficient sensitivity to detect small differences in autolytic activity among mutants and various organisms and are also suitable for large-scale isolation of autolysin for purification and characterization studies.
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Forsberg CW, Wyrick PB, Ward JB, Rogers HJ. Effect of phosphate limitation on the morphology and wall composition of Bacillus licheniformis and its phosphoglucomutase-deficient mutants. J Bacteriol 1973; 113:969-84. [PMID: 4570613 PMCID: PMC285316 DOI: 10.1128/jb.113.2.969-984.1973] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Two very poorly lytic mutants of Bacillus licheniformis 6346 that had no teichuronic acid or glucose in their walls were phosphoglucomutase deficient. The walls of the mutants were less autolytic, and the lesion in the phosphoglucomutase gene and the formation of lytic amidase seemed to be interrelated. When phosphoglucomutase was regained or the effects of the deficiency were circumvented by the presence of galactose in the medium, the lytic enzyme was partially regained. When subjected to growth limitation by the supply of inorganic phosphate, the mutants ceased to make teichoic acid, and their walls contained a greatly increased proportion of mucopeptide. Under these conditions they formed irregular spheres which changed back to rods when inorganic phosphate was supplied. Both wall and protein synthesis were necessary for the changes in morphology. An intermediate crescent-shaped cell was formed in the change from sphere to a rod. The possible relationship of this morphological change to the distribution of biosynthetic sites is discussed.
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