Electron Microscope Study of Whole Mounts and Thin Sections of Micromonospora chalcea ATCC 12452

Luedemann, George M.; Casmer, Charles

doi:10.1099/00207713-23-3-243

Cited by 18 publications

(12 citation statements)

References 15 publications

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“…It is possible that warts are points of preferential wall attack and synthesis with less mechanical resistance. The sporulation septum has a typical three-layered structure similar to that of the vegetative cross-wall, as has been reported previously in M. chalcea (Luedemann & Casmer, 1973) and in M. fusca and M. globosa (Stevens, 1975). The structure of the sporulation septum and its process of formation is similar to that of Streptomyces type I (Hardisson & Manzanal, 1976).…”

Section: Discussionsupporting

confidence: 72%

“…fusca, Stevens (1975) did not find mesosomes directly associated with the septum until its completion. As Luedemann & Casmer (1973) pointed out, warts are formed on the spore wall before the deposition of the material of the new layers of the spore wall has begun. Perhaps the origin of the warts is linked to the swelling of the hyphal tip at the beginning of sporogenesis.…”

Section: Discussionmentioning

confidence: 99%

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Fine Structure of Spore Formation and Germination in Micromonospora chalcea

Hardisson

Súarez

1979

Journal of General Microbiology

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I N T R O D U C T I O NThe genus Micromonospora contains filamentous bacteria which form a monopodially branched mycelium from one asexual spore. Spores are produced on this mycelium and, under appropiate conditions, these germinate and repeat the cycle.The fine structure of the genus was studied by Luedemann & Casmer (1973) who related the mycelial and spore structure seen in thin sections to the silhouettes obtained by the electron microscopy of whole mounts. They presented electron micrographs of different stages of sporogenesis in M . chalcea, but all of them after the formation of the sporulation septum. The ultrastructure of sporogenesis was studied in M . globosa and M . fusca by Stevens (1975), and Sharples & Williams (1976) have described the ultrastructure of spore germination in M . melanosporea. However, we know of no previous studies of both sporogenesis and germination in the neotype strain M . chalcea. M E T H O D SCiilfure conditions. Micromonospara chalcea ATCC 12452, neotype strain, (Luedemann, 1971) was inoculated by streaking on GAE solid medium (Hardisson & Manzanal, 1976) in Petri dishes and incubated at 28 "C. After 6 to 12 d, well-isolated colonies were selected for an ultrastructural study of sporulation.Preparation ofspore suspensions. Organisms were grown for 20 d at 28 "C in 250 ml flasks containing 75 ml GAE broth, and spore suspensions were prepared as previously described (Hardisson et a/., 1978).Germination. Recently harvested spore suspensions were germinated as described previously (Hardisson et a/., 1978). Spores at different stages of germination (dormant, swollen and spores with germ tubes), as revealed by phase-contrast microscopy, were selected.Electron microscopy. Samples for the study of sporulation and germination were treated as previously described (Hardisson & Manzanal, 1976;Hardisson et al., 1978) except that they were stained with uranyl acetate for 30 min and poststained with lead citrate (Reynolds, 1963) for 4 min. Photographs were taken with a Philips EM-300 electron microscope operating at 80 kV. R E S U L T SSporulation septum formation. The early stages of sporogenesis in M . chalcea were characterized by a lateral or apical swelling of a hypha and the formation of a sporulation septum (Fig. l a , b, c, d). The sporulation septum had a three-layered structure similar to that of the vegetative cross-wall (Fig. 1 a) from the onset of the process (Fig. 1 b). Mesosomes were associated with the developing septum and the nuclear region (Fig. 1 a, b, c, d). Warts were observed on the developing spore wall before completion of the sporulation septum ( Fig. 1 b, c) but more clearly after its completion (Fig. 1 d). The cytoplasmic membrane seemed to follow the contours of the warts (Fig. Id).Spore maturation. After completion of the sporulation septum, a series of changes transformed the newly delimited swollen hyphal tip into a mature spore. There was a

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Section: Discussionsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Fine Structure of Spore Formation and Germination in Micromonospora chalcea

Hardisson

Súarez

1979

Journal of General Microbiology

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“…Pseudonocardia spinosa (Henssen et al, 1983) of actinomycetes forms budding aerial hyphae resulting in spore formation. Micromonospora chalcea (Luedemann and Casmer, 1973) and Kineosporia sp. (Pagani and Parenti, 1978) of actinomycetes were also described as showing budding sporulation; however, photographs of TEM in each description indicated that those spores are formed by differentiation from the cell at the end of branched mycelia, and therefore those sporulation modes may be arthrospore formation such as Saccharomonospora and Actinomadura formosensis, not a budding mode.…”

Section: Resultsmentioning

confidence: 99%

A life cycle of branched aerial mycelium- and multiple budding spore-forming bacterium Thermosporothrix hazakensis belonging to the phylum Chloroflexi

Yabe¹,

Aiba

Sakai³

et al. 2010

J. Gen. Appl. Microbiol.

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As far as known, sporulation modes in prokaryotes include formation of endospores exemplifi ed by Firmicutes bacteria, myxospores by myxobacteria and arthrospores by actinomycetes. Here we describe Thermosporothrix hazakensis strain SK20-1 T belonging to the phylum Chlorofl exi with a life cycle including a novel prokaryotic sporulation mode. Microscopic observations showed that strain SK20-1 T formed multiple exospores per mother cell by budding in branched aerial mycelia. Although branched aerial mycelia are characteristic of actinomycetes, multiple budding sporulation has not been previously described in prokaryotes. The strain SK20-1 T could be a model microbe for cellular differentiation with multiple budding spore formation.

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“…Electron microscopic analysis of spores reveals the presence of warts which arise from the outer portion of the spore wall (Fig. 2), as described by Luedemann and Casmer for Micromonospora chalcea spores (16).…”

mentioning

confidence: 99%

Micromonospora rosaria sp. nov., nom. rev., the Rosaramicin Producer

Horan¹,

Brodsky²

1986

International Journal of Systematic Bacteriology

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The name of the produter of the macrolide antibiotic rosaramicin, Micromonospora rosaria NRRL 3718* (T = type strain), was not included on the Approved Lists of Bacterial Names because the original publication did not contailr a full description of this strain. Following its first appearance in the literature and its subsequent availability, M . rosaria NRRL 3718 frequently appeared in studies as a comparative organism when new antibiotic-producing species of Micrornonsporu were described. Therefore, we formally revive the name M . rosaria, present a full species description, and designate strain NRRL 3718 as the type strain.Wagman et al. (23) described a new macrolide antibiotic produced by an organism designated Micromonospora rosaria. Although the producing culture was named and deposited in the Northern Utilization and Research Division, U.S. Department of Agriculture, Peoria, Ill., as strain NRRL 371gT (T = type strain), a full description of the strain was not given. Therefore, the species was not included on the Approved Lists of Bacterial Names (19).Since that initial publication, M . rosaria NRRL 37MT has been used as a reference strain in numerous studies describing new species of antibiotic-producing micromonosporae (4, 7, 11, 17, 24). In an attempt to provide continuity in the literature, we propose to revive the name Micromonospora rosaria in accordance with Rule 28a and Provisional Rules B2 and B3 of the International Code of Nomenclature of Bacteria (9).Strains. Since the initial discovery of rosaramicin, we have isolated rosaramicin-producing strains from soil, and our co-workers have generated mutants, including strains blocked in the production of rosaramicin (5,22). The species description given below is based on a taxonomic analysis of strain NRRL 37BT and six of these strains ( Table 1).Procedures described by Horan and Brodsky (8) were used for maintenance of strains and preparation of inocula. The observation and characterization of micromonospora were incubated for 14 to 21 days at 30°C. Each color designation assigned to the vegetative mycelial pigments consisted of a color name (21) and a color chip number (3).Carbon utilization was determined by the procedures of Luedemann and Brodsky (15) The species description is given below. Micromonospora rosaria sp. nov., nom. rev. (ex Wagman, Waitz, Marquez, Murawski, Oden, Testa, and Weinstein, 1972). The specific epithet refers to the wine red diffusible pigment formed by strain NRRL 37NT.The vegetative hyphae are branched and approximately 0.5 pm in diameter. Spores that are 1.5 to 1.8 km in diameter occur along the length of the hyphae, are borne singly, and are either sessile or on short sporophores. Growth and sporulatioh is of the open web type of Luedemann (13) (Fig.

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Electron Microscope Study of Whole Mounts and Thin Sections of Micromonospora chalcea ATCC 12452

Cited by 18 publications

References 15 publications

Fine Structure of Spore Formation and Germination in Micromonospora chalcea

Fine Structure of Spore Formation and Germination in Micromonospora chalcea

A life cycle of branched aerial mycelium- and multiple budding spore-forming bacterium Thermosporothrix hazakensis belonging to the phylum Chloroflexi

Micromonospora rosaria sp. nov., nom. rev., the Rosaramicin Producer

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