The boundary layer of PHA inclusion bodies isolated from Chromatiumvinosum, Pseudomonas oleovorans, and Rhodococcus ruber was investigated by negative staining and transmission electron microscopy. A typical boundary layer exhibits a basic lattice composed of regularly arranged phasin molecules and phospholipids, forming a thin, nevertheless mechanically stable cover surrounding the content of the inclusion body. Depending on the bacterial strain under investigation, the lattice parameters of the boundary layer may vary. Usually, values between 3.3 and 9.6nm are observed for the spacing, and the lattice is rectangular. Enzyme particles interpreted as PHA synthase particles are attached to, or inserted into the basic lattice. They cover not more than 20% of the total surface of the inclusion body. These enzyme particles measure between 8 and 12nm in diameter, are made up of subunits and occur as single units or small aggregates. No indications have been obtained which would support the view that the boundary layer is a double-layer of proteins with phospholipids in between. Rather, a visual inspection of detached boundary layers revealed that the boundary layer is a monolayer exhibiting only one kind of basic lattice. In regions where this monolayer had been artificially removed from the inclusion body, the surface of the contents of the inclusion body was exposed.
Reverse-phase high-performance liquid chromatography and photodiode array detection were used to analyze the microbial quinones of influent sewage and activated sludge in a sewage treatment plant. Significant differences in quinone patterns were noted between the sewage and activated sludge. Unlike the activated sludge, the sewage had low ratios of menaquinones to ubiquinones, and contained menaquinone-6 as the most abundant menaquinone and negligible amounts of partially hydrogenated menaquinones. A photodiode array analysis revealed that the sewage also contained considerable amounts of plastoquinones and vitamin K1, both of which are specific to photosynthetic electron transport in cyanobacteria and chloroplasts. These results suggest that the microbial population structure of sewage is markedly different from that of activated sludge. Relationships between changes in the community structure of the sewage and activated sludge were also discussed on the basis of the results of a numerical analysis of lipoquinone patterns.
The type strain of Bullera hannae produces a thermolabile protease-sensitive fungicidal toxin that was specified as mycocin. This killer toxin did not act against ascomycetous, sporidiobolaceous and ustilaginaceous yeasts. Its killing pattern is restricted to tremellaceous yeasts and includes the species of Fibulobasidium, Filobasidium, Holtermannia, Sirobasidium, Trimorphomyces, and Tsuchiyaea. The members of the genera Bulleromyces, Cystofilobasidium, Mrakia, Sterigmatosporidium, and Xanthophyllomyces were insensitive to this mycocin. The anamorphic genera Bullera, Cryptococcus, Fellomyces, Kockovaella, Trichosporon, and Udeniomyces were heterogeneous in this respect. The taxonomic significance of the sensitivity to the mycocin of B. hannae is discussed.
The taxonomic relationship of 32 species in the genus Candida Berkhout was examined by characterizing the restriction patterns of nuclear internal transcribed spacers and coenzyme Q types. A matrix of 116 characters was generated from 32 species and seven restriction endonucleases, and phenetically analyzed. Unweighted pair-group arithmetic average (UPGMA) analysis was used to construct the phenograms. The 32 species fell into five major groups corresponding with their genetic relationships. The medically important Candida species clustered together, except C. glabrata. Almost identical restriction patterns were observed between C. hydrocarbofumarica and C. blankii, C. stellatoidea, and C. albicans, and C. steatolytica, and C. inositophila due to synonymous or opposite mating type relationships. The members in each group did not show the same coenzyme Q types, whereas the closely clustered members in each group exhibited the same coenzyme Q types. The results of this study, analyzing ITS-RFLPs and the coenzyme Q type, provided an insight into the various genetic origins of Candida species as well as their genetic relationships.
Resistance to Zn2+ in Vibrio parahaemolyticus was induced when the bacteria were pretreated with lower concentrations of Zn2+. However, only a little resistance to Cd2+ and Co2+ was induced with Zn2+ and no resistance to Zn2+, Cd2+, or Co2+ was induced with Cd2+ or Co2+. The change of composition of outer membrane proteins from the bacteria grown in 3% NaCl-LB broth containing Zn2+ was more remarkable than that from the cells grown in the medium containing Cd2+ or Co2+. The amount of outer membrane protein with an apparent molecular weight of 48, 000 was increased with increasing Zn2+ concentrations in the medium.
The sequence of the small subunit ribosomal coding gene (SSU rDNA) was determined for the type strains of seven species of the genus Bullera and two species which are now regarded as synonyms of species in the genera Bullera and Udeniomyces. The phylogenetic trees for these yeasts were constructed by neighbor joining and maximum likelihood methods, including supposedly related yeasts and filamentous fungi whose SSU rDNA sequences were already known. Fifteen presently recognized species of Bullera were divided into two phylogenetic groups. Bulleramrakii, B. huiaensis, B. sinensis, B. oryzae, B. coprosmaensis, B. crocea, B. armeniaca, and B. variabilis constitute one cluster. In this cluster, the topologies of B. variabilis and orange-colored species, B. crocea and B. armeniaca, are different according to the neighbor-joining and maximum likelihood trees. Bullera pseudoalba, B. alba, B. unica, B, hannae, B. globispora, B. miyagiana, and B. dendrophila constitute another cluster. In this cluster, B. pseudoalba, B. alba, B, unica, and B. hannae constitute a branch but B. globispora, B. miyagiana, and B. dendrophila are located at positions far from one another although the former two species constitute a cluster in the maximum likelihood tree. Among the above species, B. dendrophila constitutes a cluster with Tsuchiyaea wingfieldii and Filobasidiella neoformans. The neotype strain of B. grandispora, which is now regarded a synonym of Udeniomyces piricola, is located close to the position of type strain U. piricola.