Oceanimonas Doudoroffii Research Articles

Genome analysis of a plastisphere-associated Oceanimonas sp. NSJ1 sequenced on Nanopore MinION platform

Oceanimonas sp. NSJ1 was isolated from macroplastic debris collected previously from Junput, an intertidal beach, facing the northeast coastal Bay of Bengal of the Northern Indian Ocean. The genome of this isolate is closely related to Oceanimonas doudoroffii with a genome size of 3.56 Mbp. The genome annotation confirmed the presence of 5919 total genes, out of which 5809 were CDSs (coding sequences) and all are protein-coding. The genome codes for 110 RNA with 25 rRNA, 84 tRNA (transfer RNA), and one tmRNA (transfer-messenger RNA). Analyses of the annotated genome of Oceanimonas sp. NSJ1 revealed the presence of enzymes involved in the degradation of polycyclic aromatic hydrocarbons. The presence of phthalate 4,5-dioxygenase oxygenase reductase subunit pht2 within the genome also highlights the novelty of this isolate and future functional potential for studying phthalate degradation in marine environment.

The effects of the recombinant YeaZ of Vibrio harveyi on the resuscitation and growth of soil bacteria in extreme soil environment.

Numerous bacteria entered the viable but non-culturable state due to the stresses of dry and salt in soils. YeaZ of Gram-negative bacteria is a resuscitation promoting factor (Rpf) homologous protein could resuscitate bacteria of natural environment in VBNC state. To investigate the promoting effect of YeaZ on the isolation of viable but non-culturable (VBNC) bacteria from soil samples in extreme environments, the recombinant YeaZ of Vibrio harveyi was prepared and added to the soil samples from volcanic soil and saline soil in Northwest China. The study has shown that YeaZ can promote the recovery and growth of soil microorganisms, and the number of cultivable bacteria in volcanic and saline soil has increased from 0.17 × 103 and 2.03 × 103 cfu⋅ml−1 to 1.00 × 103 and 5.55 × 103 cfu⋅ml−1, respectively. The 16S rDNA gene sequencing and phylogenetic analysis showed that YeaZ played an essential role in the increase of composition and diversity of bacteria. A total of 13 bacterial strains were isolated from the volcanic soil samples, which belong to phyla Actinobacteria, Firmicutes and Gamma-proteobacteria. Four species, including Ornithinimicrobium kibberense, Agrococcus citreus, Stenotrophomonas rhizophila and Pseudomonas zhaodongensis were found in the control group, while Micrococcus antarcticus, Kocuria rose, Salinibacterium xinjiangense, Planococcus antarcticus, Ornithinimicrobium kibberense and Pseudomonas zhaodongensis were isolated from the treatment groups (addition of YeaZ). Twenty-one strains were isolated from the saline soil samples, including eight species from the control group and thirteen species from the treatment groups, among which nine species were only found, including Bacillus oceanisediminis, Brevibacillus brevis, Paenibacillus xylanilyticus, Microbacterium maritypicum, B. subtilis, B. alcalophilus, B. niabensis, Oceanimonas doudoroffii and Zobellella taiwanensis. The results suggest that addition of YeaZ to soil samples can promote the recovery of VBNC. This method has the implications for the discovery of VBNC bacteria that have potential environmental functions.

Oceanimonas marisflavi sp. nov., a polycyclic aromatic hydrocarbon-degrading marine bacterium.

A Gram-stain-negative, strictly aerobic, motile and rod-shaped bacterial strain, designated 102-Na3T, was isolated from sediment of Sinduri beach in Taean, Republic of Korea. Strain 102-Na3T grew optimally at 28-37 °C, at pH 7.0-11.0 and in the presence of 1-3 % (w/v) NaCl, but NaCl was not an absolute requirement for growth. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain 102-Na3T joined the clade comprising the type strains of Oceanimonasspecies. Strain 102-Na3T exhibited 16S rRNA gene sequence similarity values of 98.8, 98.3 and 98.0 % to the type strains of Oceanimonas doudoroffii MBIC1298T, Oceanimonas baumannii GB6T and Oceanimonas smirnovii 31-13T, respectively. Strain 102-Na3T contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0 and C12 : 0 as major fatty acids. The major quinone was ubiquinone-8. The polar lipids were composed of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and two unidentified amino lipids. The DNA G+C content was 56.8 mol%. Strain 102-Na3T exhibited DNA-DNA relatedness values of 25.7, 21.7 and 14.8 % to the type strains of O. doudoroffii, O. baumannii and O. smirnovii, respectively. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain 102-Na3T is separated from recognized species of the genus Oceanimonas. On the basis of the data presented, strain 102-Na3T (=KCTC 62271T=JCM 32358T=DSM 106032T) is considered the type strain of a novel species of the genus Oceanimonas, for which the name Oceanimonas marisflavi sp. nov. is proposed.

Crystal structure and modeling of the tetrahedral intermediate state of methylmalonate-semialdehyde dehydrogenase (MMSDH) from Oceanimonas doudoroffii.

The gene product of dddC (Uniprot code G5CZI2), from the Gram-negative marine bacterium Oceanimonas doudoroffii, is a methylmalonate-semialdehyde dehydrogenase (OdoMMSDH) enzyme. MMSDH is a member of the aldehyde dehydrogenase superfamily, and it catalyzes the NAD-dependent decarboxylation of methylmalonate semialdehyde to propionyl-CoA. We determined the crystal structure of OdoMMSDH at 2.9 Å resolution. Among the twelve molecules in the asymmetric unit, six subunits complexed with NAD, which was carried along the protein purification steps. OdoMMSDH exists as a stable homodimer in solution; each subunit consists of three distinct domains: an NAD-binding domain, a catalytic domain, and an oligomerization domain. Computational modeling studies of the OdoMMSDH structure revealed key residues important for substrate recognition and tetrahedral intermediate stabilization. Two basic residues (Arg103 and Arg279) and six hydrophobic residues (Phe150, Met153, Val154, Trp157, Met281, and Phe449) were found to be important for tetrahedral intermediate binding. Modeling data also suggested that the backbone amide of Cys280 and the side chain amine of Asn149 function as the oxyanion hole during the enzymatic reaction. Our results provide useful insights into the substrate recognition site residues and catalytic mechanism of OdoMMSDH.

Screening of Marine Bacteria To Synthesize Polyhydroxyalkanoate from Lignin: Contribution of Lignin Derivatives to Biosynthesis by Oceanimonas doudoroffii

To convert lignin and lignin derivatives to biopolyesters, six types of marine bacterial strains were investigated with mineral salt media containing lignin and lignin derivatives. Our results showed that Oceanimonas doudoroffii, which was isolated from an area of the sea polluted with allantoin, directly synthesized polyhydroxyalkanoate (PHA) using lignin or several lignin derivatives as sole carbon sources. Based on the PHA accumulation data, the conversion from lignin to PHA can be carried out mainly via sinapinic acid and syringic acid rather than other lignin derivatives. This is the first study to show the direct microbial conversion from lignin to biopolyester, which will open the door for lignin-based biorefinery applications.

Multiple DMSP lyases in the γ-proteobacterium Oceanimonas doudoroffii

The marine γ-proteobacterium Oceanimonas doudoroffii was shown to have at least three different enzymes, each of which can cleave dimethylsulfoniopropionate (DMSP), an abundant compatible solute made by different classes of marine phytoplankton. These various DMSP lyases have similarities, but also some differences to those that had been identified in other bacteria. This was demonstrated by cloning each of the corresponding genes and transferring them into other species of bacteria in which backgrounds they conferred the ability to catabolise DMSP, releasing dimethyl sulfide (DMS) as one of the products (Ddd+ phenotype; DMSP-dependent DMS). One of these genes resembled dddD, which was in a cluster with other ddd genes variously involved in subsequent steps of DMSP catabolism, in DMSP import and in DMSP-dependent transcriptional regulation. The other two gene products both had sequence similarity to the previously identified DddP lyase. However, these two Oceanimonas DddP polypeptides were not particularly similar to each other and were in two different sub-branches compared to those that had been studied in strains of the Roseobacter clade of bacteria. One of these O. doudoroffii enzymes, DddP1, most closely resembled gene products in a disparate group of microbes that included two bacteria, Vibrio orientalis and Puniceispirillum marinum and, more strikingly, some Ascomycete fungi that can catabolise DMSP. Previously, the only bacteria known to have multiple ways to catabolise DMSP were in the Roseobacter clade, which were also the only bacteria that had been shown to have functional DddP DMSP lyases. Thus Oceanimonas doudoroffii is unusual on more than one count and likely acquired its dddD, dddP1 and dddP2 genes by independent horizontal gene transfer events.

Arsenic-resistant bacteria isolated from agricultural soils of Bangladesh and characterization of arsenate-reducing strains

To analyse the arsenic-resistant bacterial communities of two agricultural soils of Bangladesh, to isolate arsenic-resistant bacteria, to study their potential role in arsenic transformation and to investigate the genetic determinants for arsenic resistance among the isolates. Enrichment cultures were performed in a minimal medium in the presence of As(III) and As(V) to isolate resistant bacteria. Twenty-one arsenic-resistant bacteria belonging to different genera of Gram-positive and Gram-negative bacteria were isolated. The isolates, with the exception of Oceanimonas doudoroffii Dhal Rw, reduced 2 mmol l(-1) As(V) completely to As(III) in aerobic conditions. Putative gene fragments for arsenite efflux pumps were amplified in isolates from Dhal soil and a putative arsenate reductase gene fragment was amplified from a Bacillus sp. from Rice soil. Phylogenetically diverse arsenic-resistant bacteria present in agricultural soils of Bangladesh are capable of reducing arsenate to arsenite under aerobic conditions apparently for detoxification purpose. This study provides results on identification, levels of arsenic resistance and reduction of arsenate by the bacterial isolates which could play an important role in arsenic cycling in the two arsenic-contaminated soils in Bangladesh.

Detection of glycolate oxidase gene glcD diversity among cultured and environmental marine bacteria

Of eight laboratory cultures of marine gamma- and alpha-Proteobacteria tested, growth on glycolate as a sole carbon source was detected for only three species: Pseudomonas stutzeri, Oceanimonas doudoroffii and Roseobacter sp. isolate Y3F. Degenerate polymerase chain reaction (PCR) primers were designed to amplify glcD, which encodes the D-subunit of the enzyme glycolate oxidase; glcD could be amplified only from those cultures that grew on glycolate. The PCR primers were used to explore glcD diversity in four field samples collected from different ocean environments: an Atlantic Gulf Stream Ring, sampled above and below the thermocline and two Pacific coastal sites, Parks Bay and San Juan Channel, WA. Environmental glcD sequences belonged to six major bacterial phylogenetic groups, with most sequences forming novel clades with no close relatives. Different patterns of glcD diversity were observed within and between the two nutrient regimes. Comparison of glcD and 16S rDNA diversity and analyses of available bacterial genomes and a metgenomic library from the Sargasso Sea show that glycolate-utilizing potential exists in only a subset of bacteria. Glycolate is produced in marine environments mainly by phytoplankton. Examination of glcD diversity will aid in understanding the influence of phytoplankton on bacterial community structure.

Zobellella denitrificans gen. nov., sp. nov. and Zobellella taiwanensis sp. nov., denitrifying bacteria capable of fermentative metabolism

Two denitrifying strains of heterotrophic, facultatively anaerobic bacteria, designated ZD1(T) and ZT1(T), were isolated from sediment samples collected from mangrove ecosystems in Taiwan. The isolates were Gram-negative. Cells grown in broth cultures were straight rods that were motile by means of a single polar flagellum. The isolates grew optimally in 1-3 % NaCl, but NaCl was not an absolute requirement for growth; only strain ZT1(T) grew in 13-14 % NaCl. Both isolates grew between 10 and 45 degrees C, with optimum growth at 30-35 degrees C. They were capable of anaerobic growth by denitrifying metabolism using nitrate or nitrous oxide as terminal electron acceptors or, alternatively, by fermenting glucose, sucrose or mannitol as substrates. C(18 : 1)omega7c was the most abundant fatty acid (32.6-35.7 %). The other major fatty acids included C(16 : 1)omega7c (27.5-29.4 %) and C(16 : 0) (20.1-22.0 %). The two isolates had 16S rRNA gene sequence similarity of 96.8 % and shared 94.1-96.8 % sequence similarity with the most closely related species, Oceanimonas doudoroffii, Oceanimonas baumannii, Oceanimonas smirnovii and Oceanisphaera litoralis. They could be distinguished from these species in that they were capable of fermentative metabolism, had relatively high DNA G+C contents (62.0-64.0 mol%) and contained C(18 : 1)omega7c instead of C(16 : 1)omega7c as the most abundant fatty acid. Characterization data accumulated in this study revealed that the two denitrifying isolates could be classified as representatives of two novel species in a new genus, Zobellella gen. nov., with Zobellella denitrificans sp. nov. (type strain ZD1(T) = BCRC 17493(T) = JCM 13380(T)) as the type species and Zobellella taiwanensis sp. nov. (type strain ZT1(T) = BCRC 17494(T) = JCM 13381(T)) as a second species.

Comparison of selenium and sulfur volatilization by dimethylsulfoniopropionate lyase (DMSP) in two marine bacteria and estuarine sediments

The volatile forms of selenium emitted from soils and plants have been identified by others as dimethylselenide and dimethyldiselenide. Dimethylselenoniopropionate, a possible precursor of dimethylselenide, is the selenium analogue of the common marine osmoprotectant, dimethylsulfoniopropionate. Dimethylselenoniopropionate was organically synthesized from dimethylselenide and acrylate and used in a comparative study with dimethylsulfoniopropionate as a growth substrate, an inducer and substrate for dimethylsulfoniopropionate lyase in two marine bacterial isolates, Alcaligenes sp. strain M3A and Pseudomonas doudoroffii, and in salt marsh sediments and estuarine creek water samples. In P. doudoroffii, the rate of dimethylselenoniopropionate transport into cells was about half that observed with dimethylsulfoniopropionate; Alcaligenes does not take up these molecules. The rate and extent of induction of dimethylsulfoniopropionate lyase in P. doudoroffii at low concentrations of dimethylselenoniopropionate were similar to that of dimethylsulfoniopropionate. In Alcaligenes the low constitutive level of dimethylsulfoniopropionate lyase cleaved dimethylselenoniopropionate into dimethylselenide and acrylate, but induction of dimethylsulfoniopropionate lyase by dimethylselenoniopropionate did not follow. Dimethylsulfoniopropionate lyases from both strains, when induced by dimethylsulfoniopropionate, utilized dimethylselenoniopropionate as a substrate with emission of dimethylselenide. Rates of partially purified dimethylsulfoniopropionate lyase activity with dimethylselenoniopropionate were half those with dimethylsulfoniopropionate. Anoxic salt marsh sediments catalyzed dimethylsulfoniopropionate and dimethylselenoniopropionate degradation at equal rates. In sediments containing high organic matter, both dimethylsulfide and dimethylselenide served as substrates for methanogenesis. These data support the hypothesis that organic selenium molecules can be volatilized by the same biochemical pathways as organic sulfur molecules.

Comparison of selenium and sulfur volatilization by dimethylsulfoniopropionate lyase (DMSP) in two marine bacteria and estuarine sediments

The volatile forms of selenium emitted from soils and plants have been identified by others as dimethylselenide and dimethyldiselenide. Dimethylselenoniopropionate, a possible precursor of dimethylselenide, is the selenium analogue of the common marine osmoprotectant, dimethylsulfoniopropionate. Dimethylselenoniopropionate was organically synthesized from dimethylselenide and acrylate and used in a comparative study with dimethylsulfoniopropionate as a growth substrate, an inducer and substrate for dimethylsulfoniopropionate lyase in two marine bacterial isolates, Alcaligenes sp. strain M3A and Pseudomonas doudoroffii, and in salt marsh sediments and estuarine creek water samples. In P. doudoroffii, the rate of dimethylselenoniopropionate transport into cells was about half that observed with dimethylsulfoniopropionate; Alcaligenes does not take up these molecules. The rate and extent of induction of dimethylsulfoniopropionate lyase in P. doudoroffii at low concentrations of dimethylselenoniopropionate were similar to that of dimethylsulfoniopropionate. In Alcaligenes the low constitutive level of dimethylsulfoniopropionate lyase cleaved dimethylselenoniopropionate into dimethylselenide and acrylate, but induction of dimethylsulfoniopropionate lyase by dimethylselenoniopropionate did not follow. Dimethylsulfoniopropionate lyases from both strains, when induced by dimethylsulfoniopropionate, utilized dimethylselenoniopropionate as a substrate with emission of dimethylselenide. Rates of partially purified dimethylsulfoniopropionate lyase activity with dimethylselenoniopropionate were half those with dimethylsulfoniopropionate. Anoxic salt marsh sediments catalyzed dimethylsulfoniopropionate and dimethylselenoniopropionate degradation at equal rates. In sediments containing high organic matter, both dimethylsulfide and dimethylselenide served as substrates for methanogenesis. These data support the hypothesis that organic selenium molecules can be volatilized by the same biochemical pathways as organic sulfur molecules.

Evidence for Intracellular and Extracellular Dimethylsulfoniopropionate (DMSP) Lyases and DMSP Uptake Sites in Two Species of Marine Bacteria

The kinetics of dimethylsulfoniopropionate (DMSP) uptake and dimethylsulfide (DMS) production from DMSP in two bacterial species, Alcaligenes sp. strain M3A, an isolate from estuarine surface sediments, and Pseudomonas doudoroffii, from seawater, were investigated. In Alcaligenes cells induced for DMSP lyase (DL) activity, DMS production occurred without DMSP uptake. In DL-induced suspensions of P. doudoroffii, uptake of DMSP preceded the production of DMS, indicating an intracellular location of DL; intracellular DMSP levels reached ca. 7 mM. DMSP uptake rates in noninduced cells showed saturation at three concentrations (K(inft) [transport] values, 3.4, 127, and 500 (mu)M). In DL-induced cells of P. doudoroffii, DMSP uptake rates increased ca. threefold (V(infmax), 0.022 versus 0.065 (mu)mol of DMSP taken up min(sup-1) mg of cell protein(sup-1)), suggesting that the uptake binding proteins were inducible. DMSP uptake and DL activity in P. doudoroffii were both inhibited by CN(sup-), 2,4-dinitrophenol, and membrane-impermeable thiol-binding reagents, further indicating active uptake of DMSP by cell surface components. The respiratory inhibitors had limited or no effect on DL activity by the Alcaligenes sp. Of the structural analogs of DMSP tested for their effect on DMSP metabolism, glycine betaine (GBT), but not methyl-3-mercaptopropionic acid (MMPA), inhibited DMSP uptake by P. doudoroffii, suggesting that GBT shares a binding protein with DMSP and that MMPA is taken up at a separate site. Two models of DMSP uptake, induction, and DL location found in marine bacteria are presented.

Comparative Physiology of Dimethyl Sulfide Production by Dimethylsulfoniopropionate Lyase in Pseudomonas doudoroffii and Alcaligenes sp. Strain M3A

Dimethylsulfoniopropionate (DMSP) lyase enzymatically cleaves DMSP, an algal metabolite, to produce acrylate, a proton, and dimethyl sulfide (DMS), the most abundant volatile sulfur compound emitted from oceans. The physiology of DMS production by DMSP lyase was studied in vivo in an Alcaligenes-like organism, strain M3A, a salt marsh bacterial isolate, and in a marine strain, Pseudomonas doudoroffii. Enzymes from both strains were induced at optimum rates by 1 mM DMSP and vigorous aeration. P. doudoroffii was very sensitive to continued aeration and lost activity rapidly; the enzyme was more stable when aeration ceased. In addition to DMSP, acrylate and several of its analogs acted as inducers of DMSP lyase in Alcaligenes sp. strain M3A but not in P. doudoroffii. Turnover of DMSP by P. doudoroffii was enhanced by 3.5% NaCl or seawater, whereas the Alcaligenes sp. strain M3A enzyme was not salt dependent and salt did not greatly affect its activity. The pH profile showed two peaks of DMSP lyase activity (6.5 and 8.8) for Alcaligenes sp. strain M3A and a single peak at pH 8 for P. doudoroffii. Enzyme activity in both organisms was inhibited by methyl-3-mercaptopropionate and homocysteine. Cyanide, azide and p-chloromercuribenzoate inhibited only the P. doudoroffii DMSP lyase. The apparent K(infm) values for DMSP for cell cultures of Alcaligenes sp. strain M3A and P. doudoroffii were ca. 2 mM and <20 (mu)M, respectively. The differences in the physiology of DMSP metabolism in these two bacterial isolates may enable them to exist in diverse ecological niches.

Characterization of a DMSP-degrading bacterial isolate from the Sargasso Sea

A bacterium which cleaves dimethylsulfoniopropionate (DMSP) to form dimethylsulfide (DMS) was isolated from surface Sargasso Sea water by a DMSP enrichment technique. The isolate, here designated LFR, is a Gram-negative, obligately aerobic, rod-shaped, carotenoid-containing bacterium with a DNA G+C content of 70%. Sequencing and comparison of its 16S ribosomal ribonucleic acid (rRNA) with that of known eubacteria revealed highest similarity (91% unrestricted sequence similarity) to Roseobacter denitrificans (formerly Erythrobacter species strain OCh114), an aerobic, bacteriochlorophyll-containing marine representative of the α-Proteobacteria. However, physiological differences between the two bacteria, and the current lack of other characterized close relatives, preclude assignment of strain LFR to the Roseobacter genus. Screening of fifteen characterized marine bacteria revealed only one, Pseudomonas doudoroffii, capable of degrading DMSP to DMS. Strain LFR is deposited with the American Type Culture Collection (ATCC 51258) and 16S rRNA sequence data are available under GenBank accession number 15345.

Taxonomy of Marine Pseudomonas Species: P. stanieri sp. nov.; P. perfectomarina sp. nov., nom. rev.; P. nautica: and P. doudoroffii

Recent studies of the evolutionary relationships of nonfermentative, gram-negative, rod-shaped, polarly flagellated, marine bacteria have indicated that some are members of the lineage which includes the type species of the genus Pseudomonas, Pseudomonas aeruginosa. As a result of these findings, one species equivalent (group G-1) with a guanine plus cytosine content slightly beyond the lower limit proposed for Pseudomonas is now included in this genus under the designation Pseudomonas stanieri sp. nov. (type strain 146 = ATCC 27130). In addition, “Pseudomonas perfectomarinus,” an organism not included in the Approved List of Bacterial Names, is a recognizable species and part of this lineage. This name has, therefore, been revived and corrected to Pseudomonas perfectomarina sp. nov. nom. rev. (type strain 218 = ATCC 14405). The phenotypes of these two species and their type strains are described along with those for two other marine Pseudomonas, Pseudomonas nautica and Pseudomonas doudoroffii.

Catabolism of D-fructose and D-ribose by Pseudomonas doudoroffii. I. Physiological studies and mutant analysis.

Pseudomonas doudoroffii, a strict aerobe of marine origin, was able to utilize fructose and ribose but not glucose, gluconate, or other hexoses, pentoses, or sugar alcohols as sole sources of carbon and energy. Evidence was presented indicating that in this organism fructose was utilized via an inducible P-enolpyruvate: fructose phosphotransferase system (FPTS) which catalyzed the phosphorylation of fructose in the 1 position. The resulting fructose-1-P (F-1-P) was converted to fructose-1,6-P2 (FDP) by means of an inducible 1-P-fructokinase (1-PFK). The subsequent conversion of FDP to pyruvate involved enzymes of the Embden-Meyerhof pathway (EMP) which, with the exception of glyceraldehyde-3-P dehydrogenase (G3PDH), were constitutive. Two G3PDH activities were detected, one of which was inducible and NAD-dependent while the other was constitutive and NADP-dependent. Cell-free extracts of P. doudoroffii also contained enzymes of the methylglyoxal pathway (MGP) which converted dihydroxyacetone-P to pyruvate. The low specific activities of enzymes of this pathway as compared to the EMP suggested that the major route of FDP catabolism was via the latter pathway. 2. Ribose catabolism appeared to involve an inducible uptake system and an inducible ribokinase, the resulting ribose-5-P being converted to glyceraldehyde-3-P and fructose-6-P (F-6-P) by means of constitutive activities of the pentose-P pathway. The F-6-P formed as a result of these reactions was converted to FDP by means of a constitutive 6-P-fructokinase (6-PFK). Since no activity converting fructose or F-1-P to F-6-P could be detected in cell-free extracts of P. doudoroffii, the results suggested that fructose and ribose were catabolized via 1-PFK and 6-PFK, respectively, the two pathways converging at the level of FDP. Further evidence for this suggestion was obtained from a mutant which lacked an NAD-dependent G3PDH, accumulated FDP from both fructose and ribose, and was not able to grow on either of these compounds. 3. Ribose grown cells had increased amounts of the fructose uptake system and 1-PFK suggesting that a compound (or compounds) common to the catabolism of both fructose and ribose acted as the inducer(s) of these activities. Evidence was presented suggesting that the probable inducer(s) of 1-PFK and FPTS could be FDP, glyceraldehyde-3-P, or dihydroxyacetone-P. 4. A mutant unable to grow on fructose was characterized and found to lack FPTS while retaining 1-PFK and other enzyme activities of the EMP and MGP, indicating that a functional FPTS was essential for growth on fructose and suggesting that all or most of this sugar was catabolized via F-1-P.