Fermentation Of D-mannitol Research Articles

Providencia manganoxydans sp. nov., a Mn(II)-oxidizing bacterium isolated from heavy metal contaminated soils in Hunan Province, China

A facultatively anaerobic, Gram-negative, rod-shaped bacterial strain designated as LLDRA6T, was isolated from heavy metal contaminated soils collected near a ceased smelting factory at Zhuzhou, Hunan Province, China. Strain LLDRA6T has the ability to oxidize Mn(II) and generate biogenic manganese oxides. The strain can grow in a wide range of temperature from 10-42°C and pH from 5 to 10. Comparative analysis of its complete 16S rRNA gene sequence suggests that strain LLDRA6T is highly similar to species within the genus Providencia. The complete genome of LLDRA6T is 4 342 370 bp with 40.18 mol% of G+C content and contains no plasmids. In comparison to the genomes of type strains in Providencia, LLDRA6T shows average nucleotide identity values between 76.60 and 80.89 %, and digital DNA-DNA hybridization values in a range of 21.2-24.6 %. Both multilocus sequence analysis and genomic phylogenetics indicate a new taxonomic status for LLDRA6T in Providencia. Chemotaxonomic analyses for LLDRA6T show that the predominant cellular fatty acids are C16 : 0, C14 : 0 and cyclo-C17 : 0, accounting for 32.7, 16.1 and 10.3 % of total fatty acids, respectively. The polar lipids consist of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, four unidentified aminolipids, one unidentified phospholipid and three unidentified lipids. Within the cell wall, ribose and meso-diaminopimelic acid are the characteristic constituents for saccharides and amino acids, respectively. Respiratory quinones on cell membranes are composed of menaquinone (MK) and ubiquinone (coenzyme Q), including MK-8 (100.0 %), Q-7 (13.7 %) and Q-8 (86.3 %). Moreover, the positive results from d-lyxose and d-mannitol fermentation tests indicate that LLDRA6T is totally different from all the type strains within the genus Providencia. In summary, strain LLDRA6T represents a novel species in the genus Providencia, for which the name Providencia manganoxydans sp. nov. (type strain LLDRA6T=CCTCC AB 2021154T=KCTC 92091T) is proposed.

Characteristics of Vibrio vulnificus isolates from clinical and environmental sources

Researchers have developed multiple methods to characterize clinical and environmental strains of Vibrio vulnificus. The aim of our study was to use four assays to detect virulence factors in strains from infected patients and those from surface waters/sediments/oysters of South Carolina and the Gulf of Mexico. Vibrio vulnificus strains from clinical (n = 81) and environmental (n = 171) sources were tested using three real-time PCR methods designed to detect polymorphisms in the 16S rRNA, vcg and pilF genes and a phenotypic method, the ability to ferment D-mannitol. Although none of the tests correctly categorized all isolates, the differentiation between clinical and environmental isolates was similar for the pilF, vcgC/E and 16S rRNA assays, with sensitivities of 74.1–79.2% and specificities of 77.4–82.7%. The pilF and vcgC/E assays are comparable in efficacy to the widely used 16S rRNA method, while the D-mannitol fermentation test is less discriminatory (sensitivity = 77.8%, specificity = 61.4%). Overall percent agreement for the D-mannitol fermentation method was also lower (66.7%) than overall percent agreement for the 3 molecular assays (78.0%–80.2%). This study demonstrated, using a large, diverse group of Vibrio vulnificus isolates, that three assays could be used to distinguish most clinical vs environmental isolates; however, additional assays are needed to increase accuracy.

Lytic Activity of Staphylococcal Bacteriophage on Different Biotypes of Staphylococcus aureus

Bacteriophage is a virus that infects a bacterium by injecting a phage genome into a bacterial cytoplasm and uses a host cell as a propagation mechanism. The studied models of phages show a narrow range of hosts. Previous studies on the investigation of lytic activity of staphylococcal bacteriophages were focused on determining the sensitivity of S. aureus isolated from patients from different clinical material and clinically healthy people. However, there is no information as to how refractory are the already described agents against S. aureus ecovars, isolated from animals. The purpose of the work is to study the lytic activity of the agent “Staphylococcal Bacteriophage” in relation to different biotypes of Staphylococcus aureus. Microbiological treatment of samples for isolation of S. aureus was performed using BD Baird-Parker Agar according to standard techniques. To confirm the presence of S. aureus, tests were used for catalase, coagulase, oxidase, for D-mannitol fermentation, DNase production and acetoin. In cultures belonging to S. aureus, the biotype was determined using the scheme: determining the colour of pigment, the presence of beta hemolysis, the activity of coagulase in the bovine plasma, the formation of colonies in a medium with crystal violet. Determination of the range of action of bacteriophages in relation to clinical isolates of microorganisms was carried out by droplet method. The results of determining the lytic activity of staphylococcal bacteriophage in relation to S. aureus isolates of various biological origin showed that the lytic activity of staphylococcal bacteriophage is most active against S. aureus var. hominis. From the studied cultures S. aureus var. hominis full lysis in the course of dripping were found only in 4.8%, and in 42.8% of cultures showed a semiconfluent lysis. 14.3% of cultures S. aureus var. hominis were subjected to weak lytic activity of the bacteriophage. Also, there were detected 4,8% of cultures of this biotype, which were resistant to staphylococcal bacteriophage. In the study of lytic activity of staphylococcal bacteriophage up to 35 cultures S. aureus var. bovis, the manifestation of the lytic action of only one culture is established. Moreover, the level of lysis was estimated at “+/–”, that is, they showed less than 20 phage colonies. At the same time, the studied by us staphylococcal bacteriophage did not show the lytic action on S. aureus var. avium and S. aureus var. canis. Therefore, conducted studies have shown that the lytic activity of the agent “Staphylococcal Bacteriophage” is directed mainly to S. aureus var. hominis, and practically does not work on other biotypes. In consideration of the apparent lack of activity of phage agents in relation to the studied biotypes, attention should be focused on the specificity of phages, not only within the species of bacteria, but also within their biotypes.

Characteristics and Pathogenicity for Japnaes Eel Anguilla japonica of Vibrio vulnificus Isolated from Oyster, Sediment and Seawater in the Korea Coast

Biotyping of Vibrio vulnificus strains isolated from marine environments along the south coast of Korea showed that the majority of the isolates (94.7%) belonged to biotype 1 and the remaining isolates (5.3%) belonged to biotype 2. Analysis of 16S rRNA V. vulnificus strains isolated from marine environments using a multiplex polymerase chain reaction (PCR) revealed that 78.7% were type A and 21.3% were type B. Random amplified polymorphic DNA (RAPD) was used to analyze the genomic differences in V. vulnificus among the biotype 2 strains isolated from marine environments (newly isolated strains group) and reference strains obtained from infected eels (reference strains group). The two groups had distinctly different profiles of the amplicons produced from RAPD. Additionally, biochemical comparison of these strains revealed that all four strains isolated from marine environments differed from the strains isolated from eels in their ability to promote D-mannitol fermentation. Two (NH 1 and NH 2) out of four isolates of biotype 2 from marine environments showed pathogenicity in eels Anguilla japonica in a challenge test. These isolates did not agglutinate with antisera against V. vulnificus NCIMB 2137 (serovar E), ATCC 27562 (non-serovar E), and ATCC 33816 (atypical serovar E).

Genotype to phenotype: identification of diagnostic vibrio phenotypes using whole genome sequences

Vibrios are ubiquitous in the aquatic environment and can be found in association with animal or plant hosts. The range of ecological relationships includes pathogenic and mutualistic associations. To gain a better understanding of the ecology of these microbes, it is important to determine their phenotypic features. However, the traditional phenotypic characterization of vibrios has been expensive, time-consuming and restricted in scope to a limited number of features. In addition, most of the commercial systems applied for phenotypic characterization cannot characterize the broad spectrum of environmental strains. A reliable and possible alternative is to obtain phenotypic information directly from whole genome sequences. The aim of the present study was to evaluate the usefulness of whole genome sequences as a source of phenotypic information. We performed a comparison of the vibrio phenotypes obtained from the literature with the phenotypes obtained from whole genome sequences. We observed a significant correlation between the previously published phenotypic data and the phenotypic data retrieved from whole genome sequences of vibrios. Analysis of 26 vibrio genomes revealed that all genes coding for the specific proteins involved in the metabolic pathways responsible for positive phenotypes of the 14 diagnostic features (Voges-Proskauer reaction, indole production, arginine dihydrolase, ornithine decarboxylase, utilization of myo-inositol, sucrose and L-leucine, and fermentation of D-mannitol, D-sorbitol, L-arabinose, trehalose, cellobiose, D-mannose and D-galactose) were found in the majority of the vibrios genomes. Vibrio species that were negative for a given phenotype revealed the absence of all or several genes involved in the respective biochemical pathways, indicating the utility of this approach to characterize the phenotypes of vibrios. The absence of the global regulation and regulatory proteins in the Vibrio parahaemolyticus genome indicated a non-vibrio phenotype. Whole genome sequences represent an important source for the phenotypic identification of vibrios.

Correlation of Mannitol Fermentation with Virulence-Associated Genotypic Characteristics inVibrio vulnificusIsolates from Oysters and Water Samples in the Gulf of Mexico

Vibrio vulnificus strains (n = 469) isolated from the Gulf of Mexico oysters and waters over a period of 2 years were subjected to phenotypic and genotypic characterizations. Of the strains that could be definitively genotyped (n = 465), 58% were classified as genotype A, 29% as genotype B, and 13% as genotype A/B by 16S rRNA genotyping. When the same strain bank was characterized by virulence-correlated gene (vcg) typing, 65% were genotype E while 35% were genotype C. Further analysis focusing on strains falling into typical genotype categories (i.e., 16S rRNA types A or B, excluding type A/B strains) showed a high degree of concordance (93%) when comparing the two genotyping methods. d-Mannitol fermentation was also predictive of genotype, with an 86% agreement between 16S rRNA genotype and mannitol fermentation patterns, and an 85% agreement between vcg genotype and mannitol fermentation patterns. d-Mannitol fermentation should be considered as a simple and less expensive alternative to screen V. vulnificus isolates for virulence potential, particularly when analyzing large strain banks.

Photobacterium rosenbergii sp. nov. and Enterovibrio coralii sp. nov., vibrios associated with coral bleaching

Six new Vibrio-like isolates originating from different species of bleached and healthy corals around Magnetic Island (Australia) were investigated using a polyphasic approach. Phylogenetic analyses based on 16S rRNA, recA and rpoA gene sequences split the isolates in two new groups. Strains LMG 22223(T), LMG 22224, LMG 22225, LMG 22226 and LMG 22227 were phylogenetic neighbours of Photobacterium leiognathi LMG 4228(T) (95.6 % 16S rRNA gene sequence similarity), whereas strain LMG 22228(T) was related to Enterovibrio norvegicus LMG 19839(T) (95.5 % 16S rRNA gene sequence similarity). The two new groups can be distinguished from closely related species on the basis of several phenotypic features, including fermentation of d-mannitol, melibiose and sucrose, and utilization of different compounds as carbon sources, arginine dihydrolase activity, nitrate reduction, resistance to the vibriostatic agent O/129 and the presence of fatty acids 15 : 0 iso and 17 : 0 iso. The names Photobacterium rosenbergii sp. nov. (type strain LMG 22223(T)=CBMAI 622(T)=CC1(T)) and Enterovibrio coralii sp. nov. (type strain LMG 22228(T)=CBMAI 623(T)=CC17(T)) are proposed to accommodate these new isolates. The G+C contents of the DNA of the two type strains are respectively 47.6 and 48.2 mol%.

Butyrate and propionate production from D-mannitol in the large intestine of pig and rat

Fermentation of D-mannitol and the bacteria responsible for it were analyzed by 13C-NMR spectroscopy and amplified ribosomal restriction analyses (ARDRA) on intestinal bacteria in pig cecal digesta and in a rat in vivo feeding trial. [1-13C]-Mannitol was fermented by pig cecal digesta mainly to [2-13C]-propionate, [3-13C]-propionate, [2-13C]-butyrate, and [4-13C]-butyrate. Dietary D-mannitol at a 5% level induced significantly higher cecal butyrate concentration in the rat model. The evolution of rat fecal bacteria due to feeding with D-mannitol suggested the involvement of a lactate-utilizing butyrate producer, Clostridium indolis, in the stimulation of butyrate production. Rat intestinal microbiota is often difficult to extrapolate to that of humans, but the stimulation of the lactate-utilizing butyrate producers and propionate producers was suggested by the 13C-NMR spectroscopy of the end products of pig cecal fermentation and ARDRA on rat fecal bacteria. These results suggest the potential of D-mannit...

Enzymatic studies on the conversion of erythritol fermentation to D-mannitol fermentation in n-alkane-grown yeast Candida zeylanoides.

In the polyol fermentation by Candida zeylanoides KY6166, which occurred preferentially by keeping the pH of medium at acidic side (below 4.0), phosphate ion played a precise role in the conversion of erythritol fermentation to d-mannitol fermentation. Enzymatic studies on the conversion mechanism provided the following evidences.The enzymes involved in pentosephosphate cycle were considerably depressed in polyol production phase in which intracellular pH ranged from 5.5 to 5.7. Particularly transaldolase responsible for the synthesis of erythrose 4-phosphate and fructose 6-phosphate from glyceraldehyde 3-phosphate plus d-sedoheptulose 7-phosphate was significantly depressed at pH 5.5. Besides, transketolase which participated directly in the formation of erythrose 4-phosphate from fructose 6-phosphate was significantly inhibited by phosphate ion. Glucose 6-phosphate dehydrogenase was slightly inhibited by phosphate ion.The enzymes involved in pentosephosphate cycle were considerably depressed in polyol p...

Studies on Lactic Acid Fermentation

1. Pyruvate and acetaldehyde were detected as intermediates in the pathway of heterolactic fermentation by L. fermenti. 2. Acetaldehyde was accumulated aerobically as an oxidation product of ethanol in the pre-sence of semicarbazide. 3. Dismutation of acetaldehyde to ethanol and acetate was observed when acetaldehyde was added to the system of glucose fermenta-tion. 4. Alcohol dehydrogenase in an ammonium sulfate fraction catalyzes both DPN- and TPN-dependent oxidation of ethanol to acetaldehyde. Acetyl CoA was reduced in the presence of either TPN or DPN with the same fraction. 5. By coupling of D-xylose degradation with mannitol utilization appreciable increase of ethyl alcohol was observed with resting cells of heterolactic microorganisms. 6. With the continuous supply of reduced methyl viologen approximately half molarity of acetate to be produced from D-xylose was transformed to ethyl alcohol in an absolutely anaerobic condition. From L-arabinose only poor amount of ethyl alcohol was produced by both strains of microorganisms. 7. A metabolic pathway of lactic acid fer-mentation including D-mannitol fermentation was suggested.