ALBERT

Description: Vancomycin-resistant Enterococci (VRE) is a serious concern for public health. Serious infections with VRE have very limited effective antimicrobial therapy, and alternative treatment approaches are highly desirable. One promising approach might be the photodynamic antimicrobial chemotherapy. In the present study, we investigated the photodynamic inactivation (PDI) of two VRE strains mediated by 5-aminolevulinic acid (5-ALA) and its derivative 5-ALA methyl ester (MAL). The photodynamic damages to bacteria on the level of genomic DNA, the leakage of cell components, and the changes of membrane structure were investigated. After treated with 10 mM 5-ALA and irradiated by the 633 ± 10 nm LED for 60 min, 5.37 and 5.22 log 10 reductions in bacterial survival were achieved for the clinical isolate of VRE and E. faecalis (ATCC 51299), respectively. After treated with 10 mM MAL and irradiated by the LED for 60 min, 5.02 and 4.91 log 10 reductions in bacterial survival were observed for the two VRE strains, respectively. In addition, the photocleavage on genomic DNA and the rapid release of intracellular biopolymers were detected in PDI-treated bacteria. The intensely denatured cytoplasm and the aggregated ribosomes were also found in PDI-treated bacteria by transmission electron microscopy. Although 5-ALA and MAL-mediated PDI could induce the photocleavage on genomic DNA, the PDI of the two VRE strains might be predominantly attributed to the envelope injury, the intracellular biopolymers leakage, and the cytoplasm denature.

Description: Earlier findings on the nutritional benefits of diacylglycerols (DAGs) have attracted much attention on the synthesis of DAGs. In this study, we reported an improved method for the lipase-catalyzed synthesis of 1,3-diolein by the irreversible glycerolysis of vinyl oleate with glycerol. The effects of reaction system, lipase loading, molar ratio of vinyl oleate to glycerol, reaction temperature and time on 1,3-diolein content in crude reaction mixture were investigated. When the reaction was conducted in a solvent-free system at 30 °C for 8 h by reacting 2 mmol vinyl oleate with 1 mmol glycerol with 8 % (w/w, relative to total reactants) Lipozyme RM IM (Novozymes, Beijing, China) as catalyst, there were 90.5 ± 2.9 % (area/area) 1,3-diolein and (3.3 ± 0.3) % 1,2-diolein produced. After purification, 1,3-diolein was obtained at 81.4 % yield with 98.2 % purity. The lipase-catalyzed synthesis of 1,3-diolein using vinyl oleate as acyl donor by glycerolysis was also conducted using a medium with 50 mmol of glycerol and 100 mmol vinyl oleate. Compared to enzymatic esterification in a solvent, enzymatic glycerolysis for the synthesis 1,3-diolein is more effective due to the irreversible reaction, mild due to the low reaction temperature, and environmentally benign due to the use of solvent-free reaction system.

Description: The biosynthesis of integric acid, a secondary metabolite of the wood-decay fungus Xylaria feejeensis strain 2FB-PPM08M, has been studied. Labeling experiments using [1- 13 C], [2- 13 C] and [1,2- 13 C 2 ] acetate and l -methionine (methyl- 13 C) were separately performed with fungal culture. The labeling patterns of these metabolites indicated the same origin, and determined that integric acid was formed through the condensation of a sesquiterpene and a polyketide. These experiments showed that side chain of compounds would be synthesized by the polyketide pathway, while the ring carbon indicated the biosynthesis of compounds via the mevalonate pathway.

Description: Two-component systems are important regulatory systems that allow bacteria to adjust to environmental conditions, and in some bacteria are used in pathogenesis. We identified a novel two-component system in Burkholderia cenocepacia , an opportunistic pathogen that causes pneumonia in cystic fibrosis (CF) patients. The putative operon encodes BceS, a sensor kinase, and BceR, a response regulator. Our studies indicated that the bceR mutant showed a statistically significant decrease in protease, swimming motility, and quorum sensing when compared to the wild-type, but there was no significant difference in phospholipase C activity, swarming, and biofilm formation. In addition, the mutant showed a statistically significant reduction in virulence compared to the wild-type using the alfalfa plant model. Examination of the Burkholderia cepacia complex (a group of organisms that are phenotypically similar, but genotypically distinct) revealed that this system is prevalent in B. ambifaria , B. multivorans , B. vietnamiensis and B. dolosa . Interestingly, all these organisms have been associated with CF patients. The collective results indicate that BceSR influences various activities important in Burkholderia physiology and possibly pathogenesis. This information could be important in the design of novel therapeutics for Burkholderia infections.

Description: Canolol-enriched extracts obtained from the extraction of fluidized bed treated canola meal with supercritical carbon dioxide were added to high-oleic canola oil in different concentrations (200, 500 and 750 mg/kg). After 30 h of deep-fat frying, oils fortified with canolol-enriched extracts showed a two to three times better frying performance in comparison to the commonly used antioxidants (TBHQ, 200 mg/kg; rosemary extract, 40 and 200 mg/kg) and a control without antioxidants with regards to the formation of di- and polymer triacylglycerols, total polar compounds, secondary degradation products (anisidine value) and the iodine value. The canolol-enriched extracts were also able to slow down the degradation of α- and γ-tocopherol during frying resulting in significant amounts of tocopherols after 30 h of frying in comparison to the other oils. The influence of the canolol-enriched extracts indicated strongly concentration-dependent performance. With increasing concentration of the extract, the thermal stability of the fortified oil was improved. The only disadvantage of the addition of the extracts was an increase in the initial acid value, but within the frying time, only oil fortified with 750 mg canolol-enriched extract/kg reached the limit given in different countries.

Description: The endophytic actinomycete F4-20 was isolated from Tripterygium wilfordii Hook.f. and was confirmed to produce wilforgine, a secondary metabolite discovered in its host. F4-20 showed a close phylogenetic relationship to Streptomyces species. To seek elicitors that may enhance the production of wilforgine in F4-20, four plant stress molecules were applied to the in vitro liquid cultures. Results showed that methyl jasmonate (MeJA), salicylic acid (SA), and hydrogen peroxide (H 2 O 2 ) inhibited bacterial growth, whereas glutathione (GSH) treatment significantly increased bacterial growth. The wilforgine contents in the mycelia of F4-20 were reduced by MeJA and GSH but were induced by SA and H 2 O 2 . When added in the end of the culture period (7 day), 1 mM SA and 5 mM H 2 O 2 resulted in 69.35 ± 1.71 and 71.80 ± 3.35 µg/g DW of wilforgine production, 1.55 and 1.60 fold to that of control (44.83 ± 1.35 µg/g DW), respectively. Though this improved production was about 6.5 times lower than that of the natural root (454.00 µg/g dry root bark), it provided an alternative method for the production of valuable plant secondary metabolites.

Description: Magnetotactic bacteria synthesize intracellular magnetite and/or greigite magnetosome crystals. They play a significant role in both iron and sulfur cycles in sedimentary aquatic environments. To get insight into the bio-geochemical contribution of MTB, more studies concerning their ecology and their distribution in diverse habitats are necessary. The MTB community of an oil-industry polluted area of the French Mediterranean coast has been previously investigated. Here, we investigate the MTB community from coastal sediments of a Mediterranean pristine area using optical and transmission electron microscopy and phylogenetic analysis based on 16S rRNA gene sequences. A particularly high diversity of MTB was observed, with cocci phylogenetically distributed across the order Magnetococcales, including a novel cluster with sequences from the Mediterranean Sea designated as “Med group”, and novel morphotypes.

Description: A strictly aerobic, Gram-negative, beige-pigmented, short-rod-shaped, non-motile and chemoheterotrophic bacteria, designated K2-48 T was isolated from seawater collected in the Western North Pacific Ocean near Japan. Preliminary analysis based on the 16S rRNA gene sequence revealed that the novel isolate was affiliated with the family Oceanospirillaceae within the class Gammaproteobacteria and that it showed the highest sequence similarity (93.7 %) to Neptunomonas qingdaonensis P10-2-4 T . The strain could be differentiated phenotypically from recognized members of the family Oceanospirillaceae . The major fatty acids of strain K2-48 T were identified as summed feature 3 (C16:1 ω 7c and/or iso-C15:0 2-OH) and C16:0 as defined by the MIDI system. The DNA G+C content was determined to be 43.2 mol%, the major respiratory quinone was identified as ubiquinone 9 and a polar lipid profile was present consisting of phosphatidylethanolamine, a phosphatidylglycerol and an unidentified phospolipid. On the basis of polyphasic taxonomic studies, it was concluded that strain K2-48 T represents a novel genus sp. We propose the name Pelagitalea pacifica gen. nov., sp. nov. for this strain; its type strain is K2-48 T (=KCCM 90119 T ).

Description: Enterococcus faecalis has the ability to conjugate with the aid of aggregation substance (AS) and inducible sex pheromones to exchange genetic elements in food matrix. To evaluate the food safety condition and the transferable factor, 250 tetracycline-resistant food-borne E.   faecalis were collected in Korea. Among the isolates, a majority of tetracycline-resistant isolates (49.6 %) harbored both the tet (M) and tet (L) genes together, followed by tet (M) (19.6 %), and tet (L) (6.8 %) alone. Also, we found the combination of tet (L)/ tet (M)/ tet (O) or tet (M)/ tet (O). We identified two tet (S) genes including the isolate carrying tet (M) +  tet (S) genes. Additionally, most E. faecalis were positive for cpd and ccf (both 96.8 %) followed by cob (57.2 %). Through mating experiments, we confirmed E.   faecalis possessing the Int - Tn gene and/or any AS gene successfully transferred tet genes to JH2-2 E.   faecalis , whereas neither E.   faecalis carrying AS genes nor the Int - Tn gene showed the conjugation. Pulsed-field gel electrophoresis results supported a distinct pattern, implying transfer of genetic information. Our study revealed a high occurrence of tetracycline resistance genes in E.   faecalis from various foods. The widespread dissemination of tetracycline resistance genes would be promoted to transfer tetracycline resistance genes by pheromone-mediated conjugation systems.

Description: Successful colonization is the initial step for plant-bacteria interactions; therefore, the development of strategies to improve adherence to plant surfaces is critically important for environmental bacteria. Biofilm formation is thought to be one such strategy for bacteria to establish stable colonization on inert and living surfaces. Although biofilms play potential roles in enabling persistent bacterial colonization, little attention has been paid to biofilms formed by plant-associated bacteria. In this study, we characterized the biofilm-forming ability of 6 species of bacteria from the family Pseudomonadaceae: Pseudomonas protegens , Pseudomonas fluorescens , Pseudomonas putida , Pseudomonas stutzeri , Pseudomonas mendocina , and Pseudomonas syringae. These strains exhibit different degrees of biofilm formation depending on incubation time and nutrient availability. Distinct preferences for growth media were observed, as biofilms were formed by P. protegens with rich nutrients and by P. fluorescens and P. putida with poor nutrients. Likewise, P. stutzeri did not form biofilms with rich nutrients but did form biofilms under nutrient-poor conditions. These observations indicate that particular components in media may influence biofilm formation. P. putida , one of the strains with high biofilm-forming ability, showed the highest ability for initial attachment, which may be mediated by the hydrophobicity of its cell surface. P. mendocina also has high ability for initial attachment, and this strain produces cell surface-attached extracellular polysaccharides that promote cell aggregation. Thus, each strain possesses different properties that facilitate biofilm formation. Shedding light on bacterial strategies for colonization via biofilm formation would enable a better understanding of plant–bacteria interactions.

Description: The development of alternative energy sources by applying lignocellulose-based biofuel technology is critically important because of the depletion of fossil fuel resources, rising fossil fuel prices, security issues regarding the fossil fuel supply, and environmental issues. White-rot fungi have received much attention in recent years for their valuable enzyme systems that effectively degrade lignocellulosic biomasses. These fungi have powerful extracellular oxidative and hydrolytic enzymes that degrade lignin and cellulose biopolymers, respectively. Lignocellulosic biomasses from either agricultural or forestry wastes are abundant, low-cost feedstock alternatives in nature but require hydrolysis into simple sugars for biofuel production. This review provides a complete overview of the different lignocellulose biomasses and their chemical compositions. In addition, a complete list of the white-rot fungi-derived lignocellulolytic enzymes that have been identified and their molecular structures, mechanism of action in lignocellulose hydrolysis, and biochemical properties is summarized in detail. These enzymes include ligninolytic enzymes (laccase, manganese peroxidase, lignin peroxidase, and versatile peroxidase) and cellulolytic enzymes (endo-glucanase, cellobiohydrolase, and beta-glucosidase). The use of these fungi for low-cost lignocellulolytic enzyme production might be attractive for biofuel production.

Description: Cottonseed meal (CSM), a common agricultural by-product, was used as a nutrient source for the production of eicosapentaenoic acid (EPA) by Pythium irregulare . CSM can support good cell growth performance, as can yeast extract (YE). In terms of the maximum EPA content and EPA yield, CSM is superior to YE. Low concentrations of CSM are beneficial to lipid synthesis, and high concentrations favor the EPA content. Utilizing response surface methodology (RSM) analysis, the optimum contents of glucose and CSM in the fermentation medium were determined to be 40.2 and 16.1 g/l, respectively. After 6 days of fermentation at 25 °C and optimal conditions, the EPA yield and productivity were 245.3 and 40.9 mg/l day, respectively. Particle size of CSM was found to affect the EPA production, and a finely ground CSM (100 mesh) was determined to be best for EPA production. The variation in the fatty acid content of total fatty acid (TFA) indicates that EPA was synthesized through the n-6 route in P. irregulare and Δ12 desaturase was the key enzyme for EPA biosynthesis. Sodium carbonate was determined to be notably good at removing free gossypol attached to biomass. After fungal biomass from each flask had been harvested from Na 2 CO 3 -supplemented medium, 1 % (w/v) Na 2 CO 3 solution was used to wash the mycelia three times; free gossypol (FG) was not detected (detection limit 0.0018 %). This work provides a new approach using cottonseed meal to produce EPA through fungal fermentation.

Description: One of the issues that most concerns to both winemakers and producers of active dry yeasts is the stuck and sluggish fermentations of grape musts with high levels of sugar, reflecting the inability of inoculated yeast strain to complete the fermentation process. It is difficult to obtain a wine strain that possesses both adequate oenological and technological properties; thus, the correct approach to solving these problems is the application of breeding programs primarily focused on both properties. The first step toward this process is to characterize the phenotypic diversity between potential parental strains. In the present study, we have analyzed the fermentative behavior of 26 Saccharomyces cerevisiae wine strains in high-sugar conditions at 20 °C, using a range of tests, such as sporulation ability, spore viability, and tetrad analysis to determine the tolerance of these yeasts to several stress conditions. Most tested strains were homothallic and heterozygous for more than one character. Two auxotrophic derivatives with defects in amino acid or nucleic acid metabolism were obtained, and these strains could potentially be used for the development of hybridization techniques without using laboratory strains.

Description: Steryl glucosides (SG) are common contaminants in biodiesel that form precipitates, which form and cause problems due to fouling during transport and storage. Therefore, their quantification is necessary to assess the quality of this fuel. The methods currently available for SG analysis require expensive instrumentation, need a previous concentration step by solid-phase extraction (SPE) or are of limited use for the quantitative assessment. We developed an enzymatic method for SG quantification in biodiesel samples based on the hydrolysis of the glucoside catalyzed by a broadly specific beta glucosidase and the subsequent determination of the glucose released by the reaction. The method is non-expensive, sensitive and was adapted to 96-well format fluorescence plate reader, making it useful for the parallel assay of multiple samples. The enzymatic assay presented here represent a valuable tool for both quality control and the development of improved biodiesel production and purification procedures.

Description: Di-hydroxylated soybean oil (DSO), a biobased polyol synthesized from epoxidized soybean oil (ESO) could be used to formulate resins for adhesives; however, current DSO synthesis requires harsh reaction conditions that significantly increase both cost and waste generation. In this paper, we investigate the kinetics of oxirane cleavage in ESO to DSO by water and elucidate the role of different process parameters in the reaction rate and optimization of reaction conditions. Our kinetic study showed that ESO oxirane cleavage was a first-order reaction and that the ESO oxirane cleavage rate was greatly influenced by tetrahydrofuran (THF)/ESO ratio, H 2 O/ESO ratio, catalyst content, and temperature. Optimized reaction parameters were THF/ESO of 0.5, H 2 O/ESO of 0.25, catalyst content of 1.5 %, and reaction time of 3 h at 25 °C. DSO with hydroxyl value of 242 mg KOH/g was obtained under these conditions. We also characterized the structure, thermal properties, adhesion performance, and viscoelasticity of UV-polymerized resins based on this DSO. The resin tape exhibited peel adhesion strength of 3.6 N/in., which is comparable to some commercial tapes measured under similar conditions.

Description: Bacillus thuringiensis is a kind of insecticidal microorganism which can produce a variety of toxin proteins, it is particularly important to find an effective strategy to identify novel toxin proteins rapidly and comprehensively with the discovery of the wild-type strains. Multi-dimensional high-performance liquid chromatography combined with mass spectrometry has become one of the main methods to detect and identify toxin proteins and proteome of B. thuringiensis . In this study, protein samples from B. thuringiensis strain 4.0718 were analyzed on the basis of two-dimensional liquid chromatography–tandem mass spectrometry (2D-LC–MS/MS), and tryptic peptides of whole cell from the late sporulation phase were eluted at different concentration gradients of ammonium chloride and followed by secondary mass spectrum identification. 831 and 894 proteins were identified from two biological replicates, respectively, while 1,770 and 1,859 peptides were detected correspondingly. Among the identified proteins and peptides, 606 proteins and 1,259 peptides were detected in both replicates, which mean that 1,119 proteins and 2,370 peptides were unique to the proteome of this strain. A total of 15 toxins have been identified successfully, and seven of them were firstly discovered in B. thuringiensis strain 4.0718 that were Crystal protein (A1E259), pesticidal protein (U5KS09), Cry2Af1 (A4GVF0), Cry2Ad (Q9RM89), Cry1 (K4HMB5), Cry1Bc (Q45774), and Cry1Ga (Q45746). The proteomic strategy employed in the present study has provided quick and exhaustive identification of toxins produced by B. thuringiensis.

Description:    Sediments from Xuanwu Lake have been dredged in the past 3 years to improve the water quality, but methanogenesis should still exist in the newly settled sediment. Methane production, methanogens, and physiochemical parameters were detected in the surface sediments (0–5 cm) and/or vertical sediments (0–21 cm, segmented at interval of 3 cm). Methane flux at water–air interface varied among five detected sites. Principal component analysis showed that CH 4 flux, content of water and the concentration of total nitrogen (TN), CH 4 and organic matters (OM) weighed most heavily on the component I in surface sediments while different patterns were observed for vertical sediments. The copy number of the 16S rRNA gene for bacteria was lower in the surface sediment (0–6 cm) than that in deeper sediments (12–21 cm), while 16S rRNA genes of Archaea were almost evenly distributed in the vertical sediments. Representatives belonging to the orders Methanobacteriales , Methanomicrobiales , and Methanosarcinales were detected in all samples of the vertical sediments, except that no members of the Methanococcales were detected in the samples at 0–6 cm. The level of Methanobacteriales reached a highest density at 18.1 × 10 4  copies g −1  dry weight (dw) at 6–9 cm; for Methanosarcinales (76.89 × 10 6  copies g −1  dw) and Methanococcales (82.70 × 10 3  copies g −1  dw) at 12–15 cm, whereas for Methanomicrobiales (43.37 × 10 6  copies g −1  dw) at 9–12 cm. Methanosarcinaceae and Methanosaetaceae reached to their highest densities at 6–9 and 9–12 cm, respectively. These data provided useful information for better understanding the methanogenesis in the newly settled sediments of a recently dredged lake. Content Type Journal Article Pages 1-6 DOI 10.1007/s00284-012-0103-x Authors Dong-Lin Zhu, The State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing, 210046 Jiangsu, China Cheng Sun, The State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing, 210046 Jiangsu, China Huan He, The State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing, 210046 Jiangsu, China Journal Current Microbiology Online ISSN 1432-0991 Print ISSN 0343-8651