Glyceraldehyde-3-phosphate dehydrogenase as a moonlighting protein in bacteria

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is considered a housekeeping protein that is present in virtually all organisms, where it performs metabolic functions essential for survival. GAPDH plays an essential role in the process of energy production, and is also involved in numerous biological processes. GAPDH belongs to a subset of proteins called moonlighting proteins, in which different functions are associated with a single polypeptide chain. The multifunctionality of GAPDH has been described in pathogenic and probiotic microorganisms, in mammals and in plants. In this review, we summarize the moonlighting role of GAPDH in bacteria.

Glyceraldehyde-3-phosphate dehydrogenase as a moonlighting protein in bacteria

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is considered a housekeeping protein that is present in virtually all organisms, where it performs metabolic functions essential for survival. GAPDH plays an essential role in the process of energy production, and is also involved in numerous biological processes. GAPDH belongs to a subset of proteins called moonlighting proteins, in which different functions are associated with a single polypeptide chain. The multifunctionality of GAPDH has been described in pathogenic and probiotic microorganisms, in mammals and in plants. In this review, we summarize the moonlighting role of GAPDH in bacteria.

Glyceraldehyde-3-phosphate dehydrogenase as a moonlighting protein in bacteria

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is considered a housekeeping protein that is present in virtually all organisms, where it performs metabolic functions essential for survival. GAPDH plays an essential role in the process of energy production, and is also involved in numerous biological processes. GAPDH belongs to a subset of proteins called moonlighting proteins, in which different functions are associated with a single polypeptide chain. The multifunctionality of GAPDH has been described in pathogenic and probiotic microorganisms, in mammals and in plants. In this review, we summarize the moonlighting role of GAPDH in bacteria.

Interactions of bacteria and fungi on decomposing litter: differential extracellular enzyme activities

Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradativeenzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria

Combined dielectrophoretic and impedance system for on-chip controlled bacteria concentration: Application to Escherichia coli

The present paper reports a bacteria autonomous controlled concentrator prototype with a user-friendly interface for bench-top applications. It is based on a micro-fluidic lab-on-a-chip and its associated custom instrumentation, which consists in a dielectrophoretic actuator, to pre-concentrate the sample, and an impedance analyser, to measure concentrated bacteria levels. The system is composed by a single micro-fluidic chamber with interdigitated electrodes and a instrumentation with custom electronics. The prototype is supported by a real-time platform connected to a remote computer, which automatically controls the system and displays impedance data used to monitor the status of bacteria accumulation on-chip. The system automates the whole concentrating operation. Performance has been studied for controlled volumes of Escherichia coli (E. coli) samples injected into the micro-fluidic chip at constant flow rate of 10 μL/min. A media conductivity correcting protocol has been developed, as the preliminary results showed distortion of the impedance analyser measurement produced by bacterial media conductivity variations through time. With the correcting protocol, the measured impedance values were related to the quantity of bacteria concentrated with a correlation of 0.988 and a coefficient of variation of 3.1%. Feasibility of E. coli on-chip automated concentration, using the miniaturized system, has been demonstrated. Furthermore, the impedance monitoring protocol had been adjusted and optimized, to handle changes in the electrical properties of the bacteria media over time.

Immobilization of laccase on hybrid layered double hydroxide

Crystals of Mg/Al layered double hydroxide were synthesized by alkaline precipitation and treated in an aqueous solution of glutamic acid. The glutamate ions were not intercalated into the interlayer space, but were detected in the material by Fourier transform infrared spectroscopy, suggesting that only the external surfaces of crystals were modified with glutamate ions. The resulting hybrid material was tested as a support for immobilization of the enzyme laccase (Myceliophthora thermophila). The immobilized enzyme preparation was characterized by electronic paramagnetic resonance spectroscopy and by assays of catalytic activity. The activity of the immobilized laccase was 97% of the activity in the free enzyme. Layered double hydroxide is a suitable support for use in remediation of soil studies.

Metabolic response induced by endophytic fungi and bacteria in H. marrubioides Epling in vitro microplants

Hyptis marrubioides Epling is a native plant from Brazilian Cerrado. In this paper, the response of in vitro microplants of this species to inoculation with bacterial and fungal endophytic isolates is evaluated. HPLC-DAD analysis showed the presence of 3,4-O-(Z)-dicaffeoylquinic acid and quercetin-7-O-glucoside as the main components. GC/MS analysis demonstrated that the sesquiterpenes τ-cadinol and caryophyllene oxide were only produced in microplants inoculated with endophytic bacteria, while methyl hexadecanoate, methyl heptadecanoate and methyl (Z,Z,Z) 9,12,15-octadecatrienoate and the triterpene methyl 3β-hydroxy-urs-12-en-28-oate were overexpressed only when the microplant was treated with endophytic fungi.

Preparation and immobilization of diNOsarcobalt(III) complex in zeolite y for the catalyzed production of hydrogen peroxide

A complex cation, diNOsarcobalt(III), [Co(diNOsar)]3+, (diNOsar = 1,8-dinitro-3,6,10,13,16,19-hexaazabicyclo-[6.6.6]eicosane), was synthesized and immobilized in the cavities of a Y zeolite by the reaction of precursor species in the pores of the zeolite. The encapsulated material was compared to the compound diNOsarcobalt(III) chloride, [Co(diNOsar)]Cl3. Both diNOsarcobalt(III) chloride and the zeolite-encapsulated complex, [Co(diNOsar)]3+/zeolite, were obtained in high yield and characterized by ultraviolet-visible and infrared spectroscopy. X-ray diffraction demonstrated the incorporation of the complex cation into the pores of the zeolite. The catalytic production of hydrogen peroxide from oxygenated water confirmed the successful synthesis of the complex diNOsarcobalt(III) immobilized in the zeolite.

A new approach to evaluate immobilization of β-galactosidase on Eupergit® C: structural, kinetic, and thermal characterization

This study aimed to evaluate β-galactosidase immobilization. For this purpose, the ionic strength of the buffer, reaction time, amount of the immobilization support, and pH were evaluated by a central composite design. Assay 8, which consisted of 1.5 mol L-1 phosphate buffer (pH 7.5) and a reaction time of 2 h, produced the maximum yield. Eupergit® C (400 mg) was subsequently used as an immobilization support. Immobilization kinetics wereinvestigated, and a significant increase in the yield was obtained after immobilization compared with that obtained from assay 8 (22.0 U mL-1 vs. 15.6 U mL-1). The enzyme efficiency of actuation was evaluated using o-nitrophenyl-β-D-galactopyranoside and lactose, with lactose providing better results. The reuse of β-galactosidase was evaluated, and more than 50% of the initial enzyme activity was maintained after five cycles of use. Enzyme characterization revealed that immobilization improved some aspects of the thermostability of β-galactosidase.

CARBOXYLATION OF SILVER NANOPARTICLES FOR THE IMMOBILIZATION OF β-GALACTOSIDASE AND ITS EFFICACY IN GALACTO-OLIGOSACCHARIDES PRODUCTION

The present study investigated the carboxylation of silver nanoparticles (AgNPs) by 1:3 nitric acid-sulfuric acid mixtures for immobilizing Aspergillus oryzae β-galactosidase. Carboxylated AgNPs retained 93% enzyme upon immobilization and the enzyme did not leach out appreciably from the modified nanosupport in the presence of 100 mmol L-1 NaCl. Atomic force micrograph revealed the binding of β-galactosidase on the modified AgNPs. The optimal pH for soluble and carboxylated AgNPs adsorbed β-galactosidase (IβG) was observed at pH 4.5 while the optimal operating temperature was broadened from 50 ºC to 60 ºC for IβG. Michaelis constant, Km was increased two and a half fold for IβG while Vmax decreases slightly as compared to soluble enzyme. β-galactosidase immobilized on surface functionalized AgNPs retained 70% biocatalytic activity even at 4% galactose concentration as compared to enzyme in solution. Our study showed that IβG produces greater amount of galacto-oligosaccharides at higher temperatures (50 ºC and 60 ºC) from 0.1 mol L-1 lactose solution at pH 4.5 as compared to previous reports.

Efficiency of phylloplane bacteria in controlling aerial tomato diseases under field conditions

The capacity of two bacteria isolated from the tomato phylloplane to control late blight (Phytophthora infestans) was investigated in the field, and compared against the effectiveness of spraying with the fungicide chlorothalonil (1.5 g a.i. L-1) or water (control). A 55% reduction in late blight intensity was observed in the leaves of the middle of the plant and 62% in those of the upper leaves when using the antagonist UFV-STB 6 (Novosphingobium capsulatum) as compared to the control. Isolate UFV-IEA 6 (Bacillus cereus) was able to reduce disease intensity by 55%, but only in the upper leaves of the tomato plants. Treatment with isolate UFV-STB 6 also led to a significant reduction in the percentage of fruits with late blight symptoms. The results demonstrate the potential of these two bacteria in controlling this disease.

Antimicrobial activity of extracellular metabolites from antagonistic bacteria isolated from potato (Solanum phureja) crops

Microorganisms for biological control are capable of producing active compounds that inhibit the development of phytopathogens, constituting a promising tool toob tain active principles that could replace synthetic pesticides. This study evaluatedtheability of severalpotentialbiocontrol microorganismsto produce active extracellular metabolites. In vitro antagonistic capability of 50 bacterial isolates from rhizospheric soils of "criolla" potato (Solanum phureja) was tested through dual culture in this plant with different plant pathogenic fungi and bacteria. Isolates that showed significantly higher antagonistic activity were fermented in liquid media and crude extracts from the supernatants had their biological activities assessed by optical density techniques. Inhibitory effecton tested pathogens was observed for concentrations between 0.5% and 1% of crude extracts. There was a correlation between the antimicrobial activity of extracts and the use of nutrient-rich media in bacteria fermentation. Using a bioguided method, a peptidic compound, active against Fusarium oxysporum, was obtained from the 7ANT04 strain (Pyrobaculum sp.). Analysis by nuclear magnetic resonance and liquid chromatography coupled to mass detector evidenced an 11-amino acid compound. Bioinformatic software using raw mass data confirmed the presence of a cyclic peptide conformed by 11 mostly non-standard amino acids.

Immobilization of Burkholderia cepacia Lipase: Kinetic Resolution in Organic Solvents, Ionic Liquids and in Their Mixtures

Immobilization of Burkholderia cepacia Lipase: Kinetic Resolution in Organic Solvents, Ionic Liquids and in Their Mixtures Biocatalysis opens the door to green and sustainable processes in synthetic chemistry allowing the preparation of single enantiomers, since the enzymes are chiral and accordingly able to catalyze chemical reactions under mild conditions. Immobilization of enzymes enhances process robustness, often stabilizes and activates the enzyme, and enables reuse of the same enzyme preparation in multiple cycles. Although hundreds of variations of immobilization methods exist, there is no universal method to yield the highly active, selective and stable enzyme catalysts. Therefore, new methods need to be developed to obtain suitable catalysts for different substrates and reaction environments. Lipases are the most widely used enzymes in synthetic organic chemistry. The literature part together with the experimental part of this thesis discusses of the effects of immobilization methods mostly used to enhance lipase activity, stability and enantioselectivity. Moreover, the use of lipases in the kinetic resolution of secondary alcohols in organic solvents and in ionic liquids is discussed. The experimental work consists of the studies of immobilization of Burkholderia cepacia lipase (lipase PS) using three different methods: encapsulation in sol-gels, cross-linked enzyme aggregates (CLEAs) and supported ionic liquids enzyme catalysts (SILEs). In addition, adsorption of lipase PS on celite was studied to compare the results obtained with sol-gels, CLEAs and SILEs. The effects of immobilization on enzyme activity, enantioselectivity and hydrolysis side reactions were studied in kinetic resolution of three secondary alcohols in organic solvents, in ionic liquids (ILs), and in their mixtures. Lipase PS sol-gels were shown to be active and stable catalysts in organic solvents and solvent:IL mixtures. CLEAs and SILEs were highly active and enantioselective in organic solvents. Sol-gels and SILEs were reusable in several cycles. Hydrolysis side reaction was suppressed in the presence of sol-gels and CLEAs.

Removal of cyanobacterial toxins by strains of probiotic bacteria

Nedbrytning av blågrönalgtoxiner med hälsobefrämjande mjölksyrebakterier Blomningar av cyanobakterier (blågrönalger) har blivit ett världsomfattande fenomen i eutrofierade vattenmiljöer. Cyanobakterier producerar toxiner, både levergifter och nervgifter, vilka utgör en hälsorisk för människan. Exponeringsrutter omfattar både dricksvatten och förorenade matvaror. Rening av dricksvatten från dessa toxiner är således av hög prioritet. Konventionella vatttenreningsprocesser är inte alltid tillräckligt effektiva mot cyanotoxiner. Därför behövs utveckling av nya effektiva biologiska metoder för vattenrening, vilka kunde komplettera de redan existerande metoderna. FM Sonja Nybom har i sin doktorsavhandling undersökt eliminering av cyanotoxiner från dricksvatten med hjälp av probioter. Probiotiska bakterier, såsom mjölksyrebakterier och bifidobakterier, finns i den naturliga tarmfloran och har även visats ha gynnsamma effekter för människans hälsa. I avhandlingen visades flera olika stammar av probiotiska mjölksyrebakterier och bifidobakterier effektivt eliminera cyanotoxiner, såsom levergiftiga microcystiner, från vatten. Elimineringen undersöktes under olika omständigheter och visades vara beroende av bland annat vattentemperatur, pH, celldensitet och närvaro av kolkälla (glukos) för bakterierna. Metaboliskt aktiva, levande bakterier krävdes för effektiv toxineliminering. En kombination av flera probiotstammar resulterade i effektivare nedbrytning av toxiner i jämförelse med enskilda bakteriestammar. Även reaktionstiden var av betydelse för effektiviteten; efter ett dygns inkubering åstadkoms nästan total nedbrytning. Sammanfattningsvis tyder resultaten på att metoder utnyttjande dessa hälsobefrämjande probiotiska bakterier kunde utvecklas till att användas vid rening av dricksvatten från cyanotoxiner samt användas som en personlig skyddsmekanism mot cyanotoxiner i mag-tarmkanalen.