| 1. |
- Boija, Susanne, et al.
(author)
-
Determination of conditional stability constants for some divalent transition metal ion-EDTA complexes by electrospray ionization mass spectrometry
- 2014
-
In: Journal of Mass Spectrometry. - : Wiley. - 1076-5174 .- 1096-9888. ; 49:7, s. 550-556
-
Journal article (peer-reviewed)abstract
- Conditional stability constants of coordination complexes comprising divalent transition metals, Cu2+, Ni2+, Zn2+, Co2+, and ethylenediaminetetraacetic acid (EDTA) were determined utilizing electrospray ionization mass spectrometry. The deviation of signal response of a reference complex was monitored at addition of a second metal ion. The conditional stability constant for the competing metal was then determined through solution equilibria equations. The method showed to be applicable to a system where Co2+ and Zn2+ competed for EDTA at pH 5. When Cu2+ and Ni2+ competed for EDTA, the equilibrium changed over time. This change was shown to be affected in rate and size by the type of organic solvent added. In this work, 30% of either methanol or acetonitrile was used. It was found that if calibration curves are prepared for both metal complexes in solution and the measurements are repeated with sufficient time space, any change in equilibrium of sample solutions will be discovered. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.
|
|
| 2. |
- Ljunggren, Joel, et al.
(author)
-
Antifungal efficiency of individual compounds and evaluation of non-linear effects by recombining fractionated turpentine
- 2020
-
In: Microchemical journal (Print). - : Elsevier BV. - 0026-265X .- 1095-9149. ; 153
-
Journal article (peer-reviewed)abstract
- A combination between a reductive and a holistic assay was employed to investigate whole fraction, synergistic, antagonistic and individual compound efficacy of vacuumdistilled turpentine fractions against the economically important brown-rot fungus Coniophora puteana. The fungus was subjected to recombinations of turpentine fractions at a concentration of 1000 ppm. All combinations exhibited useful antifungal properties, but some antifungal mixtures showed a more pronounced effect than the expected level of inhibition. Synergistic effects by a two-fold factor and minor antagonistic effects were observed. Complete growth inhibition of C. puteana was observed by a fraction obtained after distilling 1 L turpentine at 111–177°C (0.5 mbar) as well as by mixing it with another fraction withdrawn at 70–79°C (0.5 mbar). Chemical compositions of distilled fractions were determined through GC–MS analysis and Orthogonal Partial Least Squares (OPLS) multivariate data analysis of GC–MS chromatograms was employed to zoom in on the most active compounds responsible for antifungal activity. Isomers of epicubenol, the hydrocarbon aromatic compound ar-himachalene and α-cadinol are suggested as effective antifungal compounds. In addition, a subsequent fractionation of the most effective fraction was performed with preparatory gas chromatography and subfractions showed similar or better efficacy than previously observed. Our work demonstrates the possibility to retain adequate synergistic antifungal efficiency and offers an opportunity to explore the effects of individual compounds originating from the same crude sample.
|
|
| 3. |
- Ljunggren, Joel
(author)
-
Biochemical Interactions of Some Saproxylic Fungi
- 2015
-
Licentiate thesis (other academic/artistic)abstract
- Interactions are all around us, and as humans we may use words and gestures to communicate our intentions. At the micro level of fungi, communications are replaced by chemical signals and structure. These interactions fall into three distinctive categories: synergistic, where organisms help each other, as is the case with ectomycorrhizal fungi and tree roots, deadlock, or combat, where organisms fight for or defend a resource. When it comes to fungi-tree interactions, the fungi group of basidiomycetes fall into the latter category. At the onset of fungal infection, a living tree defends itself by producing resinous substances such as terpenes. These compounds are frequently found in hydrodistilled turpentine, which makes turpentine a prime source of antifungal compounds. A D-optimal design of fractionated turpentine together with gas chromatography (GC) coupled to a mass spectrometer was employed to find the most biologically active constituent of turpentine. Growth rate of Coniophora puteana was used to assess the efficacy of the mixed fractions. The partial least squares projection model had an excellent predictive power (R2 = 0.988, Q2 = 0.825) and validity. A putative sesquiterpene was identified as the most active compound for inhibiting fungal growth. The model was corroborated by an external validation assay employing preparative GC. After the death of a tree, fungi are no longer hindered by secondary metabolites from the tree. Instead, other interspecies interactions and intraspecies interactions, such as fungi-fungi interactions, occur. We found that when the white-rot fungus Heterobasidion parviporum and brown-rot fungus Gloeophyllum sepiarium interact with each other, amino acids are used to a higher extent. Amino acids may be used to produce antifungal compounds to hinder the other species from growing. Lysine in particular was utilized to a greater extent during interaction. Glutamine was the only amino acid that increased in concentration. Glutamine might be exuded or converted by enzymes from already existing glutamic acid. Dry weights suggest that the fungi were in a deadlock and that nutrient limitation might be a determining factor. It seemed that H. parviporum was favoured by a decrease in pH while the opposite pattern may be true for G. sepiarium.
|
|
| 4. |
- Ljunggren, Joel, et al.
(author)
-
Changes in Extracellular Amino Acids, pH and Growth when Fungi Interact at the Near-contact Level: Heterobasidion parviporum vs. Gloeophyllum sepiarium
-
Other publication (other academic/artistic)abstract
- Heterobasidion parviporum and Gloeophyllum sepiarium are fungal species representing two different ecological niches. H. parviporum is a parasitic white-rot fungus and early colonizer of felled wood, while the brown-rot fungus G. sepiarium is an early-middle colonizer in the natural fungi succession order. In this study, we quantitatively examined the utilization of amino acids in the μM range, pH and final dry weight from common liquid glucose-malt extract medium when the two fungi were interacting at the near-contact level. An increase in glutamine concentration was observed, and lysine was utilized in a greater extent when fungi were interacting compared to when they grew on their own. Our results also show fungal interaction is a process with high variability both in pH, growth and amino acid utilization, depending on the type of interaction. A connection between the growth, according to dry weight, and pH is suggested in the interaction between H. parviporum and G. sepiarium.
|
|
| 5. |
- Ljunggren, Joel, et al.
(author)
-
Combinatorial Retention-Activity Relationship of Fractionated Turpentine on Fungal Growth
-
Other publication (other academic/artistic)abstract
- Essential oils from plants are often used in growth inhibition assays against bacteria, fungi, insects and viral infections. Turpentine from Norway spruce (Picea abies) is an essential oil produced in large quantities as a waste product in paper production. It is a complex mixture of secondary metabolites that is rich in terpenes and terpenoids. These compounds protect the tree from fungal and bacterial infection; turpentine should therefore be a good source for biologically active substances for inhibiting fungal growth. In this study, a combination of a reductive and a holistic approach was employed to find the most inhibiting compound; an approach that we have called an intermistic approach. The most inhibiting compounds was determined in three steps against growth of the saproxylic fungus Coniophora puteana: rejecting half of the turpentine search space in a reductive manner, finding the optimal concentration and finally combining fractions of the most active half of turpentine in a quadratic D-optimal design to investigate it holistically. Multivariate data analysis of gas chromatography coupled with mass spectrometry (GC-MS) chromatograms was used to zoom in on the most active compounds responsible for antifungal activity. The growth rate of C. puteana in mm/day was used as y-variable and the relative area percentage of 36 GC-MS peaks from the mixtures was used as x-variables to construct a partial least squares (PLS) regression model. The final model was reduced to 12 peaks and used to find the most promising antifungal compound within the mixture. In addition, an external validation was performed with preparatory GC on the most active fraction. From the model, one putative sesquiterpene was identified along with at least two other sesquiterpenes and one diterpene warrant further investigation. Herein, a general method for finding biologically active compounds against wood-rotting fungi, and potentially other organisms from a complex mixture, is proposed.
|
|
| 6. |
- Ljunggren, Joel, et al.
(author)
-
Evaluation of fractionally distilled Picea abies TMP-turpentine on wood-decaying fungi : in vitro, microcosm and field experiments
- 2020
-
In: Wood Science and Technology. - : Springer Science and Business Media LLC. - 0043-7719 .- 1432-5225. ; 54, s. 847-868
-
Journal article (peer-reviewed)abstract
- Synthetic and heavy metal antifungals are frequently used as wood preservatives. However, they exhibit relatively inert biodegradation and toxic properties when leached; this makes their replacement with environmentally degradable yet functional alternatives a key target in the wood protection industry. In this context, distilled fractions of raw thermomechanical pulp turpentine (TMP-T) from Picea abies were assessed for their wood protecting capabilities against wood-decaying fungi. Antifungal bioactivity of fractions and some of their combinations were screened on agar-plates against the brown-rot fungus Coniophora puteana. Addition of TMP-T fractions showed a significant fungal growth rate reduction, while mixtures indicated the presence of synergistic and antagonistic effects. One fraction, obtained after distilling 1 L TMP-T at 111–177 °C at 0.5 mbar, showed complete growth inhibition of Antrodia sinuosa, Serpula lacrymans, Serpula himantioides and significant inhibition of Antrodia serialis, Antrodia xantha, Gloeophyllum sepiarium, Heterobasidion parviporum at a concentration of 1000 ppm. This fraction was further examined for long- and medium-term effects on wood decay in microcosm soil-jar and field experiment, respectively. The known antifungal compounds benzisothiazolinone, 2-octyl-4-isothiazolin-3-one, 3-iodo-2-propynyl N-butylcarbamate and two commercial wood preservatives were used as reference treatments. Commercial preservatives instilled long-term efficacy against C. puteana wood decay in a soil-jar microcosm experiment, but no noticeable protection with antifungal compounds or the present treatments was found. However, a moderate effect by the TMP-T fraction from the in vitro assay was observed and the TMP-turpentine distillation residue showed a similar fungal inhibition effect to the most potent commercial treatment after 29 months in the field.
|
|
| 7. |
|
|
| 8. |
- Svanedal, Ida, 1979-, et al.
(author)
-
Metal Ion Coordination, Conditional Stability Constants and Solution Behavior of Chelating Surfactant Metal Complexes
- 2014
-
In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 30:16, s. 4605-4612
-
Journal article (peer-reviewed)abstract
- Coordination complexes of some divalent metal ions with the DTPA (diethylenetriaminepentaacetic acid)-based chelating surfactant 2-dodecyldiethylenetriaminepentaacetic acid (4-C12-DTPA) have been examined in terms of chelation and solution behavior. The headgroup of 4-C 12-DTPA contains eight donor atoms that can participate in the coordination of a metal ion. Conditional stability constants for five transition metal complexes with 4-C12-DTPA were determined by competition measurements between 4-C12-DTPA and DTPA, using electrospray ionization mass spectrometry (ESI-MS). Small differences in the relative strength between the coordination complexes of DTPA and 4-C12-DTPA indicated that the hydrocarbon tail only affected the chelating ability of the headgroup to a limited extent. The coordination of Cu2+ ions was investigated in particular, using UV-visible spectroscopy. By constructing Job's plots, it was found that 4-C12-DTPA could coordinate up to two Cu2+ ions. Surface tension measurements and NMR diffusometry showed that the coordination of metal ions affected the solution behavior of 4-C 12-DTPA, but there were no specific trends between the studied divalent metal complexes. Generally, the effects of the metal ion coordination could be linked to the neutralization of the headgroup charge of 4-C 12-DTPA, and the resulting reduced electrostatic repulsions between adjacent surfactants in micelles and monolayers. The pH vs concentration plots, on the other hand, showed a distinct difference between 4-C12-DTPA complexes of the alkaline earth metals and the transition metals. This was explained by the difference in coordination between the two groups of metal ions, as predicted by the hard and soft acid and base (HSAB) theory.
|
|
