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Azeem, Muhammad
Publications (3 of 3) Show all publications
Azeem, M., Barba Aliaga, M., Borg-Karlson, A.-K., Terenius, O., Broberg, A. & Rajarao, G. K. (2019). Heterobasidion-growth inhibiting Bacillus subtilis A18 exhibits medium- and age-dependent production of lipopeptides. Microbiology Research, 223-225, 129-136
Open this publication in new window or tab >>Heterobasidion-growth inhibiting Bacillus subtilis A18 exhibits medium- and age-dependent production of lipopeptides
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2019 (English)In: Microbiology Research, ISSN 0944-5013, E-ISSN 1618-0623, Vol. 223-225, p. 129-136Article in journal (Refereed) Published
Abstract [en]

Heterobasidion annosum s.s. and H. parviporum are severe pathogens of conifers causing butt rot and root rot thus reducing the economic value of timber. Here, the antifungal activity of Bacillus subtilis isolate A18 against these two Heterobasidion species was investigated. Five different culture media with different culture age were investigated to study the effect of substrate composition and culture age for metabolite production. Bacterial cultures and cell-free culture filtrates were tested for antifungal activity. Inhibition of fungal growth was analysed using the agar disc-diffusion method. MALDI-TOF and LC-HRMS analyses were used to identify the antifungal metabolites. Substrate composition and age of culture were found to be active variables with direct effect on the antifungal activity of bacterial culture extracts. High anti-fungal activity was observed when B. subtilis was cultured in PDB, SGB and LB media for four days. Mass-spectrometry analysis showed the presence of lipopeptides in culture filtrates identified as members of the surfactins, polymixins, kurstakins and fengycins. A culture filtrate containing fengycin-type lipopeptides showed the highest bioactivity against Heterobasidion species. Bacterial cultures had higher bioactivity compared to their respective cell free culture filtrates. The results of the present study suggest that B. subtilis A18 is a powerful biocontrol agent against Heterobasidion infections of tree wounds and stumps.

Place, publisher, year, edition, pages
Elsevier GmbH, 2019
Keywords
Anti-fungal compounds, Biocontrol, Co-culturing, Conifers, Inhibition, Lipopeptides, Bacteria, Bacteriology, Enzyme inhibition, Forestry, Mass spectrometry, Metabolites, Substrates, Antifungal compounds, Antifungal metabolite, Heterobasidion annosum, Mass spectrometry analysis, Metabolite production, Substrate composition, Fungi, Bacillus subtilis, Bacteria (microorganisms), Coniferophyta, Heterobasidion, Heterobasidion parviporum
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-252448 (URN)10.1016/j.micres.2019.04.006 (DOI)2-s2.0-85065092748 (Scopus ID)
Note

QC 20190715

Available from: 2019-07-15 Created: 2019-07-15 Last updated: 2019-07-15Bibliographically approved
Kännaste, A., Laanisto, L., Pazouki, L., Copolovici, L., Suhorutšenko, M., Azeem, M., . . . Niinemets, Ü. (2018). Diterpenoid fingerprints in pine foliage across an environmental and chemotypic matrix: Isoabienol content is a key trait differentiating chemotypes. Phytochemistry, 147, 80-88
Open this publication in new window or tab >>Diterpenoid fingerprints in pine foliage across an environmental and chemotypic matrix: Isoabienol content is a key trait differentiating chemotypes
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2018 (English)In: Phytochemistry, ISSN 0031-9422, E-ISSN 1873-3700, Vol. 147, p. 80-88Article in journal (Refereed) Published
Abstract [en]

Diterpenoids constitute an important part of oleoresin in conifer needles, but the environmental and genetic controls on diterpenoid composition are poorly known. We studied the presence of diterpenoids in four pine populations spanning an extensive range of nitrogen (N) availability. In most samples, isoabienol was the main diterpenoid. Additionally, low contents of (Z)-biformene, abietadiene isomers, manoyl oxide isomers, labda-7,13,14-triene and labda-7,14-dien-13-ol were quantified in pine needles. According to the occurrence and content of diterpenoids it was possible to distinguish ‘non diterpenoid pines’ ‘high isoabienol pines’ ‘manoyl oxide – isoabienol pines’ and ‘other diterpenoid pines’. ‘Non diterpenoid pines’ ‘high isoabienol pines’ and ‘other diterpenoid pines’ were characteristic to the dry forest, yet the majority of pines (>80%) of the bog Laeva represented ‘high isoabienol pines’. ‘Manoyl oxide – isoabienol pines’ were present only in the wet sites. Additionally, orthogonal partial least-squares analysis showed, that in the bogs foliar nitrogen content per dry mass (NM) correlated to diterpenoids. Significant correlations existed between abietadienes, isoabienol and foliar NM in ‘manoyl oxide – isoabienol pines’ and chemotypic variation was also associated by population genetic distance estimated by nuclear microsatellite markers. Previously, the presence of low and high Δ-3-carene pines has been demonstrated, but the results of the current study indicate that also diterpenoids form an independent axis of chemotypic differentiation. Further studies are needed to understand whether the enhanced abundance of diterpenoids in wetter sites reflects a phenotypic or genotypic response.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Chemotypic variability, Diterpenoids, Isoabienol, N content, Pinus sylvestris L., Terpenoid signatures
National Category
Forest Science
Identifiers
urn:nbn:se:kth:diva-220957 (URN)10.1016/j.phytochem.2017.12.007 (DOI)000425562300009 ()2-s2.0-85039861742 (Scopus ID)
Note

QC 20180111

Available from: 2018-01-11 Created: 2018-01-11 Last updated: 2018-03-13Bibliographically approved
Albabtain, R., Azeem, M., Wondimu, Z., Lindberg, T., Borg-Karlson, A.-K. & Gustafsson, A. (2017). Investigations of a Possible Chemical Effect of Salvadora persica Chewing Sticks. Evidence-based Complementary and Alternative Medicine, Article ID 2576548.
Open this publication in new window or tab >>Investigations of a Possible Chemical Effect of Salvadora persica Chewing Sticks
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2017 (English)In: Evidence-based Complementary and Alternative Medicine, ISSN 1741-427X, E-ISSN 1741-4288, article id 2576548Article in journal (Refereed) Published
Abstract [en]

Salvadora persica is commonly used chewing sticks in many parts of the world as an oral hygiene tool. This study measured the amount of benzyl isothiocyanate (BITC) released into the mouth and assessed its retention time in saliva. The study also tested if the released amount of BITC could potentially be antibacterial or cytotoxic. Twelve subjects brushed their teeth with fresh Miswak once, twice, and four times. The amount of BITC in the saliva and in the used brushes was quantified using gas chromatography-mass spectrometry. The antibacterial effect of BITC and Miswak essential oil (MEO) was tested against Haemophilus influenzae, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. The cytotoxic effect on gingival fibroblasts and keratinocytes was tested using MTT. The highest amount of the active compounds was detected in saliva after using the Miswak tip for once and immediately. It significantly decreased when the Miswak tip was used more than once and thus after 10 min. The growth of the tested bacteria was inhibited by MEO and BITC in a dose dependent manner, P. gingivalis being the most sensitive. MTT assay showed that BITC and MEO were cytotoxic towards gingival fibroblasts while oral keratinocytes showed resistance. This study suggests that the Miswak tip should be cut before each use to ensure the maximum effect.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2017
National Category
Other Medical Sciences
Identifiers
urn:nbn:se:kth:diva-208281 (URN)10.1155/2017/2576548 (DOI)000399374500001 ()2-s2.0-85018944736 (Scopus ID)
Note

QC 20170609

Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2017-06-09Bibliographically approved
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