Antibiotic Activity of Actinomycetes Isolated from Young Tectona Grandis (L.) Wood and Pith

Actinomycetes are a source for novel bioactive compounds and justify obtaining new species from various sources. Hardwoods such as Tectona grandis (L.) have not been studied for actinomycete isolation. We aim to isolate endophytic actinomycetes from young Tectona grandis wood and pith and screen for antibiotic activity. Five young wood were cut and surface sterilized using ethanol and hypochlorous acid. The wood and pith of each sample are placed in eight plates of Humic acid-vitamin B (HV), Tap water Yeast extract (TWYE), and Yeast Extract Casein Digest (YECD) medium and incubated at 27°C for four weeks. Actinomycetes were isolated from such medium, observed every week, and transferred to an International Streptomyces Project-2 (ISP-2) medium for identification and antibiotic production tested against Staphylococcus aureus, Helicobacter pylori, and Escherichia coli using the Kirby-Bauer method. Seven actinomycetes were isolated from the wood, primarily from YECD and TWYE media, with varying morphological characteristics. One isolate having maroon-colored aerial and vegetative mycelium with grey spores showed moderate antibacterial activity against S. aureus and H. pylori (13.49±1.03 mm and 14.9±0.7 mm, respectively), while two other actinomycetes showed weak activity against these bacteria. However, none of the actinomycetes show any activity against E. coli. Tectona grandis (L.) is a potential source for novel actinomycetes with an antibiotic activity which warrants further exploration

Dianthiamides A–E, Proline-Containing Orbitides from Dianthus chinensis

Orbitides are plant-derived small cyclic peptides with a wide range of biological activities. Phytochemical investigation of the whole plants of Dianthus chinensis was performed with the aim to discover new bioactive orbitides. Five undescribed proline-containing orbitides, dianthiamides A–E (1–5), were isolated from a methanolic extract of Dianthus chinensis. Their structures were elucidated by extensive analysis of 1D and 2D NMR and HRESI–TOF–MS as well as ESI–MS/MS fragmentation data. The absolute configuration of the amino acid residues of compounds 1–5 was determined by Marfey’s method. All compounds were tested for their cytotoxic activity, and dianthiamide A (1) exhibited weak activity against A549 cell line with IC50 value of 47.9 μM.

Bioprospection of Enggano Macroscopic Fungi as Antibacterial and Antioxidant Agents

Macrofungi in Indonesia have not been widely studied for their pharmacological activity, especially as a source of antibacterial and antioxidant properties, even though Indonesia as a tropical country has quite a high diversity of macrofungi. This study aims to reveal the potential of macrofungi from the Enggano forest as a source of antibacterial and antioxidant compounds. Four types of macrofungi were collected and their metabolites were extracted using four types of organic solvents. Antibacterial and antioxidant activity assay of the extract was carried out using the TLC Bioautography method. From the sixteen macrofungal extracts, there is one extract that has the strongest antibacterial activity compared to the others, namely n-hexane Coriolopsis polyzona. It showed moderate antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC values of 256–128 μg/mL, respectively. Meanwhile, the antioxidant activity of the macrofungal extracts showed weak activity with IC50 values of 3080–7370 μg/mL (AAI values of 0.033–0.079).

Multifunctional and Durable Coatings for Stone Protection Based on Gd-Doped Nanocomposites

The development of nanocomposite materials with multifunctional protective features is an urgent need in many fields. However, few works have studied the durability of these materials. Even though TiO2 nanoparticles have been extensively applied for self-cleaning effect, it displays a weak activity under visible light. Hence, in this study, pure and Gd-doped TiO2 nanoparticles (molar ratios of doping ions/Ti are 0.1 and 1) were synthesised, characterised, and then mixed with polydimethylsiloxane (PDMS), used as a binder, in order to produce a homogenised thin film on a very porous stone substrate. To our knowledge, Gd-doped TiO2/PDMS protective coatings are studied for the first time for application on historic structures. The protective coatings developed in this work are intended to reduce the surface wettability of the stone and protect the historic stones from dye pollution and microorganism colonisation. Moreover, in this study, the durability of the developed nanocomposite was deeply studied to evaluate the stability of the coatings. Results confirmed that samples treated with the lowest concentrations of Gd ions (0.1 mol%) showed acceptable chromatic variations, a good repellent feature, acceptable water vapour permeability, good durability, the highest self-cleaning activity, and good inhibitory behaviour against microbial colonisation.

Oxidation Modification of Fuorinated Graphite and Its Reaction Mechanism

In this paper, Hummers method was used to oxidize fluorinated graphite in order to study the modification mechanism. The chemical composition and microstructure of the products before and after the reaction were characterized and analyzed. Oxidized fluorinated graphite (OFG) obtained by oxidation has a thin layered structure and different oxygen content. The main mechanism of KMnO4 modification is that MnO3+ with Lewis acid property can catalyze the activation of the fluorocarbon bond, which breaks to form F ion. At the same time, the unsaturated carbon bond is oxidized, resulting in the increase of carbon oxygen bond content and the generation of some OFG nano fragments. With the increase in KMnO4 dosage, the fluorocarbon bond will be gradually catalyzed to react according to its activity while the unsaturated carbon bond is oxidized, finally there are still some isolated fluorocarbon bonds with weak activity.

Crystallisation and polymorph selection in active Brownian particles

We explore crystallisation and polymorph selection in active Brownian particles with numerical simulation. In agreement with previous work (Wysocki et al. in Europhys Lett 105:48004, 2014), we find that crystallisation is suppressed by activity and occurs at higher densities with increasing Péclet number ($${ Pe }$$ Pe ). While the nucleation rate decreases with increasing activity, the crystal growth rate increases due to the accelerated dynamics in the melt. As a result of this competition, we observe the transition from a nucleation and growth regime at high $${ Pe }$$ Pe to “spinodal nucleation” at low $${ Pe }$$ Pe . Unlike the case of passive hard spheres, where preference for FCC over HCP polymorphs is weak, activity causes the annealing of HCP stacking faults, thus strongly favouring the FCC symmetry at high $${ Pe }$$ Pe . When freezing occurs more slowly, in the nucleation and growth regime, this tendency is much reduced and we see a trend towards the passive case of little preference for either polymorph.

Bioactivity Study of Thiophene and Pyrazole Containing Heterocycles

Chalcones3a-fwere prepared by reacting thiophene containing pyrazolyl aldehyde (2) with different 2-hydroxy acetophenones 1a-f. The compounds3a-f were transformed into different Pyrazolines 4a-f. The formation of chromene derivatives 5a-f occurred from the cyclization of 3a-f, which were then transformed into pyrazole derivatives 6a-f. Newly synthesized compounds have promising antibacterial activity against S.typhii and S.aureus, while weak activity against B.subtilis and E.coli. Compounds 5d and 6d had significant antifungal action towardsA. niger, while most of the compounds were moderately active towards T.viride. Some of the synthesized compounds showed promising α-amylase inhibitory activity at 1 mg/mL concentration.

Antimycobacterial cycloartane derivatives from the roots of Trichilia welwistchii C. DC (Meliaceae)

Chemical investigation of the roots of Trichilia welwitschii yielded a cycloartane type terpenoid 28,29-bis-norcycloart-24-en-3β,4α,6α-triol (1), isolated as pure compound for the first time, three coumarins and three sterols. New cycloartane derivatives (1a) and (1b+1c) were obtained by hemi-synthetic reaction of compound 1. The structures of 1a–c were established by spectroscopic methods including 1D and 2D-NMR analysis, HR-EIMS, chemical transformations and by comparison of these data with those of related compounds. Evaluated for their antimycobacterial potential, compound 1 and 1b+1c were determined to show significant activities against Mycobacterium tuberculosis MIC values of 6.25 μg mL−1 while compound 1a displayed weak activity showing MIC > 100 μg mL−1. Compounds 2–4 displayed moderate activity with MIC values range from 12.5 to 50 μg mL−1.

Antimycobacterial Activity of the Extract and Isolated Compounds From the Stem Bark of Zanthoxylum leprieurii Guill. and Perr.

Zanthoxylum leprieurii Guill. and Perr. (Rutaceae) stem bark is used locally in Uganda for treating tuberculosis (TB) and cough-related infections. Lupeol (1), sesamin (2), trans-fagaramide (3), arnottianamide (4), ( S)-marmesinin (5), and hesperidin (6) were isolated from the chloroform/methanol (1:1) extract of Z. leprieurii stem bark. Their structures were elucidated using spectroscopic techniques and by comparison with literature data. Furthermore, the extract and isolated compounds were subjected to antimycobacterial activity. The extract exhibited moderate activity against the susceptible (H37Rv) TB strain, but weak activity against the multidrug resistant (MDR)-TB strain with minimum inhibitory concentrations (MICs) of 586.0 and 1172.0 μg/mL, respectively. Compound 3 (trans-fagaramide) showed significant antimycobacterial activity against the susceptible (H37Rv) TB strain (MIC 6 μg/mL), but moderate activity against the MDR-TB strain (MIC 12.2 μg/mL). Compounds 2, 5, 6, and 1 showed moderate activities against the susceptible (H37Rv) strain (MIC 12.2-98.0 μg/mL) and moderate to weak activities against the MDR-TB strain (MIC 24.4-195.0 μg/mL). This study reports for the first time the isolation of compounds 1 to 6 from the stem bark of Z leprieurii. trans-Fagaramide (3) may present a vital template in pursuit of novel and highly effective TB drugs.

Two Fusarium copper radical oxidases with high activity on aryl alcohols

Background Biomass valorization has been suggested as a sustainable alternative to petroleum-based energy and commodities. In this context, the copper radical oxidases (CROs) from Auxiliary Activity Family 5/Subfamily 2 (AA5_2) are attractive biocatalysts for the selective oxidation of primary alcohols to aldehydes. Originally defined by the archetypal galactose 6-oxidase from Fusarium graminearum, fungal AA5_2 members have recently been shown to comprise a wide range of specificities for aromatic, aliphatic and furan-based alcohols. This suggests a broader substrate scope of native CROs for applications. However, only 10% of the annotated AA5_2 members have been characterized to date. Results Here, we define two homologues from the filamentous fungi Fusarium graminearum and F. oxysporum as predominant aryl alcohol oxidases (AAOs) through recombinant production in Pichia pastoris, detailed kinetic characterization, and enzyme product analysis. Despite possessing generally similar active-site architectures to the archetypal FgrGalOx, FgrAAO and FoxAAO have weak activity on carbohydrates, but instead efficiently oxidize specific aryl alcohols. Notably, both FgrAAO and FoxAAO oxidize hydroxymethyl furfural (HMF) directly to 5-formyl-2-furoic acid (FFCA), and desymmetrize the bioproduct glycerol to the uncommon L-isomer of glyceraldehyde. Conclusions This work expands understanding of the catalytic diversity of CRO from AA5_2 to include unique representatives from Fusarium species that depart from the well-known galactose 6-oxidase activity of this family. Detailed enzymological analysis highlights the potential biotechnological applications of these orthologs in the production of renewable plastic polymer precursors and other chemicals.