Search

Aims: The aim of the study was to evaluate the in vitro antioxidant, antimicrobial and immunomodulatory activities of facial serum that was formulated with Melaleuca cajuputi essential oil (MCEO). Methodology and results: The MCEO was obtained from the leaves of M. cajuputi and it was added into facial serum formulations in different concentrations (1%, 2% and 4%, v/v). The antioxidant potential of the formulated facial serum was evaluated using a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. The time-kill assay was used to test the antimicrobial activity kinetics of different facial serum formulations against Cutibacterium acnes. The immunomodulatory activities of the formulations were tested using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, cytokine assay and Griess assay. The MCEO-formulated facial serum showed significantly higher (p<0.05) antioxidant activity at 2% (v/v) and 4% (v/v) when compared to the facial serum without MCEO. Time-kill kinetic assay had shown the MCEO formulated facial serum (1%, 2% and 4%, v/v) exhibited a bactericidal effect against C. acnes in a concentration-dependent manner after 4-8 h. MCEO formulated facial serum at concentrations of 1%, 2% and 4% (v/v) significantly enhanced (p<0.05) the viability of the macrophages after 48 h. The level of cytokines such as IFNγ, TNFα, TGFβ1, IL6, IL17 and IL23 was significantly high (p<0.05) in the treated macrophages at a concentration of 4%. Macrophages treated with MCEO-formulated facial serum at 4% concentration exhibited significantly higher nitric oxide production (p=0.018) than the untreated macrophages. Conclusion, significance and impact of study: MCEO-formulated facial serum possesses antioxidant, antimicrobial and immunomodulatory activities. This study highlights MCEO as a potential natural ingredient in facial serum formulations for cosmeceutical industries. [ABSTRACT FROM AUTHOR]

Melaleuca williamsii subsp. synoriensis (Myrtaceae) has been found in Rome (central Italy) along the banks of the river Tevere, representing the first discovery outside its native range (E-Australia). Description, distribution in Italy, phenology, and original photographs are provided. [ABSTRACT FROM AUTHOR]

In the restoration of drained and degraded tropical peat swamp forest (PSF) it is not well understood whether fire suppression on its own is sufficient to facilitate regeneration, or if rewetting plays a key role. We attempt to answer this question in the Merang area, a 23,000-ha peatland located in South Sumatra province, Indonesia. As with more than 90 % of PSF in Southeast Asia, the area has been largely degraded by logging and drainage canals, along with multiple fires. It has been designated and managed as an ecosystem restoration area since 2016, by which time only a single 254 ha patch of original PSF habitat remained. However, scattered remnant PSF trees (< 1 % cover) occurred throughout the area, along with seedlings of pioneer woody species in a landscape otherwise dominated by sedges and ferns. Peatland rehabilitation began with installation of 84 box dams in 2017, followed by 212 peat compaction dams mainly between late 2019 and early 2020. Since installation of the latter, the average water table depth (WTD) has decreased by 20–120 cm. In parallel with reduced WTD and fire prevention, regrowth has been vigorous, with total cover of woody plants increasing by almost a third, from 28.6 % in 2016 to 39.4 % in 2021. At the same time, changes in normalised difference vegetation index (NDVI) indicate a doubling in increase of woody vegetation cover between 20172020 and 20202021. Reduced WTD supports the recovery of woody vegetation cover, but Principal Component Analysis (PCA) strongly suggests that fire history determines the species composition of regenerated woody pioneer vegetation. Melaleuca cajuputi dominates where fires have been most frequent (on average > 4 fires), while Macaranga pruinosa, Melicope glabra and Melicope lunu-ankenda dominate in regenerating areas that have experienced 12 fires. While fire suppression is essential to prevent further loss of vegetation, effective rewetting is required before woody vegetation can recover.

Key message: We examined leaves of a suite of microphyllous woody plants and describe a little-known form of leaf peltation for the first time and also investigate strongly reflexed leaves in two distantly related lineages. Plants cope with a range of environmental conditions, especially related to water relations, and have developed an array of physiological and structural solutions to maintain a functional water balance. There has been considerable recent work on physiological solutions to water deficit but little attention paid to leaf characteristics. In many species there is a change in leaf form from seedlings to adults. We examine such changes in several small-leaved species from the distantly related Asteraceae and Myrtaceae, some of which develop micropeltate or reflexed leaves as adults. All are native to dry or seasonally dry sites. Three major morphological groups were recognised as follows: (1) leaves erect, nonpeltate and scale-like (Ozothamnus hookeri), (2) leaves erect and peltate (Phaenocoma prolifera, Regelia inops), (3) Leaves reflexed (Olearia lepidophylla, Ozothamnus scutellifolius, Ozothamnus reflexifolius, Melaleuca diosmifolia). The microphyllous peltation in P. prolifera and R. inops in the absence of a meristematic fusion/bridge differs from typically peltate leaves. These small-leaved taxa occur in open, high light environments which are very different from the mesic, shaded understorey habitats of typical peltate-leaved plants. Many small-leaved species have leaves closely appressed to the stem and often with recurved margins. The erect leaves are functionally similar to reflexed leaves. Environmental filtering leads to superficially similar plant forms that may have somewhat different ontological origins. Such morphological forms are examples of convergent evolution in distantly related species but within each family are likely phylogenetically related. [ABSTRACT FROM AUTHOR]

Trees with a decreasing level of health and structure can become a threat to life and property if they are not properly managed. Thus, a regular visual tree assessment (VTA) is essential to monitor the trees' conditions. A recent assessment, July 2022, by VTA on an existing Melaleuca citrina in the Forest Research Institute Malaysia (FRIM) showed poor canopy growth colonised by parasitic plants with the emergence of fruiting bodies (conk or mushroom) on its trunk, indicating internal wood decay. Tree inspection using an advanced approach of PiCUS Sonic Tomograph (PiCUS) was performed to evaluate the severity of the decayed trunk. As a non-invasive method, PiCUS measures the wood deterioration in trees using sound wave velocity that moves through the density of the wood. The thicknesses of the residual wall of trees with internal defects were recorded as colour-coded tomograms. The results were then compared with previous observations in the year 2017. The soil penetration test, pH and "The Jar Test" were also adopted to analyse soil properties and condition around the tree. The tomogram images showed an increased percentage of decay from 2017 to 2022 of approximately 2 to 78%, respectively. The sound wood also decreased from 82 to 14% for the respective period. The soil is categorised as silt loamy with pH value of 5.6 to 6.4 while the soil penetration test exceeds a value of 2.06 MPa, which restricts the root growth. This information is vital for further maintenance of urban trees and very useful for managerial decisions. [ABSTRACT FROM AUTHOR]

The formation of acid mine drainage (AMD) is a common environmental problem in the mining industry. Its passive management through wetland construction has gained more consideration in recent years. However, the application in the field is constrained by the large area and relatively shallow depth. Indonesia has no passive technology to neutralize AMD in deep water. One solution is to apply a floating treatment wetland (FTW) system. Therefore, this study aimed to determine the ability of several hyperaccumulator plants, such as Melaleuca cajuputi, Nauclea orientalis, and Vetiveria zizanioides, to neutralize AMD using a floating system by conducting FTW trials. The method used was a Completely Randomized Design (CRD) with 3 treatments and control/without plants. Each treatment had 3 replications, resulting in 12 experimental units. The results showed that the FTW with or without plants could increase pH and decrease dissolved Mn by 75.31-90.74%. Heavy metals were chelated by organic matter, absorbed by plants, and deposited in the form of metal sulfides. The results also indicated that besides having a positive effect on pH and heavy metal reduction, the organic-based floating wetland increased biological oxygen demand (BOD) from 61.08-79.71%. [ABSTRACT FROM AUTHOR]

Context: Melaleuca quinquenervia is a widespread, keystone species of eastern Australian coastal forested wetlands. Populations of M. quinquenervia in the fringes of Myall Lakes, New South Wales, Australia exhibit low numbers of juveniles, infrequent recruitment and a dominance of mature individuals, raising concerns about stand replacement from conservation managers. In contrast, M. quinquenervia often recruits in large numbers and is highly invasive in wetlands around the world. Aims: To explore factors that limit recruitment of M. quinquenervia within its native range. Methods: Field deployed seed traps; soil-core sampling; a burial longevity trial and depth of emergence experiment; laboratory temperature, salinity and light germination experiments; a transplantation experiment; monitoring of field germination; and a litter/leachate experiment. Key results: Low seed viability (5–26%) is offset by high canopy seed loads (250 000 to 120 million seeds per tree) released continuously throughout the year with a peak fall in summer (2000 to 5000 viable seeds per m2 per month), coinciding with optimal germination temperatures. Seedling emergence is reduced below 5 mm soil depth, there is a very low soil seedbank reserve, and germination is light-dependant. M. quinquenervia exhibited reduced germination percentage and rate as well as reduced survival of seedlings at salinities higher than 15 dS m−1 EC (electrical conductivity). The most favourable sites for seedling establishment are permanently moist with low salinity, protected from wave action via sedge vegetation, and sheltered from prevailing winds. There is an inhibitory effect of Casuarina leachate on germination. Conclusions: Germination in the field is episodic, and tied to specific environmental conditions. Highest losses occur at the seedling establishment phase. Implications: Future research avenues and management recommendations are provided. Germination of M. quinquenervia in the field is episodic, and tied to specific environmental parameters. High losses occur at the seedling establishment phase. A series of laboratory- and field-based investigations showed that the most favourable sites for recruitment are permanently moist, with salinity lower than 15 dS m−1, sheltered from wave action and desiccation. There is an inhibitory effect of Casuarina leachate on germination. [ABSTRACT FROM AUTHOR]

Abstract Bovine infectious mastitis is largely resistant to antibacterial treatment, mainly due to mechanisms of bacterial resistance in the biofilms formed by Staphylococcus aureus. Melaleuca (MEO) and citronella essential oils (CEO) are promising agents for reducing or eliminating biofilms. Free melaleuca oil presented a medium Minimum Inhibitory Concentration (MIC) of 0.625% and a Minimum Bactericidal Concentration (MBC) of 1.250%, while free citronella oil showed medium MIC and MBC of 0.313%. Thus, free CEO and MEO demonstrate bacteriostatic and bactericidal potential. We generated polymeric nanocapsules containing MEO or CEO and evaluated their efficacy at reducing biofilms formed by S. aureus. Glass and polypropylene spheres were used as test surfaces. To compare the responses of free and encapsulated oils, strains were submitted to 10 different procedures, using free and nanoencapsulated essential oils (EOs) in vitro. We observed no biofilm reduction by MEO, free or nanoencapsulated. However, CEO nanocapsules reduced biofilm formation on glass (p=0.03) and showed a tendency to diminish biofilms on polypropylene (p=0.051). Despite nanoencapsulated CEO reducing biofilms in vitro, the formulation could be improved to modify the CEO component polarity and, including MEO, to obtain more interactions with surfaces and the biofilm matrix.

Restoring degraded agricultural lands to their original coastal wetland cover is an approach for enhancing blue carbon storage. This approach enhances carbon sequestration in biomass and soils whilst reducing greenhouse gas emissions and delivering other conservation benefits such as enhancing biodiversity, improving water quality, and protecting coastlines from sea level rise. In Queensland, Australia, tens of thousands of hectares of coastal land have been converted to agriculture since the 1900s, often through drainage. We evaluated the characteristics of degraded agricultural land to identify opportunities for blue carbon restoration projects. Degraded agricultural land was identified through visual inspection of satellite imagery. Our analysis revealed degradation was associated with historical Melaleuca-dominated wetland vegetation and current land uses other than intensive agriculture. Field sampling of a subset of paired degraded and non-degraded sites found that water content, organic carbon, and electrical conductivity were significantly higher at degraded sites. We also observed standing water, drainage structures, and dead trees at degraded sites. From our analyses, we inferred land degradation is likely caused by waterlogging, salinisation, and land management choices. Degraded land historically vegetated by Melaleuca-dominated wetlands could be targeted for blue carbon restoration projects that protect remaining soil carbon and enhance carbon storage, restore ecosystem services, and provide new income streams for landowners. Further characterisation of the distribution of degraded lands may contribute to prioritisation of sites suitable for restoration. [ABSTRACT FROM AUTHOR]

In the restoration of drained and degraded tropical peat swamp forest (PSF) it is not well understood whether fire suppression on its own is sufficient to facilitate regeneration, or if rewetting plays a key role. We attempt to answer this question in the Merang area, a 23,000-ha peatland located in South Sumatra province, Indonesia. As with more than 90 % of PSF in Southeast Asia, the area has been largely degraded by logging and drainage canals, along with multiple fires. It has been designated and managed as an ecosystem restoration area since 2016, by which time only a single 254 ha patch of original PSF habitat remained. However, scattered remnant PSF trees (< 1 % cover) occurred throughout the area, along with seedlings of pioneer woody species in a landscape otherwise dominated by sedges and ferns. Peatland rehabilitation began with installation of 84 box dams in 2017, followed by 212 peat compaction dams mainly between late 2019 and early 2020. Since installation of the latter, the average water table depth (WTD) has decreased by 20-120 cm. In parallel with reduced WTD and fire prevention, regrowth has been vigorous, with total cover of woody plants increasing by almost a third, from 28.6 % in 2016 to 39.4 % in 2021. At the same time, changes in normalised difference vegetation index (NDVI) indicate a doubling in increase of woody vegetation cover between 2017-2020 and 2020-2021. Reduced WTD supports the recovery of woody vegetation cover, but Principal Component Analysis (PCA) strongly suggests that fire history determines the species composition of regenerated woody pioneer vegetation. Melaleuca cajuputi dominates where fires have been most frequent (on average > 4 fires), while Macaranga pruinosa, Melicope glabra and Melicope lunu-ankenda dominate in regenerating areas that have experienced 1-2 fires. While fire suppression is essential to prevent further loss of vegetation, effective rewetting is required before woody vegetation can recover. [ABSTRACT FROM AUTHOR]

The genus Melaleuca (Myrtaceae) is a valuable plant resource for research and applications in medicine, pharmacy, the pharmaceutical industry and folklore medicine. The present study aimed to investigate the chemical components and biological properties of the essential oils (EOs) of three Melaleuca species. Gas chromatography-mass spectrometry analyses revealed that the EOs extracted from the leaves of M. cajuputi, M. quinquenervia and M. leucadendra contained 19-21 compounds with high amounts of oxygenated monoterpenes and sesquiterpenes. Subsequent bioassays demonstrated that the EOs of M. cajuputi, M. quinquenervia and M. leucadendra exhibited antimicrobial activity against all tested microorganisms, including Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aegurinosa and Candida albicans, with minimum inhibitory concentrations in the range 640-2,560 µg/ml. The same EOs exerted inhibitory effects against α-amylase, α-glucosidase, acetylcholinesterase and xanthine oxidase with IC50 values ranging from 331.9±20.64 to 1,453±93.79 µg/ml. The findings obtained in the present study provide additional insight into the enzyme inhibitory properties of the leaf EOs from Melaleuca species that have not been reported in previous research, at least to the best of our knowledge. [ABSTRACT FROM AUTHOR]

Aims: The rise of drug-resistant infectious diseases worldwide has spurred experts' interest in developing safe and effective alternative medicine. Melaleuca cajuputi extracts have been shown to exhibit antimicrobial activity in vitro against various bacterial species. This study evaluated the antimicrobial activity of local M. cajuputi leaf extracts (MCEs) against Candida albicans. Methodology and results: Phytoconstituents of aqueous and ethanolic MCEs were screened conventionally using chemical tests. Broth microdilution assay and scanning electron microscope (SEM) were performed to study the anti- Candida activity of the extracts. Both MCEs contained terpenoids, phenols, flavonoids and tannins. Aqueous and ethanolic MCEs showed good fungicidal activity against the tested organism with minimum inhibitory concentration (MIC) values of 50 mg/mL and 25 mg/mL, respectively and a minimum fungicidal concentration (MFC) to MIC ratio of less or equal to 2. Scanning electron micrographs revealed yeast cell surface morphology alterations when treated with both MCEs at 1x MIC. Conclusion, significance and impact of study: In conclusion, MCEs have anti-Candida properties and thus, M. cajuputi extract could be an excellent potential source of natural antimicrobial agents for disease remedies. [ABSTRACT FROM AUTHOR]

Austropuccinia psidii, the fungus causing myrtle rust, was detected in Western Australia for the first time in June 2022. Few Western Australian plant species have been screened for response to the pathogen. Melaleuca thyoides, Melaleuca marginata and Melaleuca leucadendra grown from seeds sourced from Western Australian populations were all highly susceptible to an isolate of the pathogen from eastern Australia. [ABSTRACT FROM AUTHOR]

Two leaf imprints have been studied of the Middle Miocene flora from Ruzhintsi village, Northwest Bulgaria. One was determined as Macclintockia basinervis and the second as Tristaniopsis aff. laurina. New evidence has been obtained that Macclintockia is affiliated to the Myrtaceae family. In that context, the Australian species Melaleuca quinquenervia has been acknowledged as the nearest living relative to the first fossil species. In the course of determination of the second leaf imprint, a considerable morphological identity has been found with another representative of the family Myrtaceae, again from the Australian flora, namely, Tristaniopsis laurina. That recent species has been acknowledged as the nearest rlative to the fossil material, for the taxonomic determination of which the combination Tristaniopsis aff. laurina was applied. [ABSTRACT FROM AUTHOR]

Coastal wetland restoration is an important activity to achieve greenhouse gas (GHG) reduction targets, improve water quality, and reach the Sustainable Development Goals. However, many uncertainties remain in connection with achieving, measuring, and reporting success from coastal wetland restoration. We measured levels of carbon (C) abatement and nitrogen (N) removal potential of restored coastal wetlands in subtropical Queensland, Australia. The site was originally a supratidal forest composed of Melaleuca spp. that was cleared and drained in the 1990s for sugarcane production. In 2010, tidal inundation was reinstated, and a mosaic of coastal vegetation (saltmarshes, mangroves, and supratidal forests) emerged. We measured soil GHG fluxes (CH4, N2O, CO2) and sequestration of organic C in the trees and soil to estimate the net C abatement associated with the reference, converted, and restored sites. To assess the influence of restoration on water quality improvement, we measured denitrification and soil N accumulation. We calculated C abatement of 18.5 Mg CO2−eq ha−1 year−1 when sugarcane land transitioned to supratidal forests, 11.0 Mg CO2−eq ha−1 year−1 when the land transitioned to mangroves, and 6.2 Mg CO2−eq ha−1 year−1 when the land transitioned to saltmarshes. The C abatement was due to tree growth, soil accumulation, and reduced N2O emissions due to the cessation of fertilization. Carbon abatement was still positive, even accounting for CH4 emissions, which increased in the wetlands due to flooding and N2O production due to enhanced levels of denitrification. Coastal wetland restoration in this subtropical setting effectively reduces CO2 emissions while providing additional cobenefits, notably water quality improvement. [ABSTRACT FROM AUTHOR]

As leveduras do gênero Candida têm grande importância pela alta frequência com que colonizam e infectam o hospedeiro humano, sendo a espécie C. albicans a mais comum. A busca por produtos naturais que apresentem uma ação antifúngica eficiente frente a microrganismos se mostra uma alternativa para o controle de infecções. O óleo essencial de Melaleuca alternifolia Cheel (Myrtaceae) possui comprovada ação antimicrobiana contra bactérias e fungos, e tem sido apontado como uma opção para o tratamento de infecções fúngicas causadas pelo gênero Candida. O objetivo deste trabalho foi verificar a atividade antifúngica, em diferentes concentrações, do óleo essencial comercial de M. alternifolia contra cepa de isolado clínico da espécie C. albicans. Para a avaliação da atividade antifúngica foram utilizadas concentrações de 5 a 100% do óleo essencial puro de M. alternifólia em testes de sensibilidade a antimicrobianos por discodifusão, segundo norma estabelecida pelo Clinical and Laboratory Standards Institute, com modificações. De acordo com os resultados obtidos, o óleo essencial apresentou atividade, inibindo o crescimento do microrganismo, com a formação de halo de inibição a partir da concentração de 25%, com variação dos halos de 3 a 17 mm. Dessa forma, pode-se dizer que a cepa do isolado clínico avaliada apresentou sensibilidade ao óleo essencial de M. alternifolia, o que demonstra potencial antimicrobiano do óleo estudado, despertando grande interesse farmacêutico.

Medicinal plants are used for the prevention and treatment of many diseases as they are rich in phytochemical constituents (like terpenes, flavonoids, and alkaloids) responsible for the pharmacological effects of these plants. Genus Melaleuca named the tea tree, belonging to the family Myrtaceae, is cultivated in Australia as well as in the Pacific and some regions of Asia. It has been employed in Australian traditional medicine for its broad antimicrobial activity because of its contents of phenolic compounds, monoterpenes, tannins, flavonoids, sesquiterpenes, and essential oils. Owing to the valuable uses of plants of genus Melaleuca, for different medical purposes, it was deemed interest to summarize the previous studies reported from 2004 to 2020 in the available literature about the phytochemistry and pharmacological potential of both volatile and non-volatile components of Melaleuca species. Accordingly, this article may help researchers work on plants of genus Melaleuca to promote clinical applications towards the development of novel drugs of diverse pharmacological activities, including inhibitory effects on COVID 19 obtained from Melaleuca species. [ABSTRACT FROM AUTHOR]

Coal mining is one of economic sector that requires forestry area in Indonesia. Most of coal mining concession are forestry area loan use from the government and during mining operation facing with acid mine drainage (AMD). AMD passive treatment can be integrated with revegetation process that related with better handling of overburden (OB) with potential acid forming (PAF) during reclamation processed. The most expensive methods and uncertainty process are the use of quick lime in treatment of AMD. During operation and preparing mine closure stage need to create the effective one to comply with the regulation. "Swampy Forest (SF) system" is an alternative method of sustainable and naturally process. Selecting the appropriate tree species as a preliminary process to develop a better SF system by batch experiment in the form of a forest constructed wetland. The tree species selected are Nauclea orientalis (lonkida tree) and Melaleuca cajuputi (kayuputih tree) as non-local species then Nauclea subdita (bangkal tree) and Melaleuca leucadendron (galam tree) as local species have been selected. Local species higher in Fe and Mn adsorption in pH of AMD <4 then nonlocal species higher in Fe and Mn adsorption on pH of AMD >4 condition. [ABSTRACT FROM AUTHOR]

The essential oil from Melaleuca leucadendra L. leaves has been widely used as a perfume and traditional remedy, cosmetics and pharmaceutical products ingredient since many years ago. The common technology to recover the oil is hydro-distillation and steam-distillation. However, all oil can not be fully extracted from the leaves by this method due to the recalcitrant structure of leaves that hindrance the access of the solvent. Adding a submerged fermentation as a pretreatment step prior to the extraction process helped to loosen the lignocellulose structure and enhance oil release in the extraction process. In this study, the raw materials were collected from the natural forest in Buru Island, Maluku, Indonesia. The biological agents applied in these processes were Phanerochaete chrysosporium ITBCC136 and Trichoderma viride ITBCC143. The oil extraction process was conducted by method of steam-distillation, the oil was analysed using gas chromatography-mass spectroscopy (GC-MS), and the lignocellulose content in the biomass was measured by the fractionation method. The treatment using T.viride provided the highest increase in yield percentage up to 3.47% as compared with control of 1.45%, with the lowest percentages of the remained cellulose, while the fermentation with the presence of P.chrysosporium did not affect the oil yield even the lignin content was decrease as much as 21%. The percentages of 1,8-cineole in the oil were almost unchanged, which was about 20% of the oil. [ABSTRACT FROM AUTHOR]

Candida auris readily colonizes skin and efficiently spreads among patients in healthcare settings worldwide. Given the capacity of this drug-resistant fungal pathogen to cause invasive disease with high mortality, hospitals frequently employ chlorhexidine bathing to reduce skin colonization. Using an ex vivo skin model, we show only a mild reduction in C. auris following chlorhexidine application. This finding helps explain why chlorhexidine bathing may have failures clinically, despite potent in vitro activity. We further show that isopropanol augments the activity of chlorhexidine against C. auris on skin. Additionally, we find both tea tree (Melaleuca alternifolia) oil and lemongrass (Cymbopogon flexuosus) oil to further enhance the activity of chlorhexidine/isopropanol for decolonization. We link this antifungal activity to individual oil components and show how some of these components act synergistically with chlorhexidine/isopropanol. Together, the studies provide strategies to improve C. auris skin decolonization through the incorporation of commonly used topical compounds. [ABSTRACT FROM AUTHOR]

Plants in the genus Melaleuca have been widely used as traditional medicine mainly because of their broad spectrum antimicrobial activity. In this study, we reported the complete chloroplast genome of Melaleuca cajuputi subsp. cumingiana. The chloroplast genome of this species is 158,855 bp in length, including a pair of inverted repeat regions (IRs) (26,727 bp) that is divided by a large single-copy (LSC) area (87,338 bp) and a small single-copy (SSC) area (18,063 bp). The circular chloroplast genome of M. cajuputi subsp. cumingiana contains 135 unique genes, composing of 87 protein-coding genes, 40 tRNA genes, and eight rRNA genes. Phylogenetic analysis indicates that M. cajuputi subsp. cumingiana was clustered with species in the tribe Melaleuceae. This complete chloroplast genome of M. cajuputi subsp. cumingiana will provide a powerful tool to accelerate breeding, biotechnological and phylogenetic study.

Plants of the genus Melaleuca which belong to family Myrtaceae, commonly named "tea trees", are economically important plants. When talking about tea trees, the essential oils are the center of attention, leaving all other phytoconstituents in their shade. Many reviews addressed the composition and pharmacological activities of Melaleuca alternifolia L. essential oil as the most common one. To date, there are no detailed reviews summarizing the phytochemical and pharmacological properties of the non-volatile components of members of the genus Melaleuca. After distillation of the volatile oil, large amounts of these plants' waste remain untapped. This review indicates that this genus is a rich source of diverse groups of bioactive phytochemicals, including flavonoids, triterpenoids, benzylic phloroglucinol-terpene derivatives, polyphenols, hydrolysable tannins, and other compounds. It also discusses the diverse pharmacological activities reported for plants of this genus. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is one of the most common bacterial isolates found in wounds. Thus, innovative dressings, such as hydrogels, are interesting vehicles for incorporating bioactive compounds like those from Melaleuca alternifolia essential oil (MaEO). In this study, we evaluated the antimicrobial and anti-inflammatory potential of MaEO incorporated into an alginate and chitosan hydrogel for treating wounds infected by S. aureus. The hydrogel incorporated with MaEO 1% (HMa 1%) was homogeneous with a bright pale-yellow color and the characteristic smell of Melaleuca. The incorporation of MaEO 1% does not affect the stability of the hydrogel, which was stable up to 90 days of storage. The Scanning electron microscopy analysis revealed that hydrogels showed irregular surfaces and interconnected porous structures with accumulations of oil crystals distributed throughout the formulation. HMa 1% has a high moisture content (95.1%) and can absorb simulated wound fluid. Regarding the antimicrobial effects, HMa 1% reduced the growth of S. aureus ATCC 6538 in both in vitro conditions and in an ex vivo model of wounds using porcine skin. In addition, the dairy topical treatment of murine skin lesions with HMa 1% induced a significant reduction of the wound area, inflammation score, and bacterial load, as well as tissue re-epithelialization and modulation of inflammatory mediators. Therefore, hydrogel incorporated with MaEO 1% has excellent potential to be used in the pharmacotherapy of infected wounds. [Display omitted] • Essential oil of M. alternifolia inhibits S. aureus in vitro, in vivo and ex vivo. • Hydrogel of Melaleuca reduces the severity of S. aureus- infected wounds. • Treatment with HMa 1% improves re-epithelialization of infected wounds. • Hydrogel of Melaleuca inhibits the production of nitric oxide in mice. • Treatment with HMa 1% stimulates the production of IL-10 in mice. [ABSTRACT FROM AUTHOR]

Jane EM GibbsSchool of Medicine, Griffith University, Gold Coast, Queensland, AustraliaPurpose: Prevailing opinion is that wind-pollinated plants affect asthma negatively and that insect- pollinated ones do not. “Thunderstorm” asthma, too, is attributed to bursting grass pollens. Additional biogenic volatile organic compounds (BVOCs) are identified here. Essential oils’ BVOCs are inhaled from plants, oil diffusers, candles, room “fresheners”, perfumes, and hygiene products. Claims of BVOC “safety” for sensitive respiratory systems are questioned.Methods: Fourteen volunteers, of mixed-age and gender, with seasonal asthma recorded peak expiratory flow (PEF) and 11 symptom scores. BVOCs were collected on Tenax tubes from ambient air in autumn and spring, as were live flower emissions, before and after a thunderstorm. Gas chromatography–mass spectrometry analysis identified frequently occurring BVOCs. Air spora, meteorological, outdoor air pollution variables, and BVOCs predict respiratory symptoms in univariate linear regression models, seasonally.Results: Increased pinene, camphor, linalool, linalyl acetate, benzaldehyde, and benzoic acid predict respiratory symptoms, including reduced PEF, and increased nasal congestion; day length, atmospheric pressure and temperature predict symptoms in both seasons, differently; other variables predict a range of symptoms (0.0001≤p≤0.05). Thunder predicts different BVOC emissions in spring, compared to autumn (p≤0.05). An uncut Grevillea flower emitted linalool and hexenal before a storm; the latter is also emitted from cut grass. Increased nitrogen oxides and pinene in autumn may combine to form harmful oxidation products.Conclusion: This research supports BVOCs as contributors to seasonal asthma and allergic rhinitis, and “thunderstorm” asthma. Pinene emissions from Myrtaceae species (Eucalyptus, Melaleuca, Leptospermum, Callistemon), Brassicaceae (canola), and conifers, worldwide, may induce respiratory inflammation and maintain it, by inhibiting eosinophilic apoptosis. Widely used essential oil products containing BVOCs, like linalool, are associated here with respiratory symptoms. Lagged responses suggest that users’ cognitive associations between exposure and response are unlikely, increasing potential for impaired health for vulnerable children.Keywords: asthma, allergic rhinitis, BVOC, terpenes, Eucalyptus, essential oils

Sepsis represents a complex clinical syndrome that results from a harmful host response to infection. The infections most associated with sepsis are pneumonia, intra-abdominal infection, and urinary tract infection. Tea tree oil (TTO) has shown high antibacterial activity; however, it exhibits low aqueous solubility and high volatility, which have motivated its nanoencapsulation. In this study, the performance of nanoemulsions (NE) and nanocapsules (NC) loaded with TTO was compared. These systems were prepared by spontaneous emulsification and nanoprecipitation methods, respectively. Poly-ε-caprolactone or Eudragit ® RS100 were tested as polymers for NCs whereas Tween ® 80 or Pluronic ® F68 as surfactants in NE preparation. Pluronic ® F68 and Eudragit ® RS100 resulted in more homogeneous and stable nanoparticles. In accelerated stability studies at 4 and 25 °C, both colloidal suspensions (NC and NE) were kinetically stable. NCs showed to be more stable to photodegradation and less cytotoxic than NEs. After sepsis induction by the cecal ligation and puncture (CLP) model, both NE and NC reduced neutrophil infiltration into peritoneal lavage (PL) and kidneys. Moreover, the systems increased group thiols in the kidney and lung tissue and reduced bacterial growth in PL. Taken together, both systems showed to be effective against injury induced by sepsis; however, NCs should be prioritized due to advantages in terms of cytotoxicity and physicochemical stability., (© 2024. Controlled Release Society.)

Tree stem methane emissions are important components of lowland forest methane budgets. The potential for species-specific behaviour among co-occurring lowland trees with contrasting bark characteristics has not been investigated. We compare bark-mediated methane transport in two common lowland species of contrasting bark characteristics (Melaleuca quinquenervia featuring spongy/layered bark with longitudinally continuous airspaces and Casuarina glauca featuring hard/dense common bark) through several manipulative experiments. First, the progressive cutting through M. quinquenervia bark layers caused exponential increases in methane fluxes (c. 3 orders of magnitude); however, sapwood-only fluxes were lower, suggesting that upward/axial methane transport occurs between bark layers. Second, concentrated methane pulse-injections into exposed M. quinquenervia bark, revealed rapid axial methane transport rates (1.42 mm s -1 ), which were further supported through laboratory-simulated experiments (1.41 mm s -1 ). Laboratory-simulated radial CH 4 diffusion rates (through bark) were c. 20-times slower. Finally, girdling M. quinquenervia stems caused a near-instantaneous decrease in methane flux immediately above the cut. By contrast, girdling C. glauca displayed persistent, though diminished, methane fluxes. Overall, the experiments revealed evidence for rapid 'between-bark' methane transport independent from the transpiration stream in M. quinquenervia, which facilitates diffusive axial transport from the rhizosphere and/or sapwood sources. This contrasts with the slower, radial 'through-bark' diffusive-dominated gas transportation in C. glauca., (© 2023 The Authors New Phytologist © 2023 New Phytologist Foundation.)

In April 2010, the exotic rust fungus Austropuccinia psidii was detected for the first time in Australia, with the host range rapidly increasing to >350 species from 58 genera within the family Myrtaceae. Commonly known as myrtle rust, the disease is well established in native ecosystems, particularly in New South Wales (NSW) and Queensland, impacting on a range of species and associated environments. While fire is considered an important selection agent in the development of Australia's native flora, re-sprouting and germination of seedlings en masse is ideal for the development and spread of A. psidii. Our study took advantage of a unique opportunity to assess the impacts of myrtle rust on species of Myrtaceae regenerating after a wildfire in a northern NSW coastal heath environment. Austropuccinia psidii infection was found on all species of regenerating Myrtaceae with impacts ranging from minor leaf spotting to severe repeated dieback and death of affected trees. This is the first investigation into the impact of myrtle rust in regenerating Myrtaceae following wildfire and highlights a need for more detailed studies. [ABSTRACT FROM AUTHOR]

The increasing incidence of resistance in tuberculosis and in atypical mycobacterial infections has prompted the search for alternative agents. We explored the antimycobacterial activity of Melaleuca cajuputi essential oil against tubercular and non tubercular mycobacterials isolates. The good activity observed towards M. cajuputi indicated that this essential oil might represent a promising antimicrobial agents, particularly in the management of microbial resistance. [ABSTRACT FROM AUTHOR]

Gibbs JEM. J Asthma Allergy. 2020;12:169–182. On page 172, Floral and air and thunderstorm sampling section, and on page 173, Results, Floral emissions before and after a storm section, the supplementary information link is no longer working. The updated link is http://www.dove press.com/get_supplementary_file.php?f=286369.pdf. The author apologizes for any inconvenience. Read the original article

Abstract Laboratory evidence has demonstrated the antimicrobial effect of Melaleuca alternifolia (MEL) against oral microorganisms. This randomized, double-blind, crossover clinical trial, compared the anti-biofilm and anti-inflammatory effects of MEL nanoparticles with 0.12% chlorhexidine gluconate (CHX) on biofilm-free (BF) and biofilm-covered (BC) surfaces. Before each experimental period, the participants refrained from all oral hygiene practices for 72 hours. The 60 participants were randomly assigned to professional prophylaxis in two quadrants (Q1–Q3 or Q2–Q4), and rinsed with MEL or CHX for four days. The Quigley & Hein plaque index (QHPI), gingival crevicular fluid (GCF) volume, and participants’ perceptions were assessed. CHX showed significantly lower mean QHPI on BF (2.65 ± 0.34 vs. 3.34 ± 0.33, p < 0.05) and BC surfaces (2.84 ± 0.37 vs. 3.37 ± 0.33, p < 0.05). Intragroup comparisons indicated reductions in GCF in all the groups, with significant differences only for CHX on BF surfaces (p < 0.05). Intergroup comparisons revealed no significant differences (p > 0.05). Based on individual perceptions, CHX had better taste and biofilm control, but resulted in a greater change in taste. Nevertheless, MEL demonstrated anti-inflammatory effects similar to those of CHX. Further clinical trials testing different protocols, concentrations and follow-up periods are required to establish its clinical application.

Wetlands can increase resilience to extreme climatic events and have a key role in protection and water quality improvement in coastal ecosystems. Studies in tropical coastal wetlands at a catchment scale are scarce, and most work has been undertaken on small, temperate wetlands. In this study, we tested whether natural coastal wetlands in a tropical catchment (Tully-Murray, Queensland, Australia) could ameliorate nitrogen (N) exported to the Great Barrier Reef during a flood event. We measured denitrification rates in different types of coastal wetlands (mangroves, saltmarshes, waterbodies with macrophytes, and floodplain wetlands dominated by Melaleuca spp.) to assess their potential contribution to N losses during the 6-day duration of a flood in March 2018. Denitrification potential was variable across the landscape, and we identified “hotspots” in sub-catchments with high NO3--N concentrations (0.4–0.6 mg L−1) and large areas of wetlands (>800 ha, >40% of the sub-catchment). These hotspots can denitrify up to 10 t of NO3--N per day during a flood. We used our measured denitrification rates to provide input parameters for a model that includes the main biogeochemical processes affecting N transformations within wetlands (nitrification, denitrification, plant uptake, sedimentation, anammox, and mineralization), and accounts for transport via the duration, depth, and flow of water. Model simulations of a sub-catchment of the Tully-Murray indicate that flood inundation of large areas of natural wetlands (>40% of the sub-catchment area) could potentially remove 70% of the incoming NO3--N load in the first 24 h of the flood. The management and restoration of coastal tropical wetlands could play a critical role in sustaining the health of coastal ecosystems through water quality improvement.

Cherax quadricarinatus has been widely translocated within Australia, and a number of self-sustaining feral populations have established, and persisted, in central-eastern Australia for over 20 years: however, the biology and ecology of feral populations remain poorly understood. Using the loss-by-ignition method, this study investigated differences in the total content of incombustible material (as a proxy for total mineral content), between feral C. quadricarinatus populations in southeast Queensland and northeastern New South Wales. A total of 102 C. quadricarinatus were ignited, and percent total incombustible material was not proportional to the body size, or gender of the crayfish. Incombustible content was however, significantly different between some locations of capture (i.e., waterbodies). The site where incombustible content in crayfish was atypical, Lake Ainsworth, is a naturally acidic coastal lake, and we suggest that acidity and low concentration of calcium in that waterbody are likely responsible for the difference in mineral content detected in that population. Mechanism(s) driving the difference detected in the Lake Ainsworth population are unknown, but we suggest the acidic environment could directly impact maintenance of internal calcium reserves in the crayfish (intermoult), during recalcification of the cuticle (postmoult), or both. Limited calcium availability in the lake may also be a direct, or indirect, contributing factor. The ability of C. quadricarinatus to occupy acidic habitats while managing biomineralization challenges possibly could enable additional range-expansion of the species, and potential impacts on both endangered ecological communities and other biota occupying the acidic coastal habitats of Eastern Australia.

Legionella pneumophila is a Gram-negative bacterial pathogen that colonizes natural and artificial water systems and has the ability to form a biofilm. The biofilm protects L. pneumophila from various environmental factors and makes it more resistant to chlorine-based disinfectants. This study investigated the anti-bacterial properties of tea tree ( Melaleuca alternifolia (Maiden and Betche) Cheel) oil and lemon eucalyptus tree ( Eucalyptus citriodora Hook) essential oils (EOs) and their synergistic, additive inhibitory and anti-adhesive effects against L. pneumophila biofilm formation on polystyrene. The minimum effective concentration (MEC) for tea tree is 12.8 mg ml -1 and for lemon eucalyptus tree EO 6.4 mg ml -1 . In the checkerboard assay, different combinations of these two EO show synergistic and additive anti-microbial activity. The minimum anti-adhesive concentration (MAC) for tea tree is 12.8 mg ml -1 and for lemon eucalyptus tree EO 6.4 mg ml -1 . A combination of 3.2 mg ml -1 tea tree EO and 0.8 mg ml -1 lemon eucalyptus tree EO showed the strongest anti-adhesive effect against L. pneumophila on polystyrene. The tested oils and their combination showed intriguing potential to inhibit L. pneumophila biofilm formation.

The Australian continent spans coastal wetland settings ranging from extensive mangrove forest and sabkha plains occupying in the tropical north, to the southern half of the continent, where high wave energy constrains wetlands within numerous barrier-fronted estuaries, drowned river valleys and coastal embayments. Only on the island of Tasmania are mangroves absent; elsewhere mangroves, Casuarina, Melaleuca and saltmarsh interact in ways illustrative of the effects of ongoing climate, tidal and sea-level change. Observations over several decades have suggested that recent anthropogenic climate change may already be impacting Australian coastal wetlands in important ways. A period of accelerating sea-level rise has been associated with saline intrusion, mangrove encroachment and Melaleuca dieback in the tropical north, punctuated by widespread mangrove mortality in drought periods. The consistent trend of mangrove encroachment and replacement of saltmarsh in the south, is associated with an "accretion deficit" in saltmarsh during contemporary sea-level rise. We review the ecological and cultural implications of these changes, including impacts on habitat provision for migratory birds, fisheries values, carbon sequestration and Indigenous cultural values. Current legislative and policy protections may not be sufficient to meet the increasingly dynamic impacts of climate change in altering wetland boundaries, composition and function. [ABSTRACT FROM AUTHOR]

Excess nitrogen (N) leading to the eutrophication of water and impacts on ecosystems is a serious environmental challenge. Wetlands can remove significant amounts of N from the water, primarily through the process of denitrification. Most of our knowledge on wetland denitrification is from temperate climates; studies in natural tropical wetlands are very scarce. We measured denitrification rates during a dry and a wet season in five floodplain forests dominated by Melaleuca spp., a coastal freshwater wetland of tropical Australia. We hypothesised that the denitrification potential of these wetlands would be high throughout the year and would be limited by N and carbon (C) availability. Mean potential denitrification rates (D t) were 5.0 ± 1.7 mg m2 h–1, and were within the reported ranges for other tropical and temperate wetlands. The rates of D t were similar between the dry and the wet seasons. From the total unamended denitrification rates (D w, 3.1 ± 1.7 mg m2 h–1), 64% was derived from NO3– of the water column and the rest from coupled nitrification–denitrification. The factor most closely associated with denitrification was background water NO3–-N concentrations. Improved management and protection of wetlands could play an important role in improving water quality in tropical catchments. One hectare of wetlands dominated by tea trees (Melaleuca) has the potential to remove 400 kg of nitrogen per year. The capacity of these wetlands to remove nitrogen is mostly driven by how much nitrate is in the water. We should protect, restore and create new wetlands for improving water quality within tropical catchments. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the anti-oxidant, anti-inflammatory and anti-acetylcholine esterase activities of betulinic acid (BA) and 3β- acetoxybetulinic acid (BAA) from Melaleuca bracteata. 'Revolution Gold'. Methods: Betulinic acid was isolated from the ethyl acetate extract of M. braceteata while BAA was synthesized by acetylation of BA. Structural elucidation of the compounds was achieved by spectroscopic methods. Antioxidant potential was determined using superoxide dismustase (SOD) and catalase assay kits while iron chelation activity assessed with ferrozin. Anti-inflammatory activity was determined using cotton pellet-induced granuloma rat model. Cyclooxygenase (COX) activity evaluated by COX kits; acetylcholine kit was used for anti-acetylcholinesterase (ACHE) study. Results: The compounds significantly (p < 0.05) dose-dependently inhibited ACHE and inflammatory activity. They also significantly decreased the inhibition of SOD, catalase activity but increased iron chelation activities in a dose-dependent manner. However, BAA showed higher activity than BA for all the parameters. BAA also had a greater inhibitory effect on COX-2 than on COX-1. BAA (IC50, 0.88 mg/mL) showed better iron chelation than citric acid (0.96 ± 0.04) and EDTA (1.04 ± 0.03), the positive control. Conclusion: BA and BAA possess anti-ACHE, anti-inflammatory, antioxidant and anti-COX activities. Structural modification of BAA influences its biological activities. Therefore, BAA can potentially serve as a scaffold in synthesizing potent neurodegeneration drugs. [ABSTRACT FROM AUTHOR]

Cherax quadricarinatus has been widely translocated within Australia, and a number of self-sustaining feral populations have established, and persisted, in central-eastern Australia for over 20 years: however, the biology and ecology of feral populations remain poorly understood. Using the loss-by-ignition method, this study investigated differences in the total content of incombustible material (as a proxy for total mineral content), between feral C. quadricarinatus populations in southeast Queensland and northeastern New South Wales. A total of 102 C. quadricarinatus were ignited, and percent total incombustible material was not proportional to the body size, or gender of the crayfish. Incombustible content was however, significantly different between some locations of capture (i.e., waterbodies). The site where incombustible content in crayfish was atypical, Lake Ainsworth, is a naturally acidic coastal lake, and we suggest that acidity and low concentration of calcium in that waterbody are likely responsible for the difference in mineral content detected in that population. Mechanism(s) driving the difference detected in the Lake Ainsworth population are unknown, but we suggest the acidic environment could directly impact maintenance of internal calcium reserves in the crayfish (intermoult), during recalcification of the cuticle (postmoult), or both. Limited calcium availability in the lake may also be a direct, or indirect, contributing factor. The ability of C. quadricarinatus to occupy acidic habitats while managing biomineralization challenges possibly could enable additional range-expansion of the species, and potential impacts on both endangered ecological communities and other biota occupying the acidic coastal habitats of Eastern Australia. [ABSTRACT FROM AUTHOR]

Highlights • We study the problem of optimal allocation of resources for invasive species control. • We use observations of a first survey to fit a Hidden Markov Random Field, accounting for spatial structure of the observations, imperfect detection and misclassification errors. • The model is then used to compute posterior probabilities of the species being present on each site. • Posterior probabilities are used to maximize the number of occupied sites under cost constraint. • We illustrated the method on simulated examples and provide a ready-to-use Matlab interface. Abstract Imperfect detection and misclassification errors are often ignored in the context of invasive species management. Here we present an approach that combines spatially explicit models and an optimization technique to design optimal search and destroy strategies based on noisy monitoring observations. We focus on two invasive plants, melaleuca (Melaleuca quinquenervia) and Old World climbing fern (Lygodium microphyllum), which continue to cause important damages to the Everglades ecosystem. We present a methodological framework that combines Hidden Markov Random Field (HMRF, initially developed for image analysis) and linear programming to optimally search for invasive species. A benefit of this approach is that it accounts for the spatial structure of the system by using a spatially explicit modeling approach (i.e. HMRF), and does not require repeated visits to model the probability of occurrence of species. We found on simulated cases that our approach can lead to substantial improvements in control efficiency when compared to state of the art model-free approaches. For example, in the case of the old world fern, simulations showed that the optimal strategy would allow managers to control up to 34% more sites than with model-free approaches that ignored misclassification and imperfect detection. For melaleuca it was possible to control up to 20% more sites. The vast increase in imagery data obtained from different sources (e.g. unmanned aerial systems, and satellite) provides great opportunities to improve management of natural resources by applying modern computational methods such as the one we present. Our approach can substantially increases the efficiency of invasive species control by accounting for imperfect detection, misclassification error and the spatial structure of the system. Our approach is applicable to other systems and problems, for example it could be applied to the control of plant pathogens, or optimal extraction of resources (e.g. minerals or biological resources). [ABSTRACT FROM AUTHOR]

Laboratory evidence has demonstrated the antimicrobial effect of Melaleuca alternifolia (MEL) against oral microorganisms. This randomized, double-blind, crossover clinical trial, compared the anti-biofilm and anti-inflammatory effects of MEL nanoparticles with 0.12% chlorhexidine gluconate (CHX) on biofilm-free (BF) and biofilm-covered (BC) surfaces. Before each experimental period, the participants refrained from all oral hygiene practices for 72 hours. The 60 participants were randomly assigned to professional prophylaxis in two quadrants (Q1-Q3 or Q2-Q4), and rinsed with MEL or CHX for four days. The Quigley & Hein plaque index (QHPI), gingival crevicular fluid (GCF) volume, and participants' perceptions were assessed. CHX showed significantly lower mean QHPI on BF (2.65 ± 0.34 vs. 3.34 ± 0.33, p < 0.05) and BC surfaces (2.84 ± 0.37 vs. 3.37 ± 0.33, p < 0.05). Intragroup comparisons indicated reductions in GCF in all the groups, with significant differences only for CHX on BF surfaces (p < 0.05). Intergroup comparisons revealed no significant differences (p > 0.05). Based on individual perceptions, CHX had better taste and biofilm control, but resulted in a greater change in taste. Nevertheless, MEL demonstrated anti-inflammatory effects similar to those of CHX. Further clinical trials testing different protocols, concentrations and follow-up periods are required to establish its clinical application. [ABSTRACT FROM AUTHOR]