Phytochemical Modulation of Ion Channels in Oncologic Symptomatology and Treatment.

Modern chemotherapies offer a broad approach to cancer treatment but eliminate both cancer and non-cancer cells indiscriminately and, thus, are associated with a host of side effects. Advances in precision oncology have brought about new targeted therapeutics, albeit mostly limited to a subset of patients with an actionable mutation. They too come with side effects and, ultimately, 'self-resistance' to the treatment. There is recent interest in the modulation of ion channels, transmembrane proteins that regulate the flow of electrically charged molecules in and out of cells, as an approach to aid treatment of cancer. Phytochemicals have been shown to act on ion channels with high specificity regardless of the tumor's genetic profile. This paper explores the use of phytochemicals in cancer symptom management and treatment.

Cross-Inoculation of Commercial Forestry, Amenity, and Horticulture Tree Species with Ceratocystis Isolates Collected from Different Host Species.

Ceratocystis manginecans has caused significant losses in forestry productivity in Indonesia and neighboring nations. It also infects horticultural trees, but the host range of individual isolates of C. manginecans is poorly studied. So, this study aimed to better understand the potential host range and evaluate aggressiveness against forestry and fruit tree species of C. manginecans isolated from various tree species in Indonesia. Five C. manginecans isolates, four from different tree species and one from the shot-hole borer Euwallacea perbrevis, were used to inoculate seven fruit and six forest tree species, including E. pellita and Acacia mangium. Many of the inoculated trees produced typical canker disease symptoms, such as rough, swollen, and cracked lesions on the bark, but some trees did not have any external symptoms. Mortality in the most susceptible clone of A. mangium was 40% within 8 weeks. Forest tree species were more susceptible than fruit trees, with the length of xylem discoloration ranging from 0.4 to 101 cm. In fruit trees, the average extent of xylem discoloration was lower, ranging from 0.4 to 20.5 cm; however, mortalities were recorded in two fruit tree species, Citrus microcarpa and Durio zibethinus. Host-isolate interaction was evident; isolate Ep106C from Eucalyptus pellita caused the greatest xylem discoloration in Citrus sp., whereas Hy163C from Hymenaea courbaril was the most damaging in D. zibethinus, Artocarpus heterophyllus, and Mangifera indica. Increasingly globalized food and fiber systems increase risk of disease spread, and the serious threat of C. manginecans incursions into countries where it is not present must be evaluated more thoroughly.

Improvement of pasture biomass modelling using high-resolution satellite imagery and machine learning.

Robust quantification of vegetative biomass using satellite imagery using one or more forms of machine learning (ML) has hitherto been hindered by the extent and quality of training data. Here, we showcase how ML predictive demonstrably improves when additional training data is used. We collated field datasets of pasture biomass obtained via destructive sampling, 'C-Dax' reflective measurements and rising plate meters (RPM) from ten livestock farms across four States in Australia. Remotely sensed data from the Sentinel-2 constellation was used to retrieve aboveground biomass using a novel machine learning paradigm hereafter termed "SPECTRA-FOR" (Spectral Pasture Estimation using Combined Techniques of Random-forest Algorithm for Features Optimisation and Retrieval). Using this framework, we show that the low temporal resolution of Sentinel-2 in high latitude regions with persistent cloud cover leads to extensive gaps between cloud-free images, hindering model performance and, thus, contemporaneous ability to forecast real-time pasture biomass. By leveraging the spectral consistency between Sentinel-2 and Planet Lab SuperDove to overcome this limitation, we used ten spectral bands of Sentinel-2, four bands of Sentinel-2 as a proxy for pre-2022 SuperDove (referred to as synthetic SuperDove or SSD), and the actual SuperDove (ASD), given that SuperDove imagery has a higher resolution and more frequent passage compared with Sentinel-2. Using their respective bands as input features to SPECRA-FOR, model performance for the ten bands of Sentinel-2 were R2 = 0.87, root mean squared error (RMSE) of 439 kg DM/ha and mean absolute error (MAE) of 255 kg DM/ha, while that for SSD increased to an R2 of 0.92, RMSE of 346 kg DM/ha and MAE = 208 kg DM/ha. The study revealed the importance of robust data mining, imagery harmonisation and model validation for accurate real-time modelling of pasture biomass with ML.

Effects of soil- and climate data aggregation on simulated potato yield and irrigation water requirement.

Input data aggregation affects crop model estimates at the regional level. Previous studies have focused on the impact of aggregating climate data used to compute crop yields. However, little is known about the combined data aggregation effect of climate (DAEc) and soil (DAEs) on irrigation water requirement (IWR) in cool-temperate and spatially heterogeneous environments. The aims of this study were to quantify DAEc and DAEs of model input data and their combined impacts for simulated irrigated and rainfed yield and IWR. The Agricultural Production Systems sIMulator Next Generation model was applied for the period 1998-2017 across areas suitable for potato (Solanum tuberosum L.) in Tasmania, Australia, using data at 5, 15, 25 and 40 km resolution. Spatial variances of inputs and outputs were evaluated by the relative absolute difference (rAD¯) between the aggregated grids and the 5 km grids. Climate data aggregation resulted in a rAD¯ of 0.7-12.1%, with high values especially for areas with pronounced differences in elevation. The rAD¯ of soil data was higher (5.6-26.3%) than rAD¯ of climate data and was mainly affected by aggregation of organic carbon and maximum plant available water capacity (i.e. the difference between field capacity and wilting point in the effective root zone). For yield estimates, the difference among resolutions (5 km vs. 40 km) was more pronounced for rainfed (rAD¯ = 14.5%) than irrigated conditions (rAD¯ = 3.0%). The rAD¯ of IWR was 15.7% when using input data at 40 km resolution. Therefore, reliable simulations of rainfed yield require a higher spatial resolution than simulation of irrigated yields. This needs to be considered when conducting regional modelling studies across Tasmania. This study also highlights the need to separately quantify the impact of input data aggregation on model outputs to inform about data aggregation errors and identify those variables that explain these errors.

An assessment of ectomycorrhizal fungal communities in Tasmanian temperate high-altitude Eucalyptus delegatensis forest reveals a dominance of the Cortinariaceae.

Fungal diversity of Australian eucalypt forests remains underexplored. We investigated the ectomycorrhizal (EcM) fungal community characteristics of declining temperate eucalypt forests in Tasmania. Within this context, we explored the diversity of EcM fungi of two forest types in the northern highlands in the east and west of the island. We hypothesised that EcM fungal community richness and composition would differ between forest type but that the Cortinariaceae would be the dominant family irrespective of forest type. We proposed that EcM richness would be greater in the wet sclerophyll forest than the dry sclerophyll forest type. Using both sporocarps and EcM fungi from root tips amplified by PCR and sequenced in the rDNA ITS region, 175 EcM operational taxonomic units were identified of which 97 belonged to the Cortinariaceae. The Cortinariaceae were the most diverse family, in both the above and below ground communities. Three distinct fungal assemblages occurred within the wet and dry sclerophyll forest types and two geographic regions that were studied, although this pattern did not remain when only the root tip data were analysed. EcM sporocarp richness was unusually higher than root tip richness and EcM richness did not significantly differ among forest types. The results are discussed in relation to the importance of the Cortinariaceae and the drivers of EcM fungal community composition within these forests.

Perception of climate change and its impact by smallholders in pastoral/agropastoral systems of Borana, South Ethiopia.

This study investigates the perception of historic changes in climate and associated impact on local agriculture among smallholders in pastoral/agropastoral systems of Borana in southern Ethiopia. We drew on empirical data obtained from farm household surveys conducted in 5 districts, 20 pastoral/agropastoral associations and 480 farm households. Using this data, this study analyses smallholders' perception of climate change and its associated impact on local agriculture, and the effect of various household and farm attributes on perception. Results suggest that most participants perceived climatic change and its negative impact on agricultural and considered climate change as a salient risk to their future livelihoods and economic development. Different levels of perception were expressed in terms of climate change and the impact on traditional rain-fed agriculture. Age, education level, livestock holding, access to climate information and extension services significantly affected perception levels. Household size, production system, farm and non-farm incomes did not significantly affect perception levels of smallholders. Smallholders attributed climate change to a range of biophysical, deistic and anthropogenic causes. Increased access to agricultural support services, which improves the availability and the quality of relevant climate information will further enhance awareness of climate change within of the rural community and result in better management of climate-induced risks in these vulnerable agricultural systems.

Whole-plant versus leaf-level regulation of photosynthetic responses after partial defoliation in Eucalyptus globulus saplings.

Increases in photosynthetic capacity (A1500) after defoliation have been attributed to changes in leaf-level biochemistry, water, and/or nutrient status. The hypothesis that transient photosynthetic responses to partial defoliation are regulated by whole-plant (e.g. source-sink relationships or changes in hydraulic conductance) rather than leaf-level mechanisms is tested here. Temporal variation in leaf-level gas exchange, chemistry, whole-plant soil-to-leaf hydraulic conductance (KP), and aboveground biomass partitioning were determined to evaluate mechanisms responsible for increases in A1500 of Eucalyptus globulus L. potted saplings. A1500 increased in response to debudding (B), partial defoliation (D), and combined B&D treatments by up to 36% at 5 weeks after treatment. Changes in leaf-level factors partly explained increases in A1500 of B and B&D treatments but not for D treatment. By week 5, saplings in B, B&D, and D treatments had similar leaf-specific KP to control trees by maintaining lower midday water potentials and higher transpiration rate per leaf area. Whole-plant source:sink ratios correlated strongly with A1500. Further, unlike KP, temporal changes in source:sink ratios tracked well with those observed for A1500. The results indicate that increases in A1500 after partial defoliation treatments were largely driven by an increased demand for assimilate by developing sinks rather than improvements in whole-plant water relations and changes in leaf-level factors. Three carbohydrates, galactional, stachyose, and, to a lesser extent, raffinose, correlated strongly with photosynthetic capacity, indicating that these sugars may function as signalling molecules in the regulation of longer term defoliation-induced gas exchange responses.

Ceratocystis species, including two new species associated with nitidulid beetles, on eucalypts in Australia.

The genus Ceratocystis includes important fungal pathogens of trees, including Eucalyptus spp. Ironically, very little is known regarding the diversity or biology of Ceratocystis species on Eucalyptus species in Australia, where most of these trees are native. The aim of this study was to survey for Ceratocystis spp., and their possible insect associates, on eucalypts in Australia and thus to establish a foundation of knowledge regarding these fungi on the continent. Collections were made in three states of Australia from wounds on trees, as well as from nitidulid beetles associated with these wounds. Ceratocystis spp. were identified based on morphology and multigene sequence comparisons. Of the 54 isolates obtained, two previously unknown species of Ceratocystis were found and these are described here as Ceratocystis corymbiicola sp. nov. and Ceratocystis tyalla sp. nov. Furthermore, the distribution of Ceratocystis pirilliformis is expanded to include Eucalyptus spp. in Tasmania.

Photosynthetic responses of field-grown Pinus radiata trees to artificial and aphid-induced defoliation.

The phloem-feeding aphid Essigella californica represents a potential threat to the productivity of Pinus radiata plantations in south-eastern Australia. Five- and nine-year-old field trials were used to characterize the effects of artificial and natural aphid-induced (E. californica) defoliation, respectively, on shoot photosynthesis and growth. Photosynthetic capacity (A(max)) was significantly greater following a 25% (D25) (13.8 µmol m(-2) s(-1)) and a 50% (D50) (15.9 µmol m(-2) s(-1)) single-event upper-crown artificial defoliation, 3 weeks after defoliation than in undefoliated control trees (12.9 µmol m(-2) s(-1)). This response was consistently observed for up to 11 weeks after the defoliation event; by Week 16, there was no difference in A(max) between control and defoliated trees. In the D50 treatment, this increased A(max) was not sufficient to fully compensate for the foliage loss as evidenced by the reduced diameter increment (by 15%) in defoliated trees 36 weeks after defoliation. In contrast, diameter increment of trees in the D25 treatment was unaffected by defoliation. The A(max) of trees experiencing upper-crown defoliation by natural and repeated E. californica infestations varied, depending on host genotype. Despite clear differences in defoliation levels between resistant and susceptible genotypes (17 vs. 35% of tree crown defoliated, respectively), growth of susceptible genotypes was not significantly different from that of resistant genotypes. The observed increases in A(max) in the lower crown of the canopy following attack suggested that susceptible genotypes were able to partly compensate for the loss of foliage by compensatory photosynthesis. The capacity of P. radiata to regulate photosynthesis in response to natural aphid-induced defoliation provides evidence that the impact of E. californica attack on stem growth will be less than expected, at least for up to 35% defoliation.

Induced resistance to pests and pathogens in trees.

Tree resistance can be enhanced by a variety of biotic and abiotic inducers, including nonpathogenic and pathogenic microbes, and herbivores, resulting in enhanced protection against further biotic injury. Induced resistance (IR) could be a valuable tool in sustainable pest management. IR has been actively studied in herbaceous plant species, and, in recent years, in woody plant species, and is fast emerging as an intriguing, eco-friendly concept for enhancing tree resistance. However, before application of IR becomes possible, there is a need to increase our knowledge of the mechanisms of defence in forest trees. A richer understanding of these phenomena will play a critical role in developing sustainable integrated pest management strategies. This review summarizes our current knowledge of IR in forest trees, focusing on inducible defence mechanisms, systemic induction of resistance and phytohormone signalling networks. We conclude by discussing the potential advantages and limitations of applying IR-based management tools in forest systems.

Shifts in biomass and resource allocation patterns following defoliation in Eucalyptus globulus growing with varying water and nutrient supplies.

In woody species, potential mechanisms to compensate for tissue loss to herbivory and diseases have been related to post-event shifts in growth, biomass and internal resource allocation patterns, as modulated by external resource limitations. We examined the interactive effects of belowground resource limitations by varying nutrient and water availability, and aboveground carbon limitation imposed by a single defoliation event (40% leaf removal) on stem growth, whole-tree and within-tree resource allocation patterns (total non-structural carbohydrate and nitrogen) and below- and aboveground biomass allocation patterns in 8-month-old, field-grown Eucalyptus globulus Labill. saplings. Two months after treatments were imposed, the direction of the stem growth response to defoliation depended on the abiotic treatment. Five months after defoliation, however, we found little evidence that resource availability constrained the expression of tolerance to defoliation. With the exception of the combined low-nutrient and low-water supply treatment, saplings grown with (1) adequate water and nutrient supplies and even with (2) low-water supply or (3) low-nutrient supply were able to compensate for the 40% foliage loss. The observed compensatory responses were attributed to the activation of several short- and longer-term physiological mechanisms including reduced biomass allocation to coarse roots, mobilization of carbohydrate reserves, robust internal N dynamics and increased ratio of foliage to wood dry mass.

Defoliation and nitrogen effects on photosynthesis and growth of Eucalyptus globulus.

Plant responses to defoliation are complex. We established a field experiment in a nine-month-old Eucalyptus globulus Labill. plantation to examine the effects of pattern (upper crown versus lower crown removal), frequency (single, double or triple defoliation within a 12-month period) and severity (25 versus 38% of leaf area removed) of defoliation and the effect of soil nitrogen (N) on photosynthetic processes and stem growth. The photosynthetic responses observed following defoliation could be attributed to changes in source:sink ratios. Light-saturated CO(2) uptake (A(max)) increased with increasing severity and frequency of defoliation irrespective of defoliation pattern. Seedlings defoliated in autumn did not exhibit increases in A(max) until the following spring, whereas there was no such delay in photosynthetic responses associated with spring defoliation. Application of N before defoliation allowed trees to compensate for the effect of defoliation on stem diameter growth, which could not be explained simply in terms of increases in A(max). The observed increases in stem diameter increment following N fertilization of defoliated trees suggested increases in leaf area development, and there were changes in the leaf area:leaf dry mass ratio that may have increased light absorption by the crown. Nitrogen fertilization also increased partitioning of dry mass to branches at the expense of main stems, suggesting that N supply was important in rebuilding crowns following a defoliation event.

Physiology and anatomy of lenticel-like structures on leaves of Eucalyptus nitens and Eucalyptus globulus seedlings.

Intumescences or abnormal, non-pathogenic, blister-like protuberant growths, form on Eucalyptus globulus Labill. and, to a much lesser extent, Eucalyptus nitens (Deane and Maiden) Maiden leaves when plants are grown in a high relative humidity environment. We examined the histology of intumescences and their effects on leaf photosynthetic processes. Intumescences were induced by placing E. globulus and E. nitens seedlings in a relative humidity of 80% in a greenhouse for 5 days. Symptomatic and asymptomatic leaves of plants with intumescence development were compared with leaves of control plants. Light-saturated carbon dioxide (CO(2)) assimilation (A(max)) and responses of CO(2) assimilation (A) to varying intercellular CO(2) partial pressure (C(i)) were measured. Symptomatic and asymptomatic leaf samples were fixed and sectioned and cellular structure was examined. Intumescences greatly reduced the photosynthetic capacity of E. globulus leaves and were associated with reduced electron transport rate and ribulose bisphosphate (RuBP) regeneration capacity. Tissue necrotization and cellular collapse of the palisade mesophyll and deposition of phenolic compounds in the affected areas, probably reduced light penetration to photosynthesizing cells as well as reducing the amount of photosynthesizing tissue. Photosynthetic capacity of E. nitens was unaffected. The intumescences resembled simple lenticels, both morphologically and developmentally. To our knowledge, this is the first time that lenticel-like structures developed in response to environmental conditions have been described on leaves.

Comparison of antifungal and antioxidant activities of Acacia mangium and A. auriculiformis heartwood extracts.

The effect of heartwood extracts from Acacia mangium (heartrot-susceptible) and A. auriculiformis (heartrot-resistant) was examined on the growth of wood rotting fungi with in vitro assays. A. auriculiformis heartwood extracts had higher antifungal activity than A. mangium. The compounds 3,4',7,8-tetrahydroxyflavanone and teracacidin (the most abundant flavonoids in both species) showed antifungal activity. A. auriculiformis contained higher levels of these flavonoids (3.5- and 43-fold higher, respectively) than A. mangium. This suggests that higher levels of these compounds may contribute to heartrot resistance. Furthermore, both flavonoids had strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and laccase inhibition. This suggests that the antifungal mechanism of these compounds may involve inhibition of fungal growth by quenching of free radicals produced by the extracellular fungal enzyme laccase.

Novel detection of formylated phloroglucinol compounds (FPCs) in the wound wood of Eucalyptus globulus and E. nitens.

This study characterized the chemical responses of Eucalyptus globulus and Eucalyptus nitens to artificial inoculation with a basidiomycete decay fungus. Nine-year-old trees responded to mechanical wounding or inoculation with the decay fungus by producing new wound wood characterized by the presence of dark extractives 17 months after wounding. Analysis of crude wound wood extracts by HPLC coupled to negative ion electrospray mass spectrometry revealed the presence of a complex mixture of many unidentified formylated phlorglucinol compounds (FPCs), in addition to a diverse range of other polyphenolic compounds (hydrolyzable tannins, proanthocyanidins, flavanone glycoside, stilbene glycosides). Prior to this study, FPCs have only been reported from leaves and buds of Eucalyptus spp. Unequivocal evidence for the presence of macrocarpal A and B, and sideroxylonal A and B in the crude extracts was obtained, as well as evidence for a wide range of as yet unreported FPCs. Subsequent preliminary in vitro fungal and bacterial bioassays did not support an antimicrobial role for FPCs in host-pathogen interactions in eucalypts.

Species delimitation in the African Armillaria complex by analysis of the ribosomal DNA spacers.

Thirteen Armillaria isolates, collected from various geographical areas in tropical Africa and previously characterized by cultural morphology, pairing tests and isozyme analysis, were evaluated using the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). DNA regions corresponding to the intergenic spacer (IGS) and internal transcribed spacer (ITS) were amplified and analyzed by restriction enzyme digestion. The IGS amplification products were about 875 bp long and uniform in length among the isolates. The amplified-ITS region showed two different lengths corresponding to two groups. The first group included the isolates believed to belong to A. mellea ssp. africana and two Kenyan isolates (K11 and K12) belonging to a yet unnamed biological species. The second group included isolates identified as A. heimii and a Tanzanian isolate (T7). Each length variant of the ITS showed distinct RFLP banding patterns. Digestion with EcoRI confirmed the two polymorphic groups while the endonucleases AluI and NdeII discriminated the A. mellea isolates from the Kenyan isolates K11 and K12. In addition, the latter enzyme showed a slight dissimilarity between the A. heimii isolates from Western and Eastern Africa (C1 and Z1). Digestion with HinfI cleaved the isolates of A. heimii into two sub-groups corresponding to the heterothallic and homothallic forms. This endonuclease also indicated that the isolate T7, originating from Tanzania, was clearly similar to the heterothallic species A. heimii. Data presented support the maintenance of three distinct species of Armillaria in tropical Africa with A. heimii as a variable species, the isolates of which were separated in accordance with their sexual system. The results indicate that PCR-RFLP can be used as a simple and speedy taxonomical tool for the ecological studies of Armillaria species.