Effects of biotic and abiotic stress on induced accumulation of terpenes and phenolics in red pines inoculated with bark beetle-vectored fungus

This study characterized the chemical response of healthy red pine to artificial inoculation with the bark beetle-vectored fungusLeptographium terebrantis. In addition, we sought to determine whether stress altered this induced response and to understand the implications of these interactions to the study of decline diseases. Twenty-five-year-old trees responded to mechanical wounding or inoculation withL. terebrantis by producing resinous reaction lesions in the phloem. Aseptically wounded and wound-inoculated phloem contained higher concentrations of phenolics than did constitutive tissue. Trees inoculated withL. terebrantis also contained higher concentrations of six monoterpenes,-pinene,-pinene, 3-carene, limonene, camphene, and myrcene, and higher total monoterpenes than did trees that were mechanically wounded or left unwounded. Concentrations of these monoterpenes increased with time after inoculation. Total phenolic concentrations in unwounded stem tissue did not differ between healthy and root-diseased trees. Likewise, constitutive monoterpene concentrations in stem phloem were similar between healthy and root-diseased trees. However, when stem phloem tissue was challenged with fungal inoculations, reaction tissue from root-diseased trees contained lower concentrations of-pinene, the predominant monoterpene in red pine, than did reaction tissue from healthy trees. Seedlings stressed by exposure to low light levels exhibited less extensive induced chemical changes when challenge inoculated withL. terebrantis than did seedlings growing under higher light. Stem phloem tissue in these seedlings contained lower concentrations of-pinene than did nonstressed seedlings also challenge inoculated withL. terebrantis. It is hypothesized that monoterpenes and phenolics play a role in the defensive response of red pine against insect-fungal attack, that stress may predispose red pine to attack by insect-fungal complexes, and that such interactions are involved in red pine decline disease. Implications to plant defense theory and interactions among multiple stress agents in forest decline are discussed.To whom correspondence should be addressed at USDA Forest Service, 2500 Shreveport Hwy., Pineville, Louisiana 71360.     

Treatment costs in a medical intensive care unit: a comparison of 1992 and 1997

BACKGROUND AND OBJECTIVE: Treatment in an intensive care unit (ICU) is very expensive. Aim of this study was to determine the exact composition of costs and to analyse what factors are responsible for the rise in costs over the last 5 years. METHODS: In a prospective investigation all 790 patients who had been treated at the ICU of the Medical Department of Frankfurt University during 1992 were included, findings being compared with data on all 208 patients treated in the ICU in May and June 1997. All important diagnostic and therapeutic measures were quantitatively determined each day. RESULTS: The mean age of the ICU patients rose in the 5 years from 55 to 59 years (P < 0.001). Mean period of stay in the ICU remained unchanged (4.1 days), total duration of hospital stay (15 and 12 days, respectively), and treatment intensity (sum of points according to the "Therapeutic Intervention Scoring System" per ICU stay: 96 and 77, respectively). The mortality rate in the ICU fell from 16.3% to 10.6% (P = 0.02), hospital mortality rate from 23% to 14% (P = 0.01). Total cost rose from DM 797,860 to DM 1,148,945 per 100 patients (+44%). Of this total, personnel costs were DM 286,885 in 1992 and 356,091 in 1997 (+24%), costs for apparatus-based diagnostic and therapeutic tests were DM 169,743 and 245,156, respectively (+44%), DM 98,496 and 129,222 for drugs (+31%), and DM 60,399 and 186,671 (+209%) for blood and clotting products (in each category per 100 patients). Per case costs rose from DM 7970 to 11,489, per day costs from DM 1943 to 2831. 90% of cost increases were due to new strategies in the treatment of patients with myocardial infractions and those with severe clotting disorders and a rise in personnel costs. CONCLUSION: The costs of a stay in the ICU has greatly increased over the last 5 years, the main causes being a change to new forms of treatment, especially in patients with myocardial infarction and those with haemophilia.     

Sympathetic re-innervation after heart transplantation: dual-isotope neurotransmitter scintigraphy, norepinephrine content and histological examination

Cardiac transplantation entails surgical disruption of the sympathetic nerve fibres from their somata, resulting in sympathetic denervation. In order to investigate the occurrence of sympathetic re-innervation, neurotransmitter scintigraphy using the norepinephrine analogue iodine-123 metaiodobenzylguanidine (MIBG) was performed in 15 patients 2-69 months after transplantation. In addition, norepinephrine content and immunohistochemical reactions of antibodies to Schwann cell-associated S100 protein, to neuron-specific enolase (NSE) and to norepinephrine were examined in 34 endomyocardial biopsies of 29 patients 1-88 months after transplantation. Anterobasal 123I-MIBG uptake indicating partial sympathetic re-innervation could be shown in 40% of the scintigraphically investigated patients 37-69 months after transplantation. In immunohistochemical studies 83% of the patients investigated 1-72 months after transplantation showed nerve fibres in their biopsies but not positive reaction to norepinephrine. Significant norepinephrine content indicating re-innervation could not be detected in any biopsy. It was concluded that in spite of the lack of norepinephrine content there seemed to be immunohistological and scintigraphic evidence of sympathetic re-innervation. An explanation for this contradictory finding may be the reduced or missing norepinephrine storage ability compared to the restored uptake ability of regenerated sympathetic nerve fibres.     

Combined chemical defenses against an insect-fungal complex

This study considered how host plant allelochemicals may contribute to defense against insects and fungi that jointly colonize the subcortical tissues of trees, the relative roles of constitutive and inducible chemistry in these defenses, and how the actions of two different feeding guilds might be interrelated. Our model consisted of the coniferous treePinus resinosa, the root- and lower stem-colonizing beetlesHylastes porculus andDendroctonus valens, and their associated fungiLeptographium procerum andL. terebrantis, and the stem-colonizing bark beetleIps pini and its associated fungusOphiostoma ips. In a novel bioassay, extracts from reaction tissue elicted by wound inoculation withL. terebrantis were more repellent to beetles than were similar extracts from constitutive or mechanically wounded tissue. The effect on beetle behavior was more pronounced in nonpolar extracts, which contain mostly monoterpenes, than in polar extracts, which contain mostly phenolics. Synthetic monoterpenes at concentrations present in the various tissues exerted similar effects and were likewise repellent in dose-response experiments. Growth ofL. procerum andL. terebrantis was inhibited by polar extracts from constitutive and reaction tissue. Inhibition was higher in wounded than control tissue, but the inhibition response did not vary with the type of wounding. Synthetic monoterpenes strongly inhibited spore germination and mycelial growth of both fungi. Colonization of red pine roots byLeptographium spp. altered the subsequent effects of extracts of stem phloem tissue onI. pini. These effects varied with host condition. Beetles preferred extracts from constitutive stem phloem tissue of healthy trees to that of root-diseased trees. However, extracts from reaction tissues of healthy trees were more repellent toI. pini than were the reaction tissues of root-diseased trees. The implications of these results to plant defense against insect-fungal complexes and interactions among different feeding guilds are discussed.     

Effects Of Tree Phytochemistry On The Interactions Among Endophloedic Fungi Associated With The Southern Pine Beetle

We examined the interaction between host trees and fungi associated with a tree-killing bark beetle, Dendroctonus frontalis. We evaluated (1) the response of four Pinus species to fungal invasion and (2) the effects of plant secondary metabolites on primary growth of and secondary colonization of three consistent fungal associates. Two of these fungi, Entomocorticium sp. A and Ophiostoma ranaculosum, are obligate mutualists with D. frontalis, and the third associate is a blue-staining fungus, O. minus, that is commonly introduced by beetles and phoretic mites. O. minus negatively affects beetle larvae and in high abundance can impact D. frontalispopulation dynamics. Size of lesions formed and quantity of secondary metabolites produced in response to fungal inoculations varied significantly among Pinus species. However, monoterpene composition within infected tissue did not significantly vary across treatments. While all eight tested metabolites negatively affected the growth rate of O. minus, only 4-allylanisole, p-cymene, and terpinene reduced the growth of the mycangial fungi. Surprisingly, growth rates of mycangial fungi increased in the presence of several secondary metabolite volatiles. O. minus out-competed both mycangial fungi, but the presence of secondary metabolites altered the outcome slightly. O. ranaculosum out-performed E. sp. A in the presence of dominant conifer monoterpenes, such as - and -pinene. Volatiles from the mycangial fungi, particularly E. sp. A, had a negative effect on O. minus growth. In general, phloem phytochemistry of particular Pinus species appeared to alter the relative growth and competitiveness of mutualistic and non-mutualistic fungi associated with D. frontalis. The outcome of interactions among these fungi likely has important consequences for the population dynamics of D. frontalis.     

Electrophysiological and Olfactometer Responses of Two Histerid Predators to Three Pine Bark Beetle Pheromones

We measured electrophysiological responses in the antennae of two predaceous hister beetles, Platysoma parallelum and Plegaderus transversus, exposed to racemic mixtures of primary aggregation pheromones of scolytid bark beetle prey, ipsenol, ipsdienol, and frontalin. No significant differences were found for either histerid species between male and female antennal responses to any of the three pheromones. Measurement of antennal threshold responses indicated that Pla. parallelum has increasing antennal sensitivity to ipsdienol, ipsenol, and frontalin. In contrast, Ple. transversus exhibited similar detection thresholds to all three pheromones. Pla. parallelum antennae exhibited different response amplitudes to the three pheromones at quantities above the detection threshold, while Ple. transversus had similar responses to each. Behavioral responses to the same three pheromones were evaluated for both histerid species using pedestrian olfactometer bioassays. Both species were attracted to frontalin and ipsenol, but not ipsdienol. Pla. parallelum was significantly more attracted to frontalin than ipsenol, while Ple. transversus showed no significant preference for either compound. Our results suggest that histerids that prey upon pine bark beetles may have different host or host habitat preferences, which could reduce interspecific competition.     

Perpendicular Alignment of 2D Nanoplatelet Emitters in Electrospun Fibers: A Result of the Barus Effect?

Stable jet electrospinning (SJES) is a special form of optical fiber generation that prevents chaotic fiber whipping typical for conventional electrospinning procedures. Incorporation of highly emissive semiconductor nanoplatelets (NPLs) in such fibers has very high potential in optical data transmission, optological circuits, fiber lasers, solar light concentrators and many other fields because NPLs exhibit strongly directed emission from their surface plane due to various in-plane transition dipole moments. However, potential orientation control of 2D-NPLs in SJES is entirely unknown as electric fields and various mechanical forces contribute in a complex manner simultaneously. Here, the observation of counter-intuitive yet very beneficial orientation of rectangular CdSe/CdS 2D-NLP in SJES perpendicular to the fiber drawing axis is reported. Scanning electron microscopy, 3D-single particle excitation polarization microscopy, 3D-photogoniometry, polarized emission spectroscopy and small angle X-ray scattering (SAXS) demonstrate aggregation free perpendicular alignment of the NPLs in poly(methyl methacrylate) (PMMA) fibers, resulting in dominant emission in directions parallel to the fiber. It is suggested that the observed vertical alignment is due to normal forces resulting from viscoelastic expansion when the polymer solution leaves the cannula (Barus effect) and that using such perpendicular nano-emitter alignment forces allows for the generation of novel materials also beyond fibers.     

Physico-chemical characterization of walnut shell biochar from uncontrolled pyrolysis in a garden oven and surface modification by ex-situ chemical magnetization

The shells of walnuts (WS) are major refuse in the global fruits and nuts trade. This, otherwise discarded, lignin-rich material can be carbonized to biochar—a value-added product with environmental applications such as carbon sequestration, soil amelioration, and pollutant adsorption. These applications are dictated by structural and chemical characteristics of the biochar carbon. Conventional controlled pyrolysis (CPy) of biomass is cost-intensive and technically too complex for widespread adoption, especially in emerging economies. Here, walnut shell biochar (BWS0) is derived through uncontrolled pyrolysis (UCPy) in a pyrolysis oven and further hybridized as magnetic biochar through ex-situ chemical co-precipitation. The physico-chemical characteristics of biochar and its water-extractable fractions are comprehensively investigated to understand their carbon structure and environmental applicability. The sp² amorphous carbon sequestered in BWS0 is 0.84 kg_CO2/kg_biomass with a BET (N₂) surface area of 292 m²/g and is comparable to biochar from CPy in terms of carbon structure. The polyaromatic hydrocarbons present are only trace amounts of naphthalene, biphenyl, and phenanthrene. The magnetization decreases porosity of BWS0 while greatly facilitating its separation from aqueous media. BWS0 is suitable for adsorption of cations (between pH 2.8 and 9.45) and hydrophobic pollutants with only 19 mg L⁻¹ fouling from their intrinsic dissolved organic carbon. In combination with fast-release N, P fertilizers, BWS0 (C/N of 24.8) is suitable for application in hydrophilic soils at higher loading rates. The results suggest an avenue where WS biochar can also be prepared via UCPy for direct environmental applications. Future investigations into soil incubation and adsorption tests are recommended.

Graphical abstract