Nematotoxic activity of essential oils from <Emphasis Type="Italic">Monarda</Emphasis> species

Bioactivity of essential oils (EOs) from Monarda species has never been investigated on phytoparasitic nematodes. In this study, the EOs from two Italian ecotypes of Monarda didyma and M. fistulosa and their main compounds, carvacrol, γ-terpinene, o-cymene, and thymol, were evaluated for their in vitro activity on the infective stages of phytoparasitic nematodes Meloidogyne incognita and Pratylenchus vulnus, as well as on M. incognita egg hatch. Soil treatments with the two EOs were also investigated for their suppressiveness on M. incognita on tomato. Both EOs were strongly active on M. incognita juveniles, as a only 1.0 μL mL^?1 LC50 value was evaluated after a 24-h exposure to both EOs, whereas a lower activity was recorded on P. vulnus (15.7 and 12.5 μL mL^?1 LC50 values for M. didyma and M. fistulosa EOs, respectively). Among the EOs’ main compounds, carvacrol was highly active also at a short exposure in low concentrations, whereas γ-terpinene and thymol were much less active on both nematode species and o-cymene showed a discrete activity on P. vulnus only at the highest concentration. Hatch percent of M. incognita eggs treated with M. didyma and M. fistulosa EOs was always significantly lower than in water or in Tween 20 and Oxamyl solutions. In the experiment in soil, the multiplication of M. incognita and gall formation on tomato roots was significantly reduced by soil treatments with both EOs. The strong nematicidal activity of both Monarda EOs may suggest them as potential sources of new sustainable nematicidal products.     

Insecticidal properties of <Emphasis Type="Italic">Thymus persicus</Emphasis> essential oil against <Emphasis Type="Italic">Tribolium castaneum</Emphasis> and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT₅₀) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT₅₀ values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC₅₀ values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.     

Insecticidal activity of synthetic antioxidants,natural phytochemicals,and essential oils against an <Emphasis Type="Italic">Aspergillus</Emphasis> section <Emphasis Type="Italic">Flavi</Emphasis> vector (<Emphasis Type="Italic">Oryzaephilus surinamensis</Emphasis> L.) in microcosm

The purpose of this study is to investigate the insecticidal activity of two benzoic acids 2(3)-tert-butyl-4 hydroxyanisole (BHA) and 2,6-di(tert-butyl)-p-cresol (BHT); two phenolic acids 3-phenyl-2-propenoic acid (CA) and trans-4-hydroxy-3-methoxycinnamic acid (FA); and two essential oils of Eugenia caryophyllata (clove tree) and Thymus vulgaris (thyme) against Oryzaephilus surinamensis (L.) vector carrier of aflatoxigenic fungi on stored peanut. The weight loss of peanut, susceptibility of insects, Aspergillus isolation frequency from insects and peanut, and aflatoxin B₁ analyses from peanut were determined. BHA, BHT, and BHA/BHT mixture were highly effective against O. surinamensis, these chemical agents give 100% mortality at the doses assayed. Essential oil of thyme at 2,000 and 3,000 ppm were highly effective against O. surinamensis, these concentrations gave 100% mortality. No Aspergillus section Flavi contamination was observed in dead insects collected from peanut treated with BHA/BHT mixture. No differences were observed in the fresh weight of pods peanut among treatments with and without chemical agents. All samples of treated peanut pods showed complete inhibition of this toxin after 120 days of storage. Our results indicate that these substances could be evaluated further for the control of pest vectors of aflatoxigenic fungi of stored peanut.     

Composition and antitermite activities of essential oils from <Emphasis Type="Italic">Melaleuca</Emphasis> species

 The composition and antitermite activities of nine essential oils from two Melaleuca species, gelam and cajuputi, were compared using gas chromatography–mass spectrometry analysis and bioassays. Gelam oils were rich in compounds whose boiling points were high, and they were separated into the elemene-rich type and the γ-terpinene- and terpinolene-rich type. Cajuputi oils in this experiment were categorized into three chemotypes according to their 1,8-cineole content: high, low, none. In the termiticidal activity test, gelam oils were stronger than most cajuputi oils in the contact condition. The elemene-rich gelam lost its activity in the noncontact condition, whereas another type of gelam kept its termiticidal activity. The authentic sample of elemene showed the same result as the elemene-rich gelam, indicating that the termiticidal activity of gelam was caused by at least two types of compound: elemene and “others.” 1,8-Cineole exhibited the same tendency as elemene, but it was weak. Hence the 1,8-cineole content of cajuputi was irrelevant to termiticidal activity of samples that exhibited strong activity under both conditions despite their high content. The appearances of gelam and cajuputi leaves are easily confused, a problem that has not yet been solved. Other scientific methods, such as genetic analysis, are required to identify gelam. The difference in the compositions and antitermite activities, however, were charified in this experiment. Received: November 30, 2001 / Accepted: June 5, 2002 Correspondence to:M. Yatagai     

Biological performance of <Emphasis Type="Italic">Eucalyptus camaldulensis</Emphasis> leaf oils from Thailand against the subterranean termite <Emphasis Type="Italic">Coptotermes formosanus</Emphasis> Shiraki

The antitermitic activities of leaf oils and their constituents, taken from three clones of Eucalyptus camaldulensis Dehnh. in Thailand, against Coptotermes formosanus Shiraki were investigated in contact and noncontact tests. The termiticidal mechanism was also examined. Antitermitic tests demonstrated that E. camaldulensis leaf oils were both contact toxicants and fumigants to C. formosanus with LC₅₀ values ranging between 12.68 and 17.50 mg/g by the contact method, and between 12.65 and 17.50 mg/petri dish (100 cm³) by the noncontact method. p-Cymene and γ-terpinene were primarily responsible for the contact toxicity and 1,8-cineole was responsible for fumigation. From the investigation of termiticidal mechanism, E. camaldulensis leaf oils exhibited the inhibition of acetylcholinesterase activity and showed the common symptoms of a neurotoxic mode of action against C. formosanus. Part of this report was presented at the 58th Annual Meeting of the Japan Wood Research Society, Tsukuba, March 2008     

Antibacterial activity of Nepalese wild mushrooms against <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> and <Emphasis Type="Italic">Propionibacterium acnes</Emphasis>

The present study aims to reveal the antibacterial potential of the wild mushrooms of Nepal. Despite the recognition of the medicinal potential of the natural resources in this country, a systematic study on the bioactivities of the wild mushrooms is still lacking. Therefore, in an attempt to fill this gap, ethanol extracts of 90 Nepalese wild mushroom samples were tested for antibacterial activity against Staphylococcus aureus and Propionibacterium acnes. Staphylococcus aureus was comparatively more susceptible with Inonotus clemensiae exhibiting the least minimum bactericidal concentration (MBC) of 100 μg/mL. The major compound in I. clemensiae was identified to be hispidin using high resolution liquid chromatography–electron spray ionization mass spectrometry (LC–ESI-MS) and nuclear magnetic resonance (NMR) analyses. Furthermore, the minimum inhibitory concentration (MIC) and MBC values of hispidin were determined to be 25 and 100 µg/mL for S. aureus and P. acnes, respectively. These findings show that the Nepalese wild mushrooms have the potential to be a novel addition to the functional ingredients industry due to their strong antibacterial potential.     

Successful <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of <Emphasis Type="Italic">Populus tomentosa</Emphasis> with apple <Emphasis Type="Italic">SPDS</Emphasis> gene

The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase （SPDS） genes derived from an apple by an Agrobacterium-mediated method. Four transgenic clones were confu＇med by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.     

Aboveground biomass equations for individual trees of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis>, <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> and <Emphasis Type="Italic">Larix kaempferi</Emphasis> in Japan

Generic equations are proposed for stem, branch and foliage biomass of individual trees in even-aged pure stands of Cryptomeria japonica, Chamaecyparis obtusa and Larix kaempferi. Biomass data was collected from a total of 1,016 individual trees from 247 stands throughout Japan, and five regression models were assessed by root mean square error, mean bias, fit index (FI), and AIC. The results show that a power equation using diameter at breast height (dbh) and height is the most suitable for all species and components. This equation is more accurate than the familiar power equation that uses ‘dbh² height’, and it expresses the greater volume of branch and foliage mass of trees with a lower height/diameter ratio. A power equation using dbh is more reasonable for models with dbh as the only independent variable and more accurate than a power equation using ‘dbh² height’ for estimating branch and foliage mass. Estimating error for branch and foliage mass is larger than that for stem mass, but the entire aboveground biomass can be estimated with an error of less than 19%, except in the case of small trees with dbh less than 10 cm.     

Comparative efficacy of NeemAzal and local botanicals derived from <Emphasis Type="Italic">Azadirachta indica</Emphasis> and <Emphasis Type="Italic">Plectranthus glandulosus</Emphasis> against <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> on maize

The efficacy of NeemAzal powder, two local neem (Azadirachta indica ) products [neem seed powder (NSP) and neem seed oil (NSO)], as well as a local Lamiaceae, Plectranthus glandulosus leaf powder, applied at four different rates for the control of Sitophilus zeamais was determined. Mortality was recorded 1, 3, 7 and 14 days after S. zeamais infestation, followed by the determination of F₁ progeny production. Grain damage, population increase and grain germination were assessed for treated grains that were stored for 4 months. Grains treated with P. glandulosus powder and NSP had relatively low mortality (5.0–22.5%) after 3 days whereas NeemAzal and NSO had higher mortality (55.0–98.8%). Maximum mortality of 99, 100, 96 and 74% were achieved for NeemAzal (12 g/kg after 14 days), NSO (4 ml/kg after 7 days), NSP (40 g/kg after 14 days) and P. glandulosus powder (40 g/kg, after 14 days), respectively. In the same order, 7-day LC₅₀ values were 0.02 g/kg, 1.46 ml/kg, 12.44 g/kg and 28.9 g/kg. The three neem products greatly reduced progeny emergence, while P. glandulosus powder was less effective. NeemAzal protected the grains against S. zeamais damage better than the local neem products, which in turn provided far better grain protection against the weevil damage than P. glandulosus powder. NeemAzal was superior to the local neem products in grain protection against germination loss, with P. glandulosus being the least effective. NeemAzal and NSO had sufficient efficacy to be a component of an integrated management package for S. zeamais.     

Antibacterial activity of moso bamboo shoot skin (<Emphasis Type="Italic">Phyllostachys pubescens</Emphasis>) against <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

This study examined the antibacterial activity of moso bamboo shoot skin (Phyllostachys pubescens). Bamboo shoot skin itself and its dichloromethane extract had antibacterial activity against Staphylococcus aureus. Results suggest the possibility of effective utilization of antibacterial materials from bamboo shoot skins that are mainly discarded at present.     

An inoculation experiment of Japanese <Emphasis Type="Italic">Bursaphelenchus</Emphasis> nematodes on Japanese black and red pine, <Emphasis Type="Italic">Pinus thunbergii</Emphasis> and <Emphasis Type="Italic">P. densiflora</Emphasis>

The pinewood nematode (PWN) Bursaphelenchus xylophilus is an invasive pathogen that was introduced from North America to Asian countries and Portugal and is devastating native pine forests. Some native European and Asian Bursaphelenchus nematodes also have weak to moderate pathogenicity to native pine species. To evaluate the potential risk of native Bursaphelenchus species, we inoculated ten Japanese Bursaphelenchus species into native pine species (the dominant forest species) in Japan, and evaluated their pathogenicity using mortality and tracheal tissue damage as indices. Inoculation was conducted on August 3, 2007, and the symptoms were observed every 2 weeks until February 1, 2008. None of the inoculated trees, excluding the pathogenic PWN inoculated control, showed external disease symptoms; however, four species [a less pathogenic PWN isolate, B. luxuriosae, Bursaphelenchus sp. NK215 (undescribed), and NK224 (undescribed)] caused tracheal tissue damage in inoculated seedlings and showed weak pathogenicity. Therefore, we conclude that there are some potentially pathogenic native species of nematodes distributed in Japan. Interestingly, two of these weakly pathogenic species, B. luxuriosae and NK215, are not associated with Pinaceae trees, suggesting that nematode pathogenicity may be a pre-adaptive character. More experimental studies under different conditions are necessary to accurately evaluate the potential risk of these pathogens.     

Chemical composition and anti-inflammatory activity of <Emphasis Type="Italic">Boswellia ovalifoliolata</Emphasis> essential oils from leaf and bark

We isolated the essential oils from Boswellia ovalifoliolata N.P.Balakr and A.N.Henry using hydrodistillation, identified the obtained compounds using gas chromatography–mass spectrometry (GC–MS) and Fourier transform-infrared spectroscopy (FT-IR), and studied the photophysical and electrochemical properties using UV–visible and fluorescence spectroscopy and cyclic voltammetry. On the basis of GC–MS spectra, 38 compounds were identified in the essential oil from leaves and 26 in the oil from bark. The bark oil contained 13.44% β-Farnesene (sesquiterpene), 10.45% caryophyllene oxide (sesquiterpene) and 6.6% spathulenol, (2Z,6E)-(sesquiterpene alcohol); the leaf oil contained 11.1% spathulenol (sesquiterpene alcohol), 9.0% caryophyllene oxide (sesquiterpenoids) and 6.3% decyl acetate (ester). FT-IR spectra confirmed the presence of aliphatic aldehydes and ketones, carboxylic acid, alcohols, esters and ethers in both oil types. UV–visible absorption spectra showed maximum absorbance at 245, 290 and 402 nm for bark oil, and 250, 285 and 325 nm for leaf. Bark oil showed strong emission with maximum emission wavelength at 456 nm was higher than that of leaf oil at 414 nm. The essential oil had significant anti-inflammatory activity, and the reduction potential of the leaf oil was ?0.44 and ?0.56 eV for bark.     

Effectiveness of Neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) insecticides against Brassica pod midge (<Emphasis Type="Italic">Dasineura brassicae</Emphasis> Winn<Emphasis Type="Italic">.</Emphasis>)

The efficiency of the botanical insecticide (BI) NeemAzal T/S (containing 1% Azadirachtin A), on the basis of azadirachtin applied in a dose of 20 g a.i. ha⁻¹ against Brassica pod midge (Dasineura brassicae), has been monitored for 4 years. The biological efficiency of BI was compared with the efficiency of some synthetic insecticides. It was ascertained that BI was very efficient in decreasing the number of damaged oilseed rape pods (ranging from 56.5 to 85.9% compared to untreated plants) and its efficiency was comparable with synthetic insecticides based on Chloronicotinyl (Thiacloprid) and Neonicotinoid (Acetamiprid). BI’s efficiency was, in some years, even significantly higher compared to pyrethroid (λ-cyhalothrin). The high biological efficiency of azadirachtin that we ascertained was significantly reflected in increasing potential crop yields. The yield increase of azadirachtin ranged between 9.3 and 19.4% compared to the control sample. Azadirachtin showed the highest yield for the whole time of experimentation, and in some years the yield increase was significantly higher compared to some synthetic agents.     

Lethal and sublethal responses of <Emphasis Type="Italic">Sitophilus zeamais</Emphasis> populations to essential oils

The present study aimed to assess the lethal and sublethal responses of five populations of S. zeamais to the essential oils of Ocimum basilicum and Piper hispidinervum, through toxicity, locomotor behavior (flight and walking activities) and physiological (respiration rate and body mass) evaluations. The populations of S. zeamais were obtained from Machado—MG, Paracatu—MG, Piracicaba—SP, Recife—PE and Tunápolis—SC. To estimate the LC₅₀ of each oil for each population, fumigation tests were performed. The population from Recife exhibited the lowest instantaneous rate of increase (ri) as well the lowest consumption of grain mass. However, Piracicaba was considered the susceptibility pattern, presenting the lowest LC₅₀ for both essential oils, no statistical difference was observed among populations or treatments in the flight activity bioassays. The essential oils effect on walking activity and respiration rates varied among populations. The population from Recife presented the highest walked distance and walk speed, with the lowest resting time and number of stops, as well as the lowest respiration rate and body mass. The present study highlights the importance of the study on population responses, as the five populations of S. zeamais exhibited different patterns of toxic and behavioral effects when subjected to the essential oils of P. hispidinervum and O. basilicum.     

Antifungal agents from heartwood extract of <Emphasis Type="Italic">Taiwania cryptomerioides</Emphasis> against brown root rot fungus <Emphasis Type="Italic">Phellinus noxius</Emphasis>

Taiwania (Taiwania cryptomerioides Hayata) is a native and plantation species in Taiwan, and its heartwood has demonstrated excellent decay resistance. Brown root rot fungus Phellinus noxius has caused severe damage to more than 100 tree species in Taiwan. The aims of this study were to investigate the antifungal activities of Taiwania heartwood extracts against P. noxius and to identify the antifungal compounds. Antifungal activities were examined using the agar dilution method (a direct contact assay) and the inverted lid method (a vapor contact assay). Active compounds were purified using liquid–liquid partition, open-column chromatography and HPLC. Among four soluble fractions (n-hexane, ethyl acetate, n-butanol and water soluble fractions), results showed that n-hexane soluble fraction (HSF) can significantly inhibit the growth of P. noxius via the agar dilution method. Moreover, active compounds present in HSF were obtained using antifungal assay-guided fractionation. Results showed that ferruginol, T-cadinol, α-cadinol and T-muurolol were found to exhibit excellent antifungal activities against P. noxius, and their IC₅₀ values were 16.9, 25.8, 33.8 and 50.6 μg/mL, respectively. According to the current findings, phytochemicals (ferruginol, T-cadinol, α-cadinol and T-muurolol) of Taiwania heartwood had the potential to be used as environmentally benign antifungal agents against P. noxius in place of synthetic or inorganic fungicides.     

Aphidicidal activity of some indigenous plant extracts against bean aphid <Emphasis Type="Italic">Aphis </Emphasis><Emphasis Type="Italic">craccivora</Emphasis> Koch (Homoptera: Aphididae)

Aphidicidal activity of hot and cold water extracts of some indigenous plants, Azadirachta indica A. Juss (neem), Calotropis procera (Aiton) W.T. Aiton (akanda), Polygonum hydropiper L. (biskatali) and Ipomoea sepiaria J. Koenig ex Roxb. (bankalmi), were tested against the bean aphid, Aphis craccivora Koch. Hot water extract of P. hydropiper and A. indica was found to be the most effective (87.6–94.5 and 80.47–89.6% mortality respectively, P < 0.01) among all the extracts. Other hot and cold water extracts also appeared to be useful (59.5–87.5% mortality) as pesticides for A. craccivora. The highest yield (3.25 kg per plant) was obtained using hot water extract of P. hydropiper followed by hot water extract of A. indica (3.15 kg per plant). The lowest yield (0.32 kg per plant) was recorded from the control block. All the phytoproduct treatments had significantly (P < 0.01) better yield than the control block.     

Resistance of wood from black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> var. <Emphasis Type="Italic">austriaca</Emphasis>) against weathering

At present tapped wood of black pines (Pinus nigra var. austriaca) is mainly combusted. The priority of material use over thermal recycling has led to some considerations regarding the utilization of tapped wood. The high content of extractives suggests a higher natural durability, and therefore, the suitability for outdoor applications. Tapped and not tapped wood boards from black pine (sapwood and heartwood) were subjected to weathering tests to find out its resistance against abiotic stress. Additionally tapped wood particles with a high content of resin were exposed to weathering and to composting. Weathering caused roughness to increase. Infrared spectral characteristics revealed the differences before and after tapping and weathering. Principal component analyses supported the grouping according to the chemical changes. In heartwood the lignin band at 1510 cm^??1 disappears and the typical resin band at 1688 cm^??1 decreases considerably. The lignin band of resinous parts is affected neither by weathering nor by composting. However, the resin band shows an intensity decrease and broadening due to weathering and disappears during composting.     

Bioremediation of CCA-treated wood by brown-rot fungi <Emphasis Type="Italic">Fomitopsis palustris</Emphasis>, <Emphasis Type="Italic">Coniophora puteana</Emphasis>, and <Emphasis Type="Italic">Laetiporus sulphureus</Emphasis>

This study evaluated oxalic acid accumulation and bioremediation of chromated copper arsenate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. palustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2 g/l and 3.2 g/l for these fungi, respectively. Fomitopsis palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85%, respectively; however, C. puteana remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palustris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.An erratum to this article can be found at     

High level expression of glucose-6-phosphate dehydrogenase gene <Emphasis Type="Italic">PsG6PDH</Emphasis> from <Emphasis Type="Italic">Populus suaveolens</Emphasis> in <Emphasis Type="Italic">E. coli</Emphasis>

In order to investigate the functions of the gene PsG6PDH and the mechanisms underlying freezing tolerance of Populus suaveolens, the recombinant expression vector pET-G (pET30a-G6PDH), which contained full encoding region of PsG6PDH gene, was established. The recombinant was identified by lawn-PCR and double enzyme digestion and then transformed into expression host XA90 and induced by isopropyl-â-D-thiogalactoside (IPTG) to express 100 kD polypeptide of G6PDH fusion protein. The results showed that the expressed amount of the fusion protein culminated after 1 mmol&#8226;L^–1 IPTG treatment for 4 h and that pET-G product was predominately soluble and not extra-cellular secreting.