Paulo C. Vieira

Pine wilt disease : a worldwide threat to forest ecosystems

I: Pine wilt disease: global issues, surveys, trade and economic impact. Session Summary. I.1. Eradication program for the pinewood nematode in Portugal. I.2. Incursion management in the face of multiple uncertainties: a case study of an unidentified nematode associated with dying pines near Melbourne, Australia. I.3. The risk of pine wilt disease to Australia and New Zealand.I.4. Potential threat and present status of survey of pine wood nematode in Turkey. I.5. Investigations on wood-inhabiting nematodes of the genus Bursaphelenchus in pine forests in the province Brandenburg, Germany. I.6. Official survey for Bursaphelenchus xylophilus carried out on the territory of the Republic of Poland. I.7. Bursaphelenchus spp. in wood packaging intercepted in China. II: Pine wood nematode: biology and microbial inter-relationships. Session Summary. II.1. Developmental biology and cytogenetics of B. xylophilus. II.2. The relationship between PWN and fungi cohabiting in pine trees inoculated with thee PWN. II.3. Influence of fungi on multiplication and distribution of the pinewood nematode. III: PWN taxonomy and detection methods. Session Summary. III.1. Taxonomic databases for Bursaphelenchus and other aphelenchoid nematodes. III.2. The enlargement of the xylophilus group in the genus Bursaphelenchus. III.3. Interspecific variation in ITS rDNA of Bursaphelenchus species of different groups. III.4. Molecular characterization of isolates of the Bursaphelenchus sexdentati group using ITS-RFLP and ribosomal DNA sequences. III.5. Analysis of Bursaphelenchus xylophilus provenances using ISSR and RAPD fingerprints. III.6. Satellite DNA as a versatile genetic marker for Bursaphelenchus xylophilus. III.7. An effective PCR-based diagnostic method for the detection of PWN in wood samples. IV: The insect vectors: biology, ecology and interaction with PWN. Session Summary IV.1. Biological studies relevant to the vector role of Monochamus species for pinewood nematode. IV.2. Potentialinsect vectors of Bursaphelenchus spp. in Spanish pine forests. IV.3. Genetic structure of Monochamus alternatus in Japan. IV.4. Distribution of nematodes (Bursaphelenchus xylophilus) in the beetle of Monochamus alternatus and its exiting transmission way. V: Ecology and modelling. Session Summary. V.1. Modelling PWN-induced wilt expression: a mechanistic approach. V.2. Field diagnosis of the asymptomatic carrier of pinewood nematode. VI: The tree: physiology, resistance and histopathology as a result of pine wilt disease. Session Summary.VI.1. Inoculation of pine trees with avirulent pinewood nematode under experimental conditions: risk-benefit analysis.VI.2. Rapidity of disease development seems to result in high mortality - insight from an inoculation test using hybridized populations between a virulent and an avirulent isolates of Bursaphelenchus xylophilus.VI.3. Defense systems of Pinus densiflora cultivars selected as resistant to pine wilt disease.VI.4. Histological observations of Bursaphelenchus xylophilus in symptomatic tissues of pinewood. VI.5. Development of external and internal symptoms in pine seedlings (Pinus sylvestris) due to inoculation with Bursaphelenchus vallesianus.VII: PWN and insect vector control methods. Session Summary. VII.1. Screening and isolation of antinematodal metabolites against Bursaphelenchus xylophilus produced by fungi and plant. VII.2. Microbial control of Bursaphelenchus xylophilus by fungi. VII.3. Attraction trap for monitoring Monochamus alternatus adults - its usefulness and limitations. VII.4. Studies on Scleroderma guani to control the pine sawyer, Monochamus alternatus. VII.5. Effect of aerial spraying insecticide as a control measure of pine wilt disease. VII. 6. Control program of pine wilt disease for landscape conservation - the case of Amanohashidate in Kyoto, Japan.

Limonoids from andiroba oil and Cedrela fissilis and their insecticidal activity

Nine limonoids were isolated from Carapa guianensis and Cedrela fissilis. Among them, 1,2-dihydro-3b-hydroxy-7-deacetoxy-7-oxogedunin is a new compound. Moreover, the assignments of some chemical shifts of xyloccensin k have been corrected and 1H NMR data of 7-deacetylgedunin have been assigned for the first time. These isolated limonoids were assayed on Atta sexdens rubropilosa workers showing moderate insecticidal activities.

Toxicity of sesame extracts to the symbiotic fungus of leaf-cutting ants

Extracts of different sesame plant (Sesamum indicum) Linnaeus organs inhibited the in vitro growth of the fungus Leucocoprinus gongylophorus (Moller) (=Rozites gongylophora Moller), which is cultivated by the leaf-cutting ants of the species Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae). The presence of the factor responsible for this inhibition was detected in methanol or chloroform extracts and is constant in the plant.

Trypanocidal activity of Meliaceae and Rutaceae plant extracts.

The in vitro trypanocidal activity of 22 extracts and 43 fractions of plants belonging to the families Meliaceae and Rutaceae was evaluated. The extracts from leaves of Conchocarphus heterophyllus and branches of Trichilia ramalhoi were the most active. The trypanocidal activity seems to be increased by fractionation of the extracts. Fractions from C. heterophyllus and Galipea carinata were the most active and a 100% lysis of the parasites was observed for five fractions. From one of them were isolated two flavonoids: flavone and 7-methoxyflavone, which showed weak trypanocidal activity. The results obtained from the extracts and fractions revealed that the order Rutales is a promising source for the search of new drugs for Chagas disease. Phytochemical studies with the other active fractions are underway in order to isolate compounds, which could be associated with observed activities.

Aurapten, a coumarin with growth inhibition against Leishmania major promastigotes

Several natural compounds have been identified for the treatment of leishmaniasis. Among them are some alkaloids, chalcones, lactones, tetralones, and saponins. The new compound reported here, 7-geranyloxycoumarin, called aurapten, belongs to the chemical class of the coumarins and has a molecular weight of 298.37. The compound was extracted from the Rutaceae species Esenbeckia febrifuga and was purified from a hexane extract starting from 407.7 g of dried leaves and followed by four silica gel chromatographic fractionation steps using different solvents as the mobile phase. The resulting compound (47 mg) of shows significant growth inhibition with an LD50 of 30 microM against the tropical parasite Leishmania major, which causes severe clinical manifestations in humans and is endemic in the tropical and subtropical regions. In the present study, we investigated the atomic structure of aurapten in order to determine the existence of common structural motifs that might be related to other coumarins and potentially to other identified inhibitors of Leishmania growth and viability. This compound has a comparable inhibitory activity of other isolated molecules. The aurapten is a planar molecule constituted of an aromatic system with electron delocalization. A hydrophobic side chain consisting of ten carbon atoms with two double bonds and negative density has been identified and may be relevant for further compound synthesis.

Norlimonoids from seeds of Toona ciliata

Abstract Further examination of the seeds of Toona ciliata led to the isolation of two new norlimonoids which were identified on the basis of spectroscopic analysis as 5α,6β,8α-trihydroxy-28-norisotoonafolin and 5α,6β,8α,12α-tetrahydroxy-28-norisotoonafolin. In addition, the known limonoids cedrelone and toonacilin and the sterols sitosterol, stigmasterol, campesterol and 3β-O-β- d -glucopyranosylsitosterol were also isolated and characterised. These results show that Toona has a less pronounced relationship to the Swietenioideae.

Limonoids from leaves of Khaya senegalensis

Abstract The leaves of Khaya senegalensis yielded two new limonoids. These compounds were identified on the basis of spectroscopic analysis as methyl 1α-acetoxy-3β,6,8α-trihydroxy-2α-methoxy-2β,14β-epoxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate and methyl 1α-acetoxy-6,8α,14β,30β-tetrahydroxy-3-oxo [3.3.1 10,2 .1 1,4 ]-tricyclomeliac-7-oate. Scopoletin, β-quercitrin and rutin were also isolated.

Sesquiterpenes, triterpenoids, limonoids and flavonoids of Cedrela odorata graft and speculations on the induced resistance against Hypsipyla grandella

Abstract From the stem of Cedrela odorata grafted on Toona ciliata var. australis were isolated calamenene, cycloeucalenol, sitosterol, stigmasterol, campesterol, gedunin, 7-deacetylgedunin, 7-deacetoxy-7-oxogedunin, methylangolensate, febrifugin, azadiradione, 20,21,22,23-tetrahydro-23-oxoazadirone, 3β-deacetylfissinolide and, catechin, together with the new limonoid 1α-methoxy-1,2-dihydrogedunin and the new cycloartane 3β-O-β- d - glucopyranosylcycloeucalenol . The limonoids were of little value to clarify the basis of the induced resistance in the graft against Hypsipyla grandella. The cycloartanes and catechin could have been translocated from Toona stock to the Cedrela graft.

Biological Activity of Quinoline Alkaloids from Raulinoa echinata and X-ray Structure of Flindersiamine

Phytochemical survey of stems and leaves extracts of the South Brazilian endemic plant Raulinoa echinata Cowan, Rutaceae, led to the isolation of known furoquinoline alkaloids: the widespread skimmianine; kokusaginine, maculine, flindersiamine, and also quinolone derivatives: 1-methyl-2-n-nonyl-4-quinolone, 2-n-nonyl-4-quinolone and 1-methyl-2-phenyl-4-quinolone. These alkaloids showed antifungal activity against Leucoagaricus gongylophorus; the symbiotic fungus of leaf-cutting ants (Atta sexdens). They were inactive or displayed weak inhibitory activity when assayed in vitro against trypomastigote forms of Trypanosoma cruzi. In this paper, the isolation, structure elucidation and bioactivity results of these compounds are reported together with the X-ray structure of flindersiamine.

In vitro activity of Rutaceae species against the trypomastigote form of Trypanosoma cruzi.

The activity of crude plant extracts of nine species of Rutaceae against the trypomastigote form of Trypanosoma cruzi was evaluated at 4 mg/ml. Thirty-two crude extracts were tested and eight of them showed significant activity (>80%). The most active extract was obtained from the stems of Pilocarpus spicatus (97.3%). Fractionation of the active crude extracts provided 25 fractions which were tested against the trypomastigote form of T. cruzi at 2 mg/ml. Of these six showed significant activity (>80%). The most active fractions (100%) were obtained from the leaves of Almeidea coerulea (butanol fraction) and Conchocarpus inopinatus (dichloromethane fraction).