Emerging Hyalomma lusitanicum: From identification to vectorial role and integrated control

In the Mediterranean basin, the tick species Hyalomma lusitanicum Koch stands out among other species of the Hyalomma genus due to its wide distribution, and there is great concern about its potential role as a vector and/or reservoir and its continuous expansion to new areas because of climate warming and human and other animal movements. This review aims to consolidate all the information on H. lusitanicum, including taxonomy and evolution, morphological and molecular identification, life cycle, sampling methods, rearing under laboratory conditions, ecology, hosts, geographical distribution, seasonality, vector role and control methods. The availability of adequate data is extremely relevant to the development of appropriate control strategies in areas where this tick is currently distributed as well as in new areas where it could become established in the near future.

Indole alkaloids from Geissospermum reticulatum

Ten indole alkaloids were isolated from Geissospermum reticulatum, seven (1-7) from the leaves and three (8-10) from the bark. Seven were aspidospermatan-type alkaloids (1-3, 5-9), including four (5-8) with a 1-oxa-3-cyclopentene group in their molecule, which we named geissospermidine subtype. Compounds 1-3, 5-8, and 10 had not been reported previously as natural products, while 4 and 9 were the known alkaloids O-demethylaspidospermine and flavopereirine. Their structures were determined by spectroscopic techniques including 1D and 2D NMR experiments (COSY, NOESY, HSQC, HMBC). Additionally, X-ray crystallographic analyses of 1, 2, and 6 were performed. Antiparasitic activities of the ethanolic and alkaloidal extracts and of the pure alkaloids were tested against Trypanosoma cruzi and Leishmania infantum. In general, the extracts exhibited selective action and were more active against Leishmania than against Trypanosoma. Alkaloid 4 was also very active against L. infantum.

Heliotropium huascoense resin exudate: chemical constituents and defensive properties

From the resinous exudate of Heliotropium huascoense a new compound, rel-(8R,9R)-carrizaloic acid, (1) (3-[rel-(8R,9R-9-hydroxy-9,13,13-trimethyl-12-oxo-10-cyclohexenyl)methyl]-4-methoxybenzoic acid), and three known flavonoids, [3-methylgalangin, 3,7-dimethylgalangin, and (-)-alpinone] have been isolated. The structure of 1 was determined by spectral and chemical methods. Several plant defensive properties of 1 (insecticidal and antifungal) have been evaluated.

Minor diterpenes from Persea indica: their antifeedant activity

The new diterpenes anhydrocinnzeylanone, garajonone and 2,3-didehydrocinnzeylanone, and the known anhydrocinnzeylanine, have been isolated from Persea indica. The antifeedant activity of these compounds has been evaluated showing the importance of the 11-hemiketal group for the antifeedant effects of ryanodane diterpenes.

Defensive chemistry of Senecio miser

Three eremophilanolides, 1alpha-acetoxy-8beta-methoxy-10betaH-eremophil-7(11)-en-8alpha,12-olide (1); 1alpha-angeloyloxy-6beta-hydroxy-8beta-methoxy-10betaH-eremophil-7(11)-en-8alpha,12-olide (2); and 1alpha-angeloyloxy-8betaH,10betaH-eremophil-7(11)-en-8alpha,12-olide (3), and two pyrrolizidine alkaloids, integerrimine (4) and its N-oxide (5), were isolated from bioactive fractions of Senecio miser. The structures of the new compounds 1 and 2 were established by NMR spectroscopic analysis and chemical transformation. The X-ray analysis of compound 1 was also performed. Eremophilanolides 1 and 2 and alkaloids 4 and 5 were found to be strong insect antifeedants, further supporting a proposed defensive role for these classes of compounds.

Structure- and species-dependent insecticidal effects of neo-clerodane diterpenes

Several natural neo-clerodane diterpenoids isolated from Linaria saxatilis and some semisynthetic derivatives were tested against several insect species with different feeding adaptations. The antifeedant tests showed that the oliphagous Leptinotarsa decemlineata was the most sensitive insect, followed by the aphid Myzus persicae. The polyphagous Spodoptera littoralis was not deterred by these diterpenoids; however, following oral administration, some of these compounds did have postingestive antifeedant effects on this insect. In general terms, the antifeedant effects of these compounds were species-dependent and more selective than their toxic/postingestive effects. The study of their structure-activity relationships showed that both the decalin moiety and the chain at C-9 determined their bioactivity. Furthermore, the presence of a 4,18-epoxy/diol moiety was an important feature for both the antifeedant and the toxic/postingestive effects.

Insecticidal and mutagenic evaluation of two annonaceous acetogenins

Annonaceous acetogenins represent a new class of bioactive compounds whose primary mode of action is the inhibition of NADH-ubiquinone oxidoreductase. Given the potential pesticidal use of such a class of compounds, we have further evaluated the antifeedant and insecticidal effects of squamocin and annonacin, two annonaceous acetogenins, on Spodoptera littoralis, Leptinotarsa decemlineata, and Myzus persicae. Additionally, to partially assess their environmental risk, we have also tested their mutagenicity in Salmonella typhimurium strains TA98, TA100, and TA102 in the presence and absence of a metabolic activation system. Among the test compounds, annonacin showed antifeedant effects on L. decemlineata, while squamocin was toxic to L. decemlineata and M. persicae. Neither acetogenin was mutagenic, although both were toxic in the absence of a metabolic activation system. We compared these results with those obtained with rotenone, a well-known respiratory inhibitor that was highly toxic to L. decemlineata and M. persicae and showed no mutagenicity/toxicity in the S. typhimurium strains tested up to a concentration of 1000 microg per plate.

Selective insect antifeedant and toxic action of ryanoid diterpenes

In this work, we have studied the antifeedant and insecticidal effects of several natural ryanoid diterpenes. These compounds can be classified in two groups according to their chemical structures: ryanodol/isoryanodol-type (nonalkaloidal type) and ryanodine-type (alkaloidal type) ryanoids. The nonalkaloidal ryanoids were isolated from Persea indica (Lauraceae) while the alkaloidal ryanoids (ryanodines and spiganthines) were isolated from Spigelia anthelmia (Loganiaceae). The effects of these compounds on the feeding behavior and performance (with and without piperonyl butoxide pretreatment) of Spodoptera littoralis larvae and Leptinotarsa decemlineata adults indicate that some strongly deterred these insects, L. decemlineata being less sensitive than S. littoralis. Their antifeedant effects did not parallel their toxic action. Additionally, more than 60% of the nonalkaloidal ryanoids were antifeedants and/or toxic in contrast to 30% of active alkaloidal ones, supporting the hypothesis of a ryanodol-specific mode of action in insects.

Development of a new bioluminescent mutagenicity assay based on the Ames test

A newly developed rapid mutagenicity assay based on the adenosine triphosphate (ATP)-bioluminescence technique and the Ames test is described. Salmonella typhimurium strains TA98 and TA100 were exposed in an appropriate liquid medium to the direct mutagens 4-nitroquinoline-N-oxide and methyl methanesulphonate, respectively, and to the indirect mutagen 2-aminoanthracene. Both auxotrophic and prototrophic growth were monitored throughout the incubation period as variations in the intracellular ATP levels by means of the luciferin-luciferase assay. After 9-12 h of incubation a dose-response increase in the levels of ATP was readily detected. In order to demonstrate that this increase was due to the growth of revertant bacteria, aliquots from each culture were plated on minimal agar plates. A very good correlation between the changes in ATP levels and the appearance of revertant colonies on the plates was found. Given the rapidity of this method as compared with conventional mutagenicity assays, it has potential for industrial and environmental applications. Other potential applications are also discussed.

Genotoxicity of the insecticide rotenone in cultured human lymphocytes

We have investigated the genotoxic activity of rotenone on three genetic endpoints, sister-chromatid exchanges (SCE), chromosome aberrations (CA) and micronuclei (MN) in human lymphocyte cultures in the presence and absence of a metabolic activation system (S9 mix). Our results indicate that rotenone increases the frequency of binucleated micronucleated (BNMN) cells and causes a delay in the cell cycle but does not increase the frequency of CA and SCE at the concentrations used. The presence of S9 mix reduces the genotoxic activity of rotenone.

Antifeedant Delphinium Diterpenoid Alkaloids. Structure-Activity Relationships

The insect antifeedant and toxic activity of the Delphinium diterpene alkaloids 15-acetylcardiopetamine, cardiopetamine along with its amino alcohol, the beta,gamma unsaturated ketone, and the acetylated ketone derivatives were studied in Spodoptera littoralis and Leptinotarsadecemlineata. Cardiopetamine and 15-acetylcardiopetamine strongly inhibited the feeding activity of S. littoralis and L. decemlineata, respectively. Structure-activity studies with S. littoralis showed that the C13 and C15 hydroxy substituents are essential features of the active molecule, while a C13 hydroxy and/or a C15 acetate determined their effect on L.decemlineata. The C11 benzoate group enhanced the biological effect on both insect species. These alkaloids were not toxic to S. littoralis, while their toxicity on L. decemlineata was inversely correlated with their antifeedant effects, the beta,gamma unsaturated ketone derivative being the most toxic. Cardiopetamine showed little antifungal action against several species of plant pathogens and did not have any mutagenic effects on Salmonella typhimurium by means of the Ames test.