Chemosterilants as control agents of Ceratitis capitata (Diptera: Tephritidae) in field trials.

Lufenuron is a chitin synthesis inhibitor, which is able to impede Mediterranean fruit fly, Ceratitis capitata (Wiedemann), reproduction. In laboratory trials, following ingestion of lufenuron, the eggs laid by female Ceratitis capitata were prevented from hatching. In field trials in Valencia, Spain, lufenuron showed its effectiveness by reducing C. capitata wild populations and its continuous application to several generations of fruit fly resulted in increased pest control. This field trial was conducted in an isolated valley some 80 ha in size, over a continuous four-year period. In order to maintain the sterilizing effect in the field throughout the whole year, a new lufenuron bait gel was developed. This bait gel was introduced in to delta traps suspended in trees at a density of 24 traps ha-1, and these traps were replaced once a year during the field trial. Monitoring of the adult C. capitata population was conducted to assess the effects of the chemosterilant treatment. In the first year of treatment with sterilizing traps, a reduction of the C. capitata population was observed, indicating that the traps reduce the population right from the first generation. In the second, third and fourth years, a continuous and progressive reduction of the adult Mediterranean fruit fly population was observed. Therefore, the successive application of chemosterilization treatment has a cumulative effect on reducing the fly population year after year. Aerial treatment using malathion does not produce this cumulative effect, and consequently every year it is necessary to start again with the same number of flies as the year before. The possibility of using the chemosterilant method alone or combined with the sterile insect technique is discussed.

Zeolites as pheromone dispensers.

Modification of the chemical and structural properties of zeolites has led to the preparation of an optimized zeolitic dispenser for insect attractants such as n-decanol and trimedlure. The impact of zeolite variables such as the framework Si/Al ratio, nature of compensating cation, nature and strength of acid groups, and pore dimensions on the kinetics of emission has been studied, and the results are as follows. Zeolite pore dimensions and the presence or absence of acid sites have the greatest effect on the rate of release, decreasing with decreasing pore diameter and increasing acidity. Further tuning of the release characteristics is achieved by controlling the polarity and the polarizability of the framework by increasing the Si/Al ratio and nature of the compensating cations, i.e., the higher the polarizability and the lower the polarity, the slower the release of attractants.

Attractiveness of 79 compounds and mixtures to wild Ceratitis capitata (Diptera: Tephritidae) in field trials.

Seventy-nine volatile compounds chosen from those emitted by Mediterranean fruit fly males, fruits and food baits, were tested for their attractiveness to females of Ceratitis capitata (Wiedemann) in field trials with a wild population. To correct for density fluctuations, the results were presented as a percentage of males caught in the same type of traps baited with trimedlure, a known male attractant. The mixtures of corn steep liquor with ammonia compounds and amines were the most effective attractants for females. Other compounds exhibiting C. capitata attraction were a mixture ethyl acetate+acetic acid+ethanol for both sexes, and p-cymene, 1,3-diethylbenzene and borneol for females.

Cardiovascular effects of the methanol and dichloromethanol extracts from Mentha suaveolens Ehrh.

Methanol and dichloromethanol extracts of the leaves and stems of Mentha suaveolens Ehrh. have been tested for their effects on resting arterial blood pressure, heart rate and noradrenaline induced hypertension. Both extracts administered by i.v. bolus to urethane anaesthetized normotensive rats reduced the mean arterial blood pressure and heart rate, while only the dichloromethanol extract prevented the noradrenaline induced hypertension.

Synthesis and biological evaluation of new analogues of the active fungal metabolites N-(2-methyl-3-oxodecanoyl)-2-pyrroline and N-(2-methyl-3-oxodec-8-enoyl)-2-pyrroline (II).

New analogues of the bioactive enamides isolated from P. brevicompactum (2 and 3) have been synthesized to improve the biological activities. Two different structural modifications have been introduced: substitution of the aliphatic side chain present in the natural products (1-4) by other groups frequently found in other active compounds and use of other nitrogen-containing five-membered rings with different degrees of oxidation. In this way, the insecticidal and fungicidal activities have been improved. Thus, compound 9, which possess a 3-pyrroline ring, exhibited important insecticidal activity against third-instar nymphs of Oncopeltus fasciatus Dallas (100% mortality at 7.5 microg/cm(2)). Remarkable fungicidal activity was also found, and preliminary structure-activity relationships could be established.

Insecticidal, anti-juvenile hormone, and fungicidal activities of organic extracts from different Penicillium species and their isolated active components.

Organic extracts from mycelium and culture broth of 21 Penicillium isolates have been tested for insecticidal, insect anti-juvenile hormone (anti-JH), and antifungal activities. Culture broth extracts were the most active, mainly against insects; nearly 25% of them have shown high entomotoxicity (100% mortality at 100 microg/cm(2)). A strong in vivo anti-JH activity against Oncopeltus fasciatus Dallas was detected in the culture broth extracts from P. brevicompactum P79 and P88 isolates. The two new natural products isolated from P79, N-(2-methyl-3-oxodec-8-enoyl)-2-pyrroline (1) and 2-hept-5-enyl-3-methyl-4-oxo-6,7,8,8a-tetrahydro-4H-pyrrolo[2,1-b]-1, 3-oxazine (2), possessed anti-JH and insecticidal activity, respectively, against O. fasciatus. Synthesized natural compound 1 has shown an ED(50) of 0.7 microg/nymph when assayed on newly molted fourth-instar nymphs of O. fasciatus. Promising biological activities have also been detected in the synthetic precursors.

Synthesis and biological evaluation of new analogues of the active fungal metabolites N-(2-methyl-3-oxodecanoyl)-2-pyrroline and N-(2-methyl-3-oxodec-8-enoyl)-2-pyrroline.

To evaluate the effect of simplifying the beta-ketoamide system present in active isolated metabolites from Penicillium brevicompactum (2 and 3) on the activity, new analogues with a monocarbonylic amide functionality have been obtained. In this way, the insecticidal and fungicidal activities have been improved in relation to the natural products taken as lead molecules. Thus, two of the synthetic analogues (5a and 5b) showed very important insecticidal activities against third-instar nymphs of Oncopeltus fasciatus Dallas, with acute LD(50) values of 3.0 and 1.5 microg/cm(2), respectively. Moreover, some analogues showed good levels of fungicidal activity against a wide range of commercially important and taxonomically diverse fungi; remarkably, compound 7c has proved to be highly active against Colletotrichum gloesporoides and Colletotrichum coccodes, with ED(50) values of 2.04 and 11.7 microg/mL, respectively.

Pharmacological screening of different Juniperus oxycedrus L. extracts.

Methanol and dichloromethanol extracts of leaves and stems of Juniperus oxycedrus have been tested for their toxicity, analgesic, antiinflammatory and central effects. Both extracts showed low acute toxicity and decreased spontaneous motility. The methanol extract exhibited an analgesic effect in models of chemical, mechanical and thermal stimulation whereas dichloromethanol extract showed only a significant effect in models of pain induced by chemical stimulation. Both extracts showed a significant antiinflammatory activity and inhibition of the rat paw oedema induced by carrageenin.

Triterpenoid compounds from Araujia sericifera B. Effects on the isolated guinea pig ileum.

Different fractions from the methanol insoluble extract of Araujia sericifera were obtained by chromatography and evaluated for their antihistaminic effects on guinea pig ileum in vitro. In order to determine the compounds responsible for the pharmacological effects observed, separation of the components from the active fraction was performed using HPLC.

Antimicrobial activities on Mediterranean plants.

Antimicrobial activities were tested for 22 plant species collected in the Valencian Community, using 9 different fungal and 6 bacterial strains which contaminate food and crops. Some of them showed fungizidal and bactericidal activity against some of the microorganisms tested.

Differentiation of rice varieties by electrophoresis of embryo protein.

Variations in the embryo proteins separated by SDS-PAGE have been observed in 43 cultivated varieties of Oryza sativa L. Cluster and discriminant analysis applied to both protein components and morphological characters indicate that knowledge of the differences in embryo proteins can improve our understanding of genetic affinity and make it easier to differentiate between varieties of similar genetic backgrounds.

Chromatin changes related to dedifferentiation and differentiation in tobacco tissue culture (Nicotiana tabacum L.).

Non-histone chromosomal proteins (NHP) were isolated from different stages of Nicotiana tabacum L. pith dedifferentiation to callus and callus redifferentiation. The NHP were separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis on slab gels and analyzed by densitometry. Simultaneous histological changes are reported. In both processes, some high molecular weight protein (HMWP) bands increase drastically in an induction period, previous to cell proliferation, and decrease when cell division declines. Some low molecular weight protein bands, intense in pith tissue, decrease early when callus is forming and increase when cells differentiate. chromatin template activity is high when cells proliferate, coinciding with maximum HMWP-bands intensity.