Protection against cutaneous leishmaniasis resulting from bites of uninfected sand flies

Despite the fact that Leishmania are transmitted exclusively by sand flies, none of the experimental models of leishmaniasis have established infection via sand fly bites. Here we describe a reproducible murine model of Leishmania major infection transmitted by Phlebotomus papatasi. Prior exposure of mice to bites of uninfected sand flies conferred powerful protection against Leishmania major that was associated with a strong delayed-type hypersensitivity response and with interferon-gamma production at the site of parasite delivery. These results have important implications for the epidemiology of cutaneous leishmaniasis and suggest a vaccination strategy against this and possibly other vector-borne diseases.     

Constituents of Asparagus officinalis evaluated for inhibitory activity against cyclooxygenase-2

As part of a project directed toward the discovery of new cancer chemopreventive agents from plants, two new natural products, asparagusic acid anti-S-oxide methyl ester (1) and asparagusic acid syn-S-oxide methyl ester (2), a new acetylenic compound, 2-hydroxyasparenyn [3',4'-trans-2-hydroxy-1-methoxy-4-[5-(4-methoxyphenoxy)-3-penten-1-ynyl]-benzene] (3), as well as eleven known compounds, asparenyn (4), asparenyol (5), (+/-)-1-monopalmitin (6), ferulic acid (7), 1,3-O-di-p-coumaroylglycerol (8), 1-O-feruloyl-3-O-p-coumaroylglycerol (9), blumenol C, (+/-)-epipinoresinol, linoleic acid, 1,3-O-diferuloylglycerol, and 1,2-O-diferuloylglycerol, were isolated from an ethyl acetate-soluble fraction of the methanol extract of the aerial parts of Asparagus officinalis (Asparagus), using a bioassay based on the inhibition of cyclooxygenase-2 to monitor chromatographic fractionation. The structures of compounds 1-3 were elucidated by 1D- and 2D-NMR experiments ((1)H NMR, (13)C NMR, DEPT, COSY, HMQC, HMBC and NOESY). All the isolates were evaluated for their inhibitory effects against both cyclooxygenase-1 and -2, with the most active compound being linoleic acid.     

Experimental bases for a chemical control of Coquillettidia mosquito populations

Coquillettidia mosquitoes are not efficiently controlled by the conventional chemical practices which are known to be satisfactory against the larvae of other mosquito species. A research project was undertaken to conceive a new management strategy using plants as pesticide vectors to reach the Coquillettidia aquatic larvae. Therefore, larval mortality was measured in the presence of plants treated with phloem-translocated pesticides. The herbicide glyphosate at sub-lethal concentrations induced root epidermal cell lyses in maize plantlets cultivated in aqueous media, which clearly decreased larval fixation. Therefore, such herbicide strategy might operate through disturbing the larval physiological activities depending on fixation. The dimethoate insecticide did not affect root viability but at low concentrations seemed to disturb the plant–insect interactions. Larvae showed a lower attraction for roots and a considerable decrease in the root fixation rate. These larval behavior modifications were sufficient to induce mortality, probably due to a lack of fixation on plant roots. The effectiveness of plant foliar treatment with glyphosate or dimethoate under laboratory conditions suggested that it might be the basis for an efficient control strategy for Coquillettidia larvae and mosquitoes having the same living conditions in ponds and for which fixation on macrophyte roots is an absolute requirement (e.g.Mansonia, Mimomyia).     

Monitoring the pollution risk and water use in orchard terraces with mango and cherimoya trees by drainage lysimeters

Agricultural nonpoint-source pollution is the leading cause of water-quality degeneration of rivers and groundwater. In this context, the coast of Granada province (SE Spain) is economically an important area for the subtropical fruit cultivation. This intensively irrigated agriculture often uses excessive fertilizers, resulting to water pollution. Therefore, a 2-year experiment was conducted using drainage lysimeters to determine the potential risk of nutrient pollution in mango (Mangifera indica L. cv. Osteen) and cherimoya (Annona cherimola Mill. cv. Fino de Jete) orchards. These lysimeters were used to estimate the nutrient budgeting for each crop. NO₃-N, NH₄-N, PO₄-P and K losses according to lysimeters were, respectively, 55.1, 12.4, 3.7, and 0.6 for mango and 61.8, 17.8, 4.9, and 0.5 kg ha⁻¹ yr⁻¹, for cherimoya. NO₃, concentrations in the leachates ranged from 1.8 to 44.3 mg L⁻¹, and from 23.0 to 51.0 mg L⁻¹, for mango and cherimoya, respectively, in some cases exceeding the limits for safe drinking water. PO₄ also exceeded the permitted concentrations related to eutrophication of water, ranging from 0.07 to 0.5 mg L⁻¹ and from 0.12 to 0.68 mg L⁻¹ from mango and cherimoya lysimeters, respectively. With respect to the nutrient balance, N, P, and K removed by cherimoya fruits was 76.4, 5.5, and 22.6 kg ha⁻¹ yr⁻¹, and for mango fruits 30.2, 3.3 and 27.8 kg ha⁻¹ yr⁻¹, respectively. Nutrient losses in the leachates were surprisingly low, considering total N, P, and K applied during the year, in mango lysimeters 3.8, 0.11, and 12.6%, and in cherimoya lysimeters 7.7, 0.23 and 16.0%, respectively, indicating a potential soil accumulation and eventual loss risk, especially during torrential rains. Crop coefficient (Kc) values of mango trees varied within ranges of 0.35–0.67, 0.55–0.89, and 0.39–0.80 at flowering, fruit set, and fruit growth, respectively. Kc values for cherimoya trees had ranges of 0.58–0.67, 0.61–0.68, and 0.43–0.62 at flowering, fruit set and fruit growth, respectively. In this study, the Kc values of mango and cherimoya were significantly correlated to julian days. Therefore, the estimated WUE in the mango and cherimoya orchards reached 21.2 and 14.0 kg ha⁻¹ mm⁻¹, respectively. Thus, this study highlights the urgency to establish the optimal use of fertilizers and irrigation water with respect to crop requirements, to preserve surface-water and groundwater quality, thereby achieving more sustainable agriculture in orchard terraces.     

THE EFFECT OF TEMPERATURE IN THE MASS ON THE CHEMICAL COMPOSITION OF SILAGE

The effect of temperature on silage quality was investigated in a series of trials over a period of three years.
The results indicated that when conditions in the silage were favourable for the formation of lactic acid, either through treatment or because of the herbage itself, low temperatures in the mass had no adverse effect on silage quality.
Some results suggest that, with chopped or lacerated silage, low maximum temperatures are associated with better quality silage. The results, however, were not entirely consistent.
There appeared to be little or no advantage in allowing unchopped silage to heat to 100°F.     

THE USE OF SODIUM METABISULPHITE IN SILAGE MAKING

Three trials in which metabisulphite was used as a silage additive are described and the results discussed.
The data from two small-scale trials suggests that metabisulphite and molasses each have a similar effect on the quality of the silage produced, and that wilting appeared to be more effective than either of these two additives.
A comparison of silages in two large-scale trials indicates the necessity for uniform distribution of the metabisulphite.     

Clonal performance of perennial Oryza sativa/O. rufipogon selections and their combining ability with O. sativa cultivars for survival, stolon production and yield

In Southeast Asia, upland rice (Oryza sativa) is an annual crop typically grown for subsistence on hilly lands that are at risk for soil erosion. If perennial cultivars of upland rice were developed, they would provide farmers with an inexpensive tool to produce a preferred food while conserving soil. O. rufipogon, the undomesticated progenitor of O. sativa, includes perennial and stoloniferous forms. To evaluate the feasibility of developing perennial cultivars by combining genes of O. sativa and O. rufipogon, four trials were conducted in an upland field at IRRI: O. sativa/O. rufipogon F₁ clone and cutting height trial, F₂ family trial, and two O. sativa/stoloniferous-selection factorial mating design trials. Plants were established at the beginning of the rainy season, then subjected to a 6-month dry season and evaluated for survival after 1 year. Of the 2101 cultivar control plants, only three IR47686-1-4-B individuals survived and none produced stolons. The 18 F₁ clones, which were selected from previous trials with less drought stress, ranged in survival from 4.4 to 91.4%. Cutting height at harvest did not affect survival. Survival among the F₂ families ranged from 9.4 to 31.9%. Segregation for stolon presence did not differ from a 3:1 ratio for five of the six F₂ families, suggesting the effect of a single dominant gene. Average yields per plant for the F₂ families were 1/3 to 1/9 of yields for the cultivars. However, by crossing the F₁s to cultivars, yield potential was almost fully recovered. For the full-sib families of the factorial trials, survival ranged from 0.0 to 48.6%. Azucena and IR47686-1-4-B, both japonica cultivars, exhibited greater general combining ability for survival relative to the six other cultivar parents. Thus, the process of developing perennial cultivars of rice should include screening annual cultivars to identify those with the best combining ability for survival. To develop cultivars of perennial upland rice, drought avoidance and/or tolerance from annual upland cultivars must be combined with the capacity for perennial growth from wild perennial species. The frequency of stolonifereous testcross progeny was lower than expected and was affected by the O. sativa parent. Thus, additional genes likely affected stolon penetrance and expression. Analyses of covariance indicated that stolons improved the likelihood of survival for progenies of the factorial trials but the effect was small (b < 0.1), and that yield (g/plant) had a small negative effect on percent survival (b = −0.13 to −0.32). This study demonstrated that it was possible to introgress genes for perennial growth from wild O. rufipogon accessions into domesticated O. sativa. Additionally, strategies for developing perennial cultivars of upland rice were improved.