Persistence without pathology in phosphoglycan-deficient Leishmania major

Leishmania infections involve an acute phase of replication within macrophages, typically associated with pathology. After recovery parasites persist for long periods, which can lead to severe disease upon reactivation. Unlike the role of host factors, parasite factors affecting persistence are poorly understood. Leishmania major lacking phosphoglycans (lpg2-) were unable to survive in sand flies and macrophages, but retained the ability to persist indefinitely in the mammalian host without inducing disease. The L. major lpg2- thus provides a platform for probing parasite factors implicated in persistence and its role in disease and immunity.     

Biomass and grain oil yields in Cynara cardunculus L. genotypes grown in a Mediterranean environment

Cardoon (Cynara cardunculus L.) is a Mediterranean perennial plant. Studies were conducted on cardoon for biomass production, in order to assess the plant as an alternative low input management crop in a Mediterranean environment. The grain oil has similar composition to sunflower or saffron oils and can be easily extracted. In this work, the results of cardoon biomass and grain oil production under Sicilian (South Italy) low input conditions are shown. In a completely randomized block, during 1998–2001, 14 genotypes of C. cardunculus L., five cultivated cardoons and nine wild cardoons, were evaluated for lignocellulosic biomass production, grain yield and chemical composition of the grain. The results showed, on average for the genotypes, a 3-year cumulative aboveground biomass of 47.4 t ha⁻¹ DM, the 6.3% of which was grain. Differences within the 3 years of cultivation were observed, due to varying water availability (rainfall differences) and age of the crop. The results showed some genotypes are very promising for biomass, grain and oil production. Moreover, the good range of variability observed among genotypes is important for developing cultivars suitable for varying cropping systems in breeding programs.     

Herbage intake and milk yield in Comisana ewes as effect of 4 vs 7 h of grazing during late lactation

Thirty-two Comisana ewes at late lactation were used in two trials carried out during late spring in 2 consecutive years, with the aim to evaluate the effect of the duration of grazing on herbage intake and performance. In each trial, 16 pluriparous Comisana lactating ewes were equally divided into two groups which grazed in two separate areas of natural pasture from 11:00 to 15:00 h (group 4H) or from 10:00 to 17:00 (group 7H). A concentrate mixture (500 g/day) was also offered to each ewe. The mean maximum temperature was, respectively, 23.5 ± 3.8 °C during experiment 1 and 27.0 ± 3.1 °C during experiment 2. Probably as a consequence of the differences in climatic conditions, the results on herbage intake and milk production were different during the two trials. Herbage dry matter intake was not affected by the duration of grazing during trial 1, whereas it was significantly lower in 4H group compared to that in 7H group (0.67 vs 1.02 kg/day; P < 0.001) during trial 2. It could be hypothesised that while with lower environmental temperature (trial 1), the 4H ewes were able to reach good intake levels despite grazing during the hottest hours; with higher temperatures throughout the trial (trial 2), the 4H ewes reduced ingestion. Milk production was higher in 4H group during trial 1 (778 vs 707 g/day; P = 0.006), whereas it was not affected by the number of hours of grazing during trial 2, despite the higher intake levels reached by the 7H group. In conclusion, 3 extra hours of grazing for ewes at late lactation on a low quality pasture could be nullified in terms of yield response.     

Particulate and Mineral-Associated Organic Carbon in Aggregates as Affected by Biowaste Compost Applications in a Mediterranean Vegetables Cropping System

This study was conducted to assess the influence of biowaste compost on soil aggregation and soil organic carbon (SOC) stabilization, in a conventional tillage agro-ecosystem. Four treatments were involved: biowaste compost (Com), fertilizers nitrogen, phosphorus and potassium (NPK) (Min), biowaste compost plus mineral N (ComN) and unfertilized control (Cnt). Compared to the control, after four years, the amount of macroaggregates decreased by 23% and 69% for Com and ComN, while SOC stock increased by 17% and 10%, respectively. Most part of the SOC increases were stored in free-microaggregates and were made up for more than 70% by mineral-associated organic carbon (MOC), while no significant variation of particulate organic C (POC) was observed. Therefore, the biowaste compost application rates and time that were practiced in the studied agro-ecosystem were effective for C sequestration, but not enough to improve the macroaggregation and the POC protection.