Variation within improved cultivars and landraces of lucerne in Central Italy

Summary A variety must be distinguishable, uniform, stable and of sufficient productivity to be officially registered. In Italy landraces of lucerne are still widely used because they are characterized by a good persistence and productivity in their area of origin and adaptation.The landrace from Casalina (20 km south of Perugia, Central Italy) has higher dry matter production than many other commercial cultivars. The objective of this paper was to measure the variation of the landrace Casalina and compare it with that of the commonest cultivars available on the market and with some lines selected from the landrace Casalina.The experiment consisted of 11 entries: Casalina, two selections from Casalina (one for high seed yield and one for frequent cuttings), the registered landrace Italia Centrale and 7 registered cultivars. Each entry was represented by 80 genotypes transplanted in the field 60×40 cm apart in a randomized block design with 4 replications. In 1991 the following characters were recorded on a single plant basis: time of first flowering, height, number of shoots and dry matter yield at the first harvest, time of second flowering, leafiness, height, number of shoots and dry matter yield at the second harvest, height, number of shoots and dry matter yield at the third and fourth harvest. Height, number of shoots and dry matter yield at the first harvest, dry matter at the second and third harvest were recorded during the 1992 season.Casalina was as variable as the other entries in 77% of the comparisons; it was more variable in 8% of the comparisons and less variable in 15% of the comparisons. In conclusion, the variation of landrace Casalina is equal to or less than that of registered varieties so that it could be directly registered at the National Registry of Varieties.     

Effects of humic acids and herbicides,and their combinations on the growth of tomato seedlings in hydroponics

The morphology and length of roots and shoots of tomato (Lycopersicon esculentum Mill.) seedlings grown on a nutrient medium for fourteen days in a controlled environment chamber were apparently not affected, whereas the dry matter content of roots was significantly enhanced when 200 mg L^?1 of humic acid (HA) isolated from either a non-amended soil or a sewage-sludge-amended soil was present in the nutrient medium. In contrast, the HA-like fraction isolated directly from the sewage sludge caused, under the same conditions, extensive alterations of tomato morphology and a significant reduction of the length and dry weight of both shoots and roots. The presence in the nutrient medium of the herbicides alachlor or imazethapyr at concentrations of 1 and 0.01 mg L^?1, respectively, caused a marked decrease of tomato root and shoot length and dry weight. Differently, the herbicide rimsulfuron at a concentration of 0.01 mg L^?1 produced a slight decrease in shoot and root length and a slight increase in their dry weight. A combination of 200 mg L^?1 soil HA and each of the herbicides alachlor, rimsulfuron and imazethapyr at concentrations of 1, 0.01 and 0.01 mg L^?1, respectively, in the nutrient medium attenuated the growth depression of tomato shoots and roots observed in the presence of the herbicide alone. However, the simultaneous presence of sewage sludge HA and any herbicide in the nutrient solution caused negative synergistic effects on tomato growth. The volume of nutrient solution and the amount of electrolytes taken up by tomato plants during the growth experiments correlated highly significantly with the total plant dry weight. Tomato seedlings induced a pH decrease in the nutrient medium in all treatments except in those where sludge-HA was present, either alone or in combination with any herbicide.     

Effects of Iron, Ammonium and Temperature on Microcystin Content by a Natural Concentrated Microcystis Aeruginosa Population

We report results of a study conducted to evaluate effects of ammonium, iron and temperature on microcystins (MC) and proteins content in cultures of a natural Microcystis aeruginosa population, concentrated from a field sample of San Roque reservoir (Córdoba – Argentina). Based on a previous field study, we tested two temperatures (20 and 28 ^°C), two iron concentrations (1 μM and 10 μM) and two ammonium-nitrogen conditions (absence and 54 μM) in semi-continuous cultures. Total MC (TMC = MC-LR + MC-RR) and protein content per cyanobacteria cell increased when Fe concentration was enlarged. However, the ratio TMC: protein was almost the same for both iron concentrations. Thus, a high level of iron enhances both protein and MC content in the same proportion. TMC and protein content are significantly lowered in presence of 54 μM-N-ammonium. Additionally, the ratio TMC: protein is lowered by almost two folds in cultures having ammonium. Increasing the temperature does not affect the protein content or TMC per cell. However, cultures carried out at 28 ^°C maintain the same MC-LR: MC-RR ratio during all the studied period, while cultures developed at 20 ^°C show that MC-RR content is increased by 82-fold after four growth cycles (20 days total), while MC-LR remain almost constant in the same time. As a result, in our case, different temperatures produce a significant change in the pattern of MC content but not in the content of TMC per cell. The two-fold drop observed in MC content in presence of ammonium are within the range expected for physiological responses of cyanobacteria, raising questions on the probable inhibitory role of ammonium in MC production. On the contrary, the 82-fold increase of MC-RR observed at 20 ^°C exceed the effects attributable to a cell physiological response, and could be better explained by an ecological shift from the starting genotype composition. Metagenomics, or similar molecular techniques, would provide the necessary tools to elucidate the ecological effect of temperature on cyanobacteria populations.     

Natural Fasciola hepatica infection in nutria (Myocastor coypus) in Uruguay

Fascioliasis, the zoonotic disease caused by the trematode Fasciola hepatica, is expanding worldwide, with a 17 million people at risk. Rodents, often recognized as a major source of zoonotic diseases, are affected by F. hepatica, with some species playing important roles in the disease epidemiology. The case reported here in a nutria or kiyá (Myocastor coypus) is the first documented case of F. hepatica in this species in Uruguay. Parasitic burden and total egg production detected are markedly higher than reported previously for this species, confirming its potential role as an effective reservoir and disseminator of liver flukes. Although further research is needed, nutria should be considered when designing effective control programs for fascioliasis.     

仔猪球虫病的诊断

上一篇文章“Don’tforgetpigletcoccidiosis”(见本刊 2 0 0 1年第三期 52～ 53页──《猪与禽》杂志编者注 )是关于猪等孢球虫病系列文章的导言。猪等孢球虫病越来越被人们承认是仔猪腹泻的重要病因。要对此病进行治疗 ,首先要依赖于对此病的认识和诊断     

Solomonsterol A,a Marine Pregnane-X-Receptor Agonist,Attenuates Inflammation and Immune Dysfunction in a Mouse Model of Arthritis

In the present study we provide evidence that solomonsterol A, a selective pregnane X receptor (PXR) agonist isolated from the marine sponge Theonella swinhoei, exerts anti-inflammatory activity and attenuates systemic inflammation and immune dysfunction in a mouse model of rheumatoid arthritis. Solomonsterol A was effective in protecting against the development of arthritis induced by injecting transgenic mice harboring a humanized PXR, with anti-collagen antibodies (CAIA) with beneficial effects on joint histopathology and local inflammatory response reducing the expression of inflammatory markers (TNFα, IFNγ and IL-17 and chemokines MIP1α and RANTES) in draining lymph nodes. Solomonsterol A rescued mice from systemic inflammation were assessed by measuring arthritis score, CRP and cytokines in the blood. In summary, the present study provides a molecular basis for the regulation of systemic local and systemic immunity by PXR agonists.     

Synthesis of antioxidants in wheat sprouts

Aqueous and ethanolic extracts from wheat (Triticum aestivum) sprout powder were analyzed to determine its reduction and antioxidant activities. Mean and standard deviation of five independent samples were reported. The results showed that the micromoles of potassium ferricyanide reduced by aqueous and ethanolic extracts corresponding to 1 g of sprout powder (80.6 +/- 11.2 and 9.7 +/- 1.8, respectively) were higher than that reduced by 1 mg of other reducing compounds: ascorbic acid, rutin, quercetin, and reduced gluthatione (4.8 +/- 0.7, 3.8 +/- 1.2, 4.8 +/- 1.7, and 1.6 +/- 0.4, respectively). In addition, the oxygen superoxide scavenging activity performed by sprout extracts (from 1 g of powder) is comparable to that shown by 10 mg of antioxidant pure compounds (rutin and quercetin). Biochemical analysis of the sprout extracts shows that the antioxidant activity is mainly due to reducing glycoside and polyphenolic compounds.     

Rheological properties and sugar composition of locust bean gum from different carob varieties (Ceratonia siliqua L.)

The seeds of the main Italian carob varieties, Latinissima and Tantillo, and those of two selected accessions of Latinissima were evaluated in terms of yield, rheological properties, and sugar composition of the endosperm (LBG). The separation of the seed components in Latinissima and its seedlings yielded meanly 52.2% gum, 17.4% germ, and 30.5% tegument, whereas Tantillo furnished a lower gum yield (38.5%) and a higher yield of tegument (45.8%). The viscosity of 1% LBG aqueous solutions was measured at different shear rates (3-60 rpm), pH values (3.0-6.0), and temperatures (10-60 degrees C). The best results were shown by Latinissima, whereas Tantillo provided always the poorest thickening capacity. The content of free simple sugars and sucrose in the raw flours, the total monosaccharide residues after acidic hydrolysis, the mannose/galactose ratio, and the distribution of polysaccharides by size exclusion chromatography accounted for the observed viscosities. The seeds of Latinissima showed the highest technological potential.