The use of urban organic wastes in the control of erosion in a semiarid Mediterranean soil

Abstract. A two year field experiment was carried out in a semiarid Mediterranean area in order to evaluate, the effect on soil erosion of adding different urban organic wastes: a stabilized municipal waste (compost), an unstabilized municipal waste, and an aerobic sewage sludge. All the treatments significantly reduced soil erosion, compared to the control soil. The soil amended with compost was the most effective treatment, reducing soil loss by 94% and runoff by 54%.     

Genomic and Pathogenic Studies on a Glycoprotein E Variant Field Isolate of Bovine Herpesvirus 1

Glycoprotein E-negative (gE–) laboratory strains of bovine herpesvirus 1 (BHV-1) were recently introduced as novel marker vaccines, allowing serological discrimination between vaccinated and naturally infected animals on the basis of lack or presence of antibodies against gE epitopes. The applicability of this approach is based on the genetic stability of the gE. However, mutant field variants of BHV-1 with a variable response in anti-gE ELISA have been isolated. The molecular characterization of a gE variant field isolate (Salwa strain) is presented here. By comparing the gE nucleotide and amino acid sequences of the Salwa strain with those of the wild strain Jura, ten mutated bases were found in the gE strain of Salwa, six of which alter the amino acid sequence, leading to changes in five amino acids. Both strains caused respiratory disease in experimentally infected calves, but Salwa generated slightly milder signs. Both viruses were excreted in nasal and ocular discharges, and were reactivated by dexamethasone treatment. In conclusion, the rather close similarities observed in the gE gene structure and pathogenicity features of the gE mutant and of the wild strain of BHV-1 confirm the genetic stability of gE. The findings indicate that the Salwa isolate is virulent, but less virulent than wild strains. Our data support the use of gE-negative marker vaccines in eradication programmes.     

Sulphur accumulation after Verticillium dahliae infection of two pepper cultivars differing in degree of resistance

Elemental sulphur levels, sulphur localization in stems, and levels of sulphate, glutathione and cysteine were studied in pepper ( Capsicum annuum ) cvs Yolo Wonder (higher resistance) and Luesia (lower resistance) after inoculation with Verticillium dahliae , the cause of vascular wilt. Accumulation of elemental sulphur (S⁰) was first detected 10 days after inoculation in Yolo Wonder (mean S⁰ level 7·3  µ g g⁻¹ DW), and 15 days after inoculation in Luesia (mean S⁰ level 3·3  µ g g⁻¹ DW). The maximum level was reached 21 days after inoculation in Yolo Wonder (14·1  µ g g⁻¹ DW). In control plants, elemental sulphur was not detected. SEM-EDX (scanning electron microscopy-energy dispersive X-ray microanalysis) indicated that the sulphur was not restricted to a specific location, but was dispersed throughout the vascular tissue. Sulphate levels showed a decline at the end of the experiment in inoculated plants, possibly related to the increase in sulphur levels seen in the two cultivars. The differences in sulphate levels between the two cultivars may be due to faster sulphate breakdown in cv. Yolo Wonder.     

Risk factors to incidental leptospirosis and its role on the reproduction of ewes and goats of Espírito Santo state,Brazil

Ovine and caprine stockbreeding have been gaining attention in developing countries as an attractive investment. On these animals, infectious diseases of the reproductive tract, such as leptospirosis, can compromise the production leading to economic losses. The present study aimed to determine the risk factors associated with incidental leptospirosis and its influence on the reproductive parameters of ewes and goats of Espírito Santo state, Brazil. A total of 737 animals distributed on 24 herds/flocks were studied, and an overall prevalence of 10.9 % seroreactive animals was observed. Serogroup Icterohaemorrhagiae was the most frequent in goats (97.0 %) as well as in ewes (78.3 %). Regarding risk factors related to leptospirosis, the presence of waterholes and the semi-intensive breeding system were the most important associated to seroreactivity. Besides, there was an observed association between seroreactivity and reproductive failures (P?<?0.05). Moreover, seroreactive ewes (relative risk (RR)?=?1.3) and goats (RR?=?1.9) presented more chances to have abortions than seronegative animals. Furthermore, seroreactive ewes presented 11.6 more chances of having premature births when compared to the seronegative ones. It can be concluded that Leptospira infection, mainly those caused incidental strains (such as Icterohaemorrhagiae serogroup), is a significant factor to reduce the productivity of small ruminants’ herds/flocks in the studied region, and environmental measures must be considered on control programs.

     

Effects of mechanical stress in under-sized clams, Tapes philippinarum: a laboratory approach

The present study is a first attempt at evaluating the effects of repeated disturbance, such as that caused by mechanical fishing systems, on the target species, Tapes philippinarum, intensively exploited in the Lagoon of Venice (North-East Italy). In particular, in free-access fishing grounds, detrimental effects of dredging may be suffered by under-sized clams, which are disturbed by fishing tools many times throughout their lives before they are collected. Similar mechanical stress conditions are experienced by T. philippinarum in licensed areas, where they are farmed in aquaculture conditions and undergo the harmful impact of hydraulic dredging. To evaluate the effects of short-term mechanical stress, under-sized clams were subjected to experimental shaking in the laboratory, and detrimental effects on their well-being were investigated by applying the biomarker approach. Changes in physiological, biochemical and behavioural responses were evaluated by determining scope for growth, adenylate energy charge, survival in air time, reburrowing time, and shell damage level. Responses highlighted general worsening in clam condition as mechanical stress increased. Among the various measurements, survival in air and reburrowing time appeared particularly suitable as indices, their responsiveness and applicability suggesting their use in assessing mechanical stress due to dredging in field conditions.     

Induced breeding of the South American catfish, Rhamdia sapo (C. & V.)

Pituitary suspensions from the characin, Prochilodus platensis, were injected intraperitoneally into male and female Rhamdia sapo at doses between 0.37 and 6 mg dry weight per kg of body weight. Doses from 0.75 to 6.0 mg/kg effectively induced ovulation. The latent period between injection and ovulation for females held at different temperatures (17 to 27°C) decreased with increasing temperature.Stripping of gametes from both sexes, and dry method fertilization were successful and produced viable eggs. The period between ovulation and stripping for the highest hatching rates decreased from about 9 h at 20°C, to 5 h at 24°C. No viable eggs remained in samples obtained after 15 h at 20°C, or 8 h at 24°C. Hatching percentage and the fraction of deformed fry were negatively correlated (r = ?0.75; P < 0.001).     

Induced breeding of the sabalo,Prochilodus platensis Holmberg

Maturation and ovulation were induced in female Prochilodus platensis with multiple homologous pituitary extract injections (total dose 0.9 to 1.4 hypophysis/kg) or single injections of pituitary extract combined with human chorionic gonadotrophin ((1 hypophysis + 500 I.U.)/kg). One of the females given the latter treatment produced viable eggs. Latency time from injection to ovulation was 9 h (at 28°C). Hatching occurred 12 h after fertilization. Survival after 30 days of rearing was 96%.