Mycoplasma hyopneumoniae colonization of pigs sired by different boars

Differences in Mycoplasma hyopneumoniae colonization were evaluated in experimentally inoculated pigs sired by 3 different boars of the same genetic line. Forty-six pigs were used, including a treatment group and positive and negative control groups. The pigs were intratracheally inoculated with an M. hyopneumoniae suspension or with Friis media as a placebo. To evaluate differences in the magnitude of colonization during a 35-day period, nasal and tracheal swabs were collected weekly and tested by nested polymerase chain reaction (N-PCR). Temperature, weight and circulating antibodies were measured for 35 days. At 11 and 35 d postinoculation the pigs were necropsied and macroscopic and microscopic lesions were determined. A section of bronchus was tested by the indirect immunofluorescence test (IFAT), scanning electron microscopy (SEM) and N-PCR. The N-PCR results from the nasal and tracheal swabs showed that the pigs sired by one boar (B3) had a distinctive colonization pattern, different from that of the pigs from the other 2 boars and from the positive controls. SEM studies demonstrated that at 35 d postinoculation a higher proportion of B3 pigs had lower numbers of mycoplasmas attached to the cilia compared with B1 and B2 offspring. No significant differences were observed in temperature and weight gain among groups by ANOVA; however, with use of a 2 × 2 table, temperature differences were observed between pigs sired by boars B1 and B2 at 4 d postinoculation. No pigs seroconverted, showed gross or microscopic lesions, or had positive IFAT results. These results provide evidence of differences in patterns of colonization between pigs sired by different boars, suggesting a possible genetic effect.     

Some determinants of the spatio-temporal fire cycle in a mediterranean landscape (Corsica,France)

Based on recent needs to accurately understand fire regimes and post-fire vegetation resilience at a supra-level for carbon cycle studies, this article focusses on the coupled history of fire and vegetation pattern for 40 years on a fire-prone area in central Corsica (France). This area has been submitted since the beginning of the 20^th century to land abandonment and the remaining land management has been largely controlled by frequent fires. Our objectives were to rebuild vegetation and fire maps in order to determine the factors which have driven the spatial and temporal distribution of fires on the area, what were the feed backs on the vegetation dynamics, and the long-term consequences of this inter-relationship. The results show a stable but high frequency of small fires, coupled with forest expansion over the study period. The results particularly illustrate the spatial distribution of fires according to topography and vegetation, leading to a strong contrast between areas never burnt and areas which have been burnt up to 7 times. Fires, when occuring, affect on average 9 to 12% of the S, SE and SW facing slopes (compared to only 2 to 5% for the N facing slopes), spread recurrently over ridge tops, affect all the vegetation types but reburn preferentially shrublands and grasslands. As these fire-proning parameters have also been shown to decrease the regeneration capacity of forests, this study highlights the needs in spatial studies (both in terms of fire spread and vegetation dynamic) to accurately apprehend vegetation dynamic and functionning in fire-prone areas.This revised version was published online in May 2005 with corrections to the Cover Date.     

The organophosphorous insecticide chlorpyrifos affects the neuroepithelial junction, the bioelectric parameters of the skin of the frog Caudiverbera caudiverbera, and the structure of model cell membranes

The current study examines the acute effects of the organophosphorus pesticide chlorpyrifos on a sympathetic synapse of the frog Caudiverbera caudiverbera. Nerve stimulation was followed immediately by a transient increase in the short-circuit current (SCC) and in the potential difference (PD), which consisted of a rapid and then a slow component. Chlorpyrifos concentrations from 5 μM to 1.0 mM caused a dose-dependent block of both components to a 10% of their control values, which was reversed by washout. The pesticide blockade did not affect the skin response to noradrenaline. X-ray diffraction and fluorescence spectroscopy studies on membrane models showed marked phospholipid perturbation, which favors changes in ion channel conformation and interferes with receptor proteins, thus altering noradrenergic transmission and Cl⁻ secretion in the mucous glands. The foregoing results may be interpreted as a reversible inhibition of the neuroepithelial synapse to nerve stimulation, possibly due to non-specific lip μd-protein perturbation, interference with synaptic transmission, and transient Cl⁻ channel inactivation.     

Diagnosis and treatment of presumptive pyelonephritis in an Asian elephant (Elephas maximus).

A 37-yr-old female Asian elephant (Elephas maximus) presented with anorexia, restlessness, and dark-colored urine. Urinalyses showed hematuria, leukocyturia, isosthenuria, proteinuria, granular casts, and no calcium oxalate crystals. Bloodwork revealed azotemia. Urine culture revealed a pure growth of Streptococcus zooepidemicus resistant to sulfamethoxazole-trimethoprim but susceptible to cephalosporins. A presumptive diagnosis of pyelonephritis was made based on bloodwork, urinalysis, and urine culture. The animal was treated with intravenous ceftiofur, and intravenous and per rectum fluids were given for hydration. The elephant's attitude and appetite returned to normal, the abnormal blood parameters resolved, and urinary calcium oxalate crystals reappeared after treatment, supporting presumptive diagnosis. Follow-up ultrasonography revealed an abnormal outline of both kidneys with parenchymal hyperechogenicity and multiple uterine leiomyomas.     

Candidate genes underlying QTL for flowering time and their interactions in a wide spring barley (Hordeum vulgare L.) cross

Response to vernalization and photoperiod are the main determinants controlling the time to flowering in temperate cereals. While the individual genes that dete...     

Isolation and pathogenicity of Colletotrichum spp. causing anthracnose of strawberry in south west Spain

Anthracnose, caused by Colletotrichum spp., is a major disease of cultivated strawberry, Fragaria × ananassa. This study identifies the Colletotrichum spp. which causes strawberry anthracnose in the southwest of Spain. A survey of the region was carried out, and the strains isolated were identified as C. acutatum by using the polymerase chain reaction (PCR) with genus and species-specific primers, demonstrating that this species is currently the causal agent of strawberry anthracnose in the studied region. The pathogenicity of C. acutatum and C. gloeosporioides strains was evaluated on two principal strawberry cultivars (cvs Camarosa and Ventana) under field conditions, the latter being more pathogenic than the former.     

Tissue distribution of Red Spotted Grouper Nervous Necrosis Virus (RGNNV) genome in experimentally infected juvenile European seabass (Dicentrarchus labrax)

The distribution of viral genome in the tissues of juvenile European seabass (Dicentrarchus labrax) during the course of a Red Spotted Grouper Nervous Necrosis Virus (RGNNV) infection has not yet been described. The present study addresses this and indicates which target organs may be involved in viral replication. This information should enable more accurate detection of virus in asymptomatic carriers, and in turn help to control the spread of the disease. The aim of this study was to examine the pattern of expression of viral genomic segments RNA1 and RNA2, using two absolute real-time PCRs (RT-qPCR), over the course of a RGNNV infection after administering the virus by intramuscular injection. In situ hybridization was also used to locate the RNA2 viral segment in different organs throughout the infection. The experimental challenge provoked an acute form of viral nervous necrosis (VNN), with a resulting cumulative mortality of 37%. The RT-qPCRs designed allowed the detection of both genomic segments in all the organs tested (nervous and non-nervous tissues) at all sampling times examined. The highest viral RNA copy number was found in eyes, although viral replication appeared to begin in the brain. Viral replication was also recorded in pooled internal organs and in caudal fin. However, the increase in the viral RNA copy number in these organs did not result in an increased viral titre, which may indicate that a productive infection does not take place in non-nervous tissues, possibly due to a failure in a viral post-replication step.     

Lactobacillus rhamnosus strain GG is a potential probiotic for calves

Diarrhea is a common occurrence in neonatal calves. Several veterinary probiotics claiming to prevent or treat calf diarrhea are available, but have not been well studied. This study assessed the capability of Lactobacillus rhamnosus strain GG (LGG) to maintain viability in the gastrointestinal tract of calves. We also determined whether LGG can be administered in an oral rehydration solution (ORS) without compromising the efficacy of the ORS or the viability of LGG, and whether LGG produces D-lactate or not. To investigate the intestinal survival of LGG, 15 calves were randomized into 3 groups and LGG was administered orally with their morning milk feeding on 3 consecutive days at a low (LD), medium (MD), or high (HD) dosage. Fecal samples were collected on days 0 (control), 1, 2, 3, 5, and 7 and incubated for 72 h on deMan, Rogosa, Sharpe agar. Twenty-four hours after the 1st feeding, LGG was recovered from 1 out of 5 calves in the LD group, 4 out of 5 calves in the MD group, and 5 out of 5 calves in the HD group. To determine if LGG caused the glucose levels in the ORS to drop below effective levels, 1.5 L of the ORS was incubated with LGG for 2 h at 37 degrees C and the glucose concentration was measured every 20 min using a glucose meter. This ORS was then further incubated for 10 h and aliquots analyzed by high performance liquid chromatography to determine if D-lactate was produced by LGG. Glucose concentrations did not change over the 2 h of incubation, and no D-lactate was produced after 48 h. The LGG maintained viability in ORS. Therefore, this study demonstrated that LGG survives intestinal transit in the young calf, produces no D-lactate, and can be administered in an ORS.     

Food resources and cyprinid diet in permanent and temporary Mediterranean rivers with natural and regulated flow

This study addresses the differences in food availability, diet and feeding activity of the Iberian barbel, between permanent and temporary nonregulated rivers, and the effect of flow regulation on feeding parameters. A total of 267 adult barbels were seasonally collected in four nonregulated and regulated rivers from permanent and temporary basins, and their gut content was analysed. Locally available food sources were evaluated across sites and seasons. Barbels from the permanent nonregulated river exhibit a more variable and diversified diet in which invertebrates assumed a large importance, especially during high flows. Barbels from the temporary nonregulated river presented a more uniform diet composed of plant material and detritus, particularly in drought seasons. Flow regulation affected different flow components in both systems, but the effects on food resources and barbels' diet were similar, resulting in an intra‐annual stabilisation of resource availability and fish diet, with a higher consumption of plants and detritus. Changes in fish diet and feeding activity in both nonregulated and regulated rivers were strongly associated with the seasonal variability of streamflow components, particularly between low‐ and high‐flow periods, and with the reduction in flow variability in the case of dam regulation. Results from this study can be used to improve guidelines for flow requirement implementation.