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.     

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.     

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.     

Effects of vaccination against brucellosis and clostridia on the intake,performance, feeding behavior,blood parameters,and immune responses of dairy heifers calves

The aim of this study was to identify possible effects of different vaccination strategies (concomitantly or not) against brucellosis and clostridia on intake, performance, feeding behavior, blood parameters, and immune responses of dairy heifers calves. Fifty heifers calves were enrolled [38 Gyr (Zebu, Bos taurus indicus) and 12 5/8 Holstein Gyr]. At 120 d of age, animals were randomly distributed among 3 groups: B (n = 18), vaccinated against brucellosis; C (n = 14), vaccinated against clostridia and CB (n = 18), vaccinated concomitantly for both. Rectal and thermographic temperatures were evaluated on days 1, 0, 1, 2, 3, 5, 7,10, 14, and 28 relatives to the vaccination day. Feed and water intake, body weight (BW), and feeding behavior were monitored daily by an electronic feeding system. Blood was sampled on days 0, 3, 7, 14, and 28, relative to the vaccination day for determination of glucose and -hydroxybutyrate (BHBA) concentrations. Blood sampled on day 0 (prevaccination) and on days 28 and 42 were used to evaluate the immune response against Brucella abortus and clostridia. There was an increase in rectal temperature between the first and the third day postvaccination in the 3 groups. The thermography revealed an increase of local temperature for 7 d on groups B and CB. Group C had increased local temperature for a longer period, lasting for up to 14 d. Dry mater intake was reduced for groups B and CB, but no alteration was observed for group C. No alterations regarding initial BW, final BW, average daily weight gain, and feed efficiency were observed. No differences were observed for the 3 vaccination groups for blood parameters throughout the evaluation period. The concomitant vaccination against brucellosis and clostridia led to lower neutralizing antibody titers against epsilon toxin of Clostridium perfringens and botulinum toxin type C of C. botulinum (C > CB > B). When cellular proliferation assay and serological tests to B. abortus were evaluated, no differences were observed between groups B and CB. The present results indicate that the concomitant vaccination against brucellosis and clostridia has no relevant impact on the intake, performance, and feeding behavior of dairy calves. However, the concomitant vaccination of vaccines against these 2 pathogens impacts animal immunity against clostridial infections.