Shh signalling and the dynamic patterning of the vertebrate neural tube

The formation of the central nervous system depends on the patterned generation of different neuronal and glial cell types during embryogenesis. In ventral regions of the neural tube, the graded activity of the secreted molecule Sonic Hedgehog (Shh) controls the position along the dorsoventral axis at which different neuronal subtypes differentiate. Here, using chick and mouse embryos, we systematically and quantitatively documented the spatial and temporal expression patterns of the transcription factors that delineate the progenitor domains of these neurons. We investigated the coordination of the patterning activity of Shh with tissue growth and cell differentiation and discovered a high degree of conservation in pattern formation between mouse and chick. In addition, quanti"cation of the levels of Shh protein in vivo and downstream signalling activity using a mouse reporter of Gli activity con"rmed the non-linear relation between ligand concentration, levels of intracellular signalling and expression of the target genes in vivo. These data support a model in which progenitor cells respond to the cumulative amount of Gli activity. To advance our understanding of how cells transduce the Shh signal we investigated the vertebrate orthologs of Costal2, a component of the Hedgehog pathway in Drosophila. Using a gain of function assays in chick we con"rmed that one of the orthologs, the kinesin Kif7, is a negative regulator of the Shh signalling pathway, acting downstream of Smoothened. The inhibitory activity of Kif7 required only the N-terminal region containing the motor domain. By contrast, the kinesin Kif27, which appears equally similar to Costal2 as Kif7, was unable to inhibit Shh signalling. These data provided evidence that Kif7 was a novel component of the vertebrate Hh signalling and revealed a greater conservation between the Drosophila and vertebrate system than previous views suggested

A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge

The authors previously reported the construction of a glycoprotein E-deleted (gE-) mutant of bovine herpesvirus type 1.2a (BHV-1.2a). This mutant, 265gE-, was designed as a vaccinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE-. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas non-vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE- could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental virus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE- was shown to be suitable for use as a BHV-1 differential vaccine viru

Effects of vitamin B6 and tryptophan on pork quality and amount of lean meat in gilts of 70–100 kg bodyweight

Supplementary tryptophan in pig diets has shown improvement in carcass traits and pork quality by reducing the animals' response to stress at slaughter. Vitamin B6 could enhance this response since it acts as an enzymatic cofactor of many tryptophan pathways. The present experiment was designed to evaluate dietary vitamin B6 supplementation and tryptophan levels on carcass traits, organ weights, abdominal fat, and pork quality of 70–100 kg gilts. Sixty-four crossbred gilts (initial bodyweight (BW) 70.52 ± 2.95 kg) were distributed in a 2 x 4 factorial scheme, consisting of two supplementary vitamin B6 levels (1 and 5 mg kg-1) and four dietary standardized ileal digestible (SID) tryptophan (Trp) levels (0.140%, 0.167%, 0.194%, and 0.221%). No significant interactions between the dietary SID Trp levels and B6 supplementation were observed on these variables. Vitamin B6 supplementation (5 mg kg-1) showed a minor reduction in meat pH measured 24 hours after slaughter and resulted in a ham yield higher than B6 basal level (1 mg kg-1). The lean meat yield increased linearly as the SID Trp levels increased in the diet. These findings suggested that vitamin B6 supplementation enhanced the pork quality and the increasing levels of SID tryptophan enhanced the lean meat yield of 70–100 kg gilts.Keywords: Carcass yield, meat colour, organ weigh

Feline lungworm infection. An emerging concern?

Infectious feline upper respiratory tract disease is very common and Aelurostrongylus abstrusus is the most often diagnosed parasitic cause, although clinical signs may go unnoticed and diagnosis is challenging as it has several limitations. Noting that more cases have been recorded in recent years, the authors, in the present work, describe in detail the features of five cases of Aelurostrongylus abstrusus registered in their work and influence area, to alert animal health professionals to this emerging concern.info:eu-repo/semantics/publishedVersio

Canine hair follicular tumours: a retrospective study

Hair follicular tumours in dog comprise a large and heterogeneous group of neoplasms that display morphological features resembling one or several portions of the normal hair follicle which constitute a huge effort for its diagnosis. Histopathological evaluation is required to better characterize the different types of canine hair follicular tumours, in order to better understand its biological behaviour and to collaborate with the daily clinical practice. Thus, a retrospective, cross-sectional descriptive study was carried out with goal of analyse its frequency and characteristics, in order to contribute to a better understanding of this vast group of tumours. As main results the authors verified a higher incidence of follicular tumours in male dogs, being the most frequent types diagnosed trichoepithelioma, followed by, trichoblastoma, infundibular keratinizing acanthoma and pilomatricoma and the average age of dogs was 8.76 years. Also, malignant tumours represented 31.6% of all canine hair follicular tumours diagnosed (n= 114).info:eu-repo/semantics/publishedVersio

Beneficial effects of the activation of the Angiotensin-(1-7) MAS receptor in a murine model of adriamycin-induced nephropathy

Angiotensin-(1-7) [Ang-(1-7)] is a biologically active heptapeptide that may counterbalance the physiological actions of angiotensin II (Ang II) within the renin-angiotensin system (RAS). Here, we evaluated whether activation of the Mas receptor with the oral agonist, AVE 0991, would have renoprotective effects in a model of adriamycin (ADR)-induced nephropathy. We also evaluated whether the Mas receptor contributed for the protective effects of treatment with AT1 receptor blockers. ADR (10 mg/kg) induced significant renal injury and dysfunction that was maximal at day 14 after injection. Treatment with the Mas receptor agonist AVE 0991 improved renal function parameters, reduced urinary protein loss and attenuated histological changes. Renoprotection was associated with reduction in urinary levels of TGF-{beta}. Similar renoprotection was observed after treatment with the AT1 receptor antagonist, Losartan. AT1 and Mas receptor mRNA levels dropped after ADR administration and treatment with losartan reestablished the expression of Mas receptor and increased the expression of ACE2. ADR-induced nephropathy was similar in wild type (Mas(+/+)) and Mas knockout (Mas (-/-)) mice, suggesting there was no endogenous role for Mas receptor activation. However, treatment with Losartan was able to reduce renal injury only in Mas(+/+) , but not in Mas (-/-) mice. Therefore, these findings suggest that exogenous activation of the Mas receptor protects from ADR-induced nephropathy and contributes to the beneficial effects of AT1 receptor blockade. Medications which target specifically the ACE2/Ang-(1-7)/Mas axis may offer new therapeutic opportunities to treat human nephropathies

Antigenic and molecular characterization of eight samples of Aujeszky's disease virus isolated in the state of Rio Grande do Sul, Brazil, in 2003

Pseudorabies or Aujeszky's disease (AD), caused by pseudorabies virus (PRV) is a major concern in swine production. In the state of Rio Grande do Sul, Brazil, AD was only detected in 1954, in cattle. In 2003 two outbreaks of encephalitis occurred on the northern region of the state, close to the border with the state of Santa Catarina. Pseudorabies virus (PRV) was isolated from distinct farms within the region and subjected to antigenic and genomic analyses. These isolates were compared with prototype strains NIA-3 and NP. Antigenic characterization with a panel of monoclonal antibodies (Mabs) directed to viral glycoproteins (gB, gC, gD and gE-,) was performed by an imunoperoxidase monolayer assay (IPMA) on infected cell monolayers. Genomic characterization was carried out by restriction enzyme analysis (REA) of the whole DNA viral genome with Bam HI. The antigenic profile of the eight isolates from Rio Grande do Sul as well as strains NIA-3 and NP were similar. REA analysis revealed that all isolates from Rio Grande do Sul displayed a genomic type II arrangement, a genotype often found in other outbreaks of AD previously reported in other Brazilian states. The results obtained suggest that the eight isolates examined here were similar