Quantitative trait loci for early maturity and their potential in breeding for earliness in Brassica juncea

A doubled haploid population of Brassica juncea, developed from a cross between two parental lines differing for days to maturity, was used to study the efficiency of indirect selection for a primary trait through selection of secondary trait(s) over direct selection for the primary trait when quantitative trait loci information is available for both primary and secondary traits, and applied. Days to maturity was considered as primary trait, while days to first flowering, days to end of flowering, flowering period and plant height were considered as secondary traits. An RFLP linkage map was employed for QTL analysis of maturity and maturity-determinant traits, and a stable QTL B6 simultaneously affecting these two types of traits was identified. This linked QTL explained 11.7% phenotypic variation for days to maturity, 20.7% variation for days to first flowering, 24.3% variation for days to end of flowering and 14.4% variation for plant height. Phenotypic evaluation of maturity and/or maturity-determinant traits, viz. days to first flowering, days to end of flowering and plant height revealed that limited genetic advance for early maturity can be achieved through phenotypic selection of the primary and/or the secondary trait(s). However, the estimates of genetic advance for early maturity based on combined phenotypic evaluation and linked QTL data was found to be, at least, three times higher compared to genetic advance based on phenotypic evaluation only, demonstrating the potential of marker-assisted selection in breeding for early maturity in B. juncea.     

An evaluation of two autologous tendon grafting techniques in ponies

OBJECTIVE: To compare the healing and mechanical strength of a multiple split autologous tendon graft (MG) to a whole autologous tendon graft (WG) in the deep digital flexor tendon of ponies. STUDY DESIGN: In vitro evaluation of two different tendon-grafting techniques. ANIMALS OR SAMPLE POPULATION: Six ponies of mixed gender and age. METHODS: Tenotomies performed in forelimb deep digital flexor tendons (DDFT) distal to the insertion of the accessory ligament (AL-DDFT) were repaired with free autologous grafts from the hindlimb lateral digital extensor tendon (LDET). Grafts were either whole (WG) or split into three longitudinal strips (multiple graft, MG). Tendons and graft sites were collected and loaded (2.54 cm/s) to failure at either 4 or 8 weeks after surgery. Cross-sectional area was determined by both impression cast (IC) and an inkblot (IB) method. Tissue maturity and inflammation were evaluated by microscopy. RESULTS: Gap formation was a consistent finding in all repair sites. No statistical differences were found in healing or mechanical variables between MG and WG techniques. The failure stress for the 8-week repairs (15.51 +/- 3.1 MPa IB and 11.73 +/- .77 MPa IC, 16.13 +/- 2.2 MPa IB and 10.22 +/- .76 MPa IC for MG and WG, respectively) were significantly greater (P <.0005) than for 4-week repairs (3.71 +/- 1.7 MPa IB and 2.68 +/- 1.44 MPa IC, 2.81 +/- 1.46 MPa IB and 2.3 +/- 1.7 MPa IC for MG and WG, respectively). The repair tissue was more mature (P <.05) at 8 weeks than at 4 weeks, but there was no significant difference in inflammatory responses at 4 and 8 weeks. CONCLUSIONS: There was a sixfold increase in strength between 4 and 8 weeks of healing, but no significant difference in healing or strength between the MG and WG techniques. CLINICAL RELEVANCE: In ponies, autologous tendon grafting contributes to a strong repair during the early convalescent period, but splitting a tendon graft seemingly offers no appreciable advantage over use of a whole graft.     

Simulating the effect of eliminating routine bacterial screening on the negative predictive value of the Ontario fish hatchery disease monitoring program.

We determined the impact of eliminating routine screening for Aeromonas salmonicida and Yersinia ruckeri on the efficacy of the Ontario Ministry of Natural Resources (OMNR) fish disease monitoring program, using Monte Carlo simulation. Because the main purpose of the program is to prevent transferring infected fish among OMNR hatcheries, or to wild fish populations through stocking waterways, the hatchery-level negative predictive value (HNPV) was used as an indicator of monitoring efficacy. The present program (which includes both routine screening of asymptomatic hatchery fish, and diagnostic testing of hatchery mortalities and clinically diseased fish) was confirmed to have a high median HNPV (0.999) for both study pathogens. Simulations suggested that the median probabilities that a hatchery would be pathogen-free if only diagnostic testing were continued (i.e. if no asymptomatic lots were screened), and all diseased lots tested negative for A. salmonicida and Y. ruckeri would be 0.994 for both pathogens (with <5% probability that HNPV would be less than 0.953 and 0.957, respectively) - indicating acceptable monitoring efficacy. However, limitations of the theoretical monitoring model must be considered.     

An evaluation of the Irish Single Reactor Breakdown Protocol for 2005-2008 inclusive and its potential application as a monitor of tuberculin test performance

The number of recognized papillomavirus (PV) species and potential PV genera has dramatically been increasing throughout the past decade. It seems that every host species might potentially harbour a large set of PVs, while the PVs of each species appear to belong to only a few genera. In horses at least three conditions beside the equine sarcoid have been described, being supposedly PV induced namely classical equine papillomas, genital papillomas and aural plaques. We were able to identify the DNA of novel equine PVs (EcPVs) in the two latter disorders where PV involvement had been predicted. Both PV genomes were entirely cloned and sequenced. Both EcPV genomes, one derived from a penile papilloma, the other derived from an ear papilloma contain the characteristic open reading frames (ORFs) E6, E7, E1, E2, L2 and L1, a large non-coding region between the late and early region as well as a small non-coding region between the early and the late region. The viruses were consequently designated as EcPV2 and EcPV3. The genomes of the three equine PVs were analysed and compared with each other and further PVs. Upon phylogenetic analyses the equine PVs group well together. Pairwise alignment of the L1 nucleotide sequences reveals that EcPV1 shares 54.9% identities with EcPV2 and 53.2% with EcPV3. EcPV2 and EcPV3 share 51.3% identities. As the three EcPVs share less than 60% of nucleotide identities in L1, they may be regarded as belonging to different genera.