Molecular marker-based genetic linkage map of a diploid banana population (Musa acuminata Colla)

A well-saturated genetic linkage map is valuable for fundamental and applied genetic research. Genetic linkage maps of two half-sib diploid banana populations were constructed using allele-specific-polymerase chain reactions (AS-PCRs), diversity array technology (DArT), and simple sequence repeat (SSR) markers. Molecular maps were produced for each parent using the pseudo-testcross mapping strategy. The first maternal map (6142-1, 81 individuals) consisted of 231 markers divided as followed: 121 DArT, 106 SSR and 4 AS-PCR markers in 15 linkage groups (LGs) covering 670?cM. The second maternal map (6142-1-S, 58 individuals) contained a total of 152 markers including 71 DArTs, 79 SSRs, and 2 AS-PCRs mapped to 16 LGs that spanned 698?cM. The combined paternal map (139 individuals) comprised 316 markers (196 DArTs, 117 SSRs and 3 AS-PCRs) distributed over 15 LGs with a total map length of 1,004?cM. While distorted segregation of some markers was observed in all maps, this was much more frequent for the male parent. Homology between maps was assessed using common markers. While there was generally good congruity with regard to marker order across maps, incongruity in other cases may reflect chromosomal rearrangement events such as inversions, translocations, or deletions. The new banana map can provide a better understanding of the Musa genome and could be used for the identification of economically important traits and improvement of breeding strategies.     

Inheritance of rol-genes from Agrobacterium rhizogenes through two generations in Kalancho?

Transformation of Kalancho? blossfeldiana ‘Molly’ using the naturally occurring bacterium Agrobacterium rhizogenes is a non-GMO strategy to breed compact plants. In the present study, crosses resembling a commercial breeding strategy were made to determine if the improved ornamental quality observed in the T1 generation was inherited to the offspring. F1 lines were produced by crossing the commercial Kalancho? cultivar ‘Sarah’ with a selected T1 line. Subsequently, F2 populations were produced by self-pollination of individual selected lines. The rol-genes were inherited to the progeny and the presence of rol-genes was confirmed in all F1 and many F2 plant lines exhibiting dwarfism. Screening of F1 and F2 plants showed that the rol-genes were inherited together. Besides decreased plant height, several F1 and F2 lines containing rol-genes exhibited changes in plant diameter, number of branches, flower diameter and time to first open flower and duration of flowering compared to the WT ‘Molly’. Furthermore, increased ethylene tolerance was observed in several lines containing rol-genes compared to the WT ‘Sarah’. Screening of three selected F2 populations derived from self-pollination of F1 lines containing rol-genes indicated a shift in distribution towards a lower mean plant height within the entire plant population compared to a control population of plants without rol-genes. Moreover, one of these F2 populations also exhibited earlier flowering compared to the control population. Compact potted plants and lines without delayed flowering and with improved ethylene tolerance were obtained and are valuable in commercial breeding programmes without using recombinant DNA technology.     

Phenotypic and genotypic variation in flowering time in Ethiopian barleys

A set of 192 barley genotypes of wide eco-geographic origin were evaluated for flowering time (FT), the major adaptive trait in Ethiopian barleys. Morphological, functional and DArT markers were used to explore trait-marker associations, population structure, genetic diversity and extent of pair-wise linkage disequilibrium (LD). A wide magnitude of variation in FT was detected within and across environments and spanned at least 50–60?days with clear G?×?E interactions (GEI). The average DArT polymorphism estimated by gene diversity and polymorphic information content (PIC) was 0.33 and 0.27 respectively. Four distinct subpopulations, with one outlying group were identified which indicated that the populations were structured. The genome-wide LD extended up to 25?cM, with extensive variation at chromosome level. Markers associated with FT were found close to known QTLs for FT such as VRN-H1, VRN-H3, Ppd-H1, Ppd-H2 and earliness per se (Eps-2S), but also in regions known for FT-like and CO-like genes working under short days. In some QTLs the magnitudes and directions of the effects varied with environments. It is proposed that genes conditioning tolerance to drought and/or waterlogging interact with FT genes and modify the phenotype. A non-random association of alleles on different chromosomes—vrs1 (2H), BYDV resistance (3H) and srh (5H) associated with altitude and FT indicated a co-adapted gene complex. A set of 95 genotypes were selected to represent the Ethiopian section of the Barley Core Collection.     

Castration of the Vietnamese pot-bellied boar: 8 cases

Surgical techniques for castration of the Vietnamese pot-bellied boar and outcome are described. Vietnamese pot-bellied pig (VPBP) boars (n = 8) were admitted for castration. Data retrieved from medical records (2002–2011) for these pigs included signalment, history, reason for castration, perioperative management, surgical technique, and complications. Follow-up information was obtained from owners. A scrotal approach with closed technique was used for 6 boars with normally descended testes. A scrotal approach and open technique was used in 1 inguinal cryptorchid boar. In a hemicastrated abdominal cryptorchid boar an ipsilateral parainguinal approach was used. No complications occurred. Castration of the Vietnamese pot-bellied boar is associated with minimal complications and a satisfactory cosmetic outcome. We recommend the routine closure of the external inguinal rings, a simple and fast procedure that may prevent post-castration inguinal herniation.     

Retrospective evaluation of potential causes associated with clinically relevant hyperlactatemia in dogs with lymphoma

The aim of this study was to determine whether or not canine lymphoma could be associated with a clinically relevant type B hyperlactatemia (> 2.5 mmol/L). The medical database from the University of Montreal Veterinary Medical Teaching Hospital was searched for confirmed cases of canine lymphoma with a blood lactate measurement. Information retrieved included stage, clinical observations compatible with causes of type A and B hyperlactatemia other than cancer, hepatic involvement, and drugs administered. Twenty (40%) dogs were hyperlactatemic. Five dogs (10%) were classified as having cancer-related hyperlactatemia. Seventy-five percent of hyperlactatemic dogs had clinical evidence of type A hyperlactatemia. In addition to lymphoma, 70% of hyperlactatemic dogs had evidence of an additional cause of type B hyperlactatemia. A significant association (P = 0.01) was identified between corticosteroid administration and hyperlactatemia. Cytological, echographic, and/or biochemical tests revealed hepatic changes in all hyperlactatemic dogs. Lymphoma alone may not be sufficient to explain clinically relevant hyperlactatemia in dogs.     

Repeated post-exercise administration with a mixture of leucine and glucose alters the plasma amino acid profile in Standardbred trotters

Background

The branched chain amino acid leucine is a potent stimulator of insulin secretion. Used in combination with glucose it can increase the insulin response and the post exercise re-synthesis of glycogen in man. Decreased plasma amino acid concentrations have been reported after intravenous or per oral administration of leucine in man as well as after a single per oral dose in horses. In man, a negative correlation between the insulin response and the concentrations of isoleucine, valine and methionine have been shown but results from horses are lacking. This study aims to determine the effect of repeated per oral administration with a mixture of glucose and leucine on the free amino acid profile and the insulin response in horses after glycogen-depleting exercise.

Methods

In a crossover design, after a glycogen depleting exercise, twelve Standardbred trotters received either repeated oral boluses of glucose, 1 g/kg body weight (BW) at 0, 2 and 4 h with addition of leucine 0.1 g/kg BW at 0 and 4 h (GLU+LEU), or repeated boluses of water at 0, 2 and 4 h (CON). Blood samples for analysis of glucose, insulin and amino acid concentrations were collected prior to exercise and over a 6 h post-exercise period. A mixed model approach was used for the statistical analyses.

Results

Plasma leucine, isoleucine, valine, tyrosine and phenylalanine concentrations increased after exercise. Post-exercise serum glucose and plasma insulin response were significantly higher in the GLU+LEU treatment compared to the CON treatment. Plasma leucine concentrations increased after supplementation. During the post-exercise period isoleucine, valine and methionine concentrations decreased in both treatments but were significantly lower in the GLU+LEU treatment. There was no correlation between the insulin response and the response in plasma leucine, isoleucine, valine and methionine.

Conclusions

Repeated post-exercise administration with a mixture of leucine and glucose caused a marked insulin response and altered the plasma amino acid profile in horses in a similar manner as described in man. However, the decreases seen in plasma amino acids in horses seem to be related more to an effect of leucine and not to the insulin response as seen in man.     

Morphological and immunohistochemical characterisation of seminomas in Norwegian dogs

Background

Seminomas in the dog have traditionally been assumed to resemble human spermatocytic seminomas, based on their low malignancy and high occurrence in old individuals. However, recently published studies indicate that canine seminomas can be classified as classical and spermatocytic seminomas in a similar way as in man, and that classical seminomas comprise a substantial proportion of seminomas in the dog. These two factors both contribute to increasing the potential of canine seminoma as a relevant model for human testicular cancer. The aim of the present study was to characterise seminoma in Norwegian dogs using morphology and immunohistochemistry, and determine whether these tumours are comparable with human classical seminoma.

Methods

By applying diagnostic criteria from human pathology, 45 seminomas from the Norwegian Canine Cancer Register were examined histologically with hematoxylin and eosin (HE) and periodic acid-Schiff (PAS) stains. All sections were stained immunohistochemically with antibodies against human placental alkaline phosphatase (PLAP) and the transmembrane receptor c-KIT.

Results

Although two of the seminomas showed immunohistochemical staining characteristics indicative of classical seminoma (PLAP+/c-KIT+), all 45 examined seminomas were morphologically consistent with spermatocytic seminoma.

Conclusions

The value of canine seminoma as a model for SE in man remains unclear. Among the 45 investigated tumours from Norwegian dogs, none were classified as classical seminoma based on morphological criteria consistent with human seminomas. Regional or breed differences in the occurrence of classical seminoma in the dog, as well as the lack of uniform diagnostic criteria, might explain the discrepancy between the findings in the current study and the results presented by other authors.     

Latent class analysis of the diagnostic characteristics of PCR and conventional bacteriological culture in diagnosing intramammary infections caused by Staphylococcus aureus in dairy cows at dry off

Background

Staphylococcus aureus is one of the most common causes of intramammary infections in dairy cows at dry off. Reliable identification is important for disease management on herd level and for antimicrobial treatment of infected animals. Our objective was to evaluate the test characteristics of PathoProof ™ Mastitis PCR Assay and bacteriological culture (BC) in diagnosing bovine intramammary infections caused by S. aureus at dry off at different PCR cycle threshold (Ct)-value cut-offs.

Methods

Sterile quarter samples and non-sterile composite samples from 140 animals in seven herds were collected in connection with the dairy herd improvement (DHI) milk recording. All quarter samples were analyzed using BC whereas all composite samples were analyzed with PathoProof ™ Mastitis PCR Assay. Latent class analysis was used to estimate test properties for PCR and BC in the absence of a perfect reference test. The population was divided into two geographically divided subpopulations and the Hui-Walter 2-test 2-populations model applied to estimate Se, Sp for the two tests, and prevalence for the two subpopulations.

Results

The Se for PCR increased with increasing Ct-value cut-off, accompanied by a small decrease in Sp. For BC the Se decreased and Sp increased with increasing Ct-value cut-off. Most optimal test estimates for the real-time PCR assay were at a Ct-value cut-off of 37; 0.93 [95% posterior probability interval (PPI) 0.60-0.99] for Se and 0.95 [95% PPI 0.95-0.99] for Sp. At the same Ct-value cut-off, Se and Sp for BC were 0.83 [95% PPI 0.66-0.99] and 0.97 [95% PPI 0.91-0.99] respectively. Depending on the chosen PCR Ct-value cut-off, the prevalence in the subpopulations varied; the prevalence increased with increasing PCR Ct-value cut-offs.

Conclusion

Neither BC nor real-time PCR is a perfect test in detecting IMI in dairy cows at dry off. The changes in sensitivity and prevalence at different Ct-value cut-offs for both PCR and BC may indicate a change in the underlying disease definition. At low PCR Ct-value cut-offs the underlying disease definition may be a truly/heavily infected cow, whereas at higher PCR Ct-value cut-offs the disease definition may be a S. aureus positive cow.     

Detection of porcine circovirus genotypes 2a and 2b in aborted foetuses from infected swine herds in the State of S?o Paulo,Brazil

Background

Porcine circovirus type 2 (PCV2) has been associated with several disease complexes, including reproductive failure. The aim of this study was to identify the subtypes of PCV2 that are associated with reproductive failure in pigs from the State of São Paulo, Brazil and to investigate co-infections with other infectious organisms.

Findings

Samples of 168 aborted foetuses or mummified foetuses from five farrow-to-finish swine farms known to be infected with PCV2 and located in the State of São Paulo were tested for PCV2 by polymerase chain reaction (PCR). Positive samples were additionally tested for porcine parvovirus (PPV), Leptospira spp. and Brucella spp. by PCR. PCV2 was detected in 18 of the samples (10.7%). PPV, Brucella spp. and Leptospira spp were found in 2, 10 and 0 cases, respectively. Eleven PCV2 strains were sequenced and determined to be either genotype 2a (n = 1) or 2b (n = 10).

Conclusions

The findings indicate that the frequency of PCV2 infections in aborted porcine foetuses from the State of São Paulo is rather low (10.7%) and that co-infection with other pathogens is common and may be involved in PCV2 associated reproductive failure. No repeatable, characteristic amino acid motifs for regions of the PCV2 capsid protein seemed to be associated with abortion in sows.