Ploidy levels of Dioscorea alata L. germplasm determined by flow cytometry

Dioscorea alata L. is a highly important crop, widely distributed in the humid and semi-humid tropics. Flow cytometry was used to determine the ploidy levels of 74 D. alata genotypes collected mainly from West African countries. Sixty three of the genotypes were found to be tetraploid, one was hexaploid and ten were octoploid. The high percentage of tetraploids together with the small percentage of hexaploid individuals and the absence of diploid individuals gives us some more clues on the possible origin of these species. No association between ploidy level and place of cultivation was found for the tested material. The obtained results represent important knowledge for enhancing the breeding methodologies and optimize germplasm management of this species. It also offers further insights to the phylogeny and evolution of Dioscorea species.     

Canine dynamic left ventricular outflow tract obstruction: assessment of myocardial function and clinical outcome

Objective : The aims of this study were (i) to evaluate echocardiographic findings and myocardial function including pulsed wave tissue Doppler imaging in dogs with naturally occurring dynamic left ventricular outflow tract obstruction and (ii) to investigate the clinical outcome and response to therapy in these dogs. Methods : Two cases were retrospectively reviewed and three cases were prospectively evaluated including clinical findings, diagnostic test results (including standard Doppler echocardiography and pulsed wave tissue Doppler imaging), response to treatment and outcome. The two retrospective cases received no treatment. Other cases were treated with a β‐blocker. Results : All dogs had a variable intensity left apical systolic murmur. Concentric left ventricular hypertrophy, systolic anterior motion of the mitral valve and scimitar‐shaped left ventricular outflow tract Doppler flow profile were present in all cases. Pulsed wave tissue Doppler imaging interrogation of the interventricular septum revealed E′/A′ reversal in all but one patient. Regression of left ventricular hypertrophy and total resolution of the dynamic left ventricular outflow tract obstruction were observed in all cases. Clinical Significance : Young dogs are affected with a possible terrier breed predisposition. Dynamic left ventricular outflow tract obstruction may be distinguished from canine hypertrophic cardiomyopathy as progressive resolution of echocardiographic abnormalities was documented. Pulsed wave tissue Doppler imaging abnormalities provide further evidence for significant diastolic dysfunction associated with the hypertrophy.     

Implantable loop recorders: a viable diagnostic tool in veterinary medicine

Objective : The purpose of this study was to investigate whether implantable loop recorders could be used in the diagnosis of unexplained collapse in dogs. Methods : The medical records of six dogs presented to the University of Liverpool Small Animal Teaching Hospital between May 2003 and October 2006 for further evaluation of intermittent syncopal episodes, collapse or episodic weakness, were reviewed. All these dogs underwent standard investigations and had implantable loop recorders placed. Results : A provisional diagnosis of supraventricular tachycardia was made in one dog, and diagnoses of exclusion of arrhythmogenic right ventricular cardiomyopathy and idiopathic epilepsy was made in two dogs. One dog suffered no further syncopal episodes, a diagnosis was not reached in another dog and the final dog was lost to follow‐up. Clinical Significance : The implantable loop recorder can be used successfully for the diagnosis of unexplained collapse in dogs.     

Genetic background of CTX‐M‐15‐producing Enterobacter hormaechei ST114 and Citrobacter freundii ST265 co‐infecting a free‐living green turtle (Chelonia mydas)

CTX‐M‐type extended‐spectrum β‐lactamase (ESBL)‐producing Enterobacteriaceae have become identified in marine ecosystem constituting a serious ecological issue. In this respect, although contamination of coastal waters and seafood, and even colonization of seabirds and fishes have been increasingly reported, molecular data are lacking to elucidate the clinical impact of ESBL producers in infected marine animals. In this study, using a genomic approach, we have analysed the genetic background of CTX‐M‐15‐producing Enterobacter hormaechei (belonging to the international human clone ST114) and Citrobacter freundii (ST265) co‐infecting a free‐living green turtle (Chelonia mydas) suffering from septic arthritis, which progressed to generalized coelomitis and death. Wide resistome of these pathogens contributed to treatment failure and death of the animal.     

Nutrient responses and glutamate and proline metabolism in sunflower plants and calli under Na2SO4 stress

The growth of Helianthus annuus L. calli and plants was reduced in the presence of Na₂SO₄ (10, 25, 50, and 100 mM). SO₄^2— and Na concentrations increased in stressed calli and plants while NO₃^—, Cl^—, P, K, and Mg decreased in stressed plants and Ca in shoots. Stressed calli showed decreases of NO₃^—, Ca, K, and Mg concentrations. Calli adapted to 50 mM Na₂SO₄ accumulated more K and Ca and less ammonium than stressed non‐adapted calli. Proline exhibited increases in stressed calli and plants that were accompanied by decreases of proline oxidase activities while pyrroline‐5‐carboxylate reductase (P5CR) and ornithine aminotransferase (OAT) activities increased. Adapted calli accumulated more proline and had higher P5CR and OAT activities than stressed non‐adapted calli. Glutamate concentration decreased with stress, together with a stimulation of cytosolic glutamine synthetase (GS1) and a decrease of plastidal GS (GS2) activity. These data strongly suggest that the increase of P5CR and GS1 activities are responsible for the decrease of glutamate concentration leading, together with the stimulation of OAT and the inhibition of the proline oxidation metabolism, to an increase of proline levels in Na₂SO₄‐stressed sunflower cells. These data also show that salt stress increases the release of endogenous ammonium and suggests that the increase of GS1 activity plays an important role in its elimination.     

The Cardiac Biomarker NT-proBNP Is Increased in Dogs with Azotemia

Background: Amino‐terminal probrain natriuretic peptide (NT‐proBNP) has been proposed as a useful biomarker for heart disease in dogs. In humans, decreased glomerular filtration rate (GFR) increases NT‐proBNP. Objective: To investigate whether decreased GFR as indicated by plasma creatinine concentration is associated with increased NT‐proBNP in dogs without heart disease. Animals: Four groups of dogs: healthy (n= 39), azotemic (n= 36), heart disease (n= 37), and congestive heart failure (CHF) (n= 7) presented to 2 teaching hospitals. Methods: Prospective observational cohort study. Plasma creatinine concentration and NT‐proBNP were measured in every dog. Nonparametric tests were used to compare the differences among groups. The median and actual results for each group were compared with the manufacturer's recommended and previously published suggestions for cut‐off values for diagnosis of heart disease. Results: Median (range) plasma creatinine concentration was 1.47 (1.06–1.70), 4.36 (1.74–15.6), 1.22 (0.69–1.91), and 1.45 (0.63–1.64) mg/dL and median (range) NT‐proBNP was 118 (2–673), 556 (37–1,819), 929 (212–5,658), and 3,144 (432–5,500) pmol/L for the healthy, azotemic, heart disease, and CHF groups, respectively. Pair‐wise comparison indicated a significant difference among all groups for NT‐proBNP (P≤ .049). Plasma creatinine concentration was significantly higher in the azotemic group compared with other groups (P < .001) but there was no significant among other groups. Application of 3 recommended cut‐off values led to misclassification of dogs with azotemia as having heart disease. Conclusions: Azotemia results in NT‐proBNP being increased to concentrations reported as diagnostic of heart disease or heart failure in dogs. Care should be employed when interpreting the results of NT‐proBNP in patients with known or possible increased plasma creatinine concentration.     

Helicobacter spp. from gastric biopsies of stranded South American fur seals (Arctocephalus australis)

Gastrointestinal lesions with uncertain etiology have been widely described among pinnipeds. The aim of our study was to investigate the presence of Helicobacter spp. in the gastric mucosa of South American fur seals (Arctocephalusaustralis). Gastric biopsies from thirteen seals, stranded on the shores of the Southwestern Atlantic Ocean in Argentina, were evaluated for the presence of Helicobacter spp. by PCR and DNA sequence analysis. Six gastric biopsies were positive for Helicobacter spp. Pairwise sequence comparisons showed less than 95% identity to novel Helicobacter spp. described from pinnipeds from North America and Australia. However, phylogenetic analysis revealed that the South American fur seal sequences clustered with 99-100% homology with H. cetorum, a species isolated from dolphins and whales. The presence of H. cetorum in pinnipeds, if confirmed by its isolation from the gastric mucosa of these mammals, demonstrates the wide host range of this bacterium in the marine environment.     

Ploidy level studies on the <Emphasis Type="Italic">Dioscorea cayenensis</Emphasis>/<Emphasis Type="Italic">Dioscorea rotundata</Emphasis> complex core set

The Guinea yams, Dioscorea cayenensis Lam. and D. rotundata Poir. (D. cayenensis–D. rotundata complex), represent a highly important crop, widely distributed in the humid and semi-humid tropics. The ploidy levels of 170 accessions of the core set of Guinea yams from West African countries was determined using flow cytometry with propidium iodide staining. One hundred and eight of the genotypes were found to be tetraploid, 47 were hexaploid and five were octoploid. One mixoploid individual containing tetraploid and hexaploid nuclei was also detected. A deeper analysis considering each separate taxon revealed that while for D. rotundata the majority of individuals were tetraploid, for D. cayenensis this ploidy level was not detected in any of the accessions. Also, no association between ploidy level and place of cultivation was found for the evaluated germplasm. The obtained data is highly valuable for breeding programs of Guinea yam, especially for the optimization of future hybridization experiments directed to the genetic improvement of this economically important crop.     

Inheritance of coffee leaf rust resistance and identification of AFLP markers linked to the resistance gene

The most important disease of Coffea arabica is coffee leaf rust caused by the fungus Hemileia vastatrix. The purpose of this study was to characterize the inheritance of coffee resistance gene(s) to race II of this pathogen and to identify and map molecular markers linked to this trait. Different populations were used: F₂ (160 plants), BCr (20), and BCs (135), derived from a cross between the resistant genotype Híbrido de Timor UFV 427-15 and the susceptible cultivar Catuaí Amarelo UFV 2143-236 (IAC 30). The segregation analysis showed that the resistance of Híbrido de Timor to race II of the H. vastatrix is conferred by a single dominant gene. The amplification of 176 AFLP (Amplified fragment length polymorphism) primer combinations using bulked segregant analysis (BSA) allowed the identification of three molecular markers linked to the resistance gene. Genetic mapping of these three markers in the F₂ population indicated that they are distributed on both sides, flanking the resistance gene. The markers E.CTC/M.TTT405 and E.CGT/M.TGT300 were found linked to the resistance gene at 8.69 cM (LOD 18.91) and 25.10 cM (LOD 5.37), respectively, while E.CCT/M.TTC230 was localized on the other side of the gene, at 20.50 cM (LOD 6.15). These markers are the first rust resistance markers identified in Híbrido de Timor and can be useful for marker assisted selection in coffee breeding programs.     

Temporo-mandibular joint condylectomy and its effect over occlusion in cats: cadaveric study

Objective : To determine the effect of unilateral condylectomy on dental occlusion in cats. Methods : Twelve feline cadaver heads were randomly submitted to either a right or left unilateral condylectomy of the temporo‐mandibular joint. The distance between the mandibular and maxillary canine tooth was measured before (B0) and after the unilateral condylectomy (P0). A right or left latero‐‐lateral standardised force (4 N) was applied to the mandibular mentus area before and after the surgical procedure. These measurements were analysed with a linear model for repeated measures. Results : The comparative analysis between pre‐ and postsurgical values indicated no significant variation in teeth displacement following condylectomy between B0 and P0 measurements. Statistically significant differences were detected after either left or right condylectomy with respect to all measurements after application of the standardised forces. Occlusion changes are significant when comparing bites before and after surgery. Clinical Significance : Unilateral condylectomy causes a significant increase in latero‐lateral amplitude of jaw movement which might clinically affect feline dental occlusion. Clinical studies are required to determine the effect of unilateral condylectomies on mastication and dental occlusion in feline patients.