Enhanced production of dihaploid lines via anther culture of tetraploid potato (Solanum tuberosum L. ssp.tuberosum) clones

A total of 1000 anther-derived plants was regenerated from tetraploid potato (Solanum tuberosum L.) genotypes. Capacity to undergo androgenesis was analysed in 41 potato cultivars and 7 clones grown either in the greenhouse or in the field. Of the 48 genotypes, 33 produced embryos and 23 regenerated shoots from embryos. Anther-derived plantlet production was determined in genotypes 86110, Agria, Calgary, Escort, Helios, Idole, JO 0982 JO 1432, Kainuun Musta, Kardal, KE48, Matilda, Nicola, Petra, Pito, Rustica, Stirling, Torridon, Ute, Van Gogh, Vebeca, Vento and White Lady. The highest number of shoots (24 shoots/100 anthers) was obtained from cv. Calgary, when anthers were isolated from field-grown donor plants. Incubating anthers at 28 C, rather than at 20 C or 24 C, enhanced embryo production in four genotypes tested. However, shoot production was improved only in cv. Pito cultured at 28 C. When anthers of cv. Petra were cultured at 28 C for four weeks, followed by reduction of culture temperature to 24 C, a high rate of shoot production was recorded (14 shoots/100 anthers). The ratio between dihaploids and tetraploids varied among the anther-derived plants of the different genotypes. The number of dihaploids was highest in potato clone JO1432 (100%) and in cv. Calgary (93%) and lowest in cvs. Pito (21%) and Torridon (6%).     

Production and characterization of “second generation” somatic hybrids derived from protoplast fusion between interspecific somatohaploid and dihaploidSolanum tuberosum L.

Protoplasts were fused to produce somatic hybrids between a triploid (2n=3x=32-34) interspecific somatohaploid betweenSolanum brevidens Phil. andS. tuberosum L., and a dihaploid (2n=2x=24) anther-derived line ofS. tuberosum cv. Van Gogh. A total of 265 plants were regenerated from protoplast fusion derived calli and their hybridity was verified using fusion partner specific RAPD markers. These “second generation” somatic hybrids were aneuploid pentaploids (2n=5x=51-65) with a 2C DNA content ranging from 3.36 to 4.43 pg, which corresponded to the sum of the 2C values of each of the fusion partners (somatohaploid: 2.22 pg; and the dihaploid line of cv. Van Gogh: 1.87 pg). Most of the “second generation” somatic hybrids were vigorous, but variable in morphology. They were extremely resistant to PLRV and they had tolerance to PVY infection derived from the somatohaploid fusion partner. Even though most of the “second generation” hybrids tuberized, the tuber morphology was variable and most were poorly shaped. InErwinia soft rot resistance tests, the tubers showed higher level of resistance than the tetraploidS. tuberosum cultivars, the dihaploidS. tuberosum fusion partners and the hexaploid somatic hybrids betweenS. brevidens andS. tuberosum. The “second generation” somatic hybrids were all male sterile and failed to produce berries or seeds.     

Evaluation of patterns of removal and associations among culling because of lameness and sow productivity traits in swine breeding herds

OBJECTIVE: To characterize patterns of removal and evaluate the associations among culling because of lameness and sow productivity traits among culled gilts and sows. DESIGN: Cross-sectional study. SAMPLE POPULATION: Data from a convenience sample of 11 farms pertaining to the removal of 51,795 gilts and sows from January 1991 to December 2002. Mean culling and mortality (death and euthanasia) rates for all inventoried gilts and sows ranged from 23% to 50% and 4.7% to 9.5%, respectively. PROCEDURE: An analysis of categories of removal (cull, death, or euthanasia) and reasons for removal of gilts and sows was performed. Multivariate logistic regression was used to determine associations among culling because of lameness and sow productivity traits among culled gilts and sows. RESULTS: Among sows that were removed, the proportion of parity > or = 1 sows that died (both death and euthanasia) was > 3 times the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among lame sows that were removed, the proportion of parity > or = 1 sows that died (death and euthanasia) was higher than the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among sows that were removed, the proportion of sows that died (deaths and euthanasia) was higher during lactation than nonlactation. This was also observed among lame sows that were removed. CONCLUSIONS AND CLINICAL RELEVANCE: The proportion of death among removed sows, especially lame sows, was higher during lactation than nonlactation. Results indicated that risk of death is not the same for sows throughout their lifetime.     

Antimicrobial resistance in Staphylococcus spp., Escherichia coli and Enterococcus spp. in dogs given antibiotics for chronic dermatological disorders, compared with non-treated control dogs

The aim of this study was to evaluate antimicrobial resistance in canine staphylococci, Escherichia coli and enterococci, which were isolated from 22 dogs with pyoderma and a history of previous antibiotic treatment, compared to bacterial isolates from 56 non-treated control dogs. Two isolates of each bacterial species per dog were investigated, if detected. Staphylococcal isolates from dogs with pyoderma (35 isolates) were more resistant to sulphatrimethoprim than the isolates from controls (56 isolates) (57% vs. 25%, p < 0.004). Multiresistance in staphylococci was also more common in dogs with pyoderma (29% vs. 9%, p = 0.02). A similar trend among isolates of E. coli was detected (24 and 74 isolates from treated and control dogs, respectively), but the differences were not significant. Resistance for macrolide-lincosamides was approximately 20% among staphylococci in both groups. Resistance to ampicillin among enterococci was 4%-7%. The age of the dogs might have an impact on resistance: multiresistance among staphylococcal isolates from younger dogs (< or = 5 years) was more common than in older dogs (26 years) (24%, vs. 0%, 63 and 27 isolates, respectively, p = 0.02). Staphylococci in younger dogs were more resistant to tetracycline (48% vs. 11%, p < 0.001) and sulphatrimethoprim (48% vs. 15%, p < 0.01) than those in older dogs. In contrast, the isolates of E. coli from older dogs tended to be more resistant, although a significant difference was detected only in resistance to tetracycline (13% vs. 2% of 40 and 50 isolates respecthely, p = 0.04)). The results of this small study indicate that resistance in canine staphylococci in the capital area of Finland is comparable with many other countries in Europe. Resistance in indicator bacteria, E. coli and enterococci, was low.     

Contrasting effects of elevated carbon dioxide concentration and temperature on Rubisco activity,chlorophyll fluorescence,needle ultrastructure and secondary metabolites in conifer seedlings

Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings were grown for 50 days in growth chambers in an ambient or twice ambient carbon dioxide concentration ([CO2]) at a day/night temperature of 19/12 degrees C or 23/16 degrees C. Although elevated [CO2] (EC) had only slight effects on the growth parameters measured, elevated temperature (ET) increased above ground dry mass of both species. Among treatments, biomass accumulation of both species was greatest in the combined EC + ET treatment. The EC treatment induced thylakoid swelling and increased numbers of plastoglobuli observed in Scots pine needles. Although EC had little effect on Rubisco protein or N concentration of needles, ET had a large effect on N-containing compounds and enhanced N allocation from 1-year-old needles. Terpenoids were more responsive to EC and ET than total phenolics. Generally, terpene concentrations were reduced by EC and increased by ET. Increased terpenoid concentrations in response to ET might be associated with thermotolerance of photosynthesis. In Norway spruce, EC decreased total phenolic concentrations in needles, probably as a result of increased growth. We conclude that, in seedlings of these boreal species, the effects of elevated [CO2] on the studied parameters were small compared with the effects of elevated temperature.     

A rapid technique for screening banana cultivars for resistance to Xanthomonas wilt

The banana Xanthomonas wilt disease (BXW) has threatened the livelihood of millions of farmers in East Africa. Use of resistant varieties is the most cost-effective method of managing this bacterial disease. A reliable and rapid screening method is needed to select resistant banana varieties. An in vitro screening method was developed for early evaluation of Xanthomonas wilt resistance using small tissue culture-grown plantlets. Eight cultivars of banana were screened with sixteen isolates of Xanthomonas campestris pv. musacearum using this method. There were significant differences (P < 0.0001) in susceptibility among the various banana cultivars tested, whereas no significant difference (P = 0.92) in pathogenicity was observed between the pathogen isolates. The cv. Pisang Awak (Kayinja) was found to be highly susceptible and Musa balbisiana resistant. Nakitembe was found to be moderately resistant while cvs Mpologoma, Mbwazirume, Sukali Ndiizi, FHIA-17 and FHIA-25 were susceptible. The susceptibility of these cultivars was further tested in vivo by artificial inoculation of potted plants with similar results. This study shows that an in vitro screening test can serve as a convenient, cheap and rapid screening technique to discriminate BXW-resistant from BXW-susceptible banana cultivars.     

NPAS2 and PER2 are linked to risk factors of the metabolic syndrome

Background  

Mammalian circadian clocks control multiple physiological events. The principal circadian clock generates seasonal variations in behavior as well. Seasonality elevates the risk for metabolic syndrome, and evidence suggests that disruption of the clockwork can lead to alterations in metabolism. Our aim was to analyze whether circadian clock polymorphisms contribute to seasonal variations in behavior and to the metabolic syndrome.     

Genomic prediction of grain yield in commercial Finnish oat (Avena sativa) and barley (Hordeum vulgare) breeding programmes

Genomic selection has been adopted in many plant breeding programmes. In this paper, we cover some aspects of information necessary before starting genomic selection. Spring oat and barley breeding data sets from commercial breeding programmes were studied using single, multitrait and trait-assisted models for predicting grain yield. Heritabilities were higher when estimated using multitrait models compared to single-trait models. However, no corresponding increase in prediction accuracy was observed in a cross-validation scenario. On the other hand, forward prediction showed a slight, but not significant, increase in accuracy of genomic estimated breeding values for breeding cohorts when a multitrait model was applied. When a correlated trait was used in a trait-assisted model, on average the accuracies increased by 9%–14% for oat and by 11%–28% for barley compared with a single-trait model. Overall, accuracies in forward validation varied between breeding cohorts and years for grain yield. Forward prediction accuracies for multiple cohorts and multiple years’ data are reported for oat for the first time.     

Preclinical evaluation of rapeseed, raspberry, and pine bark phenolics for health related effects

Rapeseed, raspberry, and pine bark are promising bioactive sources of plant phenolics selected from among ca. 100 previously screened plant materials for in vitro preclinical evaluation of health related effects. Phenolic extracts and isolated fractions of the selected materials were investigated for antioxidant, antimicrobial, antiinflammatory, and antimutagenic properties as well as for cell permeability. It was shown that rapeseed and pine bark phenolics and raspberry anthocyanins were good or excellent antioxidants toward oxidation of phosphatidylcholine membrane (liposomes), rapeseed oil (crude) phenolics were effective radical scavengers (DPPH test), and both raspberry and pine bark phenolics inhibited LDL oxidation. Rapeseed oil phenolics, principally vinylsyringol, raspberry anthocyanins, and pinoresinol and matairesinol, the principal components of pine bark phenolic isolate, were effective against formation of the proinflammatory mediator, prostaglandin E(2). Raspberry ellagitannins inhibited the growth of Proteus mirabilis and Klebsiella oxytoca. Pine bark and rapeseed had minor effects on the permeability of model drugs in Caco-2 experiments. None of the tested extracts were mutagenic nor toxic to Caco-2 cells or macrophages. Thus, phenolic isolates from rapeseed, raspberry, and pine bark and are safe and bioactive for possible food applications including functional foods intended for health benefit.