Bioactivities of glycoalkaloids and their aglycones from Solanum species

Potatoes, tomatoes, and aubergines are all species of the Solanum genus and contain a vast array of secondary metabolites including calystegine alkaloids, phenolic compounds, lectins, and glycoalkaloids. Glycoalkaloids have been the subject of many literature papers, occur widely in the human diet, and are known to induce toxicity. Therefore, from a food safety perspective further information is required regarding their analysis, toxicity, and bioavailability. This is especially important in crop cultivars derived from wild species to prevent glycoalkaloid-induced toxicity. A comprehensive review of the bioactivity of glycoalkaloids and their aglycones of the Solanum species, particularly focused on comparison of their bioactivities including their anticancer, anticholesterol, antimicrobial, anti-inflammatory, antinociceptive, and antipyretic effects, toxicity, and synergism of action of the principal Solanum glycoalkaloids, correlated to differences of their individual molecular structures is presented.     

Changes in faecal bacteria and metabolic parameters in foals during the first six weeks of life

Many foals develop diarrhoea within the first two weeks of life which has been suggested to coincide with postpartum oestrus in their dams. To analyse the pathogenesis of this diarrhoea we have determined faecal bacteria in foals and their dams (n=30 each), and serum IGF-1 and γ-globulins for 6 weeks after birth. In addition, effects of β-carotene supplementation to mares (group 1: 1000 mg/day, n=15, group 2: control, n=15) on diarrhoea in foals were studied. Diarrhoea occurred in 92 and 79% of foals in groups 1 and 2, respectively, but was not correlated with oestrus in mares. Beta-carotene supplementation was without effect on foal diarrhoea. In mares, bacterial flora remained stable. The percentage of foals with cultures positive for E. coli was low at birth but increased within one day, the percentage positive for Enterococcus sp. was low for 10 days and for Streptococcus sp. and Staphylococcus sp. was low for 2-4 weeks. By 4 weeks of age, bacterial flora in foals resembled an adult pattern. Concentration of serum IGF-1 was low at birth (group 1: 149 ± 11, group 2: 166 ± 17ng/ml), increased after day 1 (day 7 group 1: 384 ± 30, group 2: 372 ± 36) but at no time differed between groups. Serum γ-globulin concentration in foals was low before colostrum intake and highest on day 1 (p<0.001 over time). In conclusion, neonatal diarrhoea in foals does not coincide with postpartum oestrus in their dams but with changes in intestinal bacteria and is not influenced by β-carotene supplementation given to mares.     

The Effect of Pulsed Electromagnetic Fields on Back Pain in Polo Ponies Evaluated by Pressure Algometry and Flexion Testing—A Randomized,Double-blind,Placebo-controlled Trial

This study assessed the therapeutic effect of pulsed electromagnetic fields (PEMF) on the backs of Polo ponies by measuring mechanical nociceptive thresholds (MNTs) and induced back movement. Twenty Polo ponies in regular training and competition were assigned to two groups. A double-blind, placebo-controlled, crossover field study with PEMF was performed, consisting of two 10-day therapy periods. At the beginning and end of each therapy period, the MNTs from 25 sites of the horses backs were assessed by pressure algometry (PA), and induced back movement was evaluated by flexion testing. Baseline MNTs were generally low, with means between 6.4 and 10.0 kg/cm². Significant changes in MNTs occurred nearly equally after both the PEMF and the placebo control treatments (at 5 of 25 or 6 of 25 sites, respectively) and without any regular pattern. Changes were evident, predominantly as decreased MNTs within and between treatment periods. Flexion testing revealed stiffness or avoidance in 19 of 20 horses. Results of the flexion testing showed an increased number of physiologic reactions at the end of both treatment periods compared with baseline values. The effect of PEMF on back pain and range of induced back movement could not be proven in this study. Although pretherapy values indicated the horses might have experienced back pain, all horses were still actively used in sport, and back pain might not have been severe enough to allow a significant effect to be demonstrated.     

Inheritance of Russian wheat aphid resistance from tetraploid wheat accessions during transfer to hexaploid wheat

Identification of new sources of resistance to Russian wheat aphid (RWA) (Diuraphis noxia (Kurdjumov) in wheat (Triticum aestivum L.) has become very important with the identification of several new biotypes since 2003. Our objective was to characterize inheritance and expression of resistance to RWA biotype 2 from three tetraploid wheat landraces (Triticum turgidum L. subsp. dicoccon) during transfer to hexaploid wheat. Resistant tetraploid accessions PI 624903, PI 624904, and PI 624908 were crossed to the susceptible hexaploid cultivars ‘Len’ and ‘Coteau’. Resistant F1 progeny were advanced to the F2:3 by self-pollination and to the BC1F2 and BC2F1 by backcrossing. Leaf rolling and chlorosis were recorded in standard seedling screening tests on F1 and F2:3 individuals while the F2, BC1F1, BC1F2, and BC2F1 were scored as resistant or susceptible. Segregation in the BC1F1 and BC2F1 fit a 1:1 resistant:susceptible ratio, indicative of control by a single dominant gene. Segregation for resistance in the F2 did not fit 3:1, 13:3, or 15:1 ratios for any of the resistant accessions. Expression of resistance in homogeneous resistant F2:3 lines was greater than susceptible checks, similar to the resistant tetraploid accessions, and less than a line carrying the Dn7 resistance gene. Resistance derived from these tetraploid accessions will be useful to broaden the base of RWA resistance available for use in wheat breeding.     

Assessing Potato Psyllid Haplotypes in Potato Crops in the Pacific Northwestern United States

The potato psyllid, Bactericera cockerelli (?ulc), is a vector of the bacterium ‘Candidatus Liberibacter solanacearum’ (Lso) that has been linked to the economically devastating zebra chip disease of potato. To date, four haplotypes of the potato psyllid have been identified and include Central, Western, Northwestern, and Southwestern haplotypes. Zebra chip was reported in potato crops in the Pacific Northwestern United States for the first time in 2011, and the Lso-infected psyllids collected from zebra chip-affected fields were identified as the Western haplotype. Additional studies have reported a mix of the Western and Northwestern psyllid haplotypes in the Pacific Northwest. The present study further examined psyllid population dynamics over the duration of the 2012 potato season in the Pacific Northwest by haplotype analysis of 864 potato psyllids collected from potato fields in Washington, Oregon, and Idaho. In the Yakima Valley of Washington and the lower Columbia Basin of Washington and Oregon, the Northwestern haplotype was predominant (78 %), and was detected earlier in the season than the Western haplotype. Interestingly, in south-central Idaho, all four psyllid haplotypes were identified, but the predominant haplotype was the Western haplotype (77 %). Here, Northwestern psyllids were detected early in the season from June to mid-August, whereas Central psyllids were detected in late July and thereafter. These results suggest that haplotype composition of psyllid populations in potato fields throughout the 2012 growing season in south-central Idaho differed greatly from those in Washington and Oregon. Additionally, all psyllids were analyzed for the presence of Lso, and no Lso-positive psyllids were found in Washington and Oregon, whereas Lso-positive psyllids were found in south-central Idaho. These Lso-positive psyllids consisted of the Western, Northwestern, and Central haplotypes.     

The dependence of internal brown spot development upon calcium fertility in potato tubers

Summary To determine calcium fertility and high temperature effects on internal brown spot development in potato, cv. Russet Burbank plants were fertilised with Hoagland's nutrient solution with or without calcium. Prevalence and severity of internal brown spot were greatest in tubers receiving no calcium fertilisation during growth. Internal brown spot was evident as early as tuber initiation. A high growth medium temperature (32°C) at tuber maturity with a lack of calcium increased internal brown spot incidence and severity. No tubers subjected to the high temperature and fertilised with calcium developed internal brown spot. Peel calcium concentration of tubers receiving no calcium fertilisation was lower (0.5–0.8 g/kg) than tubers receiving calcium (1.2–1.9 g/kg). Medullary tissue calcium concentration was similar under both calcium regimes. Calcium availability during early tuber growth was an influential factor in internal brown spot development, however high temperature effects may not be discounted in exacerbating the disorder. H/LA Paper No. 95-7. Project No. 1984, College of Agriculture and Home Economics Research Center, Pullman WA 99164, USA     

Damage caused by Alternaria alternata to the quality and germination of amaranth seeds

European Journal of Plant Pathology - Alternaria alternata is one of the main microorganisms responsible for affecting seeds and causing infection and eventually seed discoloration. The purpose of...