Engineering flax plants to increase their antioxidant capacity and improve oil composition and stability

The composition of polyunsaturated fatty acids in the tissues is very important to human health and strongly depends on dietary intake. Since flax seeds are the richest source of polyunsaturated acids, their consumption might be beneficial for human health. Unfortunately, they are highly susceptible to auto-oxidation, which generates toxic derivatives. The main goal of this study was the generation of genetically modified flax plants with increased antioxidant potential and stable and healthy oil production. Since among phenylpropanoid compounds those belonging to the flavonoid route have the lowest antioxidant capacity, the approach was to inhibit this route of the pathway, which might result in accumulation of other compounds more effective in antioxidation. The suppression of the chalcone synthase gene resulted in hydrolyzable tannin accumulation and thus increased antioxidant status of seeds of the transgenic plant. This was due to the partial redirecting of substrates for flavonoid biosynthesis to the other routes of the phenylpropanoid pathway. Consequently, transgenic plants produced more (20-45%) polyunsaturated fatty acids than the control and mainly α-linolenic acid. Thus, increasing the antioxidant potential of flax plants has benefits in terms of the yield of suitable oil for human dietary consumption.     

Phenolic compound profiles and antioxidant capacity of Persea americana Mill. peels and seeds of two varieties

Avocado processing by the food and cosmetic industries yields a considerable amount of phenolic-rich byproduct such as peels and seeds. Utilization of these byproducts would be favorable from an economic point of view. Methanolic (80%) extracts obtained from lyophilized ground peels and seeds of avocado (Persea americana Mill.) of the Hass and Shepard varieties were characterized for their phenolic compound profiles using the HPLC-PAD technique. The structures of the identified compounds were subsequently unambiguously confirmed by ESI-MS. Compositional analysis revealed that the extracts contained four polyphenolic classes: flavanol monomers, proanthocyanidins, hydroxycinnamic acids, and flavonol glycosides. The presence of 3-O-caffeoylquinic acid, 3-O-p-coumaroylquinic acid, and procyanidin A trimers was identified in seeds of both varieties. Intervarietal differences were apparent in the phenolic compound profiles of peels. Peels of the Shepard variety were devoid of (+)-catechin and procyanidin dimers, which were present in the peels of the Hass variety. Peels of both varieties contained 5-O-caffeoylquinic acid and quercetin derivatives. The differences in the phenolic profiles between varietals were also apparent in the different antioxidant activity of the extracts. The peel extracts had a higher total phenolic compound content and antioxidant activity when compared to the seed extracts. The highest TEAC and ORAC values were apparent in peels of the Haas variety in which they amounted to 0.16 and 0.47 mmol Trolox/g DW, respectively. No significant (p > 0.05) differences were apparent between the TEAC values of seeds of the two varieties but the ORAC values differed significantly (p < 0.05). Overall these findings indicate that both the seeds and peel of avocado can be utilized as a functional food ingredient or as an antioxidant additive.     

Genetic mapping of quantitative trait loci (QTL) for resistance to septoria tritici blotch in a winter wheat cultivar Liwilla

Septoria tritici blotch (STB), caused by Mycosphaerella graminicola (anamorph Septoria tritici, syn. Zymoseptoria tritici), is present in most wheat-growing areas worldwide. Resistance breeding appears to be the most sensible approach to disease control. An attempt was made to identify loci associated with resistance to STB in a resistant winter wheat cultivar Liwilla. In the study we used a set of 74 doubled-haploid lines generated from anthers of F₁ hybrids between the resistant cultivar Liwilla and susceptible cultivar Begra. Four monopycnidiospore isolates of M. graminicola with diverse pathogenicity were used in tests on seedlings under controlled growth conditions and on adult plants under polytunnel conditions over a six year period. In both environments, the percentage leaf area covered by necrosis and covered by pycnidia were measured; time to heading and plant height were also recorded for the polytunnel experiments. Seven isolate-specific quantitative trait loci (QTLs) were associated with STB resistance: QStb.ihar-3A.2, QStb.ihar-6A, QStb.ihar-7A.2, QStb.ihar-1B, QStb.ihar-2B.2, QStb.ihar-3B, and QStb.ihar-5D. QTL on chromosome 5D and 7A represent novel STB resistance loci. The phenotypic variance explained by individual QTLs ranged from 9.5 % to 50.3 %. Three QTLs detected on chromosomes 3A, 7A and 1B showed major effects and were detected consistently in different environments. The locations of QStb.ihar-3A.2 and QStb.ihar-1B coincide with the resistance genes Stb6 and Stb11, respectively. Locus QStb.ihar-3B and a QTL for time to heading mapped to the same location, but are most likely not associated. Most of the mapped QTLs explain the resistance associated with both low necrosis and low pycnidia coverage.     

Evaluation of the efficacy of a peroxygen disinfectant-filled footmat for reduction of bacterial load on footwear in a large animal hospital setting

OBJECTIVE-To compare the efficacy of a peroxygenbased disinfectant used in footbaths with the efficacy of the same disinfectant used in footmats for reducing bacterial contamination of footwear in a large animal hospital. DESIGN-Prospective study. SAMPLE POPULATION-Bacteria recovered from the soles of rubber boots after experimental microbial contamination and exposure to disinfectant solutions or water (water-treated control boots) or no treatment (untreated control boots). PROCEDURES-Investigators contaminated boots by walking through soiled animal bedding. Swab samples were collected from the sole of 1 untreated boot (right or left); the other boot was treated as investigators stepped through a disinfectant-filled footbath, a disinfectant-filled footmat, or water-filled footmat. Samples were collected 10 minutes after each treatment. Differences in numbers of bacteria recovered from treated and untreated boots were analyzed. RESULTS-Mean bacterial counts from peroxygentreated boots were 1.3 to 1.4 log(10) lower (95.4% to 99.8%) than the counts from untreated boots. Results were similar for footmat- and footbath-treated boots. In contrast, there were no statistically detectable differences in mean bacterial counts in samples collected from water-treated or untreated boots. CONCLUSIONS AND CLINICAL RELEVANCE-Results suggest that footmats and footbaths containing peroxygenbased disinfectant are effective in reducing bacterial contamination on the soles of boots when used in conditions representative of large animal hospitals. Similar results were achieved with use of either footmats or footbaths. The use of footbaths and footmats containing effective disinfectants may help decrease the risk for spread of nosocomial infection but should not be expected to sterilize footwear.     

Ebola outbreak killed 5000 gorillas

Over the past decade, the Zaire strain of Ebola virus (ZEBOV) has repeatedly emerged in Gabon and Congo. Each human outbreak has been accompanied by reports of gorilla and chimpanzee carcasses in neighboring forests, but both the extent of ape mortality and the causal role of ZEBOV have been hotly debated. Here, we present data suggesting that in 2002 and 2003 ZEBOV killed about 5000 gorillas in our study area. The lag between neighboring gorilla groups in mortality onset was close to the ZEBOV disease cycle length, evidence that group-to-group transmission has amplified gorilla die-offs.     

The bovine CXCR1 gene is highly polymorphic

Several single nucleotide polymorphisms (SNP) in the bovine CXCR1 gene have been implicated in resistance to mastitis and milk somatic cell counts in several sample populations of Holstein dairy cows. As such, a more thorough understanding of SNP present in and near the bovine CXCR1 gene is needed. This study identified 36 SNP in the coding region and surrounding sequences of CXCR1 in 88 Holstein dairy cows. Four SNP induced amino acid changes and 1 SNP an early stop codon. Two amino acid changes occur in the third intracellular loop and C-terminus in locations tied to intracellular signaling. The 36 SNP could be subdivided into 4 separate linkage groups. Using representative or 'tag' SNP from each linkage group, haplotypes or the combination of SNP found on a single allele were generated to increase the specificity of an animal's genetic background. Four haplotypes were identified that represented 99% of the sample population. The haplotypes generated using tag SNP agreed with haplotypes generated from SNP causing amino acid changes. In conclusion, the CXCR1 gene is highly polymorphic and has potential implications towards genetic selection and understanding host factors that increase the risk of infection.     

Association between frost tolerance and the alleles of high molecular weight glutenin subunits present in Polish winter wheats

Subunits of high molecular weight glutenins strongly influence wheat bread making quality and can be associated with important agronomic traits. Polish winter wheats show a significant quantitative dominance of the null allele over the coding alleles of the Glu-A1 locus. To identify the causes of such skewed distribution, 116 F₅ lines obtained from six cross combinations were analyzed for their HMW glutenin subunits and 11 agronomic characteristics, such as plant height and uniformity, leaf blotch and leaf rust resistance, grain yield per plot, number of grains per ear, grain yield per ear, 1000 kernel weight, frost tolerance, total protein content and the SDS-sedimentation value. The SDS-sedimentation value, resistance to leaf blotch and frost tolerance showed statistically significant associations with the status of the Glu-A1 locus. It appears that chromosome 1A with the null allele at Glu-A1 carries a closely linked locus responsible for frost tolerance. With early strong selection for winter hardiness, the null allele of Glu-A1 becomes fixed in advanced breeding materials despite its strong negative impact on the end use quality.     

Effectiveness of new sources of resistance against oat powdery mildew identified in A. sterilis

Journal of Plant Diseases and Protection - The assessment of the effectiveness of resistance sources to fungal diseases is a very important issue allowing to determine the possibilities of...