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31.
Ilze Matisone Kristne Kenigsvalde Astra Zauma Natlija Burevi
a Ilze epste Roberts Matisons Tlis Gaitnieks 《Forest Pathology》2020,50(4)
During 2017, Dutch elm disease was investigated on 67 Ulmus glabra and 29 Ulmus laevis samples from 28 sites in Latvia. The presence of Ophiostoma novo‐ulmi was detected in 61.2% of the samples from U. glabra and in 34.5% of the samples from U. laevis. In 11% of cases, hybrids between subsp. novo‐ulmi and subsp. americana were identified, particularly in the sites in the southern part of Latvia. This study presents the first verified record of Ophiostoma novo‐ulmi and its subspecies in Latvia. 相似文献
32.
33.
Tania S. Peña James R. Watson Laura I. González-Guzmán Timothy H. Keitt 《Landscape Ecology》2017,32(8):1643-1656
Context
Many nearshore species are distributed in habitat patches connected only through larval dispersal. Genetic research has shown some spatial structure of such metapopulations and modeling studies have shed light onto possible patterns of connectivity and barriers. However, little is known about human impact on their spatial structure and patterns of connectivity.Objectives
We examine the effects of fishing on the spatial and temporal dynamics of metapopulations of sedentary marine species (red sea urchin and red abalone) interconnected by larval dispersal.Methods
We constructed a metapopulation model to simulate abalone and sea urchin metapopulations experiencing increasing levels of fishing mortality. We performed the modularity analysis on the yearly larval connectivity matrices produced by these simulations, and analyzed the changes of modularity and the formation of modules over time as indicators of spatial structure.Results
The analysis revealed a strong modular spatial structure for abalone and a weak spatial signature for sea urchin. In abalone, under exploitation, modularity takes step-wise drops on the path to extinction, and modules breakdown into smaller fragments followed by module and later metapopulation collapse. In contrast, sea urchin showed high modularity variation, indicating high- and low-mixing years, but an abrupt collapse of the metapopulation under strong exploitation.Conclusions
The results identify a disruption in larval connectivity and a pattern of collapse in highly modular nearshore metapopulations. These results highlight the ability of modularity to detect spatial structure in marine metapopulations, which varies among species, and to show early changes in the spatial structure of exploited metapopulations.34.
Katarzyna Sosnowska Teresa Cegielska-Taras Alina Liersch Wojciech M. Karłowski Jan Bocianowski Laurencja Szała Katarzyna Mikołajczyk Wiesława Popławska 《Euphytica》2017,213(9):212
The allopolyploidization event that created cultivated oilseed rape Brassica napus L, followed by intense breeding, reduced its genetic diversity. Resynthesized (RS) B. napus L. obtained by interspecific hybridization between genotypes of B. rapa L. and B. oleracea L. can be a valuable source for broadening genetic diversity in cultivated oilseed rape. In this study, we determined the extent of DNA polymorphism among natural accessions of oilseed rape, resynthesized B. napus, their parental species and double-low quality semi-RS lines carrying the Rfo gene. Using 10 selected primer combinations, 522 polymorphic AFLP markers were scored in the complete set of 100 Brassica sp. To detect relationships between these genotypes, a cluster analysis was performed using the Jaccard’s distance. Resynthesized allopolyploids clustered directly between their diploid parents. Cultivated accessions of oilseed rape created a compact group away from resynthesized allopolyploids as well as semi-RS lines. The natural oilseed rape group, which consists of 49 cultivars and breeding lines of oilseed rape, is characterized by lower genetic diversity than the group of 33 accessions of resynthesized oilseed rape, and the analysis showed that the double-low quality semi-RS lines represent a specific genetic variation of B. napus. The de novo resynthesized B. napus lines and the semi-RS lines of double-low quality generated from them, provide a significant opportunity for enrichment the gene pool of oilseed rape. 相似文献
35.
Maribel Abadias Isabel Alegre Josep Usall Rosario Torres Inmaculada Viñas 《Postharvest Biology and Technology》2011,59(3):289-297
The risk of undesirable by-products from chlorine disinfection in fresh-cut industries, together with its limited efficacy, has led to a search for alternative agents. The aim of this study was to test several alternative putative antimicrobial substances to reduce Escherichia coli O157:H7, Salmonella spp. and Listeria spp. populations on fresh-cut apple. Carvacrol, vanillin, peroxyacetic acid, hydrogen peroxide, N-acetyl-l-cysteine and Citrox were selected for their results in in vitro assays against E. coli O157:H7 and Listeria spp., to be tested on fresh-cut apple plugs. Apple flesh was inoculated by dipping in a suspension of a mix of the studied pathogens at 106 cfu mL?1, and then treated with the antimicrobial substances. All treatments were compared to deionized water and a standard sodium hypochlorite treatment (SH, 100 mg L?1, pH 6.5). Pathogen population on apple plugs was monitored for up to 6 days at 10 °C. Bacterial reductions obtained by peroxyacetic acid (80 and 120 mg L?1), vanillin (12 g L?1), hydrogen peroxide (5, 10, 20 mL L?1) and N-acetyl-l-cysteine (5 and 10 g L?1) were similar or higher than reduction obtained by SH. In addition, bacterial populations were maintained at low levels throughout storage. No cells of any of the pathogens were detected in the peroxyacetic acid, hydrogen peroxide, Citrox and SH washing solutions after apple treatment. Peroxyacetic acid, hydrogen peroxide and N-acetyl-l-cysteine could be potential disinfectants for the fresh-cut industry as an alternative to chlorine disinfection. However, their effect on sensory quality and effectiveness under commercial processing conditions should be evaluated. 相似文献
36.
Pablo F. Roncallo Pavan C. Akkiraju Gerardo L. Cervigni Viviana C. Echenique 《Euphytica》2017,213(12):277
A quantitative trait loci (QTL) analysis of grain yield and yield-related traits was performed on 93 durum wheat recombinant inbred lines derived from the cross UC1113 × Kofa. The mapping population and parental lines were analyzed considering 19 traits assessed in different Argentine environments, namely grain yield, heading date, flowering time, plant height, biomass per plant, and spikelet number per ear, among others. A total of 224 QTL with logarithm of odds ratio (LOD) ≥ 3 and 47 additional QTL with LOD > 2.0 were detected. These QTL were clustered in 35 regions with overlapping QTL, and 12 genomic regions were associated with only one phenotypic trait. The regions with the highest number of multi-trait and stable QTL were 3BS.1, 3BS.2, 2BS.1, 1BL.1, 3AL.1, 1AS, and 4AL.3. The effects of epistatic QTL and QTL × environment interactions were also analyzed. QTL putatively located at major gene loci (Rht, Vrn, Eps, and Ppd) as well as additional major/minor QTL involved in the complex genetic basis of yield-related traits expressed in Argentine environments were identified. Interestingly, the 3AL.1 region was found to increase yield without altering grain quality or crop phenology. 相似文献
37.
Comparative Characterization of Enzymatic Digestion from Fish and Soybean Meal from Simulated Digestive Process of Pacific Bluefin Tuna,Thunnus orientalis 下载免费PDF全文
Ariana I. Román‐Gavilanes Emmanuel Martínez‐Montaño María Teresa Viana 《Journal of the World Aquaculture Society》2015,46(4):409-420
The digestive process of the Pacific bluefin tuna (PBT), Thunnus orientalis, was simulated through two phases of in vitro digestion: acidic digestion with porcine pepsin, followed by alkaline digestion with pancreatic crude extract (PCE) obtained from the PBT to hydrolyze fish meal (FM) and soybean meal (SBM) as protein substrates. The crude protein from FM resulted in a lower degree of hydrolysis (73.3%) compared with SBM (79.2%). However, the resulting digested products showed that FM contained 35% more small peptides, with sizes <6.5 kDa than those from the starting material (>150 kDa). The SBM had an increase of only 1.3% in the similar peptide cut‐offs found after hydrolysis. These results suggested that FM appeared to be a better source of protein according to the amount of low‐molecular weight peptides. In addition, the proteolytic activity of PCE showed that 88.9% of its alkaline proteolytic activity corresponded to trypsin and 2.9% corresponded to chymotrypsin activity. The results shown here demonstrate that peptide sizes are important in identifying suitable protein sources for aquafeed production to reinforce the primary results obtained from the in vitro digestibility using the pH‐Stat system. These results also contribute to a better understanding of the digestibility process in aquatic organisms. 相似文献
38.
Robert Manuel L. Juárez-Gómez Juan Chaires-Pacheco Mariana Peña-Ramírez Yuri J. 《New Forests》2020,51(2):335-347
New Forests - Spanish red cedar, Cedrela odorata L. (Meliaceae), is a valuable timber tree in tropical American forests. Existing demand for elite individuals endangers the conservation of... 相似文献
39.
Effect of Stocking Density on Growth,Survival, and Condition of the Mexican Cichlid Cichlasoma beani
Edgar A. Aragon‐Flores Edna F. Valdez‐Hernandez Leonardo Martinez‐Cardenas Maria R. Castaeda‐Chavez Alfonso A. Gonzales‐Diaz Miriam Soria‐Barreto Javier M. J. Ruiz‐Velazco Emilio Pea‐Messina 《Journal of the World Aquaculture Society》2014,45(4):447-453
The Mexican cichlid Cichlasoma beani is currently exploited regionally as food and can be commercialized in the aquarium trade. Natural populations of C. beani may already be negatively affected by anthropogenic alteration of the areas in which it is distributed. The aim of the present study was to examine the effect on growth, survival, and condition of C. beani cultured in three stocking densities: three (D3), six (D6), and nine (D9) fish per each 40 L tank. At the end of a 6‐wk trial the fish cultured in D3 were longer, heavier, and grew faster than the rest of the treatments but their survival was the lowest compared to D6 and D9. The mortalities were caused by a strong aggressive behavior in D3. 相似文献
40.
ABSTRACT Aims: To assess the change in body condition score (BCS) during the early and late dry periods and its association with postpartum diseases and milk yield in grazing dairy cows from central Argentina. Methods: BCS assessments during the dry period, and cow health and milk production records up to 90 days in milk (DIM), were collated for cows from 28 farms at monthly visits between 2007 and 2008. Cows were categorised into four groups; those in Group 1 (n=7,067) maintained or gained BCS during the early and late dry periods; Group 2 (n=2,615) maintained or gained BCS during the early dry period and lost BCS during the late dry period; Group 3 (n=1,989) lost BCS during the early dry period and maintained or gained BCS during the late dry period; and Group 4 (n=5,144) lost BCS during the early and late dry periods. Results: Cows in Group 1 had reduced odds of having retained fetal membranes (RFM), metritis, and clinical mastitis up to 90 DIM than cows in Group 2 (p<0.001), but the odds of disease were similar to cows in Group 3. The odds of having RFM or clinical mastitis tended to be lower in cows in Group 1 than cows in Group 4 (p=0.08). The odds of cows being culled or dying during the first 90 DIM were lower for cows in Group 1 than for those in Groups 2, 3, and 4 (p≤0.05). Mean accumulated milk yield up to 90 DIM was higher in cows in Group 1 than Group 2 and Group 4 (p<0.001), but was similar to that of cows in Group 3 (p=0.28). Conclusions and clinical relevance: Cows that lost BCS during the late dry period had increased odds of being diagnosed with several postpartum diseases and had decreased milk yield compared to cows that maintained or gained BCS during the entire dry period. Loss of BCS during any stage of the dry period was also associated with increased incidence of culling or death during the first 90 DIM. These results should raise awareness among dairy cattle producers of the importance of properly managing cow body condition during the dry period, especially during the late dry period. 相似文献