Potential of sexual reproduction among host-adapted populations of Phytophthora infestans sensu lato in Ecuador     

R. F. Oliva  L. J. Erselius  N. E. Adler  G. A. Forbes † 《Plant pathology》2002,51(6):710-719

To determine the potential of sexual reproduction among host-adapted populations of Phytophthora infestans sensu lato in Ecuador, 13 A1 isolates belonging to clonal lineages US-1, EC-1 and EC-3, and 11 A2 isolates belonging to the clonal lineage EC-2, were paired on agar plates to induce crossing. In the first experiment, six A1 isolates (three US-1, two EC-1 and one EC-3) were each crossed with three A2 isolates (total = 18 crosses). Matings involving isolates of the EC-1 lineage produced more oospores of healthy appearance than did matings with isolates of US-1 or EC-3. In the second experiment, the oospores of 35 crosses (21 EC-1 × EC-2; 10 US-1 × EC-2; four EC-3 × EC-2) were dispersed on water agar to assess oospore germination. Overall, germination percentages were low. Only one cross produced enough progeny for evaluation. Twenty-three single-oospore offspring were isolated and evaluated for mating type; electrophoretic patterns of glucose-6-phosphate isomerase ( Gpi ) and peptidase ( Pep ) alloenzyme loci; mitochondrial DNA haplotype; and genomic DNA fingerprint. Multilocus genotype data indicated that all 23 isolates resulted from meiotic recombination. Four progeny with homothallic phenotype appeared to be unstable heterokaryons. Markers at several loci segregated according to simple Mendelian expectations for a diploid organism, but the ratios of three RFLP loci and the Pep locus were not consistent with Mendelian expectations. All progeny were nonpathogenic on hosts of the parental genotypes. Reduced mating success and reduced pathogenic fitness of progeny appear to be postmating mechanisms of reproductive isolation in populations of P. infestans sensu lato in Ecuador.  相似文献   

The effects of Enterolobium contortisiliquum serine protease inhibitor on the survival of the termite Nasutitermes corniger,and its use as affinity adsorbent to purify termite proteases     

Rodrigo da Silva Ferreira  Thiago Henrique Napoleo  Rosemeire A Silva‐Lucca  Mariana Cristina Cabral Silva  Patrícia Maria Guedes Paiva  Maria Luiza Vilela Oliva 《Pest management science》2019,75(3):632-638

  相似文献   

Impacts of anthropogenic N additions on nitrogen mineralization from plant litter in exotic annual grasslands   总被引：1，自引：0，他引：1  

Abby G. Sirulnik  Edith B. Allen  Michael F. Allen 《Soil biology & biochemistry》2007,39(1):24-32

Urban regions of southern California receive up to 45 kg N ha^-1 y^-1 from nitrogen (N) deposition. A field decomposition study was done using ¹⁵N-labelled litter of the widespread exotic annual grass Bromus diandrus to determine whether elevated soil N is strictly from N deposition or whether N mineralization rates from litter are also increased under N deposition. Tissue N and lignin concentrations, which are inversely related in field sites with high and low N deposition, determine the rate at which N moves from plant litter to soil and becomes available to plants. The effect of soil N on N movement from litter to soil was tested by placing litter on high and low N soil in a factorial experiment with two levels of litter N and two levels of soil N. The litter quality changes associated with N deposition resulted in faster rates of N cycling from litter to soil. Concentrations of litter-derived N in total N, NH₄⁺, NO₃⁻, microbial N and organic N were all higher from high N/low lignin litter than from low N/high lignin litter. Litter contributed more N to soil NH₄⁺ and microbial N in high N than low N soil. At the end of the study, N mineralized from high N litter on high N soil accounted for 46% of soil NH₄⁺ and 11% of soil NO₃⁻, compared to 35% of soil NH₄⁺ and 6% of soil NO₃⁻ from low N litter on low N soil. The study showed that in high N deposition areas, elevated inorganic soil N concentrations at the end of the summer N deposition season are a result of N mineralized from plant litter as well as from N deposition.  相似文献   

ADP-Glucose Pyrophosphorylase Is Located in the Plastid and Cytosol in the Pulp of Tropical Banana Fruit (Musa acuminata)     

Solis-Badillo  Elizabeth  Agama-Acevedo  Edith  Tiessen  Axel  Lopez Valenzuela  Jose A.  Bello-Perez  Luis A. 《Plant foods for human nutrition (Dordrecht, Netherlands)》2020,75(1):76-82

Plant Foods for Human Nutrition - ADP-glucose pyrophosphorylase (AGPase) is a key enzyme of starch synthesis in seeds, tubers and fruits. UDP-glucose pyrophosphorylase (UGPase) is an important...  相似文献   

Regulation of growth, fatty acid composition and delta 6 desaturase expression by dietary lipids in gilthead seabream larvae (Sparus aurata)     

Izquierdo MS  Robaina L  Juárez-Carrillo E  Oliva V  Hernández-Cruz CM  Afonso JM 《Fish physiology and biochemistry》2008,34(2):117-127

The Δ6 and Δ5 desaturases and elongases show only very limited activity in marine fish, and little is known of the possibility of enhancing Δ6 desaturase gene expression in these fish. The use of plant oils in marine fish diets is limited by their lack of n−3 highly unsaturated fatty acids (HUFA) despite an abundant content of the 18C fatty acid precursor linoleic and α-linolenic acids. The objective of the present study was to determine the ability of larval gilthead seabream to utilize vegetable oils and assess the nutritional regulation of Δ6 desaturase gene expression. Seventeen-day-old gilthead seabream larvae were fed during a 17-day period with one of four different microdiets formulated with either sardine fish oil (FO), soybean, rapeseed or linseed oils, respectively, or a fifth diet containing defatted squid meal and linseed oil. Good larval survival and growth, both in terms of total length and body weight, were obtained by feeding the larvae either rapeseed, soybean or linseed oils. The presence of vegetable oils in the diet increased the levels of 20:2n−9 and 20:2n−6, 18:2n−9, 18:3n−6, 20:3n−6 and 20:4n−6, in larvae fed rapeseed and soybean oils in comparison to those fed FO. In addition, a sixfold increase in the relative expression of Δ6 desaturase-like gene was found in larvae fed rapeseed and soybean oils, denoting the nutritional regulation of desaturase activity through its gene expression in this fish species. However, feeding linseed oil did not increase the expression of the Δ6 desaturase gene to such a high extent.  相似文献   

Growth,Feed Utilization,and Glycemic Response in European Sea Bass,Dicentrarchus labrax,Juveniles Fed Carbohydrate of Different Complexities     

Paula Enes  Helena Peres  Ivone Almeida  Ana Couto  Aires Oliva‐Teles 《Journal of the World Aquaculture Society》2011,42(6):873-879

The effect of dietary carbohydrate complexity on growth, feed utilization, and glycemia was studied in European sea bass juveniles. Four isonitrogenous (50% crude protein) and isolipidic (15% crude lipids) diets were formulated to contain 20% pregelatinized maize starch (PGS diet), dextrin (DEX diet), maltose (MAL diet), or glucose (GLU diet). No effect of dietary carbohydrate complexity on growth was noticed. Feed efficiency and protein efficiency ratio were lower in fish fed the GLU diet than in the other groups, whereas the opposite was observed for feed intake. Plasma glucose peaked 3–4 h after feeding in fish fed the MAL and GLU diets, whereas in fish fed the PGS and DEX diets the peak was reached 5–6 h after feeding. Peak plasma glucose concentration (13 mmol/L) was higher in fish fed the GLU diet than the other diets (9 mmol/L). Shorter hyperglycemia duration was observed in fish fed the MALT and GLU diets (6 h) than the PGS and DEX diets (10 h). Complex carbohydrates delayed plasma glucose concentration peak compared with simple sugars, whereas the opposite was observed for hyperglycemia duration. Overall, dietary maltose, dextrin, and starch were apparently better utilized as energy source than glucose by European sea bass juveniles.  相似文献   

Fungicide dissipation curves in winemaking processes with and without maceration step     

Fernández MJ  Oliva J  Barba A  Cámara MA 《Journal of agricultural and food chemistry》2005,53(3):804-811

The evolution of residual levels of four fungicides (cyprodinil, fludioxonil, pyrimethanil, and quinoxyfen) during the elaboration of three types of wine with maceration (traditional red wine, carbonic maceration red wine, and red wine of long maceration and prefermentation at low temperature) and two types of wine without maceration (rose and white) has been studied. The disappearance curves of each fungicide have been analyzed during the period of each winemaking process (21 days) and during the different enological steps involved in the elaborations. The residual levels of fludioxonil reduce most quickly during the winemaking processes without maceration, whereas the decrease in levels of pyrimethanil was the slowest in practically all cases (with and without maceration). During carbonic maceration winemaking, the decay constant of cyprodinil was greater than that of the other pesticides in all assays (time and steps).  相似文献   

Accuracy of the Rotfinder instrument in detecting decay on Norway spruce (Picea abies) trees     

Jonàs Oliva  Carmen RomeraloJan Stenlid 《Forest Ecology and Management》2011,262(8):1378-1386

Rotfinder is a non-destructive decay-sensing apparatus based on resistance measurements in standing trees. The accuracy of Rotfinder in detecting decay was evaluated in 500 standing trees in three Norway spruce (Picea abies) plots. Trees were measured at three heights, 0.30, 0.66 and 1.30 m. Sections were later inspected for the presence of decay and reaction zones. Inspected trees were mostly infected by Heterobasidion annosum and showed a large variation in the amount of decay present, ranging from 0.1% to 88.0% of the section. Correctly and incorrectly classified trees were compared in terms of ion and element concentration, density and moisture. Measurements at stump level (0.30 m) were more accurate than measurements at breast height (1.30 m) where the reaction zone and decay columns showed lower moisture content. The accuracy of Rotfinder increased when trees with small decay columns were regarded as ‘non-decayed’. When only trees with more than 15% of the section decayed were regarded as ‘decayed’, Rotfinder had an accuracy of 0.86 when performing assessments at stump level. False negatives, as opposed to true positives, corresponded to trees with smaller and drier decay columns, drier reaction zones and lower K⁺ (potassium) concentration in the decay column. False positives corresponded to trees with large sapwood and high sodium content in the sapwood. Rotfinder represents an alternative to the standard method of using increment core observations to assess decay in living trees.  相似文献   

The contribution of<Emphasis Type="Italic"> Phragmites australis</Emphasis> litter to methane (CH<Subscript>4</Subscript>) emission in planted and non-planted fen microcosms   总被引：1，自引：0，他引：1  

Sari?JuutinenEmail author  Tuula?Larmola  Rainer?Remus  Edith?Mirus  Wolfgang?Merbach  Jouko?Silvola  Jürgen?Augustin 《Biology and Fertility of Soils》2003,38(1):10-14

The contribution of Phragmites australis (Cav.) Trin. ex Steud. (common reed) litter as an origin of CH ₄-C was studied in a microcosm experiment. ¹⁴C-labelled, dried and ground P. australis root and shoot litter was buried in waterlogged, planted or non-planted fen microcosms. The evolution of ¹⁴CO ₂ and ¹⁴CH ₄ from the pots was monitored during the 35-day experiment. The ¹⁴C activity in the shoots and roots of the plants, soil, and inundation water was also analysed at the end of the experiment. Up to 40% of the released CH ₄-C originated from the added litter, whereas the rest originated from old soil organic matter. The comparison of planted and non-planted pots suggested that the contribution of recent plant-derived C (i.e. root exudates) to CH ₄ emission was negligible. The proportion of litter-derived CH ₄-C was significantly higher in the planted pots, suggesting that the presence of plants enhanced the formation of CH ₄ from litter. The major part of the initial ¹⁴C activity was recovered from the soil. About 3% was recovered from the inundation water, about 10% was emitted as CO ₂, and only <0.01% as CH ₄. However, these results demonstrated that plant litter and old soil organic matter are the major sources of CH ₄-C in fens during the early growth stage of P. australis.  相似文献   

Evolution of chlorpyrifos, fenarimol, metalaxyl, penconazole, and vinclozolin in red wines elaborated by carbonic maceration of Monastrell grapes     

Navarro S  Oliva J  Barba A  Navarro G  Garcia MA  Zamorano M 《Journal of agricultural and food chemistry》2000,48(8):3537-3541

The influence of the different steps involved in the wine-making process on the disappearance of chlorpyrifos, fenarimol, metalaxyl, penconazole, and vinclozolin in red wines elaborated by carbonic maceration of Monastrell grapes was studied. The initial levels of the residues in grapes ranged from 0.28 mg/kg (penconazole) to 1 mg/kg (chlorpyrifos). Ten days after the beginning of maceration, the compound that had decreased least was chlorpyrifos (83% of initial value remaining), whereas metalaxyl, the least persistent of the residues, had decreased to 49% of its initial value. In the free-run juice, on the other hand, the highest percentage remaining corresponded to metalaxyl (10%) and the lowest to chlorpyrifos (0. 1%). After pressing, the percentages of initial values eliminated in pomace varied from 82.7% for chlorpyrifos to 17.7% for metalaxyl, whereas in the press juice the opposite was the case (37% metalaxyl and 2% chlorpyrifos remaining). In finished wine, there were residues of all the pesticides, with the exception of chlorpyrifos, metalaxyl (21%) being the most persistent. The percentages eliminated in the lees varied from 1.5 to 2.5% of the initial value.  相似文献