Highly infested soils undermine the use of resistant olive rootstocks as a control method of verticillium wilt

Verticillium wilt of olive (VWO) is probably the most devastating fungal disease for olive trees worldwide, and currently the main cultivars are susceptible or moderately susceptible to this disease. The evaluation of resistant cultivars as rootstocks to control the disease has scarcely been explored, and mainly in short-term studies under controlled conditions, which usually do not correspond with field evaluations. The main objective of this study was to assess the responses to VWO of different scion × rootstock combinations of the olive cultivars Picual, Arbequina, Changlot Real, and Frantoio in a long-term field experiment with a soil highly infested with the defoliating pathotype of Verticillium dahliae. The results showed that grafting the susceptible cultivar Picual onto resistant rootstocks delayed the onset of the disease symptoms; however, after 4 years, it was observed that all combinations that contain Picual (a) were extensively colonized by V. dahliae; (b) developed severe symptoms of the disease; and (c) had plant mortality similar to Picual growing on its own roots. This result highlights the importance of long-term field experiments to evaluate VWO and shows that grafting susceptible olive cultivars onto resistant ones does not provide a durable control of VWO under high inoculum potential, as V. dahliae is able to progress through the resistant rootstock and then extensively colonize and kill the susceptible scion. However, the high inoculum potential observed in this study does not allow us to consider the evaluated resistant cultivars as completely ineffective under lower inoculum densities.     

Lpp34, a novel putative lipoprotein from Mycobacterium avium subsp. paratuberculosis

A Mycobacterium avium subsp. paratuberculosis expression library in lambda ZAP was screened with immunized mice sera. One clone was selected, sequenced and further characterized. The sequence analysis of the hypothetical open-reading frame (ORF) predicts a protein of 20.8 kDa with a probable signal sequence compatible with Cys-acylation at Cys24, characteristic of lipoproteins. In consequence, the protein was termed Lpp34. Recombinant expression of Lpp34 was achieved by cloning the lpp34 gene into the histidine-tag expression vector pRSET-A. Western blot analysis showed a protein band with a molecular weight of 34 kDa. The native protein was localized in the membrane fraction of M. avium subsp. paratuberculosis and extracted in the detergent phase of Triton X-114. Southern blot and polymerase chain reaction showed that the gene is absent from all the non-M. avium complex mycobacterial genomes tested. Humoral reactivity using bovine sera demonstrated that this protein is widely recognized by both the infected and non-infected animals. This could partly be due to the conserved sequence in close-related environmental bacteria such as M. avium subsp. avium and to the presence of a conserved epitope in other bacteria such as Escherichia coli. In conclusion, these findings show that Lpp34 is a membrane protein and a putative lipoprotein present in M. avium complex mycobacteria and absent in the M. tuberculosis complex.     

Polyphenols in wild and weedy Mexican common beans (Phaseolus vulgaris L.)

The polyphenolic composition of 62 wild and weedy Mexican bean collections from diverse origins, grouped by their seed coat color, was assessed. According to spectrophotometric analysis, the range of total phenols, condensed tannins, and total anthocyanins presented wide differences. Furthermore, the phenolic acid, flavonoid, and anthocyanin profiles were analyzed using HPLC. Ferulic was the main phenolic acid. Kaempferol and quercetin were the main flavonoids, and the isoflavones daidzein and coumestrol were found in only low levels in few collections. Delphinidin was the main anthocyanidin found, followed by petunidin, cyanidin, malvidin, pelargonidin, and peonidin. The wide variation observed in polyphenolic contents was more related to their genotype than to the color factor. These results show that some wild and weedy beans are good sources of phenolic compounds for use in breeding programs focused on nutrition and health.     

Chemical Composition and Ruminal Degradability of Spineless Cactus Grown in Northeastern Brazil

A study was conducted to determine chemical composition and ruminal nutrient degradability of eight spineless cactus cultivars grown in northeastern Brazil. Results showed that neutral detergent fiber was similar for all cultivars and averaged 249 g · kg^-1 ± 7.3 SEM. Acid detergent fiber ranged between 148 g · kg^-1 and 207 g · kg^-1 with some significant differences between cultivars. Starch and water-soluble carbohydrates were similar for all cultivars and averaged 198 g · kg^-1 ± 6.3 SEM and 155 g · kg^-1 ± 9.0 SEM, respectively. Protein content was less than 50 g · kg^-1 with some significant differences between cultivars. Calcium was the mineral with the highest concentration followed by potassium and magnesium with no differences between cultivars. Effective ruminal degradability of dry matter and neutral detergent fiber were unaffected by cultivar and averaged 701 g · kg^-1 ± 8.4 SEM and 503 g · kg^-1 ± 5.8 SEM, respectively. It was concluded that cultivars had little impact on chemical composition and ruminal degradability of spineless cactus. Based on chemical composition and in situ ruminal degradability, spineless cactus can be considered an excellent source of fermentable carbohydrates for grazing and nongrazing ruminants. Because of its high carbohydrate quality, spineless cactus can be used an emergency feed or as part of a complete diet providing that the diet contains an adequate amount of degradable protein.     

Determination of a sedative dose and influence of droperidol and midazolam on cardiovascular function in pigs.

Twelve pigs were randomly assigned to 1 of 2 groups, droperidol or midazolam, to determine a sedative dose of each drug that would facilitate handling of the pigs. Each pig in the group received all of the test doses with 5-7 d between treatments (droperidol--0.1, 0.3, 0.6 mg/kg, or midazolam--0.25, 0.5, 1.0 mg/kg) and saline (3 mL), i.m. One investigator, unaware of the treatment administered, assessed the time of onset, degree, and duration of sedation. The 0.3 mg/kg dose of droperidol and 0.5 mg/kg dose of midazolam were judged to be the most suitable for sedation and produced similar degrees of sedation, although the onset and duration of sedation was significantly longer for the droperidol group. The effects of these 2 doses on heart rate, respiratory rate, systolic blood pressure, and rectal temperature were assessed in 12 pigs randomly assigned to 1 of the 2 treatments. Respiratory rate decreased significantly with droperidol at 10, 15, and 30 min. Temperature was significantly decreased at 60 min following midazolam. This study demonstrates that 0.3 mg/kg i.m. of droperidol and 0.5 mg/kg i.m. of midazolam induce adequate sedation in pigs with minimal cardiorespiratory changes.     

Wind dispersal of Puccinia psidii urediniospores and progress of eucalypt rust

To identify and implement Puccinia psidii control strategies, it is essential to understand the role of environmental factors on rust‐disease development and spread among eucalypt (Eucalyptus spp.) plantations. In this study, we evaluated the wind dispersal of P. psidii urediniospores and the progress of eucalypt rust in a field trial in Brazil. Urediniospores of P. psidii were trapped in a Burkard^® spore trap from July 2004 to June 2005. To evaluate the progress of eucalypt rust, plots were established in March 2002 using a clonal hedge scheme. The incidence of both branches and leaves with rust was assessed weekly from February 2003 to October 2005. Disease progress was studied using time‐series analysis. Urediniospores were trapped on 77% of the days sampled. The highest average urediniospore concentration was detected from July to November, and most of the urediniospores (58%) were trapped at night. Urediniospore concentration was negatively correlated with rainfall, light intensity, minimum, average and maximum temperatures and wind speed, whereas urediniospore concentration was positively correlated with leaf‐wetness duration and relative humidity. From December 2004 to June 2005, average urediniospore concentration was 0.22 spores m^?3 air h^?1 and had no correlation with meteorological data. The highest average urediniospore concentration was associated with a combination of low average temperature, low light intensity, low wind speed, high relative humidity and high leaf wetness, which reflect conditions observed at night. The disease incidence was positively correlated with the urediniospores trapped at 12 days prior to disease assessment. According to the models obtained by the time series, a seasonal yearly effect was found on rust progress. Using our models, we were also able to forecast disease incidence up to 3 months after the last field assessment.     

How important is clonal recruitment for population maintenance in rare plant species?: the case of the narrow endemic cactus, Stenocereus eruca, in Baja California, México

Stenocereus eruca is a postrate columnar cactus whose regeneration seems to occur mainly through clonal propagation. It is a narrow endemic species of the Sonoran desert in Baja California Sur and currently considered as threatened under Mexican legislation. In this paper we describe the demography of ramets in four populations along its distribution range and the demography of genets in one population during a 3-year-study period in order to evaluate its conservation status. We also analyze the relative contribution of sexual reproduction and clonal propagation to population maintenance and provide guidelines for the formulation of conservation programs. Elasticity analyses were used to explore the relative contribution of sexual and clonal recruitment to projected population growth rate (λ). During the three years of study, regeneration occurred only through clonal propagation while sexually derived seedlings were not detected within or outside the permanent plots. Our demographic data showed that the four population of S. eruca are in equilibrium (λ ≈ 1), and elasticity analyses showed that the relative contribution to λ of clonal recruitment was larger than sexual recruitment, at least during the analyzed ecological time scale. Simulations showed that removing sexual recruitment had a minor impact on λ, but the absence of clonal propagation alone was sufficient to keep below unity. We propose the establishment of at least one reserve with adequate protection from human disturbance to conserve S. eruca.     

Effect of household processing and unit-to-unit variability of pyrifenox, pyridaben, and tralomethrin residues in tomatoes

Residue levels of pyrifenox, pyridaben, and tralomethrin were determined in unprocessed and processed tomatoes, grown in a experimental greenhouse, to evaluate the effect of three different household processes (washing, peeling, and cooking) and the "unit to unit" variability of these pesticides in tomatoes. The study was carried out on 11 greenhouse tomato samples collected during a 5 week period in which two successive treatments with the studied pesticides were applied. Residue levels in unprocessed and processed tomato samples were determined by means of ethyl acetate extraction and gas chromatography-electron capture detection determination. The washing processing factor results were 0.9 +/- 0.3 for pyridaben, 1.1 +/- 0.3 for pyrifenox, and 1.2 +/- 0.5 for tralomethrin, whereas the peeling processing factors were 0.3 +/- 0.2 for pyridaben and 0.0 +/- 0.0 for both pyrifenox and tralomethrin. The average loss of water in the tomato pure samples during the cooking process was approximately 50%; the cooking processing factors were 2.1 +/- 0.8 for pyridaben, 3.0 +/- 1.1 for pyrifenox, and 1.9 +/- 0.8 for tralomethrin. The unit-to-unit variability factors were determined on three different greenhouse samples analyzing 10 different units of unprocessed tomatoes from each sample. In all cases, the unit-to-unit variability factor results were within the range of 1.3-2.2.     

A Bayesian analysis of boar spermatozoa kinematics and head morphometrics and their relationship with litter size fertility variables

The semen movement and sperm head size patterns of boar ejaculates were analysed using computer-assisted semen analysis (CASA)-Mot and -Morph systems. The aim of the present study was to compare morphometric and kinematics variables from boars and to determine the relationship with sow fertility variables related to litter size. The females were from maternal crossing schemes such as the continuous 3-generation cross between York (Y), Landrace (L), and Pietrain (P) hybrid sows and Pietrain boars. Semen samples were collected from 11 sexually mature boars from two sire lines. Samples were analysed using the ISAS^®v1 system to evaluate eight kinematic variables of sperm velocity, progressiveness and undulations. Four morphometric parameters of sperm head size (length, width, area and perimeter) were analysed. Bayesian analysis revealed relevant differences in four kinematic variables (VSL, LIN, STR and WOB) between sire lines, with a probability of relevance (P_R) of 0.79–0.91, and Pietrain boars were associated with higher progressive motility compared with Duroc x Pietrain boars. Moreover, there were relevant differences in all morphometric variables (P_R = 0.82–0.85) between sire lines. The dam line Y-L-50 (½ Y × ½ L) had higher total born per litter and piglets born alive, and YLP-75 (¹/₈ Y × ¹/₈ L × ³/₄ P) was associated with higher values of litter weight at birth (highest posterior density region at 95% = 9.92, 16.41 kg). There are relevant differences in kinematic variables between the assessed sire lines and the differences in morphometric and litter size variables were also relevant. The York-Landrace hybrid sows had higher total born per litter and piglets born alive, and there were relevant differences when compared with YLP-50 (¼ York × ¼ Landrace × ½ Pietrain). Differences in kinematic and morphometric variables between sire and dam lines related to fertility need to be further studied.