Endophytic bacteria from selenium-supplemented wheat plants could be useful for plant-growth promotion,biofortification and Gaeumannomyces graminis biocontrol in wheat production

In this study, we isolated putative plant-growth-promoting endophytic bacteria from selenium-supplemented wheat grown under field conditions. These bacterial strains belonged to Bacillus, Paenibacillus, Klebsiella, and Acinetobacter genera and showed genetic similarly with rhizospheric bacteria isolated in the same Andisol soil and with other endophytic strains previously reported. Strains isolated from selenium-supplemented wheat were highly tolerant to elevated selenium concentration (ranged from 60 to 180 mM), and showed potential plant-growth-promoting capabilities (auxin and siderophore production, phytate mineralization, and tricalcium phosphate solubilization). In addition, some strains like Acinetobacter sp. (strain E6.2), Bacillus sp. (strain E8.1), Bacillus sp., and Klebsiella sp. (strains E5 and E1) inhibited the growth of Gaeumannomyces graminis mycelia in vitro at 100, 50, and 30 %, respectively. These endophytic microorganisms would be useful for dual purposes: selenium biofortification of wheat plants and control of G. graminis, the principal soil-borne pathogen in volcanic soils from southern Chile.     

Quantitation of mule duck in goose foie gras using TaqMan real-time Polymerase Chain Reaction

A real-time quantitative Polymerase Chain Reaction (PCR) method has been developed for the quantitation of mule duck (Anas platyrhynchos x Cairina moschata) in binary duck/goose foie gras mixtures. The method combines the use of real-time PCR with duck-specific and endogenous control "duck + goose" primers to measure duck content and total foie gras content, respectively. Both PCR systems (duck-specific and duck + goose) were designed on the mitochondrial 12S ribosomal RNA gene (rRNA). The duck-specific system amplifies a 96 bp fragment from duck DNA, whereas the duck + goose system amplifies a 120 bp fragment from duck and goose DNA. The method measures PCR product accumulation through a FAM-labeled fluorogenic probe (TaqMan). The C(t) (threshold cycle) values obtained from the duck + goose system are used to normalize the ones obtained from the duck-specific system. Analysis of experimental duck/goose foie gras binary mixtures demonstrated the suitability of the assay for the detection and quantitation of duck in the range of 1-25%. This genetic marker can be very useful to avoid mislabeling or fraudulent species substitution of goose by duck in foie gras.     

Growth Responses of Micropropagated Cassava Clones as Affected by Glomus Intraradices Colonization

This study reports the effectiveness of an arbuscular mycorrhizal (AM) fungus Glomus intraradices on three clones (SOM-1, 05 and 50) of cassava (Manihot esculenta). Arbuscular mycorrhizal inoculation increased plant resistance to transplant stress from “in vitro” to “ex vitro” conditions and plant biomass (shoot and root) production was greatly enhanced by AM-colonization. The magnitude of AM growth stimulation over control clones was: 861% (SOM-1), 1042% (05) and 854% (50). Arbuscular mycorrhizal colonized cassava plants increased cassava water uptake in terms of percentage, 62% in clone SOM-1, 24% in clone 05, and 157% in clone 50. The highest effect of AM-colonization on water content in root of clone 50 was correlated with the greatest increment in leaf tissue production (1218% over control) and with the maximum shoot/root ratio determined. The biomass distribution between shoot and root was changed by AM symbiosis and such effect varied for each clone that may be caused by mycorrhizal changes in macro/micro-nutrients translocation/compartimentation. Cassava dependence on AM symbiosis was greatest in clone SOM-1 since AM-colonization provided the highest stem (weight, length, and diameters), leaf (weight and number), bud number, and root weight. These results lead to practical applications because AM inoculation is crucial for improving cassava yield (shoot and root) and nutrition irrespective of the clone involved. Thus, importance of AM symbiosis in micropropagated cassava clones is of great practical interest in agriculture and allows the selection of the most suitable clone for dry environments due to the particular effect on root water content that improves drought adaptation.     

Impact of Sewage Sludge Compost Utilization on Chemical Properties of Olive Grove Soils

Field experiments were conducted for four years, between 1998 and 2002, in two olive grove soils of adult olive orchards (Olea europaea L. cv. Cornicabra) in a clay loam soil in Seseña (Toledo, Spain) and in a sandy loam soil in Aranjuez (Madrid, Spain). There were four treatments, sewage sludge compost (SSC), sewage sludge compost plus urea (SSC+U), urea (U) and control (C). Each treatment was replicated four times and two depths were studied (0-15 and 15-30 cm). Once a year, before spreading sewage sludge compost, soil samples were taken at depths of 0 to 15 cm and 15 to 30 cm. Organic matter, total Kjeldhal nitrogen, phosphorus availability, pH, and electric conductivity were measured. No differences were found between treatment on organic matter and electric conductivity after four years of application of sewage sludge compost to two olive grove soils. In relation to nitrogen content, sewage sludge compost, only in Seseña, produced higher nitrogen soil content than the traditional urea treatment. Sewage sludge compost applied on olive grove soils improved the Phosphorus availability for the olive tree. In Aranjuez, the use of sewage sludge compost increased the pH of the soil with respect to Urea and Control plots. In Seseña, the reverse effect was found.     

Oomycete species associated with Theobroma cacao crops in Colombia

The study of oomycetes associated with crops is highly important due to the economic losses they might cause. In cacao, the genus Phytophthora has been extensively studied, but little is known about other genera and species of oomycetes associated with this plant. This study aimed to determine the oomycetes’ diversity present in Colombian cacao crops. A total of 146 isolates were obtained from diseased plants and soil in 11 departments. Analysis of internal transcribed spacer (ITS) and cytochrome oxidase subunit I (coxI) sequences was performed along with the assessment of morphological characteristics. Nine species were identified, distributed in four genera: Phytophthora (P. palmivora, 54%; P. nicotianae, 1%), Phytopythium (Phy. chamaehyphon, 15%; Phy. cucurbitacearum, 9%; Phy. vexans, 7%; Phy. helicoides, 1%), Globisporangium (G. splendens, 3%), and Pythium (Py. delicense, 1%; Py. inflatum,1%). Additionally, an unidentified and possibly new species of Phytophthora (5%) and three unidentified species of Phytopythium (3%) were found. This is the first report of Globisporangium, Phytopythium, and Pythium in cacao crops of Colombia and the first report of the species Phy. chamaehyphon in the country. Interestingly, some isolates of Phytopythium spp. were isolated from necrotic leaves and vascular section of stems, which may suggest a role in cacao diseases traditionally associated with Phytophthora. Also, it is proposed that the new species of Phytophthora may be contributing significantly to black pod disease in Colombian cacao crops, and we highlight that the study of P. palmivora is urgent because of its distribution all over the country.     

Evaluation of regional limb perfusion with erythromycin using the saphenous,cephalic, or palmar digital veins in standing horses

There are no reported studies evaluating the use of erythromycin for regional limb perfusion (RLP) in horses. Our hypothesis was that using the cephalic and saphenous veins for RLP will enable delivery of therapeutic concentrations of erythromycin to the distal limb. Nineteen healthy horses participated in the study. The cephalic, saphenous or palmar digital (PD) vein was used to perfuse the limb with erythromycin. Synovial samples were collected from the metacarpo/metatarso‐phalangeal (MCP/MTP) joint and blood samples were collected from the jugular vein. Maximum concentration (C_max) of erythromycin in the MCP joint using the cephalic vein was 113 mg/L. The C_max of erythromycin in the MTP joint using the saphenous vein was 38 mg/L. Erythromycin administered using the PD vein was not detectable in the MCP/MTP joint of four of six horses. Concentrations of erythromycin achieved in the synovial fluid of the MCP/MTP joint were between 152 and 452 times the minimal inhibitory concentration (MIC) for Rhodococcus equi (R. equi). In conclusion, the results indicate that when using the saphenous or cephalic veins for RLP, therapeutic concentrations of erythromycin in the MTP/MTP joint can be consistently reached.     

Addressing the Dilemmas of Measuring Amylose in Rice

Amylose content is a parameter that correlates with the cooking behavior of rice. It is measured at the earliest possible stages of rice improvement programs to enable breeders to build the foundations of appropriate grain quality during cultivar development. Amylose is usually quantified by absorbance of the amylose‐iodine complex. The International Network for Quality Rice (INQR) conducted a survey to determine ways that amylose is measured, reproducibility between laboratories, and sources of variation. Each laboratory measured the amylose content of a set of 17 cultivars of rice. The study shows that five different versions of the iodine binding method are in use. The data show that repeatability was high within laboratories but reproducibility between laboratories was low. The major sources of variability were the way the standard curve was constructed and the iodine binding capacity of the potato amylose used to produce the standard. Reproducibility is much lower between laboratories using a standard curve of potato amylose alone compared with those using calibrated rice cultivars. This study highlights the need to standardize the way amylose is measured, and presents research avenues for doing so.     

PCR-RFLP authentication of meats from red deer (Cervus elaphus), fallow deer (Dama dama), roe deer (Capreolus capreolus), cattle (Bos taurus), sheep (Ovis aries), and goat (Capra hircus)

PCR-RFLP analysis has been applied to the identification of meats from red deer (Cervus elaphus), fallow deer (Dama dama), roe deer (Capreolus capreolus), cattle (Bos taurus), sheep (Ovis aries), and goat (Capra hircus). PCR amplification was carried out using a set of primers flanking a conserved region of approximately 712 base pairs from the mitochondrial 12S rRNA gene. Restriction site analysis based on sequence data from this DNA fragment permitted the selection of MseI, MboII, BslI, and ApoI endonucleases for species identification. The restriction profiles obtained when amplicons were digested with the chosen enzymes allowed the unequivocal identification of all domestic and game meat species analyzed in the present work.     

Amine degradation by 4,5-epoxy-2-decenal in model systems

The reactions of 4,5-epoxy-2-decenal with octylamine, benzylamine, and 2-phenylglycine methyl ester were studied to investigate if amines may suffer a Strecker type degradation by epoxyalkenals analogously to amino acids. In addition to other reactions, the studied amines were converted into their corresponding Strecker aldehydes (octanal, benzaldehyde, and methyl 2-oxo-2-phenylacetate, respectively) to an extent that depended on the pH, the temperature, the amount of epoxyalkenal, and the amine involved. Each amine exhibited an optimum pH for the reaction, but the corresponding Strecker aldehydes were produced to a significant extent within a broad pH range. In addition, the temperature mostly influenced the reaction rate, which was increased between 6.5 and 9.5 times when the reaction was carried out at 60 degrees C than when it took place at 37 degrees C. Furthermore, Strecker aldehyde formation was linearly correlated with the amount of the epoxyalkenal present in the reaction mixture. Nevertheless, the reaction yield mostly depended on the amine involved. Thus, octylamine only produced trace amounts of octanal, benzylamine was converted into benzaldehyde with a yield of 4.3%, and 2-phenylglycine methyl ester was converted into methyl 2-oxo-2-phenylacetate with a reaction yield of 49%. All of these results suggest that suitable amines can be degraded by epoxyalkenals to their corresponding Strecker aldehydes to a significant extent.     

Field performance of <Emphasis Type="Italic">Pinus halepensis</Emphasis> planted in Mediterranean arid conditions: relative influence of seedling morphology and mineral nutrition

In Mediterranean arid regions, relatively small planting stock has traditionally been used in an attempt to reduce drought susceptibility, though few studies have examined influences of initial seedling morphology and nutrition on long-term plantation establishment. We fertilized Pinus halepensis Mill. seedlings in the nursery with controlled release fertilizer (CRF) varying in formulations and rates; 9-13-18 and 17-10-10 (N-P-K) formulations at 3, 5 and 7 g l⁻¹ substrate plus an unfertilized control and we evaluated growth and survival 7 years after planting in arid conditions in Almería province, southeast Spain. Interactions between initial height and fertilizer treatments occurred during the first 3 years; initial size advantages of specific fertilizer treatments (7 g l⁻¹ of 9-13-18 and 17-10-10 at 3 g l⁻¹) persisted after 7 years. The largest and most nutrient-rich seedlings from 9-13-18 at 7 g l⁻¹ (41.0 cm tall, 4.4 mg of P per g of root tissue at time of planting) exhibited the highest survival after 7 years (79%), while survival declined to 42% for non-fertilized plants (12.9 cm tall and 0.6 mg of P per g of root tissue). Initial seedling morphological parameters were most consistently correlated with field performance. Root P concentration was the nutrient variable most closely related to survival. Our data emphasizes importance of longer-term experiments to accurately assess influences of nursery treatments on field responses, particularly in arid areas. We suggest that larger seedlings with greater nutrient reserves than are currently being used should be incorporated into Mediterranean plantations.