75 years of breeding pinto bean for resistance to diseases in the United States

Diseases are major production constraints of pinto bean despite 75 years of breeding. The objectives were to (1) assess progress made and (2) discuss future breeding strategies. Bean common mosaic virus (BCMV), anthracnose, rust, white mold, common blight, and halo blight and growth habit, seed weight, and seed coat darkening were evaluated for 52 cultivars released between 1944 and 2001. Sixteen cultivars were resistant to BCMV, 12 to race 53 of rust, five to race 73 of anthracnose, two to halo blight, and none to common blight and white mold. Four were resistant to two and none to three or more diseases. Four had Type I, ten Type II, and others Type III growth habit. Bill Z, Grand Mesa, Montrose, Olathe, Othello, Ouray and Pindak darkened slower in storage. Pintoba had the largest and Cahone smallest seed. An integrated breeding strategy is suggested for simultaneous improvement of resistance to multiple-diseases.     

Interspecific variation of constitutive chemical compounds in <Emphasis Type="Italic">Pinus</Emphasis> spp. xylem and susceptibility to pinewood nematode (<Emphasis Type="Italic">Bursaphelenchus xylophilus</Emphasis>)

Pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD), was detected in Spain in 2008. This gives rise to serious concern, as the disease has caused severe environmental and economic losses in Portugal and in Asian countries. We studied interspecific variation in susceptibility to pine wilt disease and differences in constitutive chemical compounds in the xylem tissue of the seven pine species -P. canariensis, P. halepensis, P. pinaster, P. pinea, P. sylvestris, P. radiata and P. taeda. Two-year-old trees were inoculated with B. xylophilus. Water potential and nematode densities were measured for each species on specific dates; whereas, wilting symptoms were recorded weekly until the end of the assay. Chemical compounds in the xylem were determined prior to inoculation. Three different resistance groups can be established in terms of the pine species susceptibility to PWN: non- to slightly-susceptible (P. canariensis, P. halepensis, P. taeda and P. pinea), susceptible (P. pinaster and P. radiata), and highly-susceptible (P. sylvestris). Nematodes migrated downward to the roots in all seven species. Constitutive xylem nitrogen, total polyphenols, and marginally phosphorus were negatively correlated with mortality caused by PWN. The most susceptible species, Pinus sylvestris, presented high levels of constitutive lipid-soluble substances and low levels of manganese, pointing to a possible relation between these components and PWN susceptibility. The results suggest P. sylvestris, P. pinaster and P. radiata forests could be severely damaged by PWN in Spain and highlight how constitutive chemical compounds such as nitrogen might play a role in resistance mechanisms against PWN.     

Oxytetracycline depletion and withdrawal time estimation following intraperitoneal administration in three species from Chilean salmon farming

This study was conducted to evaluate the half‐time (T½) and withdrawal time (WT) of oxytetracycline (OTC) following intraperitoneal (i.p.) administration of OTC (24.8–34.7 mg/kg) in three farmed salmonid species, Coho salmon (Oncorhynchus kisutch), Rainbow trout (Oncorhynchus mikiss) and Atlantic salmon (Salmo salar). A detection technique in fish skin muscle through a high‐performance liquid chromatography (HPLC) with a diode array detector (DAD) was developed and validated. The depletion studies were carried out in controlled conditions (nine studies) and under field conditions (one study). The T½ and WT estimations from the skin muscle after the i.p. administration of OTC in salmonids appear to be longer than studies where the OTC was orally administrated. Furthermore, the OTC maximum concentration in muscle seems to be also higher in the i.p. treatment. Due to the prolonged WT following the i.p. OTC administration, cautions related to the salmon harvest time should be consider in order to prevent OTC traces in the final product.     

Cloning and expression of buffalo active chymosin in Pichia pastoris

To date, only recombinant chymosin has been obtained in its active form from supernatants of filamentous fungi, which are not as good candidates as yeasts for large-scale fermentations. Since Bos taurus chymosin was cloned and expressed, the world demand for this protease has increased to such an extent that the cheesemaking industry has been looking for novel sources of chymosin. In this sense because buffalo chymosin has properties that are more stable than those of B. taurus chymosin, it may occupy a space of its own in the chymosin market. The main objective of the present work was the production of active recombinant buffalo chymosin in the culture supernatant of Pichia pastoris . This yeast has demonstrated its usefulness as an excellent large-scale fermentation tool for the secretion of recombinant foreign proteins. RNA was extracted from the abomasum of a suckling calf water buffalo ( Bubalus arnee bubalis ). Preprochymosin, prochymosin, and chymosin DNA sequences were isolated and expressed into P. pastoris. Only the recombinant clones of P. pastoris containing the prochymosin sequence gene were able to secrete the active form of the chymosin to the culture supernatant. This paper describes for the first time the production of active recombinant chymosin in P. pastoris without the need of a previous in vitro activation. The new recombinant yeast strain could represent a novel and excellent source of rennet for the cheesemaking industry.     

Study of haemostatic disorders in experimentally induced leishmaniasis in Beagle dogs

Haemostatic alterations in dogs experimentally infected with Leishmania infantumwere studied before and after therapy with meglumine antimonate. Haemostatic function tests including platelet count, collagen-induced platelet aggregation, prothrombin time, activated partial thromboplastin time, thrombin time, plasma fibrinogen determination, and serum fibrinogen/fibrin degradation products concentration were performed. In the course of infection and before treatment, moderate thrombocytopenia (P<0·00001) decreased collagen induced platelet aggregation (P=0·0003), prolonged thrombin time (P=0·0117) and increased fibrinogen/fibrin degradation products were observed. Statistically significant differences of plasma fibrinogen concentration, prothrombin time, and activated partial thromboplastin time were not encountered. Haemostatic parameters returned to normal values after therapy. The results indicate that Leishmania infection may impair haemostasis suggesting induction of disseminated intravascular coagulation (DIC), and that treating dogs in an early stage of infection may potentially avoid the possibility of developing an uncompensated DIC.     

Detection of Feline leukemia virus in the endangered Iberian lynx (Lynx pardinus).

Feline retroviruses are rarely reported in lynx species. Twenty-one Iberian lynx (Lynx pardinus) blood and tissue samples collected from Do?ana National Park and Los Villares (Sierra Morena) in southern Spain during 1993-2003 were analyzed by polymerase chain reaction to amplify nucleic acids from feline retroviruses. Six samples were positive for Feline leukemia virus (FeLV), but no samples tested positive for Feline immunodeficiency virus. The BLAST analysis indicated that 5 of the 6 sequences were closely related to FeLV strain Rickard subgroup A, whereas 1 sequence was identical to FeLV. To the authors' knowledge, this is the first report of FeLV in the endangered Iberian lynx.     

Pharmacokinetics of albendazole sulfoxide enantiomers administered in racemic form and separately in rats

The pharmacokinetic behaviour of albendazole sulfoxide (ABZSO) enantiomers was studied in rats after the oral administration of 10 mg/kg of rac-ABZSO, 5 mg/kg of (-)-ABZSO or 5 mg/kg of (+)-ABZSO. The disposition profiles of ABZSO enantiomers were similar in all treatments, but the calculated area under the curve for the (-)-ABZSO was higher in all cases compared with (+)-ABZSO. The results suggest that there is no chiral inversion of ABZSO enantiomers. After the administration of rac-ABZSO, 17.2% of the total dose was recovered in urine as albendazole ABZ (0.1%), albendazole sulfone ABZSO(2) (0.3%), albendazole 2-aminosulfone (ABZ-SO(2)NH(2)) (3.1%) and ABZSO (13.7%). The ratio (+) to (-) was similar in urine (1.6) and blood (1.7).     

Combining the simulation crop model AquaCrop with an economic model for the optimization of irrigation management at farm level

Water resources used in irrigated agriculture are increasingly scarce, particularly in many countries where irrigation has undergone recent expansion. To optimize the limited resources available, optimization models provide useful tools for technical and economic analyses. One of the key inputs of these models is the yield response to water which is often simulated with empirical water production functions. At present, dynamic crop simulation models, such as AquaCrop (Steduto et al., 2009) offer alternative predictions of crop responses to different irrigation strategies as inputs to economic optimization. A model at farm scale was developed and applied to an area in South-western Spain to assist farmers in pre-season decision making on cropping patterns and on irrigation strategies. Yield predictions were obtained from the AquaCrop model which was validated for four different crops. The model simulated the impact on farm income of: (a) irrigation water constraints; (b) variations in agricultural policies; (c) changes in product and water prices; and, (d) variations in the communication to farmers of the specific level of irrigation water allocation. The applications of the models to the study area showed that currently, the changes in cropping patterns induced by the agricultural policy will encourage water savings more than an increase in water prices. Under water restrictions, the best strategy combines planting of low water use crops in part of the area to release water to grow more profitable crops with greater water needs. The model predicted a strong negative impact on farm income of delaying a decision on the level of seasonal water allocation by the water authority, reaching up to 300 € ha⁻¹ in the case of the study area.     

Infectivity and Effectivity of Some Frankia Strains from the Rhamnaceae Family

The nodulation ability was determined of native Frankia strains (ChI1, ReI4, ReI6, TtI42, and TqI15) isolated from rhamnaceous species indigenous to Chile. All strains tested nodulated other Rhamnaceae host species within one or more genera, i.e., TtI42 nodulated seedlings of Trevoa trinervis, Retanilla ephedra, and Talguenea quinquenervia. Trees from other families such as Casuarina (Casuarinaceae) were not nodulated by the Frankia strains mentioned above. These results suggest that the five strains isolated from rhamnales could belong to the same cross inoculation group because they exhibited the same level of promiscuity. The effectivity of Frankia for nitrogen fixation was established by measurement of acetylene reduction activity in planta. Two strains (ReI6 and TtI42) were found more effective than the others and improved the total dry weight and shoot height of Retanilla ephedra seedlings. These studies may facilitate the choice of selected rhamnaceous Frankia pairs for arid soil afforestation, since these plants are naturally adapted to this environment in Chile.