Spatial distribution of Lolium rigidum seedlings following seed dispersal by combine harvesters

This paper considers the relationships between the dispersal of seeds and the distribution pattern of an annual weed. A comparative study of seed dispersal by combine harvesters, with and without a straw chopper attached, was established using Lolium rigidum, a common weed in Mediterranean cereal crops. Seed dispersal distance was quantified and the relationships between dispersal and fine‐scale seedling distribution evaluated. Primary dispersal of L. rigidum seeds occurs in a very limited space around the parent plants, but the density of seed is low because most seeds do not fall from spikes spontaneously. In contrast, many seeds are spread by combine harvesters. In this study the maximum dispersal exceeded 18 m from established stands in cereal fields, although the modal distance was close to the origin. In addition, the action of the combine harvesters tended to accumulate L. rigidum seeds predominantly under the straw swath, with some lateral movement. This action could explain the fine‐scale banded pattern of L. rigidum in cereal fields. Although the treatment of straw by the standard and straw chopper combines differed, the resultant seed distribution showed few differences.     

Isolation and characterization of immortalized porcine aortic endothelial cell lines

Primary porcine endothelial cells have a limited life span in culture. After four to five passages, they tend to de-differentiate and eventually reach senescence. The aim of this work was to establish immortalized porcine aortic endothelial cell lines (AOCs) to facilitate in vitro studies of different pathological process involving the endothelium. Primary porcine aortic endothelial cells (PAECs) were transfected with a plasmid containing the SV40 genome and selected on the basis of morphological and phenotypical features. Flow cytometry analysis demonstrated uptake of acetylated low density lipoproteins (Ac-LDL) and constitutive expression of SLA class I, CD29, CD31, CD41/61, CD80/86, CD46, SWC3, and LAMP-1 antigens by all analyzed lines and showed little differences to primary cells. The functional similarity between primary and immortalized endothelial cells was demonstrated in a cytotoxicity assay using a human natural killer cell line (NKL) as effector. The AOCs cell lines should be valuable tools for in vitro study of the human immune response against pig endothelial cells. In addition, they would be very useful to gain insight in the pathogenesis of some viral haemorrhagic diseases of pig such as African swine fever (ASF) or classical swine fever (CSF).     

A retrospective study of pathologic findings in the Amazon and Orinoco river dolphin (Inia geoffrensis) in captivity.

River dolphins are especially susceptible to negative human impacts. For their conservation, attempts of relocation or procreation ex situ may become important in the future to avoid their extinction. Additional knowledge and medical experiences of river dolphin management in captivity may aid such conservation efforts. The medical records and necropsy and histopathology reports on 123 captive Amazon River dolphins (Inia geoffrensis) were re-viewed. Of these 123 animals, 105 were necropsied and 70 necropsies were supported with histopathology. Eighteen animals were not necropsied. Among wild-born animals, mortality was highest in the first 2 mo immediately postcapture and transport, accounting for 32 of 123 deaths. Pneumonia and skin lesions (cutaneous and subcutaneous ulcerations and abscesses) were the most common findings, found in 44 of 105 (42%) and 38 of 105 (36%) of gross diagnoses, respectively. At least 10 of 44 cases of pneumonia diagnosed grossly included a verminous component. Cachexia, from a variety of causes, was a major gross finding in 21 animals. Fifteen animals had histologic evidence of significant renal pathology, and this was the primary cause of death in 13 cases. Hepatic pathology was found in 18 cases, and bacterial sepsis was confirmed via histology in 16 cases. Based on these findings, it may be concluded that keys to successful maintenance of this species include 1) prophylactic anthelminthic and antibiotic therapy immediately post-capture; 2) maintenance of animals in larger enclosures than in past attempts, in compatible groups, and in facilities capable of separating aggressive animals; 3) maintenance in microbiologically hygienic water quality at all times; and 4) a proactive program of preventive medicine during the immediate postcapture, quarantine, and maintenance period of captivity.     

Limited host range in the idiobiont parasitoid Phymastichus coffea,a prospective biological control agent of the coffee pest Hypothenemus hampei in Hawaii

Phymastichus coffea LaSalle (Hymenoptera:Eulophidae) is an adult endoparasitoid of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera:Curculionidae:Scolytinae), which has been introduced in many coffee producing countries as a biological control agent. To determine the effectiveness of P. coffea against H. hampei and environmental safety for release in Hawaii, we investigated the host selection and parasitism response of adult females to 43 different species of Coleoptera, including 23 Scolytinae (six Hypothenemus species and 17 others), and four additional Curculionidae. Non-target testing included Hawaiian endemic, exotic and beneficial coleopteran species. Using a no-choice laboratory bioassay, we demonstrated that P. coffea was only able to parasitize the target host H. hampei and four other adventive species of Hypothenemus: H. obscurus, H. seriatus, H. birmanus and H. crudiae. Hypothenemus hampei had the highest parasitism rate and shortest parasitoid development time of the five parasitized Hypothenemus spp. Parasitism and parasitoid emergence decreased with decreasing phylogenetic relatedness of the Hypothenemus spp. to H. hampei, and the most distantly related species, H. eruditus, was not parasitized. These results suggest that the risk of harmful non-target impacts is low because there are no native species of Hypothenemus in Hawaii, and P. coffea could be safely introduced for classical biological control of H. hampei in Hawaii.

     

Comparison of levels and duration of detection of antibodies to bovine viral diarrhea virus 1, bovine viral diarrhea virus 2, bovine respiratory syncytial virus,bovine herpesvirus 1, and bovine parainfluenza virus 3 in calves fed maternal colostrum or a colostrum-replacement product

Colostrum-replacement products are an alternative to provide passive immunity to neonatal calves; however, their ability to provide adequate levels of antibodies recognizing respiratory viruses has not been described. The objective of this study was to compare the serum levels of IgG at 2 d of age and the duration of detection of antibodies to bovine viral diarrhea virus 1 (BVDV-1), bovine viral diarrhea virus 2 (BVDV-2), bovine respiratory syncytial virus (BRSV), bovine herpesvirus 1 (BHV-1), and bovine parainfluenza virus 3 (BPIV-3) in calves fed maternal colostrum (MC) or a colostrum replacement (CR) at birth. Forty newborn male Holstein calves were assigned to the CR or the MC group. Group CR (n = 20) received 2 packets of colostrum replacement (100 g of IgG per 470-g packet), while group MC (n = 20) received 3.8 L of maternal colostrum. Blood samples for detection of IgG and virus antibodies were collected from each calf at birth, at 2 and 7 d, and monthly until the calves became seronegative. Calves in the MC group had greater IgG concentrations at 2 d of age. The apparent efficiency of absorption of IgG was greater in the MC group than in the CR group, although the difference was not significant. Calves in the CR group had greater concentrations of BVDV neutralizing antibodies during the first 4 mo of life. The levels of antibodies to BRSV, BHV-1, and BPIV-3 were similar in the 2 groups. The mean time to seronegativity was similar for each virus in the 2 groups; however, greater variation was observed in the antibody levels and in the duration of detection of immunity in the MC group than in the CR group. Thus, the CR product provided calves with more uniform levels and duration of antibodies to common bovine respiratory viruses.     

Retention of xenon in quartz and Earth's missing xenon

The reactivity of xenon with terrestrial oxides was investigated by in situ synchrotron x-ray diffraction. At high temperature (T > 500 kelvin), some silicon was reduced, and the pressure stability of quartz was expanded, attesting to the substitution of some xenon for silicon. When the quartz was quenched, xenon diffused out and only a few weight percent remained trapped in samples. These results show that xenon can be covalently bonded to oxygen in quartz in the lower continental crust, providing an answer to the missing xenon problem; synthesis paths of rare gas compounds are also opened.     

Reduced metribuzin pollution with phosphatidylcholine-clay formulations

BACKGROUND: Metribuzin is a widely used herbicide that has been identified as a groundwater contaminant. In this study, slow‐release formulations of metribuzin were designed by encapsulating the active ingredient in phosphatidylcholine (PC) vesicles and adsorbing the vesicles onto montmorillonite. RESULTS: The maximum active ingredient content in the slow‐release formulations was 246 g kg^?1. Infrared spectroscopy results revealed that the hydrophobic interactions between metribuzin and the alkyl chains on PC were necessary for encapsulation. In addition, water bridges connecting the herbicide and the PC headgroup enhanced the solubility of metribuzin in PC. Adsorption experiments in soils were performed to evaluate the relationship between sorption and leaching. Funnel experiments in a sandy soil revealed that the herbicide was not irreversibly retained in the formulation matrix. In soil column experiments, PC–clay formulations enhanced herbicide accumulation and biological activity in the top soil layer relative to a commercial formulation. PC–clay formulations also reduced the dissipation of metribuzin by a factor of 1.6–2.5. CONCLUSIONS: A reduction in the recommended dose of metribuzin can be achieved by employing PC–clay formulations, which reduces the environmental risk associated with herbicide applications. Moreover, PC and montmorillonite are non‐toxic and do not negatively affect the environment. Copyright © 2010 Society of Chemical Industry     

Improvement of the desorption of the herbicide norflurazon from soils via complexation with beta-cyclodextrin

The effect of beta-cyclodextrin (beta-CD) on the removal of the herbicide norflurazon (NFL) from soils has been investigated. The interaction of NFL with beta-CD in solution yielded the formation of a water-soluble inclusion complex at 1:1 stoichiometric ratio, which gave an increase in NFL solubility. Desorption studies of NFL previously adsorbed on six soils of different characteristics have been performed in the presence of 0.01 M beta-CD or 0.01 M Ca(NO(3))(2) as extractant solutions. Positive hysteresis was observed in all soils when 0.01 M Ca(NO(3))(2) solution was used, indicating that desorption of NFL from these soils was not completely reversible. On the contrary, the application of beta-CD solutions to soils where NFL had been previously adsorbed increased very much its desorption, and a negative hysteresis was obtained for all soils studied; that is, more NFL was desorbed with respect to NFL adsorption isotherm. A clear relationship was observed between the physicochemical characteristics of the soils and the beta-CD concentration necessary to remove the herbicide, the percentages of desorption observed for each soil being inversely related to the values obtained for the Freundlich sorption capacity parameter of the herbicide, K(f). In general, high desorption yields can be obtained with very low beta-CD concentrations, which is an important advantage from an economic point of view, although in those soils that present an extremely high NFL adsorption, higher amounts of beta-CD should be used. The results obtained indicate the high extracting power of beta-CD toward the herbicide previously adsorbed on the soils and the potential use of beta-CD for in situ remediation of pesticide-contaminated soils.     

Effect of organic amendments on the retention and mobility of imazaquin in soils

The influence of two organic amendments consisting of an urban waste compost (SUW) and a commercial amendment from olive mill wastes (OW) was assessed on the sorption properties and leaching of the ionizable herbicide imazaquin on four soils with different physicochemical characteristics. A loamy sand soil (CR), a loam soil (P44), a silt loam soil (AL), and a clay soil (TM), with low-medium organic matter contents, were chosen. Sorption-desorption experiments were performed on the original soils and on a mixture of these soils with the organic amendments at a rate of 6.25% (w/w). These mixtures were used just after preparation and after aging for 3 months. Imazaquin adsorption was higher on AL soil because of its high content of amorphous iron oxides, whereas it was related to the soils' organic matter (OM) contents on TM and CR soils and to acid pH on P44 soil. Addition of exogenous OM to soils caused a decrease in the adsorption of the herbicide with the only exception of CR soil, due to blocking of adsorptive surfaces and/or equilibrium pH rise. The extent of this decrease was dependent only on the nature of the added amendment on AL soil. The adsorbed amounts of imazaquin on aged organic fertilized soils were usually fairly close to that on original soils. Results of soil column experiments indicate that addition of exogenous organic matter cannot be considered as a regular practice for retarded movement of imazaquin.     

Correlations between soil parameters and radionuclide contents in samples from Biscay (Spain)

The distribution of gamma emitting radioactive constituents in Biscay soils have been measured in 15 cm cores, at three depth levels, in fourteen sampling positions. Analyses were performed in Marinelli beakers with a gamma multichannel analyser provided with a Ge-HP detector. Additionally, each soil was characterized by a number of parameters (position, bulk density, pH, size distribution, total contents of carbon, nitrogen and hydrogen, thermogravimetric data and major cations soluble in ammonium acetate at pH 7). Seven natural radioisotopes (⁴⁰K, ²²⁸Ac, ²¹²Bi, ²⁰⁸TI, ²²⁶Ra, ²¹⁴Pb and ²¹⁴Bi) and ¹³⁷Cs were detected and measured. Relations between natural radionuclides (located before and after radon isotopes in both radioactive series) and soil parameters are mainly explained by two statistical multivariate methods (factor analysis and numerical taxonomy). The more complex dependence of radiocaesium contents on soil characteristics was elucidated by linear multiple regression.