Herbicidal,plant growth inhibitory,and cytotoxic activities of bismuthines containing aromatic heterocycles

This work presents the herbicidal and plant growth regulatory activities of tertiary bismuthines containing heterocyclic aromatic rings of the general formula (2-C(4)H(3)X)(3)Bi, where X = S (3), O (1), or NMe (2). Toxicity against Artemia salina and herbicidal activity on Lactuca sativa, Trifolium pratense, and Lolium multiflorum were tested. In addition to the effects on mitochondrial respiration obtained from roots of Phaseolus vulgaris, these compounds also demonstrated partial radical scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH). The furyl substituent is the most important structural requirement for the activity measurements observed in this study.     

Potential CO2 emissions mitigation through forest prescribed burning: A case study in Patagonia, Argentina

Wildland fire is a natural force that has shaped most vegetation types of the world. However, its inappropriate management during the last century has led to more frequent and catastrophic fires. Wildland fires are also recognized as one of the sources of CO₂ and other greenhouse gases (GHG) that influence global climate change. As one of the techniques used to reduce the risk of destructive wildfires, prescribed burning has the potential of mitigating carbon emissions, and effectively contributes to the efforts proposed as part of the Clean Development Mechanism within the Kyoto protocol. In order to apply this concept to a real case, a simulation study was conducted in pine afforestation in the Andean region of Patagonia, Argentina, with the objective of evaluating the potential of prescribed burning for reducing GHG emissions. The scenario was established for a ten year period, in which simulated prescribed burning was compared to the traditional management scheme, which included the probability of annual average of wildfire occurrence based on available wildfire statistics. The two contrasting scenarios were: (1) managed afforestation, affected by the annual average rate of wildfires occurred in the same type of afforestation in the region, without prescribed burning, and (2) same as (1) but with the application of simulated prescribed burning. In order to estimate carbon stocks, and CO₂ removals and emissions, we followed the guidelines given for GHG inventories on the Agriculture, Forestry and Other Land Uses (AFOLU) sector of the International Panel on Climate Change (IPCC), while the terminology used was the established by IPCC (2003). Data of afforested area, thinnings, and biomass growth were taken from previous surveys in the study area. Downed dead wood and litter (forest fuel load, FFL) was estimated adjusting equations fitted to those fuels, based on field data. Results show that comparing the two scenarios, prescribed burning reduced CO₂ emissions by 44% compared to the situation without prescribed burning. The prescribed burning scenario represented about 12% of the total emissions (prescribed burning plus wildfires). Furthermore, avoided wildfires by simulated prescribed burning allowed an additional 78% GHG emissions mitigation due to extra biomass growth. Simulated prescribed burning in commercial afforestation of Patagonia appears to be an effective management practice not only to prevent wildfires, but also an efficient tool to mitigate GHG emissions. However, more studies in different scenarios would be needed to generalize these benefits to other ecosystems.     

Mineralization of nitrogen in fertilizer-acidified lime-amended soils

Summary The application of NH _inf4 ^su+ -based fertilizers to soils slowly lowers soil pH, which in turn decreases nitrification rates. Under these conditions nitrification and N mineralization may be reduced. We therefore investigated the impact of liming fertilizer-acidified soils on nitrification and N mineralization. Soil samples were collected in the spring of 1987 from a field experiment, initiated in 1980, investigating N, tillage, and residue management under continuous corn (Zea mays L.). The pH values (CaCl₂) in the surface soil originally ranged from 6.0 to 6.5. After 6 years the N fertilizer and tillage treatments had reduced the soil pH to values that ranged between 3.7 and 6.2. Incubation treatments included two liming rates (unlimed or SMP-determined lime requirement), two ¹⁵N-labeled fertilizer rates (0 or 20 g N m^-2), and three replicates. Field-moist soil was mixed with lime and packed by original depth into columns. Labeled-¹⁵N ammonium sulfate in solution was surface-applied and columns were leached with 1.5 pore volumes of deionized water every 7 days over a 70-day period. Nitrification occurred in all pH treatments, suggesting that a ferilizer-acidified soil must contain a low-pH tolerant nitrifier population. Liming increased soil pH values (CaCl₂) from 3.7 to 6.2, and increased by 10% (1.5 g N m^-2) the amount of soil-derived NO₃ ^--N that moved through the columns. This increase was the result of enhanced movement of soil-derived NO₃ ^--N through the columns during the first 14 days of incubation. After the initial 14-day period, the limed and unlimed treatments had similar amounts of soil N leaching through the soil columns. Lime increased the nitrification rates and stimulated the early movement of fertilizer-derived NO₃ ^--N through the soil.     

Questionnaire-based survey on the clinical management of canine leishmaniosis in the Madrid region (central Spain)

This paper describes a questionnaire designed to gain information on how veterinarians clinically manage canine leishmaniosis (CanL) in the Madrid region (central Spain). The present survey is one of the several similar questionnaire-based surveys conducted within the framework of the project EDEN (Emerging Diseases in a changing European eNvironment). The questionnaire sought to obtain data regarding the main clinical manifestations observed, the diagnostic methods used and the preventive measures recommended. Its Spanish version was sent by post to veterinary practitioners within the study area in two lots, one sent out in December 2006 and the other in March 2007. Only 174 of the 760 questionnaires sent were completed and returned (reply rate of 23%). Among the completed questionnaires, clinics differed widely in terms of features such as the habitats of the dogs (urban, peri-urban or rural) and patient volumes. Clinics attending dogs from peri-urban/rural habitats reported more suspected (p<0.001), confirmed (p=0.001) and newly diagnosed (p=0.001) cases/year than clinics providing service to a city clientele alone. According to the veterinary practitioners, skin lesions, lymphadenomegaly and weight loss were commonly observed, although these signs are not specific to CanL. Signs described to be of high diagnostic value were epistaxis and kidney disease. All the veterinarians polled reported that a suspicion of Leishmania infantum infection was confirmed by at least a serological method; the immunofluorescence antibody test (IFAT) being the technique most used. To prevent the disease, most vets recommended topical synthetic pyrethroids applied as impregnated collars or spot-ons. It is observed that despite considerable progress is being made in clinical management and controlling the disease, in Madrid Region its incidence continues to increase.     

Response of proinflammatory and anti-inflammatory cytokines in calves with subclinical bovine viral diarrhea challenged with bovine herpesvirus-1

The aim of this work was to investigate the susceptibility of calves infected with bovine viral diarrhea virus (BVDV) against secondary infections. For this purpose, the profile of cytokines implicated in the immune response of calves experimentally infected with a non-cytopathic strain of BVDV type-1 and challenged with bovine herpesvirus 1.1 (BHV-1.1) was evaluated in comparison with healthy animals challenged only with BHV-1.1. The immune response was measured by serum concentrations of cytokines (IL-1β, TNFα, IFNγ, IL-12, IL-4 and IL-10), acute phase proteins (haptoglobin, serum amyloid A and fibrinogen) and BVDV and BHV-1.1 specific antibodies. BVDV-infected calves displayed a great secretion of TNFα and reduced production of IL-10 following BHV-1 infection, leading to an exacerbation of the inflammatory response and to the development of more intense clinical symptoms and lesions than those observed in healthy animals BHV-1-inoculated. A Th1 immune response, based on IFNγ production and on the absence of significant changes in IL-4 production, was observed in both groups of BHV-1-infected calves. However, whereas the animals inoculated only with BHV-1 presented an IFNγ response from the start of the study and high expression of IL-12, the BVDV-infected calves showed a delay in the IFNγ production and low levels of IL-12. This alteration in the kinetic and magnitude of these cytokines, involved in cytotoxic mechanisms responsible for limiting the spread of secondary pathogens, facilitated the dissemination of BHV-1.1 in BVDV-infected calves.     

Propolis specimens from different locations of central Italy: chemical profiling and gas chromatography-mass spectrometry (GC-MS) quantitative analysis of the allergenic esters benzyl cinnamate and benzyl salicylate

Propolis is a beehive product popular in natural medicine thanks to its noteworthy properties. Propolis is non-toxic but is responsible for allergic reactions in sensitive individuals. In this paper, we propose a new gas chromatography-mass spectrometry (GC-MS) analytical methodology for the quantitative analysis of two allergenic esters in propolis specimens, benzyl salicylate and benzyl cinnamate, and test it on specimens from different locations of central Italy. We also present the results obtained in the chemical characterization of the same specimens. The characterization showed that the resin fractions of all of the specimens are of poplar origin.     

Soil fauna alter the effects of litter composition on nitrogen cycling in a mineral soil

Plant chemical composition and the soil community are known to influence litter and soil organic matter decomposition. Although these two factors are likely to interact, their mechanisms and outcomes of interaction are not well understood. Studies of their interactive effects are rare and usually focus on carbon dynamics of litter, while nutrient dynamics in the underlying soil have been ignored. A potential mechanism of interaction stems from the role fauna plays in regulating availability of litter-derived materials in the mineral soil. We investigated the role of soil fauna (meso, macro) in determining the effect of surface-litter chemical composition on nitrogen mineralization and on the micro-food web in mineral soils. In a field setting we exposed mineral soil to six types of surface-applied litter spanning wide ranges of multiple quality parameters and restricted the access of larger soil animals to the soils underlying these litters. Over six months we assessed litter mass and nitrogen loss, nitrogen mineralization rates in the mineral soils, and soil microbes and microfauna. We found evidence that the structure of the soil community can alter the effect of surface-litter chemical composition on nitrogen dynamics in the mineral soil. In particular, we found that the presence of members of the meso- and macrofauna can magnify the control of nitrogen mineralization by litter quality and that this effect is time dependent. While fauna were able to affect the size of the micro-food web they did not impact the effect of litter composition on the abundance of the members of the micro-food web. By enhancing the strength of the impact of litter quality on nitrogen dynamics, the larger fauna can alter nitrogen availability and its temporal dynamics which, in turn, can have important implications for ecosystem productivity. These findings contribute to evidence demonstrating that soil fauna shape plant litter effects on ecosystem function.     

Optimisation of Key Abiotic Factors of PAH (Naphthalene, Phenanthrene and Anthracene) Biodegradation Process by a Bacterial Consortium

The aim of this work was to determine the optimum values for the biodegradation process of six abiotic factors considered very influential in this process. The optimisation of a polycyclic aromatic hydrocarbon (naphthalene, phenanthrene and anthracene) biodegradation process was carried out with a degrading bacterial consortium C2PL05. The optimised factors were the molar ratio of carbon/nitrogen/phosphorus (C/N/P), the nitrogen source, the iron source, the iron concentration, the pH and the carbon source. Each factor was optimised applying three different treatments during 168 h, analysing cell density by spectrophotometric absorbance at 600 nm and PAH depletion by HPLC. To determine the optimum values of the factors, an analysis of variance was performed using the cell density increments and biotic degradation constants, calculated for each treatment. The most effective values of each factor were: a C/N/P molar ratio of 100:21:16, NaNO₃ as nitrogen source, Fe₂(SO₄)₃ as iron source using a concentration of 0.1 mmol l^?1, a pH of 7.0 and a mixture of glucose and PAHs as carbon source. Therefore, high concentrations of nutrients and soluble forms of nitrogen and iron at neutral pH favour the biodegradation. Also, the addition of glucose to PAHs as carbon source increased the number of total microorganism and enhanced PAH biodegradation due to the augmentation of PAH degrader microorganisms. It is also important to underline that the statistical treatment of data and the combined study of the increments of the cell density and the biotic biodegradation constant have facilitated the accurate interpretation of the optimisation results. For an optimum bioremediation process, it is very important to perform these previous bioassays to decrease the process development time and, therefore, the costs.     

Characterization of phenolic components in polar extracts of Eucalyptus globulus Labill. bark by high-performance liquid chromatography-mass spectrometry

High-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) and tandem mass spectrometry (MS(n)) were used to investigate the phenolic constituents in methanol, water, and methanol/water extracts of Eucalyptus globulus Labill. bark. Twenty-nine phenolic compounds were identified, 16 of them referenced for the first time as constituents of E. globulus bark, namely, quinic, dihydroxyphenylacetic, and caffeic acids, bis(hexahydroxydiphenoyl (HHDP))-glucose, galloyl-bis(HHDP)-glucose, galloyl-HHDP-glucose, isorhamentin-hexoside, quercetin-hexoside, methylellagic acid (EA)-pentose conjugate, myricetin-rhamnoside, isorhamnetin-rhamnoside, mearnsetin, phloridzin, mearnsetin-hexoside, luteolin, and a proanthocyanidin B-type dimer. Digalloylglucose was identified as the major compound in the methanol and methanol/water extracts, followed by isorhamnetin-rhamnoside in the methanol extract and by catechin in the methanol/water extract, whereas in the water extract catechin and galloyl- HHDP-glucose were identified as the predominant components. The methanol/water extract was shown be the most efficient to isolate phenolic compounds identified in E. globulus bark.