Intercontinental spread of pyrimethamine-resistant malaria     

Roper C  Pearce R  Nair S  Sharp B  Nosten F  Anderson T 《Science (New York, N.Y.)》2004,305(5687):1124

Here we present molecular evidence demonstrating that malaria parasites bearing high-level pyrimethamine resistance originally arrived in Africa from southeast Asia. The resistance alleles carried by these migrants are now spreading across Africa at an alarming rate, signaling the end of affordable malaria treatment and presenting sub-Saharan Africa with a public health crisis.  相似文献   

Mouse mastitis model of infection for antimicrobial compound efficacy studies against intracellular and extracellular forms of Staphylococcus aureus   总被引：6，自引：0，他引：6  

Brouillette E  Grondin G  Lefebvre C  Talbot BG  Malouin F 《Veterinary microbiology》2004,101(4):253-262

Despite the general in vitro susceptibility of Staphylococcus aureus isolates that cause infectious bovine mastitis, the pathogen remains difficult to eradicate with the available antibiotics. The capacity to survive intracellularly has been proposed as a factor contributing to the persistence of S. aureus in the bovine mammary gland. The costs associated with the use of cows or goats to assess the in vivo efficacy of new antibacterial compounds constitute a major drawback. Therefore, in the present study, a mouse model of intramammary infection has been characterized for in vivo testing of new experimental drugs. An inoculum of 100 CFU of S. aureus per gland caused an important level of infection with minimal tissue damage as observed at 24 h post-inoculation. By microscopy, polymorphonuclear neutrophil cell infiltration of the infected mammary glands was observed to increase over time. At 12-24 h of infection, the pathogen was primarily found alive and dividing in neutrophils and occasionally within mammary epithelial cells. Intramuscular or intravenous injections of cephapirin at t = 0 and 10 h reduced the number of CFU/g of gland in a dose-dependent manner. In conclusion, the mouse model of infectious mastitis proposed here is suitable for primary evaluation of experimental drugs after parenteral treatment of intramammary infection with a pathogen such as S. aureus that presents both intracellular and extracellular phases of growth.  相似文献   

Effects of mineral and biofertilizers on barley growth on compacted soil     

Mustafa Y. Canbolat  Kenan Barik  Ramazan Çakmakçi  Fikrettin şahin 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(4):324-332

Abstract

Biofertilizers are an alternative to mineral fertilizers for increasing soil productivity and plant growth in sustainable agriculture. The objective of this study was to evaluate possible effects of three mineral fertilizers and four plant growth promoting rhizobacteria (PGPR) strains as biofertilizer on soil properties and seedling growth of barley (Hordeum vulgare) at three different soil bulk densities, and in three harvest periods. The application treatments included the control (without bacteria inoculation and mineral fertilizers), mineral fertilizers (N, NP and P) and plant growth promoting rhizobacteria species (Bacillus licheniformis RC04, Paenibacillus polymyxa RC05, Pseudomonas putida RC06, and Bacillus OSU-142) in sterilized soil. The PGPR, fungi, seedling growth, soil pH, organic matter content, available P and mineral nitrogen were determined in soil compacted artificially to three bulk density levels (1.1, 1.25 and 1.40 Mg m^?3) at 15, 30, and 45 days of plant harvest. The results showed that all the inoculated bacteria contributed to the amount of mineral nitrogen. Seed inoculation significantly increased the count of bacteria and fungi. Data suggest that seed inoculation of barley with PGPR strains tested increased root weight by 9–12.2%, and shoot weight by 29.7–43.3% compared with control. The N, NP and P application, however, increased root weight up to 18.2, 25.0 and 7.4% and shoot weight by 31.6, 43.4 and 26.4%, respectively. Our data show that PGPR stimulate barley growth and could be used as an alternative to chemical fertilizer. Soil compaction hampers the beneficial plant growth promoting properties of PGPR and should be avoided.  相似文献   

Calcium and humic acid affect seed germination,growth, and nutrient content of tomato (Lycopersicon esculentum L.) seedlings under saline soil conditions     

Önder Türkmen  Atilla Dursun  Metin Turan  Çeknas Erdinç 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):168-174

The effects of calcium and humic acid on seed germination, growth and macro- and micro-nutrient contents of tomato (Lycopersicon esculentum L.) seedlings in saline soil conditions were evaluated. Different levels of humic acid (0, 500, 1000 and 2000 mg kg^?1) and calcium (0, 100, 200 and 400 mg kg^?1) were applied to growth media treated with 50 mg NaCl kg^?1 before sowing seeds. Seed germination, hypocotyl length, cotyledon width and length, root size, shoot length, leaf number, shoot and root fresh weights, and shoot and root dry weights of the plant seedlings were determined. Macro- and micro-nutrient (N, P, K, Ca, Mg, S, Cu, Fe, Mn and Zn) contents of shoot and root of seedlings were also measured. Humic acid applied to the plant growth medium at 1000 mg kg^?1 concentration increased seedling growth and nutrient contents of plants. Humic acid not only increased macro-nutrient contents, but also enhanced micro-nutrient contents of plant organs. However, high levels of humic acid arrested plant growth or decreased nutrient contents. Levels of 100 and 200 mg kg^?1 Ca²⁺ application significantly increased N, Ca and S contents of shoot, and N and K contents of root.  相似文献   

Utilization of Passion Fruit Skin By-Product as Lead(II) Ion Biosorbent     

Gerola  Gislaine Passarella  Boas  Naiza Vilas  Caetano  Josiane  Tarley  César Ricardo Teixeira  Gonçalves  Affonso Celso  Dragunski  Douglas Cardoso 《Water, air, and soil pollution》2013,224(2):1-11

The impact of three commercially available nanoparticles (NPs) on trichloroethylene (TCE) adsorption onto granular activated carbon (GAC) was investigated. TCE adsorption isotherm and column breakthrough experiments were conducted in the presence and absence of silicon dioxide, titanium dioxide, and iron oxide nanoparticles. A rapid small-scale column test (RSSCT) was assessed for its ability to predict TCE adsorption in pilot-scale GAC in the presence and absence of NPs. Zeta potential of the three NPs and the GAC were measured. Particle size distribution of the NP dispersions was analyzed as a function of time. The surface area and the pore size distribution of the virgin and the exhausted GAC were obtained along with transmission electron microscopy and Fourier transform infrared spectroscopy analysis. The effect of NPs was found to be a function of their zeta potential, concentration, and particle size distribution. Due to their electrical charge, NPs attached to the GAC and blocked the pores and thus reduced the access to the internal pore structure. However, due to the fast adsorption kinetics of TCE, no effect from the three NPs was observed in the isotherm and kinetic studies. The RSSCT, on the other hand, accurately predicted the pilot-column TCE breakthrough in the presence of NPs.  相似文献   

The split application of potassium influence the production,nutrients extraction,and quality of sweet potatoes     

Carla Verônica Corrêa  Aline Mendes de Sousa Gouveia  Natália de Brito Lima Lanna  Ana Emília Barbosa Tavares  Veridiana Zocoler Mendonça  Felipe Girotto Campos 《Journal of plant nutrition》2013,36(16):2048-2056

Abstract

The current study aimed to evaluate the effect of split application of potassium (K) fertilizer on the production and quality of sweet potatoes. Ten treatments were evaluated in factorial design (3?×?3?+?1): three doses of potassium (60, 90, and 120?kg K₂O ha^?1); three application types (100% applied at planting; 50% applied at planting and 50% was given as topdressing; 25% applied at planting and 75% was given as topdressing) and one control (without the application of K₂O either at planting or topdressing). The experiment used a randomized complete block design and four repetitions. The following parameters were studied: root number; root fresh matter per plant; total dry matter; yield; total macronutrient extraction; sugar content of starch; and commercial starch. The production characteristics of the roots presented a significant interaction between the factors doses of potassium and application types (parcelaments). Finally, better results were obtained when potassium was applied 50% at planting and 50% as topdressing.  相似文献   

Forms of application of phosphorus fertilization on carrot     

Felipe Augusto Reis Gonçalves  André Mundstock Xavier de Carvalho  Leonardo Angelo de Aquino 《Journal of plant nutrition》2013,36(16):1884-1899

Abstract

The aim of this study was to evaluate the effect of forms of application and application rates of phosphate fertilizer on the agronomic characteristics of carrot. A field experiment was carried out in a 2?×?7 factorial arrangement, consisting of two forms of application of the P source (over the whole area or specifically in the strip of the double row), and seven application rates of P₂O₅ in randomized blocks, with four replicates. Shoot dry matter yield increased linearly, and root dry matter yield increased exponentially with an increase in P rate. Total and commercial yields increased exponentially, with higher yield for P application over the whole area. However, the agronomic efficiency for site-specific application was higher. Higher rates of P application caused increases in the soil attributes and technical traits of carrot, and the application of phosphorus fertilizer is more efficient when performed in a site-specific manner.  相似文献   

The effect of potassium and humic acid applications on yield and nutrient contents of wheat (Triticum aestivum L. var. Delfii) with same soil properties     

Mehmet Dinçsoy 《Journal of plant nutrition》2013,36(20):2757-2772

Abstract

This study was conducted in the farmer field between the years 2014 and 2015. In this study, 3 doses of potassium (K) (0, 10, and 20?kg da^?1) of K₂SO₄ (50% K₂O) fertilizer and 3 doses of humic acid (HA) (0, 20, and 40?kg da^?1) (85% HA) were used. Increase in the HA dose reflected significant effects on pH, salt, organic matter, phosphorus, magnesium, iron, and manganese contents of the experiment area at p?p?p?p?p?相似文献   

National soil data in EU countries,where do we stand?     

Sophie Cornu  Saskia Keesstra  Antonio Bispo  Maria Fantappie  Fenny van Egmond  Bozena Smreczak  Rafał Wawer  Lenka Pavlů  Jaroslava Sobocká  Zsófia Bakacsi  Kinga Farkas-Iványi  Sándor Molnár  Anders Bjørn Møller  Sevinc Madenoglu  Dalia Feiziene  Katrien Oorts  Florian Schneider  Maria da Conceição Gonçalves  Raquel Mano  Gina Garland  Rastislav Skalský  Lilian O'Sullivan  Raimonds Kasparinskis  Claire Chenu 《European Journal of Soil Science》2023,74(4):e13398

At the European scale, soil characteristics are needed to evaluate soil quality, soil health and soil-based ecosystem services in the context of the European Green Deal. While some soil databases exist at the European scale, a much larger wealth of data is present in individual European countries, allowing a more detailed soil assessment. There is thus an urgent and crucial need to combine these data at the European scale. In the frame of a large European Joint Programme on agricultural soils launched by the European Commission, a survey was conducted in the spring of 2020, in the 24 European participating countries to assess the existing soil data sources, focusing on agricultural soils. The survey will become a contribution to the European Soil Observatory, launched in December 2020, which aims to collect metadata of soil databases related to all kind of land uses, including forest and urban soils. Based upon a comprehensive questionnaire, 170 soil databases were identified at local, regional and national scales. Soil parameters were divided into five groups: (1) main soil parameters according to the Global Soil Map specifications; (2) other soil chemical parameters; (3) other physical parameters; (4) other pedological parameters; and (5) soil biological features. A classification based on the environmental zones of Europe was used to distinguish the climatic zones. This survey shows that while most of the main pedological and chemical parameters are included in more than 70% of the country soil databases, water content, contamination with organic pollutants, and biological parameters are the least frequently reported parameters. Such differences will have consequences when developing an EU policy on soil health as proposed under the EU soil strategy for 2023 and using the data to derive soil health indicators. Many differences in the methods used in collecting, preparing, and analysing the soils were found, thus requiring harmonization procedures and more cooperation among countries and with the EU to use the data at the European scale. In addition, choosing harmonized and useful interpretation and threshold values for EU soil indicators may be challenging due to the different methods used and the wide variety of soil land-use and climate combinations influencing possible thresholds. The temporal scale of the soil databases reported is also extremely wide, starting from the '20s of the 20th century.  相似文献   

Removal of Methylene Blue from an Aqueous Medium Using Atemoya Peel as a Low-cost Adsorbent     

Venceslau  Adneia de Fátima Abreu  Mendonça  Andressa Campos  Carvalho  Lucas Bragança  Ferreira  Guilherme Max Dias  Thomasi  Sergio Scherrer  Pinto  Luciana Matos Alves 《Water, air, and soil pollution》2021,232(11):1-17

Water, Air, & Soil Pollution - The objective of the present study was the synthesis and characterization of chitosan-alginate-based cross-linked copolymer (CACC) for the effective removal of...  相似文献