scholarly journals Impact de produits phytopharmaceutiques sur les microarthropodes du sol en culture de maïs irrigué: approche fonctionnelle par la méthode des sacs de litière

2000 ◽  
Vol 80 (2) ◽  
pp. 237-249 ◽  
Author(s):  
J. Cortet ◽  
N. Poinsot-Balaguer
Keyword(s):  
Functional Groups ◽  
Culture Conditions ◽  
Trophic Relationships ◽  
Soil Mesofauna ◽  
Litter Bags ◽  
Soil Microarthropods ◽  
Litter Bag ◽  
Normal Culture ◽  
Maize Field

The effects of two herbicides (atrazine and alachlore) and two insecticides (fipronil and carbofuran) were evaluated on soil mesofauna and organic matter decomposition, in a maize field with normal culture conditions, using the litter-bag method. The litter-bag method was discussed and considered to be adapted for this type of in situ study, especially under normal culture conditions, where it is difficult to find real control plots. However its adaptability is conditioned by some utilisation factors. The litter-bag colonization and modifications of this colonization by phytopharmaceuticals were interpreted using functional groups classification. Except for alachlore, herbicides appeared to have no differentiated effect on mesofauna. Accordingly, fipronil significantly affects the dynamics of bag colonization by selected groups belonging to soil mesofauna. Key words: Phytopharmaceuticals, maize, soil microarthropods, functional groups, trophic relationships, litter-bags

How energy crops (Maize, Field grass, Cup Plant) affect soil microarthropods and their decomposition services

2020 ◽  
Author(s):  
Pascaline Dioh Lobe ◽  
Stefan Schrader
Keyword(s):  
Mesh Size ◽  
Plant Litter ◽  
Energy Crops ◽  
Agricultural Landscapes ◽  
Ecosystem Functions ◽  
Soil Biodiversity ◽  
Litter Bags ◽  
Soil Microarthropods ◽  
Fine Mesh ◽  
Maize Field

<p>Energy crops are grown at low cost and low maintenance used in making biofuels, such as bioethanol, or combusted to generate electricity or heat. Production of energy crops as an alternative to fossil fuels will help to reduce CO<sub>2</sub> emission, thus leading to large scale changes in agricultural landscapes. Increase in the cultivation of annual energy crops such as maize (<em>Zea mays</em>) is assumed to decrease biodiversity in the agrarian landscape. This may lead to changes in soil properties, thereby affecting the soil biodiversity and its ecosystem functions and services like for instance soil microarthropod communities and their contribution to decomposition of plant litter. Perennial crops such as field grass (a mixture of Festulolium,  <em>Dactylis glomerate, Loliuim perenne, Festuca pratensis and Festuca arundinacea</em>) and cup plant (<em>Silphium perfoliatum</em>) are assumed to protect and promote soil biodiversity through less intensive management. The relationship between decomposer diversity and ecosystem functioning is little understood. So far, the role of soil microarthropods in decomposition is the most disputed aspect due to scarce empirical data.</p><p>The main aim of this field study was to assess the effect of soil microarthropods on litter of maize, field grass and cup plant, via decomposition using litter bags with 2 different mesh sizes (0.02 mm and 0.5 mm) for a period of 3 months during the vegetation period. At the end of the experiment, the decomposition rate was higher in cup plant followed by maize and field grass in the coarse mesh size, and higher in the cup plant followed by field grass and maize in the fine mesh size. A total of 55,464 soil microarthropods (73% mites, 25% collembola and 2% others) were extracted from the litter bags. The diversity and abundance of soil microarthropods was higher under cup plant cultivation followed by field grass and maize.</p>

Reductive Cleavage of Secondary Sulfonamides: Converting Terminal Functional Groups into Versatile Synthetic Handles

2019 ◽  
Author(s):  
Patrick Fier ◽  
Suhong Kim ◽  
Kevin M. Maloney
Keyword(s):  
Functional Groups ◽  
Late Stage ◽  
Reductive Cleavage ◽  
Bioactive Molecules ◽  
General Method

Sulfonamides are pervasive in drugs and agrochemicals, yet are typically considered as terminal functional groups rather than synthetic handles. To enable the general late-stage functionalization of secondary sulfonamides, we have developed a mild and general method to reductively cleave the N-S bonds of sulfonamides to generate sulfinates and amines, components which can further react <i>in-situ</i> to access a variety of other medicinally relevant functional groups. The utility of this platform is highlighted by the selective manipulation of several complex bioactive molecules.

Expression of the SMP antigen by oligodendrocytes in the developing avian central nervous system

Development ◽  
1989 ◽  
Vol 107 (4) ◽  
pp. 825-833
Author(s):  
P. Cameron-Curry ◽  
C. Dulac ◽  
N.M. Le Douarin
Keyword(s):  
Monoclonal Antibody ◽  
Schwann Cell ◽  
Basic Protein ◽  
Culture Conditions ◽  
Cell Marker ◽  
Cellular Expression ◽  
Early Expression ◽  
Different Parts

Expression of the avian antigen SMP (Schwann cell Myelin Protein, Mr 75-80000), first characterized in the PNS with a monoclonal antibody as an early and strictly specific Schwann cell marker, was further studied in the CNS. Comparing SMP immunoreactive areas in the different parts of the CNS with those expressing the Myelin Basic Protein (MBP), we showed a strict colocalisation of both phenotypes. In vitro, MBP+ oligodendrocytes express the surface antigen SMP as well. SMP cellular expression was followed in situ and in culture using nervous tissues from embryos at different stages. We were thus able to detect an early expression of this marker by oligodendroblasts before the first appearance of MBP immunoreactivity. We have also identified a subpopulation of SMP+/MBP- and SMP+/GC- cells, which persists under our culture conditions as precursors remaining in an immature state.

scholarly journals Species Diversity Induces Idiosyncratic Effects on Litter Decomposition in a Degraded Meadow Steppe

2021 ◽  
Vol 9 ◽  
Author(s):  
Iqra Naeem ◽  
Talal Asif ◽  
Xuefeng Wu ◽  
Nazim Hassan ◽  
Liu Yiming ◽  
...  
Keyword(s):  
Species Diversity ◽  
Litter Decomposition ◽  
Incubation Time ◽  
Soil Surface ◽  
Leymus Chinensis ◽  
Natural Ecosystem ◽  
Litter Bags ◽  
Litter Bag ◽  
Decomposition Dynamics ◽  
Litter Mixing

Litter decomposition is a fundamental path for nutrient cycling in a natural ecosystem. However, it remains unclear how species diversity, including richness and evenness, affects the decomposition dynamics in the context of grassland degradation. Using a litter bag technique, we investigated the litter-mixing effects of two coexisting dominant species (Leymus chinensis Lc and Phragmites australis Pa), as monocultures and mixtures with evenness (Lc:Pa) from M1 (30:70%), M2 (50:50%), and M3 (70:30%), on decomposition processes over time (60 and 365 days). The litter bags were placed on the soil surface along a degradation gradient [near pristine (NP), lightly degraded (LD), and highly degraded (HD)]. We found that 1) mass loss in mixture compositions was significantly and positively correlated with initial nitrogen (N) and cellulose contents; 2) litter mixing (richness and evenness) influenced decomposition dynamics individually and in interaction with the incubation days and the degradation gradients; 3) in a general linear model (GLM), nonadditive antagonistic effects were more prominent than additive or neutral effects in final litter and nutrients except for carbon (C); and 4) in nutrients (C, N, lignin) and C/N ratio, additive effects shifted to nonadditive with incubation time. We speculated that the occurrence of nonadditive positive or negative effects varied with litter and nutrients mass remaining in each degraded gradient under the mechanism of initial litter quality of monoculture species, soil properties of experimental sites, and incubation time. Our study has important implications for grassland improvement and protection by considering species biodiversity richness, as well as species evenness.

scholarly journals Human macrophage maturation and heterogeneity: analysis with a newly generated set of monoclonal antibodies to differentiation antigens

Blood ◽  
1986 ◽  
Vol 67 (5) ◽  
pp. 1257-1264 ◽  
Author(s):  
R Andreesen ◽  
KJ Bross ◽  
J Osterholz ◽  
F Emmrich
Keyword(s):  
Monoclonal Antibodies ◽  
Cell Surface ◽  
Cell Lineage ◽  
Culture Conditions ◽  
Human Macrophage ◽  
Blood Monocytes ◽  
Differentiation Antigens

We have analyzed the expression of late differentiation antigens during terminal in vitro maturation of human macrophages (M phi) from blood monocytes (MO) in comparison to their distribution among mature M phi residing in various tissue sites. By immunizing mice with M phi derived from blood MO by culture on hydrophobic Teflon foils, monoclonal antibodies (mAbs) were developed (MAX.1, MAX.2, MAX.3, MAX.11) that reacted with lineage-restricted differentiation antigens. These antigens were expressed exclusively on M phi or were markedly increased after in vitro differentiation. The only overlap to another hemopoietic cell lineage was observed with MAX.3, which is shared by platelets and megakaryocytes. In the course of M phi maturation in vitro, the MAX.1 and MAX.3 antigens are detected within the cytoplasm two days before they appear on the cell surface. In contrast, the MAX.11 antigen is expressed simultaneously in the cytoplasm and at the cell surface, is found in varying degrees on a minor portion of blood MO and U937 cells, and is expressed rapidly at high density during early M phi differentiation in vitro. Among conventional mAbs that do not react with MO we found those against the transferrin (TF)-receptor, the BA-2, and the PCA1 antigen to label M phi. M phi matured in vivo and isolated from body fluids were positive with some but not all MAX mAbs. Distinctive patterns were observed with pulmonary M phi, exudate M phi from pleural and peritoneal effusions, synovial fluids, and early lactation milk. M phi from the alveolar space, for example, constantly expressed the MAX.2 antigen but not the MAX.3 antigen. Pleural effusion M phi, however, did not react with the MAX.1 mAb, but in most cases, it did react with the MAX.3 mAb. The detection of novel differentiation antigens, all expressed on monocyte-derived M phi but differently expressed on site-specific M phi in situ, underlines the remarkable heterogeneity among human M phi. The expression of these antigens is flexible because those MAX antigens that were not expressed in situ could be induced if cells from distinct tissue sites were cultured in vitro for several days. MAX mAbs may be of potential value to study both the sequential stages of maturation within the M phi lineage as well as differential developments induced by various culture conditions in parallel to environmental factors in vivo.

Cu(II)-Catalyzed [3+2] Annulation of Thioamides with AIBN: Facile Access to Highly Functionalized Thiazolidine-4-ones

Synthesis ◽  
2021 ◽  
Author(s):  
Pragya Pali ◽  
Dhananjay Yadav ◽  
Gaurav Shukla ◽  
Maya Shankar Singh
Keyword(s):  
Double Bond ◽  
Functional Groups ◽  
Dual Role ◽  
Direct Access ◽  
One Pot ◽  
Simple Method ◽  
Two Component ◽  
Thiazolidine Ring ◽  
Coupling Partner

An efficient and versatile copper-catalyzed unprecedented intermolecular radical [3 + 2] annulation of thioamides with azobisisobutyronitrile (AIBN) is described. This two-component one-pot copper(II)-catalyzed transformation has been achieved via cascade formation of C-S/C−N bonds through the cyclization of in situ generated N,S-acetal intermediate from β-ketothioamide. This operationally simple method allows direct access to synthetically demanding thiazolidin-4-ones in good to excellent yields containing diverse functional groups of different electronic and steric nature. Remarkably, the readily available reaction partners, avoidance of expensive/toxic reagents and the gram scale synthesis are additional attributes to this strategy. AIBN here plays a dual role as radical initiator and unusual source of two carbon coupling partner. Notably, the products possess Z-stereochemistry with regard to the exocyclic C=C double bond at the 2-position of the thiazolidine ring.

scholarly journals Muskrat (Ondatra zibethicus) interference with aquatic invertebrate traps

2014 ◽  
Vol 128 (2) ◽  
pp. 200 ◽  
Author(s):  
Michael C. Cavallaro ◽  
Anson R. Main ◽  
Christy A. Morrissey
Keyword(s):  
Aquatic Insect ◽  
Aquatic Invertebrate ◽  
Ondatra Zibethicus ◽  
Local Fauna ◽  
Insect Emergence ◽  
Litter Bags ◽  
Structural Modifications ◽  
Aquatic Insect Emergence ◽  
Emergence Traps

In field biology, interactions between wildlife and in situ equipment occur often. These interactions have the potential to induce a variety of behaviours in local fauna. Here, we note the destructive behaviour exhibited by the Muskrat (Ondatra zibethicus) following deployment of aquatic invertebrate traps for research purposes at 12 wetlands located in central Saskatchewan. Of 24 aquatic insect emergence traps used on seven wetlands in our study, 14 (58%) required recurring repairs. In addition, on several occasions, leaf litter bags and their anchoring stakes were torn or chewed. The recurring damage took place in wetlands with Muskrat lodges. We recommend structural modifications to aquatic invertebrate traps in wetland complexes densely inhabited by Muskrats and other semi-aquatic rodents.

scholarly journals Evolution Mechanism of Macromolecular Structure in Coal during Heat Treatment: Based on FTIR and XRD In Situ Analysis Techniques

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Dun Wu ◽  
Wenyong Zhang
Keyword(s):  
Heat Treatment ◽  
Infrared Spectroscopy ◽  
Infrared Spectrum ◽  
Functional Groups ◽  
Coal Sample ◽  
Diffraction Peak ◽  
Coal Rank ◽  
Coal Structure ◽  
Temperature Range

Owing to the complexity and heterogeneity of coal during pyrolysis, the ex situ analytical techniques cannot accurately reflect the real coal pyrolysis process. In this study, according to the joint investigation of Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), the structural evolution characteristics of lignite-subbituminous coal-bituminous coal-anthracite series under heat treatment were discussed in depth. The results of the infrared spectrum of coal show that the different functional groups of coal show different changes with the increase of coal rank before pyrolysis experiment. Based on in situ infrared spectroscopy experiments, it was found that the infrared spectrum curves of the same coal sample have obvious changes at different pyrolysis temperatures. As a whole, when the pyrolysis temperature is between 400 and 500°C, the coal structure can be greatly changed. By fitting the infrared spectrum curve, the infrared spectrum parameters of coal were obtained. With the change of temperature, these parameters show regular changes in coal with different ranks. In the XRD study of coal, the absorption intensity of the diffraction peak (002) of coal increases with increasing coal rank. The XRD patterns of coal have different characteristics at different pyrolysis temperatures. Overall, the area of (002) diffraction peak of the same coal sample increases obviously with the increase of temperature. The XRD structural parameter of coal was obtained by using the curve fitting method. The changing process of two parameters (interlayer spacing (d002) and stacking height (Lc)) can be divided into two main stages, but the average lateral size (La) does not change significantly and remains at the 2.98 ± 0.09 nm. In summary, the above two technologies complement each other in the study of coal structure. The temperature range of both experiments is different, but the XRD parameters of coal with different ranks are reduced within the temperature range of less than 500°C, which reflects that the size of coal-heated aromatic ring lamellae is reduced and the distance between lamellae is also reduced, indicating that the degree of condensation of coal aromatic nuclei may be increased. Correspondingly, the FTIR parameters of coal also reflect that, with increasing temperature, the side chains of coal are constantly cracked, the oxygen-containing functional groups are reduced, and the degree of aromatization of coal may be increased.

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