Phytochemical and antimicrobial characterization of Macleaya cordata herb

Macleaya cordata (plume poppy) is a source of bioactive compounds, mainly isoquinoline alkaloids which are used in phytopreparations with anti-inflammatory and antimicrobial activities. In this study, the alkaloids sanguinarine, chelerythrine, their dihydro derivatives, protopine and allocryptopine and phenolics, gallic, protocatechuic, p-hydroxybenzoic, m-hydroxybenzoic, gentisic, p-coumaric, caffeic, ferulic and sinapic acids were determined in extracts prepared from M. cordata aerial part, seeds, and seed capsules using HPLC with UV detection and/or LC/MS with electrospray ionization. The highest content of sanguinarine and chelerythrine was found in capsules. Protopine and allocryptopine were major alkaloids in leaves including footstalks. The seed oil contained dihydrosanguinarine, dihydrochelerythrine and twelve fatty acids of which linoleic, oleic, palmitic and stearic acids predominated. In addition, sanguinarine reductase, a key enzyme in sanguinarine/dihydrosanguinarine equilibrium in plants, was found for the first time, in the soluble proteins of leaves. Finally, extracts were tested for antimicrobial activity using the microdilution method on standard reference bacterial strains.     

The effect of hedgerow density on habitat quality distorts species-area relationships and the analysis of extinction debts in hedgerows

Landscape Ecology - Hedgerows are highly important for maintaining the biodiversity in deforested landscapes. Especially for habitat specialists such as several forest plants they can provide...     

15N Fertilizer recovery in different tillage–straw systems on a Vertisol in north‐west Mexico

Tillage and residue retention affect nitrogen (N) dynamics and nutrient losses and therefore nitrogen use efficiency (NUE) and crop fertilizer use, however, there is little information about residual fertilizer effects on the subsequent crop. Micro‐plots with ¹⁵N‐labelled urea were established in 2014/2015 on a long‐term experiment on a Vertisol in north‐west Mexico. N fertilizer recovery (NFR) and the effects of residual fertilizer N for summer maize (Zea mays L.) and the subsequent wheat (Triticum durum L.) crop were studied in three tillage–straw management practices (CTB: conventionally tilled beds; PB‐straw: permanent raised beds with residue retention; PB‐burn: permanent raised beds with residue burning). Fertilizer ¹⁵N recovery rates for maize grain across all treatments were low with an average of 11%, but after wheat harvest total recovered ¹⁵N (¹⁵N in maize and wheat straw and grain, residual soil ¹⁵N) was over 50% for the PB‐burn treatment. NFR was lowest in CTB after two cropping cycles (32%). Unaccounted N from applied fertilizer for the maize crop averaged 120 kg ¹⁵N ha^?1 after wheat harvest. However, more than 20% of labelled ¹⁵N was found in the 0–90 cm soil profile in both PB treatments after wheat harvest, which highlights the need for long‐term studies and continuous monitoring of the soil nutrient status to avoid over‐application of mineral N fertilizer.     

Determination of 2H/1H and 13C/12C isotope ratios of (E)-methyl cinnamate from different sources using isotope ratio mass spectrometry

For the authenticity assessment of (E)-methyl cinnamate from different origins, combustion/pyrolysis-isotope ratio mass spectrometry (C/P-IRMS) was used by an elemental analyzer (EA) and on-line capillary gas chromatography coupling (HRGC-C/P-IRMS). For that reason, (E)-methyl cinnamate self-prepared from synthetic, natural, and semisynthetic educts was analyzed in comparison to the commercial synthetic and natural ester. In addition, (E)-methyl cinnamate from basil extract and a number of commercial natural aromas was investigated. The data of self-synthesized synthetic (E)-methyl cinnamate, i.e., delta(13)C(V)(-)(PDB) = -33.8 per thousand and delta(2)H(V)(-)(SMOW) = +349 per thousand, corresponded with that found for the commercial synthetic samples (-29.5 to -31.4 per thousand and +328 to +360 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively). The ester produced from natural educts by acid as well as Candida antarctica catalysis revealed delta(13)C(V)(-)(PDB) = -25.6 and -30.1 per thousand as well as delta(2)H(V)(-)(SMOW) = -162 and -169 per thousand, respectively. Acid-catalyzed semisynthetic products differed in their delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) values depending on the origin of their educts. For the ester from synthetic methanol and natural cinnamic acid, -27.3 and -126 per thousand were determined for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively, whereas for the ester produced from natural methanol and synthetic acid delta(13)C(V)(-)(PDB) = -30.6 per thousand and delta(2)H(V)(-)(SMOW) = +287 per thousand were found. Basil extract showed -28.9 and -133 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively. Commercial aromas declared to be natural revealed delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data ranging from -25.7 to -28.5 per thousand as well as -85 to -191 per thousand, respectively, indicating, in part, incorrect declaration.     

Arbuscular mycorrhizal fungi and their response to pesticides

Arbuscular mycorrhizal fungi (AMF) form symbioses with the majority of plant species and can provide multiple benefits to the host plant. In agro‐ecosystems, the abundance and community structure of AMF are affected by agricultural management practices. This review describes and discusses current knowledge on the effects of inorganic and organic chemical pesticides on AMF in the conflicting area between agricultural use and environmental concerns. Variable effects have been reported following chemical pesticide use, ranging from neutral to positive and negative. Moreover, a species‐specific reaction has been documented. The reported effects of pesticides on arbuscular mycorrhizal symbiosis are very diverse, and even when the same substance is investigated, the results are often contradictory. These effects depend on many parameters, such as the active substance, the mode of action, the mode of application and the dosage. In the field, determinants such as the physico‐chemical behavior of the active substances, the soil type and other soil microorganisms contribute to the fate of pesticides and thus the amount of active substances to which AMF are exposed. This review highlights that the fate of AMF following pesticide use needs to be addressed in a broader agro‐ecosystem context. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Seasonal changes in the parasite prevalence of a small Malagasy lemur species (Lepilemur edwardsi)

Parasitic infections can impact the fitness of individuals and can have influence on animals’ population dynamics. An individuals’ parasite prevalence often changes depending on external or seasonal changes, for example, rainfall and ambient temperatures, but also on internal changes, for example, changes in body condition. In this study we aimed to identify the environmental factors that may influence the intestinal parasite and ectoparasite prevalence of the folivorous Malagasy primate species, Lepilemur edwardsi, living in a seasonal dry deciduous forest. Species living in this habitat have to adapt to seasonal changes of ambient temperature, with almost no precipitation during the dry season and hence strong fluctuations of resource availability throughout the year. We sampled the feces and ectoparasites of L. edwardsi throughout the year. Intestinal parasite prevalence increased from the wet to the dry season and was highest in the late dry season, which might be due to the accompanying decrease in diet quality. Conversely, ectoparasite prevalence decreased in the dry season, presumably due to the prevailing unfavorable environmental conditions for the development of ectoparasites (i.e., mites and ticks). Paired with the higher resting metabolism and stress level of L. edwardsi during the late dry season, it seems that this species may struggle when dry seasons intensify in its habitat.     

Invasion and persistence of Mycoplasma bovis in embryonic calf turbinate cells

Mycoplasma bovis is a wall-less bacterium causing bovine mycoplasmosis, a disease showing a broad range of clinical manifestations in cattle. It leads to enormous economic losses to the beef and dairy industries. Antibiotic treatments are not efficacious and currently no efficient vaccine is available. Moreover, mechanisms of pathogenicity of this bacterium are not clear, as few virulence attributes are known. Microscopic observations of necropsy material suggest the possibility of an intracellular stage of M. bovis. We used a combination of a gentamicin protection assay, a variety of chemical treatments to block mycoplasmas entry in eukaryotic cells, and fluorescence and transmission electron microscopy to investigate the intracellular life of M. bovis in calf turbinate cells. Our findings indicate that M. bovis invades and persists in primary embryonic calf turbinate cells. Moreover, M. bovis can multiply within these cells. The intracellular phase of M. bovis may represent a protective niche for this pathogen and contribute to its escape from the host’s immune defense as well as avoidance of antimicrobial agents.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0194-z) contains supplementary material, which is available to authorized users.     

Farmers’ Fruit Tree-growing Strategies in the Humid Forest Zone of Cameroon and Nigeria

Many studies have stressed the importance of trees to rural households. Few, however, have focused on actual numbers and densities of trees in different land-use systems. Based on community-level participatory research in six communities, semi-structured household interviews and full-farm fruit tree inventories, this study aims to understand farmers’ tree-planting strategies. Relationships between the diversity, number and density of fruit trees and farm size, land-use system, land tenure, distance from the homestead, proximity to the forest, market access and household characteristics are investigated. The key factors determining the differences in tree-growing strategies between communities appear to be market access, land use and access to forest resources. Within communities, differences between individual households were less easy to explain but tenure was important as was farm size. Smaller farms had higher fruit tree densities, a relationship that was particularly strong in communities with good market access. Overall there was a great deal of variability both within and between communities and many of the factors affecting tree-planting decisions were found to be highly inter-related. Despite this complexity, trees on farm play an important role in rural household's livelihoods. Therefore, expansion of tree cultivation should be recognized as a promising pathway to achieve increased income and food production by policy makers and extensionists alike. In addition to improved tree propagation and management techniques, farmers should be strengthened in the processing and marketing of agroforestry tree products and more emphasis should be placed on the development of tree enterprises. By doing so, farmers will be able to earn a more important and consistent income from fruit trees, contributing to the Millennium Development Goals.     

Can the mammalian organoid technology be applied to the insect gut?

Mammalian intestinal organoids are multicellular structures that closely resemble the structure of the intestinal epithelium and can be generated in vitro from intestinal stem cells under appropriate culture conditions. This technology has transformed pharmaceutical research and drug development in human medicine. For the insect gut, no biotechnological platform equivalent to organoid cultures has been described yet. Comparison of the regulation of intestinal homeostasis and growth between insects and mammals has revealed significant similarities but also important differences. In contrast to mammals, the differentiation potential of available insect cell lines is limited and can not be exploited for in vitro permeability assays to measure the uptake of insecticides. The successful development of in vitro models could be a result of the emergence of molecular mechanisms of self‐organization and signaling in the intestine that are unique to mammals. It is nevertheless considered that the technology gap is a consequence of vast differences in knowledge, particularly with respect to culture conditions that maintain the differentation potential of insect midgut cells. From the viewpoint of pest control, advanced in vitro models of the insect midgut would be very desirable because of its key barrier function for orally ingested insecticides with hemolymphatic target and its role in insecticide resistance. © 2020 Society of Chemical Industry