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1.
PLoS Pathog ; 16(5): e1008502, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32407379

RESUMO

Viruses have developed different strategies to escape from immune response. Among these, viral non-coding RNAs are invisible to the immune system and may affect the fate of the host cell. Bovine leukemia virus (BLV) encodes both short (miRNAs) and long (antisense AS1 and AS2) non-coding RNAs. To elucidate the mechanisms associated with BLV non-coding RNAs, we performed phenotypic and transcriptomic analyzes in a reverse genetics system. RNA sequencing of B-lymphocytes revealed that cell proliferation is the most significant mechanism associated with ablation of the viral non-coding RNAs. To assess the biological relevance of this observation, we determined the cell kinetic parameters in vivo using intravenous injection of BrdU and CFSE. Fitting the data to a mathematical model provided the rates of cell proliferation and death. Our data show that deletion of miRNAs correlates with reduced proliferation of the infected cell and lack of pathogenesis.


Assuntos
Linfócitos B , Transformação Celular Viral , Vírus da Leucemia Bovina , MicroRNAs , RNA Antissenso , RNA Viral , Animais , Linfócitos B/metabolismo , Linfócitos B/patologia , Linfócitos B/virologia , Bovinos , Proliferação de Células , Vírus da Leucemia Bovina/genética , Vírus da Leucemia Bovina/metabolismo , Vírus da Leucemia Bovina/patogenicidade , MicroRNAs/genética , MicroRNAs/metabolismo , RNA Antissenso/genética , RNA Antissenso/metabolismo , RNA Viral/genética , RNA Viral/metabolismo
2.
Molecules ; 25(10)2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32455772

RESUMO

This work aims to study the variations in the composition of Lantana camara leaf, flower, and stem essential oils over two years. L. camara organs were harvested in Bregbo (East Côte d'Ivoire) each month from June 2015 to June 2017. The essential oils were obtained by hydrodistillation and characterized by GC-MS and 13C NMR. Eighty-four compounds accounting for 84.4-99.1% of the essential oils have been identified. The essential oils hydrodistillated from L. camara are dominated by sesquiterpenes such as (E)-ß-caryophyllene and α-humulene, which were found in all samples. Some monoterpenes such as thymol, sabinene, and α-pinene were also present. Statistical analysis (principal component analysis and clustering) revealed a high variability in essential oil composition between the different organs and also within the studied periods, as the thymol proportion was higher during flowering and fruiting months. In addition, the stem, flower, and fruit essential oils were more concentrated in thymol than the leaf essential oils. The proportions of (E)-ß-caryophyllene and α-humulene were strictly inverted with the thymol proportion throughout the harvest period or vegetative cycle. The antioxidant, anti-inflammatory and insecticidal activities of leaves and flowers essential oils were also studied. Results showed that L. camara leaf and flower essential oils displayed high antioxidant, anti-inflammatory and insecticidal activities.


Assuntos
Antioxidantes/química , Lantana/química , Óleos Voláteis/química , Óleos de Plantas/química , Antioxidantes/isolamento & purificação , Clima , Côte d'Ivoire , Flores/química , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Monoterpenos/química , Monoterpenos/isolamento & purificação , Óleos Voláteis/farmacologia , Extratos Vegetais , Folhas de Planta/química , Óleos de Plantas/isolamento & purificação , Estações do Ano , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação
3.
Phytopathology ; 109(3): 409-417, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30161014

RESUMO

Wheat crops are constantly challenged by the pathogen Zymoseptoria tritici, responsible for Septoria tritici Blotch (STB) disease. The present study reports the evaluation of five elicitor compounds (λ-carrageenan, cytosine-phosphate-guanine oligodesoxynucleotide motifs [CpG ODN], glycine betaine, Spirulina platensis, and ergosterol) for the protection of wheat against STB in order to offer new alternative tools to farmers for sustainable crop protection. Screening of elicitors of wheat defenses was carried out through a succession of experiments: biocidal in vitro tests enabled checking for any fungicidal activities, glasshouse experiments allowed determination of the efficacy of a given compound in protecting wheat against STB, and quantitative reverse-transcription polymerase chain reaction biomolecular tests investigated the relative expression of 23 defense genes in treated versus untreated plants. Therefore, we demonstrated that λ-carrageenan, CpG-ODN, glycine betaine, S. platensis, and ergosterol are potential elicitors of wheat defenses. Foliar treatment with these compounds conferred protection of wheat by up to approximately 70% against Z. tritici under semicontrolled conditions and induced both salicylic acid- and jasmonic acid-dependent signaling pathways in the plant. These findings contribute to extending the narrow list of potential elicitors of wheat defenses against Z. tritici.


Assuntos
Ascomicetos , Betaína/química , Ergosterol/metabolismo , Doenças das Plantas/microbiologia , Spirulina , Triticum/metabolismo , Carragenina , Triticum/microbiologia
4.
Phytopathology ; 109(3): 488-497, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30070618

RESUMO

Recent developments in high-throughput sequencing (HTS), also called next-generation sequencing (NGS), technologies and bioinformatics have drastically changed research on viral pathogens and spurred growing interest in the field of virus diagnostics. However, the reliability of HTS-based virus detection protocols must be evaluated before adopting them for diagnostics. Many different bioinformatics algorithms aimed at detecting viruses in HTS data have been reported but little attention has been paid thus far to their sensitivity and reliability for diagnostic purposes. Therefore, we compared the ability of 21 plant virology laboratories, each employing a different bioinformatics pipeline, to detect 12 plant viruses through a double-blind large-scale performance test using 10 datasets of 21- to 24-nucleotide small RNA (sRNA) sequences from three different infected plants. The sensitivity of virus detection ranged between 35 and 100% among participants, with a marked negative effect when sequence depth decreased. The false-positive detection rate was very low and mainly related to the identification of host genome-integrated viral sequences or misinterpretation of the results. Reproducibility was high (91.6%). This work revealed the key influence of bioinformatics strategies for the sensitive detection of viruses in HTS sRNA datasets and, more specifically (i) the difficulty in detecting viral agents when they are novel or their sRNA abundance is low, (ii) the influence of key parameters at both assembly and annotation steps, (iii) the importance of completeness of reference sequence databases, and (iv) the significant level of scientific expertise needed when interpreting pipeline results. Overall, this work underlines key parameters and proposes recommendations for reliable sRNA-based detection of known and unknown viruses.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Doenças das Plantas , Biologia Computacional , Método Duplo-Cego , Reprodutibilidade dos Testes
5.
Ecol Appl ; 28(5): 1273-1281, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29660227

RESUMO

Although the importance of large trees regarding biodiversity and carbon stock in old-growth forests is undeniable, their annual contribution to biomass production and carbon uptake remains poorly studied at the stand level. To clarify the role of large trees in biomass production, we used data of tree growth, mortality, and recruitment monitored during 20 yr in 10 4-ha plots in a species-rich tropical forest (Central African Republic). Using a random block design, three different silvicultural treatments, control, logged, and logged + thinned, were applied in the 10 plots. Annual biomass gains and losses were analyzed in relation to the relative biomass abundance of large trees and by tree size classes using a spatial bootstrap procedure. Although large trees had high individual growth rates and constituted a substantial amount of biomass, stand-level biomass production decreased with the abundance of large trees in all treatments and plots. The contribution of large trees to annual stand-level biomass production appeared limited in comparison to that of small trees. This pattern did not only originate from differences in abundance of small vs. large trees or differences in initial biomass stocks among tree size classes, but also from a reduced relative growth rate of large trees and a relatively constant mortality rate among tree size classes. In a context in which large trees are increasingly gaining attention as being a valuable and a key structural characteristic of natural forests, the present study brought key insights to better gauge the relatively limited role of large trees in annual stand-level biomass production. In terms of carbon uptake, these results suggest, as already demonstrated, a low net carbon uptake of old-growth forests in comparison to that of logged forests. Tropical forests that reach a successional stage with relatively high density of large trees progressively cease to be carbon sinks as large trees contribute sparsely or even negatively to the carbon uptake at the stand level.


Assuntos
Biomassa , Carbono/metabolismo , Florestas , Árvores/fisiologia , República Centro-Africana , Agricultura Florestal , Longevidade , Dinâmica Populacional , Árvores/crescimento & desenvolvimento , Clima Tropical
6.
Trop Anim Health Prod ; 50(3): 537-546, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29119377

RESUMO

Meat constitutes one of the major vehicles for human foodborne infections. This study aimed to assess the retail conditions and to determine the microbiological quality and safety of meat retailed within the establishments of Kigali (Rwanda). A questionnaire survey was carried out in 150 retail outlets to characterise meat retail conditions. Additionally, 270 retail meat samples were analysed for the enumeration of hygiene indicator bacteria (total mesophilic bacteria and Escherichia coli) and for the qualitative detection of Salmonella, using conventional culture methods. The results revealed that beef was the predominant meat sold within the retail premises of Kigali city, while meat from non-bovine animal species was mainly sold in large establishments. Salmonella was detected in 19.6% of all the retailed meat samples evaluated, whereas the mean loads for total mesophilic bacteria and E. coli were 7.3 and 3.5 log cfu/g, respectively. Three factors, namely the temperature conditions of the meat under retail, the cleanability of the used meat cutting boards, and the training of personnel in hygienic meat handling practices, were found to be significantly (p ≤ 0.05) associated with the risk of Salmonella occurrence in the retailed meat. The findings from this study highlight the need for improvements in hygienic meat handling practices, particularly, in small and medium meat retail establishments in Kigali.


Assuntos
Contaminação de Alimentos , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Carne/microbiologia , Infecções por Salmonella/microbiologia , Salmonella , Animais , Bactérias , Bovinos , Galinhas , Escherichia coli , Inocuidade dos Alimentos , Cabras , Humanos , Higiene , Coelhos , Carne Vermelha/microbiologia , Medição de Risco , Fatores de Risco , Ruanda , Suínos
7.
BMC Plant Biol ; 15: 195, 2015 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-26264238

RESUMO

BACKGROUND: Plant growth-promoting rhizobacteria are increasingly being seen as a way of complementing conventional inputs in agricultural systems. The effects on their host plants are diverse and include volatile-mediated growth enhancement. This study sought to assess the effects of bacterial volatiles on the biomass production and root system architecture of the model grass Brachypodium distachyon (L.) Beauv. RESULTS: An in vitro experiment allowing plant-bacteria interaction throughout the gaseous phase without any physical contact was used to screen 19 bacterial strains for their growth-promotion ability over a 10-day co-cultivation period. Five groups of bacteria were defined and characterised based on their combined influence on biomass production and root system architecture. The observed effects ranged from unchanged to greatly increased biomass production coupled with increased root length and branching. Primary root length was increased only by the volatile compounds emitted by Enterobacter cloacae JM22 and Bacillus pumilus T4. Overall, the most significant results were obtained with Bacillus subtilis GB03, which induced an 81 % increase in total biomass, as well as enhancing total root length, total secondary root length and total adventitious root length by 88.5, 201.5 and 474.5 %, respectively. CONCLUSIONS: This study is the first report on bacterial volatile-mediated growth promotion of a grass plant. Contrasting modulations of biomass production coupled with changes in root system architecture were observed. Most of the strains that increased total plant biomass also modulated adventitious root growth. Under our screening conditions, total biomass production was strongly correlated with the length and branching of the root system components, except for primary root length. An analysis of the emission kinetics of the bacterial volatile compounds is being undertaken and should lead to the identification of the compounds responsible for the observed growth-promotion effects. Within the context of the inherent characteristics of our in vitro system, this paper identifies the next critical experimental steps and discusses them from both a fundamental and an applied perspective.


Assuntos
Bactérias/metabolismo , Biomassa , Brachypodium/anatomia & histologia , Brachypodium/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/metabolismo , Brachypodium/microbiologia , Raízes de Plantas/anatomia & histologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Rizosfera
8.
Food Res Int ; 184: 114249, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38609227

RESUMO

Low temperature storage as an alternative to anti-sprouting chemicals in potato storage may induce reducing sugars (RS) accumulation (i.e. glucose and fructose) in potato tubers. This phenomenon is called "cold induced sweetening" (CIS) and occurs in certain varieties. CIS leads to a decrease in the organoleptic qualities and darkening of processed potato and the accumulation of toxic molecules such as acrylamide. To identify potato varieties suitable for storage at low temperatures, we screened six commercial processing varieties: Lady Claire (LC), Verdi, Kiebitz (KB), Pirol, Agria and Markies for their CIS characteristics and sprout-forming potential after storage at 4 °C and 8 °C. Our findings reveal that 4 °C storage allows for efficient sprout reduction in all six tested varieties for up to 4.5 months of storage. Three CIS-resistant varieties, namely Verdi, Lady Claire and Kiebitz, were identified as able to be stored for up to four months at 4 °C with limited increase in glucose content. Conversely, Pirol, Agria and Markies showed an increase in glucose content with a decrease in storage temperature and can be considered as CIS-susceptible varieties. After processing into crisps, the CIS-susceptible varieties displayed poor crisp color quality (brown to black color crisps) after storage for two months at 4 °C compared to the storage at 8 °C, whereas the CIS-resistant varieties had good crisp color quality (pale yellow color crisps) after storage at both 4 and 8 °C. Interestingly, the trends of total RS and/or glucose content in the CIS-resistant and in the CIS-susceptible varieties were correlated with the trends in Vacuolar Invertase (VInv) gene expression for most varieties, as well as with the trends in acrylamide content after processing. In addition, reconditioning of Markies variety after storage at 4 °C by gradually increasing the temperature to 15 °C resulted in a significant decrease of VInv transcript levels (reduction of 80 %), acrylamide content (reduction of 75 %) and glucose content when compared to a storage at 4 °C without reconditioning. Those results demonstrate that the reconditioning technique is a key factor for a sustainable potato storage and for improving the quality of processed potatoes.


Assuntos
Solanum tuberosum , Humanos , Criopreservação , Temperatura Baixa , Acrilamida , Glucose , beta-Frutofuranosidase
9.
Meat Sci ; 195: 108985, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36272314

RESUMO

This study aimed at understanding which molecules were responsible for the differences existing in boar taint sensory evaluation. The latter was therefore linked to the results of skatole and androstenone chemical analyses, fatty acid composition and VOC profiles of heated backfat. This study confirmed that some discrepancy exists between chemical analysis and sensory evaluation of tainted backfats. Significant correlations between human nose scores and fatty acid composition were not revealed. Strong correlations between emissions and contents in skatole and androstenone were found. Oxidation products of polyunsaturated fatty acids, with fatty odor descriptors, were found to be more present in the VOC profiles of boar fat considered untainted through the human nose methodology. Weak coefficient of determination for partial least square regression indicates that other factors, yet unknown, are responsible for sensory evaluation outcomes. These findings hence support the idea that high human nose score is mainly due to boar taint compounds rather than general differences in VOC profiles.


Assuntos
Escatol , Compostos Orgânicos Voláteis , Suínos , Masculino , Animais , Humanos , Escatol/análise , Ácidos Graxos , Carne/análise , Odorantes/análise
10.
PeerJ ; 11: e15816, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37601254

RESUMO

Recent developments in high-throughput sequencing (HTS) technologies and bioinformatics have drastically changed research in virology, especially for virus discovery. Indeed, proper monitoring of the viral population requires information on the different isolates circulating in the studied area. For this purpose, HTS has greatly facilitated the sequencing of new genomes of detected viruses and their comparison. However, bioinformatics analyses allowing reconstruction of genome sequences and detection of single nucleotide polymorphisms (SNPs) can potentially create bias and has not been widely addressed so far. Therefore, more knowledge is required on the limitations of predicting SNPs based on HTS-generated sequence samples. To address this issue, we compared the ability of 14 plant virology laboratories, each employing a different bioinformatics pipeline, to detect 21 variants of pepino mosaic virus (PepMV) in three samples through large-scale performance testing (PT) using three artificially designed datasets. To evaluate the impact of bioinformatics analyses, they were divided into three key steps: reads pre-processing, virus-isolate identification, and variant calling. Each step was evaluated independently through an original, PT design including discussion and validation between participants at each step. Overall, this work underlines key parameters influencing SNPs detection and proposes recommendations for reliable variant calling for plant viruses. The identification of the closest reference, mapping parameters and manual validation of the detection were recognized as the most impactful analysis steps for the success of the SNPs detections. Strategies to improve the prediction of SNPs are also discussed.


Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Polimorfismo de Nucleotídeo Único , Humanos , Polimorfismo de Nucleotídeo Único/genética , Genoma Viral/genética , Biologia Computacional , Conhecimento
11.
Am J Bot ; 99(9): 1453-63, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22912370

RESUMO

PREMISE OF THE STUDY: Population genetic structuring over limited timescales is commonly viewed as a consequence of spatial constraints. Indirect approaches have recently revealed reproductive isolation resulting from flowering time (so-called isolation by time, IBT). Since phenological processes can be subject to selection, the persistence of flowering asynchrony may be due to opposing selective pressures during mating, dispersal, and regeneration phases. Our study aimed to investigate phenology, fruit handling by animals, and their interaction in a timber tree species, Milicia excelsa. METHODS: We analyzed phenological data collected over 6 years on 69 genotyped trees in a Cameroonian natural rainforest complemented by data from germination trials and field observations of dispersers. KEY RESULTS: Initiation of flowering was correlated with variation in temperature and relative humidity, but was also affected by genetic factors: pairwise differences in flowering time between nearby individuals correlated with kinship coefficient, and earliness of flowering remained stable over time. A decrease in mean seed production per fruit with increasing flowering time suggests selection against late bloomers. However, germination rate was not affected by seed collection date, and the main seed disperser, the bat Eidolon helvum, seemed to increase in abundance at the end of the reproductive season and preferred trees in open habitats where early and late bloomers are expected. CONCLUSIONS: The pairwise approach performs well in detecting IBT. The persistence of different mating pools in such a case may result from a trade off between selective forces during the mating and seed dispersal processes.


Assuntos
Moraceae/fisiologia , Isolamento Reprodutivo , Dispersão de Sementes/fisiologia , Árvores/fisiologia , Clima Tropical , Animais , Camarões , Quirópteros/fisiologia , Ecossistema , Flores/fisiologia , Frutas/fisiologia , Loci Gênicos/genética , Genética Populacional , Geografia , Germinação/fisiologia , Repetições de Microssatélites/genética , Moraceae/genética , Folhas de Planta/fisiologia , Chuva , Estações do Ano , Sementes/crescimento & desenvolvimento , Fatores de Tempo , Árvores/genética
12.
Chem Biodivers ; 9(7): 1389-402, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22782885

RESUMO

Cananga odorata (Lam.) Hook.f. & Thomson forma genuina (Annonaceae) is a tropical tree, grown for the production of ylang-ylang essential oil, which is extracted from its fresh and mature flowers. Despite its economic and social importance, very little information is available on its variability and the possible factors causing it. Therefore, the relationship between the genetic structure, revealed by amplified fragment length polymorphism (AFLP), and the essential oil chemical composition, determined by GC/MS analysis, of ylang-ylang grown in semi-managed systems in three Indian Ocean islands (Grande Comore, Mayotte, and Madagascar) was investigated. Our results revealed a low genetic variation within plantations and contrasted situations between islands. Variations of the chemical composition could be observed within plantations and between islands. The genetic differentiation pattern did not match the observed pattern of chemical variability. Hence, the chemical variation could not be attributed to a genetic control. As Grande Comore, Madagascar, and Mayotte present different environmental and agronomic conditions, it can be concluded that the influence of these conditions on the ylang-ylang essential oil composition is consistent with the patterns observed. Finally, several strategies were proposed to valorize the chemical composition variations.


Assuntos
Annonaceae/química , Cananga/química , Flores/química , Óleos Voláteis/química , Cromatografia Gasosa-Espectrometria de Massas , Variação Genética , Ilhas , Polimorfismo Genético , Análise de Componente Principal , Índias Ocidentais
13.
Front Plant Sci ; 13: 803980, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35937329

RESUMO

Vegetatively propagated crops are particularly prone to disease dissemination through their seed systems. Strict phytosanitary measures are important to limit the impact of diseases as illustrated by the potato seed system in Europe. Cassava brown streak disease (CBSD) is a devastating disease caused by two viral species collectively named cassava brown streak viruses (CBSVs). CBSD can cause substantial root yield losses of up to 100% in the worst affected areas and is easily transmitted through stem cuttings. In Eastern and Central Africa, the epidemiology of CBSVs in the local socio-economical context of production remains poorly known while a better understanding would be an asset to properly manage the disease. This lack of information explains partially the limited efficiency of current regulatory schemes in increasing the availability of quality seed to smallholders and mitigating the spread of pests and diseases. This study surveyed the epidemiology of CBSVs in Uvira territory, Eastern D.R. Congo, and its drivers using a multivariate approach combining farmer's interview, field observation, sampling and molecular detection of CBSVs. Investigation on the epidemiology of CBSD revealed that three clusters in the study area could be identified using five most significant factors: (i) symptoms incidence, (ii) number of whiteflies, (iii) types of foliar symptoms, (iv) cutting's pathways and (v) plant age. Among the three clusters identified, one proved to be potentially interesting for seed multiplication activities since the disease pressure was the lowest. Through risk assessment, we also identified several key socio-economic determinants on disease epidemy: (i) factors related to farmer's knowledge and awareness (knowledge of cassava pests and diseases, knowledge of management practices, support from extension services and management strategies applied), (ii) factors related to the geographical location of farmer's fields (proximity to borders, proximity to town, distance to acquire cuttings), as well as (iii) the pathways used to acquire cuttings.

14.
Plant Dis ; 95(3): 311-316, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30743501

RESUMO

When applied preharvest, antagonistic yeasts that act as biocontrol agents of postharvest fruit diseases must survive the environmental conditions in the field. In particular, UV-B radiation (280 to 320 nm) can greatly reduce their survival and effectiveness. The influence of artificial UV-B radiation on Pichia anomala strain K, an antagonistic yeast with potential for control of postharvest fruit diseases, was evaluated in vitro and in vivo. The in vitro 50 and 90% lethal dose values were 0.89 and 1.6 Kj/m2, respectively, whereas lethal values in vivo were 3.2 and 5.76 Kj/m2, respectively. UV protectants tested in combination with strain K included congo red, tryptophan, riboflavin, lignin, casein, gelatine, folic acid, tyrosine, and four mixtures. Riboflavin, folic acid, and the mixtures 1% folic acid + 0.5% tyrosine + 0.5% riboflavin (formula 2), 0.5% folic acid + 1% tyrosine + 0.5% riboflavin (formula 3), and 0.5% folic acid + 0.5% tyrosine + 1% riboflavin (formula 4) reduced yeast mortality caused by UV-B radiation in petri dish assays. Riboflavin, folic acid, gelatine, lignin, and tyrosine reduced yeast mortality caused by UV-B radiation on apple fruit surfaces. With the exception of lignin and folic acid, none of the compounds or mixtures increased significantly the ability of strain K to control the postharvest pathogen Penicillium expansum on wounded apple fruit. In contrast, casein, gelatine, tyrosine, congo red, riboflavin, and formulas 1 to 4 significantly reduced the effectiveness of strain K. Further investigations are justified to verify a potential benefit of lignin and folic acid for UV protection of strain K in preharvest applications.

15.
J Insect Sci ; 11: 73, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21867439

RESUMO

Carrion beetles are important in terrestrial ecosystems, consuming dead mammals and promoting the recycling of organic matter into ecosystems. Most forensic studies are focused on succession of Diptera while neglecting Coleoptera. So far, little information is available on carrion beetles postmortem colonization and decomposition process in temperate biogeoclimatic countries. These beetles are however part of the entomofaunal colonization of a dead body. Forensic entomologists need databases concerning the distribution, ecology and phenology of necrophagous insects, including silphids. Forensic entomology uses pig carcasses to surrogate human decomposition and to investigate entomofaunal succession. However, few studies have been conducted in Europe on large carcasses. The work reported here monitored the presence of the carrion beetles (Coleoptera: Silphidae) on decaying pig carcasses in three selected biotopes (forest, crop field, urban site) at the beginning of spring. Seven species of Silphidae were recorded: Nicrophorus humator (Gleditsch), Nicrophorus vespillo (L.), Nicrophorus vespilloides (Herbst), Necrodes littoralis L., Oiceoptoma thoracica L., Thanatophilus sinuatus (Fabricius), Thanatophilus rugosus (L.). All of these species were caught in the forest biotope, and all but O. thoracica were caught in the agricultural biotope. No silphids were caught in the urban site.


Assuntos
Besouros/fisiologia , Meio Ambiente , Suínos/parasitologia , Animais , Bélgica , Ciências Forenses
16.
Environ Monit Assess ; 181(1-4): 335-45, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21188508

RESUMO

Bark peeling by red deer (Cervus elaphus L.) has become a serious issue for productive forests in western Europe. The damage is particularly severe on species such as spruce, as these become vulnerable to fungus attacks that result in considerably depreciated timber. This article presents a monitoring setup for recent bark peeling damage in spruce plantings in Wallonia (southern part of Belgium). This setup implies to collect data annually from a survey involving cluster sampling. It has been employed since 2004 in coniferous stands amounting to 165,000 ha of land, where Norway spruce is the predominant species. The study area was divided into blocks delineated along features preventing deer migrations. A set of indicators was computed either at the whole study area level or at block level. The resulting set of indicators enabled forest managers to follow up debarking intensity in productive forests. Additional analyses were carried out in order to assess the relationship between the social position of trees in the stand and the debarking probability on the one hand, and the relationship between the variation in damage magnitude and seasonality, namely summer versus winter, on the other hand.


Assuntos
Agricultura , Cervos/fisiologia , Monitoramento Ambiental/métodos , Casca de Planta , Traqueófitas/crescimento & desenvolvimento , Animais , Bélgica , Dinâmica Populacional , Estações do Ano
17.
Foods ; 10(2)2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33498387

RESUMO

Essential oils are used in an increasing number of applications including biopesticides. Their volatility minimizes the risk of residue but can also be a constraint if the release is rapid and uncontrolled. Solutions allowing the encapsulation of essential oils are therefore strongly researched. In this study, essential oils encapsulation was carried out within dendrimers to control their volatility. Indeed, a spontaneous complexation occurs in a solution of dendrimers with essential oils which maintains it longer. Six parameters (temperature, stirring rate, relative concentration, solvent volume, stirring time, and pH) of this reaction has been optimized by two steps: first a screening of the parameters that influence the encapsulation with a Plackett-Burmann design the most followed by an optimization of those ones by a surface response methodology. In this study, two essential oils with herbicide properties were used: the essential oils of Cinnamomum zeylanicum Blume and Cymbopogon winterianus Jowitt; and four biosourced dendrimers: glycerodendrimers derived from polypropylenimine and polyamidoamine, a glyceroclikdendrimer, and a glyceroladendrimer. Meta-analysis of all Plackett-Burman assays determined that rate and stirring time were effective on the retention rate thereby these parameters were used for the surface response methodology part. Each combination gives a different optimum depending on the structure of these molecules.

18.
PeerJ ; 9: e12494, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34900423

RESUMO

Managers need to know how to mitigate rising stream water temperature (WT) due to climate change. This requires identifying the environmental drivers that influence thermal regime and determining the spatial area where interventions are most effective. We hypothesized that (i) extreme thermal events can be influenced by a set of environmental factors that reduce thermal sensitivity and (ii) the role played by those factors varies spatially. To test these hypotheses, we (i) determined which of the environmental variables reported to be the most influential affected WT and (ii)identified the spatial scales over which those environmental variables influenced WT. To this end, the influence of multi-scale environmental variables, namely land cover, topography (channel slope, elevation), hydromorphology (channel sinuosity, water level, watershed area, baseflow index) and shade conditions, was analyzed on the three model variables (day thermal sensitivity, night thermal sensitivity, and non-convective thermal flux) in the model developed by Georges et al. (2021) of the temporal thermal dynamics of daily maximum WT during extreme events. Values were calculated on six spatial scales (the entire upstream catchment and the associated 1 km and 2 km circular buffer, and 50 m wide corridors on each side of the stream with the associated 1 km and 2 km circular buffer). The period considered was 17 extreme days during the summer identified by Georges et al. (2021) based on WT data measured every 10 min for 7 years (2012-2018) at 92 measurement sites. Sites were located evenly throughout the Wallonia (southern Belgium) hydrological network. Results showed that shade, baseflow index (a proxy of the influence of groundwater), water level and watershed area were the most significant variables influencing thermal sensitivity. Since managers with finite financial and human resources can act on only a few environmental variables, we advocate restoring and preserving the vegetation cover that limits solar radiation on the watercourse as a cost-effective solution to reduce thermal sensitivity. Moreover, management at small spatial scale (50 m riparian buffer) should be strategically promoted (for finance and staffing) as our results show that a larger management scale is not more effective in reducing thermal sensitivity to extreme events.

19.
Sci Total Environ ; 760: 143326, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33223183

RESUMO

With the greatly increased demand for animal products, the global dairy sector has experienced rapid expansion and intensification. The correspondingly increasing manure and sewage produced has been the major contributor to environmental burden and human health, especially in developing countries like China. Both worldwide environmental concerns and growing awareness of the circular economy have focused the governments' attention on environmental policies related to sustainable manure and sewage management (MSM). However, inherently dynamic decision-making processes of individual farms result in a great diversity of MSM practices, which leads to enormous difficulties and complexity in further sustainability and policy evaluation. Hence, it is essential to explore the key MSM pathways to represent diversity at a scientific and statistic view. While it is rarely practiced, particularly in China's dairy farming. We used China as a case study to develop the key MSM pathways using data from the nationwide survey of 306 scale dairy farms via a quantitative typology methodology. The results by optimal clustering solution revealed four key pathways based on the individual practices which are associated with the collection, storage, and processing and utilization stages. Furthermore, general characteristics were compared to identify potential determinant factors. It revealed that the major indicators such as resource endowments, milk productivity and quality, and revenues and expenditure showed a consistently increasing trend among pathways. The results indicated resource availability and intensive degree, to a certain extent, affected the farmers' selection. The possibilities of performing sustainability and policy evaluation at a higher scale were also demonstrated. Overall, the identified key pathways can help to know regional waste utilization and economic potential to evolve their MSM strategies. They are especially critical for developing countries to obtain typical MSM profiles and formulate targeted policies more effectively, aiming to promote dairy sustainable development and achieve the circular economy globally.

20.
Animals (Basel) ; 11(2)2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33670810

RESUMO

The use of abnormal milk mid-infrared (MIR) spectrum strongly affects prediction quality, even if the prediction equations used are accurate. So, this record must be detected after or before the prediction process to avoid erroneous spectral extrapolation or the use of poor-quality spectral data by dairy herd improvement (DHI) organizations. For financial or practical reasons, adapting the quality protocol currently used to improve the accuracy of fat and protein contents is unfeasible. This study proposed three different statistical methods that would be easy to implement by DHI organizations to solve this issue: the deletion of 1% of the extreme high and low predictive values (M1), the deletion of records based on the Global-H (GH) distance (M2), and the deletion of records based on the absolute fat residual value (M3). Additionally, the combinations of these three methods were investigated. A total of 346,818 milk samples were analyzed by MIR spectrometry to predict the contents of fat, protein, and fatty acids. Then, the same traits were also predicted externally using their corresponded standardized MIR spectra. The interest in cleaning procedures was assessed by estimating the root mean square differences (RMSDs) between those internal and external predicted phenotypes. All methods allowed for a decrease in the RMSD, with a gain ranging from 0.32% to 41.39%. Based on the obtained results, the "M1 and M2" combination should be preferred to be more parsimonious in the data loss, as it had the higher ratio of RMSD gain to data loss. This method deleted the records based on the 2% extreme predictions and a GH threshold set at 5. However, to ensure the lowest RMSD, the "M2 or M3" combination, considering a GH threshold of 5 and an absolute fat residual difference set at 0.30 g/dL of milk, was the most relevant. Both combinations involved M2 confirming the high interest of calculating the GH distance for all samples to predict. However, if it is impossible to estimate the GH distance due to a lack of relevant information to compute this statistical parameter, the obtained results recommended the use of M1 combined with M3. The limitation used in M3 must be adapted by the DHI, as this will depend on the spectral data and the equation used. The methodology proposed in this study can be generalized for other MIR-based phenotypes.

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