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Road traffic emission inventory in an urban zone of West Africa : case of Yopougon City (Abidjan, Cote d'Ivoire)
No full textRoad traffic emission inventories based on bottom-up methodology, are calculated for each road segment from fuel consumption and traffic volume data obtained during field measurements in Yopougon. High emissions of black carbon (BC) from vehicles are observed at major road intersections, in areas surrounding industrial zones and on highways. Highest emission values from road traffic are observed for carbon monoxide (CO) (14.8 t/d) and nitrogen oxides (NOx) (7.9 t/d), usually considered as the major traffic pollution tracers. Furthermore, peak values of CO emissions due to personal cars (PCs) are mainly linked to the old age of the vehicle fleet with high emission factors. The highest emitting type of vehicle for BC on the highway is PC (70.2%), followed by inter-communal taxis (TAs) (13.1%), heavy vehicles (HVs) (9.8%), minibuses (GBs) (6.4%) and intra-communal taxis (WRs) (0.4%). While for organic carbon (OC) emissions on the main roads, PCs represent 46.7%, followed by 20.3% for WRs, 14.9% for TAs, 11.4% for GB and 6.7% for HVs. This work provides new key information on local pollutant emissions and may be useful to guide mitigation strategies such as modernizing the vehicle fleet and reorganizing public transportation, to reduce emissions and improve public health
TAL effector repertoires of strains of Xanthomonas phaseoli pv. manihotis in commercial Cassava crops reveal high diversity at the country scale
No full textTranscription activator-like effectors (TALEs) play a significant role for pathogenesis in several xanthomonad pathosystems. Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of Cassava Bacterial Blight (CBB), uses TALEs to manipulate host metabolism. Information about Xpm TALEs and their target genes in cassava is scarce, but has been growing in the last few years. We aimed to characterize the TALE diversity in Colombian strains of Xpm and to screen for TALE-targeted gene candidates. We selected eighteen Xpm strains based on neutral genetic diversity at a country scale to depict the TALE diversity among isolates from cassava productive regions. RFLP analysis showed that Xpm strains carry TALomes with a bimodal size distribution, and affinity-based clustering of the sequenced TALEs condensed this variability mainly into five clusters. We report on the identification of 13 novel variants of TALEs in Xpm, as well as a functional variant with 22 repeats that activates the susceptibility gene MeSWEET10a, a previously reported target of TAL20(Xam668). Transcriptomics and EBE prediction analyses resulted in the selection of several TALE-targeted candidate genes and two potential cases of functional convergence. This study provides new bases for assessing novel potential TALE targets in the Xpm-cassava interaction, which could be important factors that define the fate of the infection
Rapid responses of pristine marine planktonic communities in experimental approach to diuron and naphthalene (Juan de Nova Island, Western Indian Ocean)
No full textPlanktonic communities from Juan de Nova lagoon were submitted to a single exposure of diuron or naphthalene in triplicate outdoor 40-L mesocosms for 5 days. The study followed the temporal changes of the assemblages by determining abundances and taxonomic level of microbial (heterotrophic prokaryotes, picocyanobacteria, heterotrophic protists and phytoplankton) and metazooplankton communities. Exposure to both contaminants did not result in significant changes in phytoplankton abundances. Microscopic identification demonstrated the dominance of Bacillariophyta (mostly Chaetoceros tenuissimus) accounting for more than 95% of the microalgae detected in all mesocosms. Using 18S rRNA metabarcoding, temporal changes in the proportion of eukaryotic operational taxonomic units (OTUs) were highlighted for most taxonomic groups. Diuron had no significant effect on the abundance of eukaryotic picoheterotrophs, ciliates, whereas naphthalene had a significant positive effect on heterotrophic prokaryotes. Metazooplankton was not significantly modified under contaminant exposure, except for copepods nauplii in presence of diuron. Multivariate analysis indicated significant responses of communities linked to the experimental time and conditions. The analysis also revealed a modification of the trophic relationships among communities over time, from a dominant multivorous food web after 48 h towards a reduced microbial loop after 120 h of experiment time
Rapid measurement of the adult worker population size in honey bees
No full textChanges in agricultural practices have lead to pollination deficits in entomophilous crops, leading to a growing interest in supplementing farmlands with managed colonies of honey bee, Apis mellifera. However, the metrics of a colony as a pollination unit is controversial due to the wide range of adult population sizes encountered in a colony, especially in relation with the time of year and beekeeping management. Correctly measuring the number of adult honey bees per hive is critical for farmers to adjust the number of colonies they need to meet crop pollination demand. We tested a simple non-invasive method to estimate the adult worker population size of colonies based on common beekeeping handlings. This method consisted in counting the number of inter-frames covered with adult bees (called IFB thereafter) from above the hive body. Based on the monitoring of 181 colonies, we investigated the nature of the relation between IFB and the adult bee population size and its context dependence to the meterological conditions and hive type. We then evaluated the possible improvement of the method with additional IFB counted in the supers and from below the hive body. Finally, we analysed the robustness of the method by comparing estimates obtained from colonies observed by experimented and naive observers. We revealed a clear-cut logarithmic relation between the IFB and the adult population size, covering the effects of meteorological conditions and hive type. The counting of IFB from above the hive body were particularly sensitive to meteorological conditions, unlike those counted from below the hive body. Moreover, the counting of additional IFB from the supers slightly improved the estimates of adult population size. Interestingly, no difference of estimate was detected between experimented and naive observers, suggesting applied simplicity of the method. The IFB counting method thus provides a simple, non-invasive and robust indicator of the adult population size of a managed honey bee colony. The counting of IFB from below the hive body should be recommend due to the sensitivity to meteorological conditions of the counting of IFB from above the hive body. Beyond crop pollination, we also highlighted application perspectives of this method as an indicator of survival probability. This method can therefore be viewed as a standard for routine field monitoring (i) to help farmers to estimate rigorously the number of colonies they need to meet the crop pollination demand and (ii) to help beekeepers assessing the mortality risk of their colonies
Lower mgpB diversity in macrolide-resistant Mycoplasma genitalium infecting men visiting two sexually transmitted infection clinics in Montpellier, France
No full textObjectives: Men engaged in high-risk sexual behaviour, such as MSM, are Likely to be infected by resistant Mycoplasma genitalium strains. Understanding the transmission dynamics is challenging. We aimed to investigate the molecular epidemiology of M. genitalium in men visiting sexually transmitted infection (STI) clinics. Patients and methods: Between June 2017 and February 2018, 95 M. genitalium-positive specimens from 78 men, including 76.9% MSM, visiting two STI clinics in Montpellier, France, were analysed for SNPs in the mgpB adhesin gene and number of tandem repeats in the MG309 gene. Macrolide and fluoroquinolone resistance were determined. Typing results were compared with antibiotic resistance, sexual behaviour, sampling site, HIV pre-exposure prophylaxis (PrEP) usage and HIV status. Results: Thirty-eight mgpB STs were identified, including 23 new STs, with ST4 being most prevalent. The mgpB/MG_309 typing method identified 52 genetic profiles, resulting in a discriminatory index of 0.979. Macrolide and fluoroquinolone resistance-associated mutations were detected in 58.3% and 10.8% of patients, respectively. The macrolide resistance rate was higher among MSM than among men who have sex with women only (68.4% versus 9.1%; adjusted OR, 1.57; 95% CI, 1.13-2.18; P=0.007). A Lower mgpB diversity of 0.870 was found among macrolide-resistant strains in comparison with 0.978 in macrolide-susceptible strains, with an overrepresentation of mgpB ST62 and ST153. Conclusions: Although macrolide resistance spread appears polyclonal in M. genitalium, the Lower diversity of mgpB types among macrolide-resistant strains may reflect the easier spread of a few specific mgpB types or the occurrence of sexual networks among MSM
Natural occurrence of mycotoxin-producing fusaria in market-bought Peruvian cereals : a food safety threat for Andean populations
No full textConsumption of cereals contaminated by mycotoxins poses health risks. For instance, Fumonisins B, mainly produced by Fusarium verticillioides and Fusarium proliferatum, and the type B trichothecene deoxynivalenol, typically produced by Fusarium graminearum, are highly prevalent on cereal grains that are staples of many cultural diets and known to represent a toxic risk hazard. In Peru, corn and other cereals are frequently consumed on a daily basis under various forms, the majority of food grains being sold through traditional markets for direct consumption. Here, we surveyed mycotoxin contents of market-bought grain samples in order to assess the threat these mycotoxins might represent to Peruvian population, with a focus on corn. We found that nearly one sample of Peruvian corn out of six was contaminated with very high levels of Fumonisins, levels mostly ascribed to the presence of F. verticillioides. Extensive profiling of Peruvian corn kernels for fungal contaminants could provide elements to refine the potential risk associated with Fusarium toxins and help define adapted food safety standards
Lack of SARS-CoV-2 among Grand Magal de Touba pilgrims consulting for respiratory symptoms in October 2020
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Compound-specific delta H-2 and delta C-13 values of n-alkanes as a tool to unravel complex petroleum mixtures in the South Viking Graben, Norway
No full textIn order to resolve oil mixtures and for oil-source correlation purposes, both hydrogen (82H) and carbon isotope compositions (delta C-13) of n-alkanes and acyclic isoprenoid alkanes have been determined in petroleum mixtures and extracts from Jurassic source rocks of distinct organic matter type, depositional setting and lithology in the South Viking Graben, Norway. delta H-2 values vary from-80 to-140 parts per thousand for n-alkanes and from-130 to-165 parts per thousand for pristane (Pr) and phytane (Ph) in oil and condensate samples. At the same maturity level, in the main oil generative window, individual n-alkanes from most oils and condensates show a H-2-enrichment with n-alkane chain length by 15 to 50 parts per thousand. With the increase in the estimated input of hydrocarbons from terrigenous source material to petroleum mixtures, the n-alkanes (>C-20) exhibit a higher 2H-enrichment while n-alkanes (C-10-C-14) show a higher C-13-enrichment. delta H-2 values of n-alkanes (>C-20) are useful to discriminate mixed oils that were not well differentiated by delta C-13 data. delta H-2 values of individual n-alkanes from oils suggest a possible exchange of C-bound H with other hydrogen during their generation from precursor molecules. We find that delta H-2 values of n-alkanes from Jurassic source rock extracts, at the onset of oil generation, were mainly controlled by the isotopic composition of biosynthetic precursors and varied from-100 to-150 parts per thousand. Combination of carbon and hydrogen isotope compositions of n-alkanes proved to be a useful tool to discriminate Jurassic petroleum mixtures from distinct sources in the Norwegian South Viking Graben
The vulnerability of shellfish farmers to HAB events : an optimal matching analysis of closure decrees
No full textHarmful Algal Blooms (HAB) events may have serious economic consequences for shellfish farmers. When toxic algae blooms threaten human health, public authorities may decide to shut down the farming business for a while, i.e. ranging from a few days to several weeks or months, according to the severity of risks. The impact of closures being temporally and spatially distributed, shellfish farmers can avoid the risky zones or develop adaptive strategies to mitigate the economic consequences and therefore reduce significantly their business sensitivity to HABs. A sequential approach by optimal matching analysis is applied to an original data set of shellfish area closure decrees between April 2004 and December 2018 in Southern Brittany and Pays de la Loire (France) to build a typology of 79 aquaculture zones affected by various HAB and microbiological hazards (ASP, DSP, Norovirus, E. Coli, oil spills). The hypothesis is that the degree of exposure to the HAB hazard assessed by zonal closures may not be correlated to the level of sensitivity revealed by the economic results of the shellfish farming industry which can develop avoidance strategies