Physical, chemical, and microbiological characterization of Kettara Mine Tailings, Morocco

The mining industry is of major importance to Morocco’s economy. However, the abandoned pyritic mines are a source of potentially toxic elements that can cause the disruption of the surrounding ecosystems, constituting a huge threat to wellbeing and human health. The present study aimed to analyze the physical and chemical characteristics of different types of tailings and to investigate the microbial populations of acidophilic bacteria involved in the oxidation of pyrite. Coarse and fine tailings collected from different zones of the mine (dike and pond) at two different depths (oxidized and non-oxidized residues) were analyzed for their pH, electrical conductivity, total organic carbon, total nitrogen, available P, major elements, and pseudo-total metal concentrations. The abundance of acidophilic bacteria was determined, and some acidophilic bacterial strains were isolated and tested for their metal tolerance. Tailings showed a pH ≈ 2, very low nutritional content, and high concentrations of Cu, As, Zn, and Pb, which were higher in the non-oxidized samples. The microbial counts of iron- and sulfur-oxidizing bacteria were higher than heterotrophic bacteria, with the highest numbers detected in the oxidized fine tailings. The five acidophilic bacteria isolated from the tailings were affiliated to genera Alicyclobacillus and Sulfobacillus, commonly found in this kind of environment.info:eu-repo/semantics/publishedVersio

The potential of facultative predatory Actinomycetota spp. and prospects in agricultural sustainability

Actinomycetota in the phylum of bacteria has been explored extensively as a source of antibiotics and secondary metabolites. In addition to acting as plant growth-promoting agents, they also possess the potential to control various plant pathogens; however, there are limited studies that report the facultative predatory ability of Actinomycetota spp. Furthermore, the mechanisms that underline predation are poorly understood. We assessed the diversity of strategies employed by predatory bacteria to attack and subsequently induce the cell lysing of their prey. We revisited the diversity and abundance of secondary metabolite molecules linked to the different predation strategies by bacteria species. We analyzed the pros and cons of the distinctive predation mechanisms and explored their potential for the development of new biocontrol agents. The facultative predatory behaviors diverge from group attack “wolfpack,” cell-to-cell proximity “epibiotic,” periplasmic penetration, and endobiotic invasion to degrade host-cellular content. The epibiotic represents the dominant facultative mode of predation, irrespective of the habitat origins. The wolfpack is the second-used approach among the Actinomycetota harboring predatory traits. The secondary molecules as chemical weapons engaged in the respective attacks were reviewed. We finally explored the use of predatory Actinomycetota as a new cost-effective and sustainable biocontrol agent against plant pathogens

La lutte biologique contre la pourriture grise de la vigne: Isolement, caractérisation de souches de bactéries Actinomycétales antagonistes à partir des sols rhizosphériques de vignes saines sauvages d'origine marocaine

L objectif de ce travail de thèse s inscrit dans la recherche et le criblage des actinomycètes PGPR capables de jouer un rôle important dans la lutte biologique contre Botrytis cinerea agent de la pourriture grise de la vigne, de promouvoir la croissance et/ou d induire les mécanismes de défenses chez cette dernière. L'isolement des actinomycètes a été réalisé à partir des sols rhizosphériques de la vigne saine sauvage du Maroc (Errachidia, Sahara, Skoura, Tinjdad, Tinghir). Ainsi, 24 isolats (17%) parmi les 142 isolats se sont avérés capables de limiter la croissance de 4 champignons tests et seulement 9 isolats sélectionnés actifs sur les cinq champignons test y compris Botrytis cinerea. Nous avons montré que les 9 souches sélectionnées cultivent bien le milieu à base des exsudats racinaires. Cependant, 5 isolats seulement présentent un pouvoir antagoniste important vis-à-vis B. cinerea sur ce milieu. Les études microscopiques des hyphes de Botrytis cinerea prélevés au niveau de la zone de confrontation avec les actinomycètes antagonistes montrent une dégradation partielle ou totale. Ceci a été confirmé par des observations réalisées en microscope à fluorescence en utilisant les colorants vitaux tels que le Red Nile et le Calcofluor white. Ces 5 souches montrent des propriétés PGPR, colonisent les surfaces racinaires, puis pénètrent dans les racines jusqu aux feuilles de vitro plantules de vigne (Vitis vinifera L.). De plus, en présence de ces souches, les plantes ne présentent pas les symptômes de la pourriture grise. L identification des isolats sélectionnés par l étude des caractères morphologiques, biochimiques et moléculaires a été réalisée. L hybridation ADN/ADN avec les souches apparentées a confirmé que trois souches antagonistes SS38, SS40 et SS10 correspondent bien à des nouvelles espèces appartenants au genre Streptomyces. La souche SS38 a été retenue pour des investigations concernant la détermination de la structure moléculaire des principes actifs élaborés. En effet, nous avons pu purifier et identifier plusieurs molécules à partir de cette souche...The aim of this study was to isolate PGPR Actinomycetes from wild healthy Vitis vinifera rhizosphere soil collected from several Moroccan regions in order to control Vitis vinifera grey mold agent Botrytis cinerea (Bc). In the course of our screening program for (Bc) antagonistic actinomycetes, we selected 142 isolates from 4 different Moroccan regions (Errachidia, Skoura, Tinjdad, Tinghir). Twenty four isolates were selected for their antifungal activity against Botrytis cinerea. Nine active isolates showing wide activity spectrum were screened for several PGPR capabilities. All 9 active isolates grow on Vitis vinifera root exudates. However, five only showed the antagonistic effect on this medium. They also produce the phytohormone-like compound of the IAA family, chitinases and siderophores making them very promising for plant growth stimulation (PGPB activity). The most powerful strains were then characterized on some physiological aspect (endophytic property, mineral phosphate solubilisation). The sequencing of the ARN 16S of these strains revealed that they are likely belonging to the genus Streptomyces. In the second part of this work, the fine taxonomic status of SS38, SS40 and SS10 strains was established using a polyphasic approach. Phylogenetic analysis based on the almost complete 16S rRNA gene sequence indicated that strain SS10 belongs to the Group I streptomycetes, branching off next to Streptomyces marokkonensis DSM 41918T from the Streptomyces violaceoruber group. DNA-DNA relatedness and phenotypic data distinguished strain SS10T from the phylogenetically closest related type strains. It is therefore proposed that strain SS10T (CCMM b35 T = DSM 41919T) represents the type strain of a novel Streptomyces species, for which the species name Streptomyces thinghirensis is proposed. SS38 strain is retained for the following investigations: extraction, purification and chemical structures identification of its produced compounds...REIMS-BU Sciences (514542101) / SudocSudocFranceF

Modeling and mapping the habitat suitability and the potential distribution of Arboviruses vectors in Morocco

Mosquitoes transmit several agents of diseases and the presence of different species represents a threat to animal and public health. Aedes and Culex mosquitoes are of particular concern giving their potential vector competence for Arbovirus transmission. In Morocco, the lack of detailed information related to their spatial distribution raises major concerns and hampers effective vector surveillance and control. Using maximum entropy (Maxent) modeling, we generated prediction models for the potential distribution of Arboviruses vectors (Aedes aegypti, Ae. vexans, Ae. caspius, Ae. detritus, and Culex pipiens) in Morocco, under current climatic conditions. Also, we investigated the habitat suitability for the potential occurrence and establishment of Ae. albopictus and Ae. vittatus recorded only once in the country. Prediction models for these last two species were generated considering occurrence datasets from close countries of the Mediterranean Basin, where Ae. albopictus is well established, and from a worldwide database for the case of Ae. vittatus (model transferability). With the exception of Ae. vittatus, the results identify potential habitat suitability in Morocco for all mosquitos considered. Existing areas with maximum risk of establishment and high potential distribution were mainly located in the northwestern and central parts of Morocco. Our results essentially underline the assumption that Ae. albopictus, if not quickly controlled, might find suitable habitats and has the potential to become established, especially in the northwest of the country. These findings may help to better understand the potential distribution of each species and enhance surveillance efforts in areas identified as high risk

Dissemination of Carbapenemases (OXA-48, NDM and VIM) Producing Enterobacteriaceae Isolated from the Mohamed VI University Hospital in Marrakech, Morocco

International audienceThe emergence and spread of carbapenem-resistant Enterobacteriaceae (CRE) represent a major clinical problem and raise serious health concerns. The present study aimed to investigate and ascertain the occurrence of CRE among hospitalized patients of Mohamed VI University Hospital, Marrakech, Morocco. Biological samples were collected over a one-year period (2018). The bacterial isolates were identified by MALDI-TOF-MS. Antibiotic susceptibility testing was performed using disc diffusion and Etest. The modified Hodge test and combined disc diffusion test were used for phenotypic detection. CRE hydrolyzing enzyme encoding genes: blaOXA-48, blaKPC, blaIMP, blaVIM, and blaNDM were characterized by PCR and DNA sequencing. In total, 131 non-duplicate CRE clinical strains resistant to Ertapenem were isolated out of 1603 initial Enterobacteriaceae. Klebsiella pneumoniae was the most common species (59%), followed by Enterobacter cloacae (24%), E. coli (10%), Citrobacter freundii (3%), Klebsiellaoxycota (2%), Serratia marcescens (1%), and Citrobacter braakii (1%). Of these, 56.49%, 21.37%, 15.27%, 3.38%, and 3.05% were collected from blood, urine, pus, catheters and respiratory samples, respectively. Approximately 85.5% (112/131) of the isolates were carbapenemase producers (40 blaOXA-48, 27 blaNDM, 38 blaOXA-48 + blaNDM and 7 blaVIM). All metallo-β-lactamases isolates were NDM-1 and VIM-1 producers. This is the first documentation of blaOXA-48 genes from C. freundii and C. braakii in Morocco

Marine Actinobacteria: Screening for Predation Leads to the Discovery of Potential New Drugs against Multidrug-Resistant Bacteria

International audienc

The potential of facultative predatory Actinomycetota spp. and prospects in agricultural sustainability

International audienceActinomycetota in the phylum of bacteria has been explored extensively as a source of antibiotics and secondary metabolites. In addition to acting as plant growth-promoting agents, they also possess the potential to control various plant pathogens; however, there are limited studies that report the facultative predatory ability of Actinomycetota spp. Furthermore, the mechanisms that underline predation are poorly understood. We assessed the diversity of strategies employed by predatory bacteria to attack and subsequently induce the cell lysing of their prey. We revisited the diversity and abundance of secondary metabolite molecules linked to the different predation strategies by bacteria species. We analyzed the pros and cons of the distinctive predation mechanisms and explored their potential for the development of new biocontrol agents. The facultative predatory behaviors diverge from group attack “wolfpack,” cell-to-cell proximity “epibiotic,” periplasmic penetration, and endobiotic invasion to degrade host-cellular content. The epibiotic represents the dominant facultative mode of predation, irrespective of the habitat origins. The wolfpack is the second-used approach among the Actinomycetota harboring predatory traits. The secondary molecules as chemical weapons engaged in the respective attacks were reviewed. We finally explored the use of predatory Actinomycetota as a new cost-effective and sustainable biocontrol agent against plant pathogens