Radionuclide biogeochemistry: from bioremediation toward the treatment of aqueous radioactive effluents.

Civilian and military nuclear programs of several nations over more than 70 years have led to significant quantities of heterogenous solid, organic, and aqueous radioactive wastes bearing actinides, fission products, and activation products. While many physicochemical treatments have been developed to remediate, decontaminate and reduce waste volumes, they can involve high costs (energy input, expensive sorbants, ion exchange resins, chemical reducing/precipitation agents) or can lead to further secondary waste forms. Microorganisms can directly influence radionuclide solubility, via sorption, accumulation, precipitation, redox, and volatilization pathways, thus offering a more sustainable approach to remediation or effluent treatments. Much work to date has focused on fundamentals or laboratory-scale remediation trials, but there is a paucity of information toward field-scale bioremediation and, to a lesser extent, toward biological liquid effluent treatments. From the few biostimulation studies that have been conducted at legacy weapon production/test sites and uranium mining and milling sites, some marked success via bioreduction and biomineralisation has been observed. However, rebounding of radionuclide mobility from (a)biotic scale-up factors are often encountered. Radionuclide, heavy metal, co-contaminant, and/or matrix effects provide more challenging conditions than traditional industrial wastewater systems, thus innovative solutions via indirect interactions with stable element biogeochemical cycles, natural or engineered cultures or communities of metal and irradiation tolerant strains and reactor design inspirations from existing metal wastewater technologies, are required. This review encompasses the current state of the art in radionuclide biogeochemistry fundamentals and bioremediation and establishes links toward transitioning these concepts toward future radioactive effluent treatments.

Preschooler screen time and temperamental anger/frustration during the COVID-19 pandemic.

BACKGROUND: In the context of increased media use and family distress during the pandemic, we examine whether preschooler screen time at age 3.5 contributes to later expressions of anger/frustration at 4.5, while also considering the inverse association. METHODS: Data are from a cohort of 315 Canadian preschool-aged children during the COVID-19 pandemic. Parent-reported measures included child h/day of screen time and child temperamental anger/frustration, both measured at 3.5 and 4.5 years of age. Indicators of family distress include use of childcare and child sleep, family income, parenting stress, and parent education, marital and employment status. We also consider child sex as a control variable. RESULTS: A crossed-lagged panel model revealed continuity in screen time between the ages of 3.5 and 4.5 (ß = 0.68) and temperamental anger/frustration from 3.5 to 4.5 (ß = 0.60). Child screen time at age 3.5 predicted increased proneness to anger/frustration at age 4.5 (ß = 0.14). Anger/frustration at age 3.5 did not predict screen time at age 4.5. CONCLUSION: Our results suggest that preschooler screen time during the pandemic may have undermined the ability to regulate negative emotions, a key component of social and academic competence. Supporting parents in implementing healthy media habits post pandemic may benefit young children's development. IMPACT: Key message: this study observes prospective bidirectional associations between preschoolers screen time and temperamental displays of anger or frustration during the COVID-19 pandemic. What does it add: we provide evidence that preschool screen time at age 3.5 prospectively contributes to the tendency to react in anger/frustration at age 4.5. In contrast, greater proneness to anger/frustration did not predict later exposure to screen time. What is the impact: health practitioners should enquire about media use habits during well-child visits to foster children's healthy development during the preschool years.

Attachment, Sexual Motives, and Sexual Satisfaction among Couples Expecting their First Child.

This study examined direct and indirect links among attachment insecurities (anxiety, avoidance) and sexual satisfaction through sexual motives in couples expecting their first child. A sample of 204 first-time pregnant couples completed online questionnaires. Dyadic path analyses revealed that attachment and sexual satisfaction were not directly associated, but rather indirectly associated through three sexual motives: partner approval, self-affirmation, and intimacy. For non-pregnant partners, attachment anxiety was related to higher sexual satisfaction through higher intimacy, whereas attachment avoidance was related to lower sexual satisfaction through lower intimacy. Results are discussed in light of clinical implications for expecting couples.

Preschooler Screen Time During the Pandemic Is Prospectively Associated With Lower Achievement of Developmental Milestones.

OBJECTIVE: The aim of this study was to assess the developmental risks associated with total screen time, and specifically newer mobile devices, in the context of the pandemic. METHODS: This study uses parent-reported data from a prospective cohort of Canadian preschool-age children. The exposure variable is child daily screen time measured at the age of 3.5 years categorized as light (<1 hr/d), moderate (1-4 hr/d), or intensive (>4 hr/d) use (N = 315). Time spent on mobile devices was considered separately as a continuous variable. Our outcome is child global development scores, which combine assessments of communication, cognitive, personal-social, and motor skills measured at the age of 4.5 years using the Ages and Stages Questionnaire (ASQ) (N = 249, 79% retained). ASQ scores were dichotomized to distinguish children at risk of developmental delays (below the 15th percentile) from those not at risk. We estimate associations between child screen time and later global development using multiple regressions adjusted for child sex and temperament, and parent education. We also examine whether associations are moderated by child and parent characteristics. RESULTS: Logistic regressions revealed that intensive users were more at risk of global developmental delays compared with light users (OR = 4.29, p = 0.020). Mobile device use was also associated with lower global scores (ß = -3.064; p = 0.028), but not with risk of delays. We found no evidence that associations were moderated by child sex and temperament, or parent education. CONCLUSION: The findings suggest that intensive screen time may be associated with delays in child global development. Early childhood professionals should encourage families with preschoolers to prioritize screen-free activities to promote optimal cognitive, language, social, and motor development.

Reducing harm and promoting positive media use strategies: new perspectives in understanding the impact of preschooler media use on health and development.

Most children grow up in homes with easy access to multiple screens. Screen use by children between the ages of 0 to 5 has become a worldwide preoccupation. In the present narrative review, we examine child and parent screen use and its contribution to physical, cognitive, and social developmental outcomes. As research has mostly focused on the adverse consequences of screen media, we aim to depict both the negative and the positive influences of screen usage. To provide a more nuanced portrait of the potential benefits and harms of screen use, we examine how consequences of media use vary according to the content of media (ex., educational, violent), context (ex., using screens during mealtimes), and the nature (ex., passive vs active use) of child screen use. Our review supports existing screen time guidelines and recommendations and suggests that media content, the context of use, and the nature of child use, as well as the parent's own screen use, be considered clinically. Future research should seek to clarify how these dimensions jointly contribute to child screen use profiles and associated consequences. Finally, child sex, behavioral/temperamental difficulties, and family adversity appear to contribute to child screen use and its consequences and should be considered in future research. Suggestions for harm-reduction approaches are discussed.

The Effects of Local Weed Species on Arbuscular Mycorrhizal Fungal Communities in an Organic Winter Wheat (Triticum durum L.) Field in Lebanon.

We examined the potential effects of weed species on the arbuscular mycorrhizal fungi (AMF) in an organic winter wheat (Triticum durum) field in Lebanon. In this agroecosystem, the field and its surroundings were covered with spontaneous vegetation corresponding to local weeds. The coexistence between wheat and weeds did not modify AM fungal community diversity and colonization in T. durum but changed their composition. We evidenced 22 operational taxonomic units (OTUs) specifically shared between wheat associated with weeds (Tdw) and weeds, regardless of their localization and 12 OTUs with an abundance of variation between wheat without neighboring weeds (Td) and Tdw. The number of AM propagules and total C and N contents were higher in soil covered with wheat associated with weeds (TdWsoil) vs. wheat without neighboring weeds (Tdsoil). In greenhouse experiments, the shoot biomass and root mycorrhizal intensity of Medicago sativa, used as a trap plant, were higher using TdWsoil vs. Tdsoil as the inoculum. Positive correlations were observed between soil AM propagule numbers and M. sativa shoot biomass, on the one hand and M. sativa mycorrhizal intensity, on the other hand. Weeds seemed to exert significant effects on root AM fungal composition in T. durum and these effects may contribute to enhanced AMF development in the field.

Role of gender in morbidity and mortality of extremely premature neonates.

We investigated the effect of gender on survival and short-term outcomes of extremely premature infants (≤27 weeks) born in Canada. The records of infants admitted between 2000 and 2005 to a neonatal intensive care unit participating in the Canadian Neonatal Network were reviewed for infant gender, birth weight, gestational age, outborn status, Score for Neonatal Acute Physiology II, and antenatal corticosteroid exposure. The following outcomes were recorded: survival at final discharge, necrotizing enterocolitis, bronchopulmonary dysplasia (BPD), intraventricular hemorrhage grade ≥3, retinopathy grade ≥3, days on ventilation, and length of hospital stay. Among 2744 extremely premature infants, 1480 (54%) were male and 1264 (46%) were female. Mean birth weight of female neonates was significantly lower at each week of gestational age. Although no significant difference in survival at discharge was found between genders overall, the prevalence of BPD, combined adverse outcomes, and mortality for infants born between 24 and 26 weeks were significantly higher in males. This study suggests that, in the postsurfactant era, males remain at higher risk of respiratory complications and may have higher mortality when born between 24 and 26 weeks of gestation.

Arbuscular mycorrhizal fungi associated with Artemisia umbelliformis Lam, an endangered aromatic species in Southern French Alps, influence plant P and essential oil contents.

Root colonization by arbuscular mycorrhizal (AM) fungi of Artemisia umbelliformis, investigated in natural and cultivated sites in the Southern Alps of France, showed typical structures (arbuscules, vesicles, hyphae) as well as spores and mycelia in its rhizosphere. Several native AM fungi belonging to different Glomeromycota genera were identified as colonizers of A. umbelliformis roots, including Glomus tenue, Glomus intraradices, G. claroideum/etunicatum and a new Acaulospora species. The use of the highly mycorrhizal species Trifolium pratense as a companion plant impacted positively on mycorrhizal colonization of A. umbelliformis under greenhouse conditions. The symbiotic performance of an alpine microbial community including native AM fungi used as inoculum on A. umbelliformis was evaluated in greenhouse conditions by comparison with mycorrhizal responses of two other alpine Artemisia species, Artemisia glacialis and Artemisia genipi Weber. Contrary to A. genipi Weber, both A. umbelliformis and A. glacialis showed a significant increase of P concentration in shoots. Volatile components were analyzed by GC-MS in shoots of A. umbelliformis 6 months after inoculation. The alpine microbial inoculum increased significantly the percentage of E-ß-ocimene and reduced those of E-2-decenal and (E,E)-2-4-decadienal indicating an influence of alpine microbial inoculum on essential oil production. This work provides practical indications for the use of native AM fungi for A. umbelliformis field culture.

Potentiality of Native Ascomycete Strains in Bioremediation of Highly Polychlorinated Biphenyl Contaminated Soils.

Polychlorinated biphenyls (PCBs) are organic pollutants that are harmful to environment and toxic to humans. Numerous studies, based on basidiomycete strains, have reported unsatisfactory results in the mycoremediation of PCB-contaminated soils mainly due to the non-telluric origin of these strains. The abilities of a five-Ascomycete-strain consortium in the mycoremediation of PCB-polluted soils and its performance to restore their sound functioning were investigated using mesocosm experiments associated with chromatography gas analysis and enzymatic activity assays. With the soil H containing 850 ppm PCB from which the strains had been isolated, a significant PCB depletion of 29% after three months of treatment was obtained. This led to an important decrease of PCBs from 850 to 604 ppm. With the soil L containing 36 ppm PCB, biodegradation did not occur. In both soils, the fungal biomass quantified by the ergosterol assay, did not increase at the end of the treatment. Biodegradation evidenced in the soil H resulted in a significantly improved stoichiometry of N and P acquiring enzymatic activities. This unprecedented study demonstrates that the native Ascomycetes display remarkable properties for remediation and restoration of functioning of the soil they originated from paving the way for greater consideration of these strains in mycoremediation.

Molecular Characterization of Fungal Biodiversity in Long-Term Polychlorinated Biphenyl-Contaminated Soils.

Polychlorinated biphenyls (PCBs) belong to the organic pollutants that are toxic to humans and harmful to environments. Numerous studies dealing with the impact of PCBs on soil microorganisms have focused on bacterial communities. The effects of PCBs on fungal communities in three different PCB-polluted soils from former industrial sites were investigated using high-throughput sequencing of the internal transcribed spacer 1 region. Significant differences in fungal alpha diversity were observed mainly due to soil physico-chemical properties. PCBs only influenced the richness of the fungal communities by increasing it. Fungal composition was rather strongly influenced by both PCBs and soil properties, resulting in different communities associated with each soil. Sixteen Ascomycota species were present in all three soils, including Stachybotrys chartarum, Fusarium oxysporum, Penicillium canescens, Penicillium chrysogenum,Penicillium citrosulfuratum and Penicillium brevicompactum, which are usually found in PCB-polluted soils, and Fusarium solani, Penicillium canescens, Penicillium citrosulfuratum and Penicillium chrysogenum, which are known PCB degraders. This study demonstrated that PCBs influence the richness and the composition of fungal communities. Their influence, associated with that of soil physico-chemical properties, led to distinct fungal communities, but with sixteen species common to the three soils which could be considered as ubiquitous species in PCB-polluted soils.

Agroecology: the key role of arbuscular mycorrhizas in ecosystem services.

The beneficial effects of arbuscular mycorrhizal (AM) fungi on plant performance and soil health are essential for the sustainable management of agricultural ecosystems. Nevertheless, since the 'first green revolution', less attention has been given to beneficial soil microorganisms in general and to AM fungi in particular. Human society benefits from a multitude of resources and processes from natural and managed ecosystems, to which AM make a crucial contribution. These resources and processes, which are called ecosystem services, include products like food and processes like nutrient transfer. Many people have been under the illusion that these ecosystem services are free, invulnerable and infinitely available; taken for granted as public benefits, they lack a formal market and are traditionally absent from society's balance sheet. In 1997, a team of researchers from the USA, Argentina and the Netherlands put an average price tag of US $33 trillion a year on these fundamental ecosystem services. The present review highlights the key role that the AM symbiosis can play as an ecosystem service provider to guarantee plant productivity and quality in emerging systems of sustainable agriculture. The appropriate management of ecosystem services rendered by AM will impact on natural resource conservation and utilisation with an obvious net gain for human society.

Plant health status effects on arbuscular mycorrhizal fungi associated with Lavandula angustifolia and Lavandula intermedia infected by Phytoplasma in France.

We investigated root communities of arbuscular mycorrhizal fungi (AMF) in relation to lavender (Lavandula angustifolia) and lavandin (Lavandula intermedia) health status from organic and conventional fields affected by Phytoplasma infection. The intensity of root mycorrhizal colonization was significantly different between diseased and healthy plants and was higher in the latter regardless of agricultural practice. This difference was more pronounced in lavender. The root AMF diversity was influenced by the plant health status solely in lavender and only under the conventional practice resulting in an increase in the AMF abundance and richness. The plant health status did not influence the distribution of root AMF communities in lavandin unlike its strong impact in lavender in both agricultural practices. Finally, among the most abundant molecular operational taxonomic units (MOTUs), four different MOTUs for each plant species were significantly abundant in the roots of healthy lavender and lavandin in either agricultural practice. Our study demonstrated that the plant health status influences root colonization and can influence the diversity and distribution of root AMF communities. Its effects vary according to plant species, can be modified by agricultural practices and allow plants to establish symbiosis with specific AMF species.

Metabolic adaptation of fungal strains in response to contamination by polychlorinated biphenyls.

Polychlorinated biphenyls (PCBs) represent a large group of recalcitrant environmental pollutants. Up to now, many studies have focused on bioremediation of PCBs by fungal strains; however, the mechanisms of adaptation of these strains towards PCBs remain unknown despite their importance in developing effective bioremediation processes. We studied five species, each consisting of two strains isolated either from PCB-polluted or PCB-unpolluted substrates (control strains). We investigated their responses to PCB contamination by studying their tolerance to PCBs, their ability to reduce these pollutants, and their expression level of Laccase genes. In Thermothelomyces thermophila, Thermothelomyces heterothallica, Thermoascus crustaceus, and Fusarium solani, all the studied strains showed a similar tolerance and PCB degradation regardless of their origin. In Schizophyllum commune, while both strains showed similar resistance to PCBs, i.e., PCBs and their degradation products presented no toxicity for these strains, the rate of PCB degradation of the strain from a PCB-polluted environment was significantly slightly higher. The PCB degradation did not correlate with the expression level of genes encoding Laccases. These results demonstrate that the tolerance and PCB degradation by the fungal strains, which did not involve Laccase genes, required different adaptation systems which seem to be constitutive or rapidly inducible by PCB according to the fungal species.

Expression of the PitA phosphate/metal transporter of Escherichia coli is responsive to zinc and inorganic phosphate levels.

Escherichia coli possesses two major systems for inorganic phosphate (P(i)) uptake. The Pst system (pstSCAB) is inducible by low phosphate concentrations whereas the low-affinity transporter (pitA) has been described as constitutively expressed. PitA catalyses transport of metal [Mg(II), Ca(II)]-phosphate complexes, and mutations in pitA confer Zn(II) resistance. Here we report that pitA transcription is not constitutive; activity of a single-copy pitA-lacZ transcriptional fusion (monolysogen) was maximal at high extracellular Zn(II) (150 microM), in the absence of added P(i), and in a well-defined pitA mutant strain. Intracellular zinc levels were unaffected by adding Zn(II) to the medium for both the wild-type and mutant strains. However, in the wild-type strain, Mg levels (per gram of dry biomass) fell by eightfold in cells grown with added Zn(II) and by 20-fold when Zn(II) and P(i) were added to cultures. Mutation of pitA reduced the effects of external Zn(II) and phosphate levels on Mg pools, consistent with competition or inhibition by Zn(II) of PitA. The mechanism of pitA regulation by extracellular Zn(II) and P(i) is unknown but appears not to involve Fur or other well-characterized regulators.

Reducing harm and promoting positive media use strategies: new perspectives in understanding the impact of preschooler media use on health and development

Abstract Most children grow up in homes with easy access to multiple screens. Screen use by children between the ages of 0 to 5 has become a worldwide preoccupation. In the present narrative review, we examine child and parent screen use and its contribution to physical, cognitive, and social developmental outcomes. As research has mostly focused on the adverse consequences of screen media, we aim to depict both the negative and the positive influences of screen usage. To provide a more nuanced portrait of the potential benefits and harms of screen use, we examine how consequences of media use vary according to the content of media (ex., educational, violent), context (ex., using screens during mealtimes), and the nature (ex., passive vs active use) of child screen use. Our review supports existing screen time guidelines and recommendations and suggests that media content, the context of use, and the nature of child use, as well as the parent's own screen use, be considered clinically. Future research should seek to clarify how these dimensions jointly contribute to child screen use profiles and associated consequences. Finally, child sex, behavioral/temperamental difficulties, and family adversity appear to contribute to child screen use and its consequences and should be considered in future research. Suggestions for harm-reduction approaches are discussed.

Permissiveness of freshly isolated environmental strains of amoebae for growth of Legionella pneumophila.

Legionella pneumophila is a pathogenic bacterium commonly found in water and responsible for severe pneumonia. Free-living amoebae are protozoa also found in water, which feed on bacteria by phagocytosis. Under favorable conditions, some L. pneumophila are able to resist phagocytic digestion and even multiply within amoebae. However, it is not clear whether L. pneumophila could infect at a same rate a large range of amoebae or if there is some selectivity towards specific amoebal genera or strains. Also, most studies have been performed using collection strains and not with freshly isolated strains. In our study, we assess the permissiveness of freshly isolated environmental strains of amoebae, belonging to three common genera (i.e. Acanthamoeba, Naegleria and Vermamoeba), for growth of L. pneumophila at three different temperatures. Our results indicated that all the tested strains of amoebae were permissive to L. pneumophila Lens and that there was no significant difference between the strains. Intracellular proliferation was more efficient at a temperature of 40°C. In conclusion, our work suggests that, under favorable conditions, virulent strains of L. pneumophila could equally infect a large number of isolates of common freshwater amoeba genera.

Population Structure in Naegleria fowleri as Revealed by Microsatellite Markers.

Naegleria sp. is a free living amoeba belonging to the Heterolobosea class. Over 40 species of Naegleria were identified and recovered worldwide in different habitats such as swimming pools, freshwater lakes, soil or dust. Among them, N. fowleri, is a human pathogen responsible for primary amoeboic meningoencephalitis (PAM). Around 300 cases were reported in 40 years worldwide but PAM is a fatal disease of the central nervous system with only 5% survival of infected patients. Since both pathogenic and non pathogenic species were encountered in the environment, detection and dispersal mode are crucial points in the fight against this pathogenic agent. Previous studies on identification and genotyping of N. fowleri strains were focused on RAPD analysis and on ITS sequencing and identified 5 variants: euro-american, south pacific, widespread, cattenom and chooz. Microsatellites are powerful markers in population genetics with broad spectrum of applications (such as paternity test, fingerprinting, genetic mapping or genetic structure analysis). They are characterized by a high degree of length polymorphism. The aim of this study was to genotype N. fowleri strains using microsatellites markers in order to track this population and to better understand its evolution. Six microsatellite loci and 47 strains from different geographical origins were used for this analysis. The microsatellite markers revealed a level of discrimination higher than any other marker used until now, enabling the identification of seven genetic groups, included in the five main genetic groups based on the previous RAPD and ITS analyses. This analysis also allowed us to go further in identifying private alleles highlighting intra-group variability. A better identification of the N. fowleri isolates could be done with this type of analysis and could allow a better tracking of the clinical and environmental N. fowleri strains.

A SDHC Founder Mutation Causes Paragangliomas (PGLs) in the French Canadians: New Insights on the SDHC-Related PGL.

BACKGROUND: More than 40% of patients with paragangliomas (PGLs) harbor a germline mutation of the known PGL susceptibility genes, mainly in the SDHB or SDHD genes. OBJECTIVE: The objective of the study was to characterize the genetic background of the French Canadian (FC) patients with PGLs and provide new clinical and paraclinical insights on SDHC-related PGLs. METHODS: Genetic testing has been offered to FC patients affected with PGLs followed up at the adrenal genetics clinic at Centre hospitalier de l'Université de Montréal. After genetic counseling, 29 FC patients consented for PGL genetic testing. RESULTS: Thirteen of 29 patients (44.8%) carried a germline mutation. The same heterozygous nonsense mutation at codon 133 of exon 5 of the SDHC gene (c.397C>T, p.[Arg133Ter]) was found in nine patients, representing 69.2% of the patients having a germline mutation. Seventy percent of these patients had head and neck PGLs. Twenty percent had multiple and 30% had malignant PGLs. We traced back the ascending genealogy of 10 index cases (nine patients from our cohort and one patient referred to us) and found that this mutation was most probably introduced in Nouvelle France by a couple of French settlers who established themselves in the 17th century. CONCLUSIONS: We found that 31% of the PGLs in the French Canadian can be explained by the SDHC mutation (c.397C>T, p.[Arg133Ter]). The dominance of the SDHC mutation is unique to the FCs and is most likely due to a French founder effect. SDHC gene analysis should be prioritized in FC patients with PGL.

Nitric oxide releases intracellular zinc from prokaryotic metallothionein in Escherichia coli.

Nitric oxide (NO) has a broad spectrum of signalling and regulatory functions and multiple molecular targets. Recently, the intrabacterial toxicity of NO and mechanisms for NO resistance have been intensively investigated. Here we report for the first time that NO elicits release of zinc from a bacterial protein. Using the zinc-responsive expression of zntA (encoding a Zn-exporting P-type ATPase) fused to lacZ, i.e. Phi(zntA-lacZ), to monitor intracellular zinc, and SmtA (the Synechococcus metallothionein) as zinc store, we have shown that the NO donors NOC-5 and NOC-7 elicit zinc ejection. No increase in Phi(zntA-lacZ) activity was observed in a zntR mutant, indicating the specificity of the zntA promoter response to zinc ions.