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1.
Am J Intellect Dev Disabil ; 129(2): 151-168, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38411244

RESUMO

Using National Longitudinal Transition Study 2012 data, this study explored parent and youth expectations in the areas of postsecondary education, employment, independent living, and financial independence. Compared to youth with other disabilities, youth with intellectual and developmental disabilities and their parents had much lower expectations for the four postschool goals, and parent expectations were much lower than youth's own expectations. Also, youth's race, along with their daily living skills and functional abilities, were positively associated with parent and youth expectations in several future goal areas. Our discussion highlights implications for improving the transition experiences of youth with intellectual and developmental disabilities.


Assuntos
Deficiência Intelectual , Motivação , Criança , Humanos , Adolescente , Objetivos , Deficiências do Desenvolvimento , Pais , Emprego
2.
Risk Anal ; 44(1): 190-202, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37029463

RESUMO

Direct policy search (DPS) is a method for identifying optimal policies (i.e., rules) for managing a system in response to changing conditions. In this article, we introduce a new adaptive way to incorporate learning into DPS. The standard DPS approach identifies "robust" policies by optimizing their average performance over a large ensemble of future states of the world (SOW). Our approach exploits information gained over time, updating prior beliefs about the kind of SOW being experienced. We first run the standard DPS approach multiple times, but with varying sets of weights applied to the SOWs when calculating average performance. Adaptive "metapolicies" then further improve performance by specifying how control of the system should switch between policies identified using different weight sets, depending on our updated beliefs about the relative likelihood of being in certain SOWs. We outline the general method and illustrate it using a case study of efficient dike heightening that simultaneously minimizes protection system costs and flood damage resulting from rising sea levels and storm surge. The solutions identified by our adaptive algorithm dominate the standard DPS on these two objectives, with an average marginal damage reduction of 35.1% for policies with similar costs; improvements are largest in SOWs with relatively lower sea level rise. We also evaluate how performance varies under different ways of implementing the algorithm, such as changing the frequency with which beliefs are updated.

3.
Environ Microbiol Rep ; 16(1): e13221, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38037543

RESUMO

Denitrification in oxic environments occurs when a microorganism uses nitrogen oxides as terminal electron acceptors even though oxygen is available. While this phenomenon is well-established, its consequences on ecological and evolutionary processes remain poorly understood. We hypothesize here that denitrification in oxic environments can modify the accumulation profiles of nitrogen oxide intermediates with cascading effects on the evolutionary potentials of denitrifying microorganisms. To test this, we performed laboratory experiments with Paracoccus denitrificans and complemented them with individual-based computational modelling. We found that denitrification in low oxic environments significantly increases the accumulation of nitrite and nitric oxide. We further found that the increased accumulation of these intermediates has a negative effect on growth at low pH. Finally, we found that the increased negative effect at low pH increases the number of individuals that contribute to surface-associated growth. This increases the amount of genetic diversity that is preserved from the initial population, thus increasing the number of genetic targets for natural selection to act upon and resulting in higher evolutionary potentials. Together, our data highlight that denitrification in low oxic environments can affect the ecological processes and evolutionary potentials of denitrifying microorganisms by modifying the accumulation of nitrogen oxide intermediates.


Assuntos
Desnitrificação , Óxido Nítrico , Humanos , Nitritos , Óxido Nitroso , Nitrogênio
4.
Laryngoscope Investig Otolaryngol ; 8(6): 1532-1546, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38130249

RESUMO

Background: Exercise-based swallowing training (EBST) and transcutaneous neuromuscular electrical stimulation (TNMES) are common modalities used to treat late dysphagia after radiotherapy for nasopharyngeal carcinoma (NPC). We aimed to investigate and compare the efficacies of EBST and TNMES as proactive treatments administered early after radiotherapy. Methods: Patients with early post-radiotherapy NPC (n = 120) underwent either TNMES or EBST. Flexible endoscopic evaluation of swallowing (FEES), quality of life (QOL), and swallowing function questionnaires were completed before the intervention as well as immediately, 6, and 12 months after the intervention. Outcome measures included the scores for the swallowing function score (SFS), penetration and aspiration scale (PAS), dynamic imaging grade of swallowing toxicity (DIGEST), functional oral intake scale (FOIS), swallowing performance status scale (SPSS), pharyngeal motor impairment (PMI), pharyngeal function impairment (PFI), and functional assessment after cancer therapy-nasopharyngeal (FACT-NP) questionnaire. Results: Three months after radiotherapy, 31 and 34 patients underwent TNMES and EBST, respectively, and completed swallowing assessments at all four assessment timepoints. All patients showed post-radiotherapy impairments in the SFS, PAS, DIGEST, PMI, and PFI. Compared with the EBST group, the TNMES group showed significant improvements in the PFI and PMI scores, with small-to-medium effect sizes. Additionally, compared with the EBST group, the TNMES group demonstrated a trend toward slightly better improvements in the PAS, DIGEST, FOIS, and SPSS scores immediately and 6 months after the intervention. The SFS scores improved from baseline in both groups; however, the TNMES group showed an earlier improvement. Finally, the TNMES group showed better QOL according to the FACT-NP than the EBST group. Conclusion: Proactive TMNES and EBST are safe and feasible modalities for improving swallowing in patients with NPC when administered early after radiotherapy. Although TNMES showed better results than EBST, these results should be interpreted with caution given the study limitations. Level of evidence: 1B.

5.
Proc Natl Acad Sci U S A ; 120(43): e2302087120, 2023 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-37844248

RESUMO

We utilize a coupled economy-agroecology-hydrology modeling framework to capture the cascading impacts of climate change mitigation policy on agriculture and the resulting water quality cobenefits. We analyze a policy that assigns a range of United States government's social cost of carbon estimates ($51, $76, and $152/ton of CO2-equivalents) to fossil fuel-based CO2 emissions. This policy raises energy costs and, importantly for agriculture, boosts the price of nitrogen fertilizer production. At the highest carbon price, US carbon emissions are reduced by about 50%, and nitrogen fertilizer prices rise by about 90%, leading to an approximate 15% reduction in fertilizer applications for corn production across the Mississippi River Basin. Corn and soybean production declines by about 7%, increasing crop prices by 6%, while nitrate leaching declines by about 10%. Simulated nitrate export to the Gulf of Mexico decreases by 8%, ultimately shrinking the average midsummer area of the Gulf of Mexico hypoxic area by 3% and hypoxic volume by 4%. We also consider the additional benefits of restored wetlands to mitigate nitrogen loading to reduce hypoxia in the Gulf of Mexico and find a targeted wetland restoration scenario approximately doubles the effect of a low to moderate social cost of carbon. Wetland restoration alone exhibited spillover effects that increased nitrate leaching in other parts of the basin which were mitigated with the inclusion of the carbon policy. We conclude that a national climate policy aimed at reducing greenhouse gas emissions in the United States would have important water quality cobenefits.

6.
Water Res ; 247: 120756, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37898004

RESUMO

Biodegradation holds promise as an effective and sustainable process for the removal of synthetic chemical pollutants. Nevertheless, rational engineering of biodegradation for pollutant remediation remains an unfulfilled goal, while chemical pollution of waters and soils continues to advance. Efforts to (i) identify functional bacteria from aquatic and soil microbiomes, (ii) assemble them into biodegrading consortia, and (iii) identify maintenance and performance determinants, are challenged by large number of pollutants and the complexity in the enzymology and ecology of pollutant biodegradation. To overcome these challenges, approaches that leverage knowledge from environmental bio-chem-informatics and metabolic engineering are crucial. Here, we propose a novel high-throughput bio-chem-informatics pipeline, to link chemicals and their predicted biotransformation pathways with potential enzymes and bacterial strains. Our framework systematically selects the most promising candidates for the degradation of chemicals with unknown biotransformation pathways and associated enzymes from the vast array of aquatic and soil bacteria. We substantiated our perspective by validating the pipeline for two chemicals with known or predicted pathways and show that our predicted strains are consistent with strains known to biotransform those chemicals. Such pipelines can be integrated with metabolic network analysis built upon genome-scale models and ecological principles to rationally design fit-for-purpose bacterial communities for augmenting deficient biotransformation functions and study operational and design parameters that influence their structure and function. We believe that research in this direction can pave the way for achieving our long-term goal of enhancing pollutant biodegradation.


Assuntos
Poluentes Ambientais , Poluentes do Solo , Consórcios Microbianos , Poluentes Ambientais/metabolismo , Biodegradação Ambiental , Bactérias/genética , Bactérias/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Microbiologia do Solo
7.
ISME J ; 17(11): 2090-2102, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37737252

RESUMO

Metabolic cross-feeding is a pervasive microbial interaction type that affects community stability and functioning and directs carbon and energy flows. The mechanisms that underlie these interactions and their association with metal/metalloid biogeochemistry, however, remain poorly understood. Here, we identified two soil bacteria, Bacillus sp. BP-3 and Delftia sp. DT-2, that engage in a two-tiered mutualism. Strain BP-3 has low utilization ability of pyruvic acid while strain DT-2 lacks hexokinase, lacks a phosphotransferase system, and is defective in glucose utilization. When strain BP-3 is grown in isolation with glucose, it releases pyruvic acid to the environment resulting in acidification and eventual self-killing. However, when strain BP-3 is grown together with strain DT-2, strain DT-2 utilizes the released pyruvic acid to meet its energy requirements, consequently rescuing strain BP-3 from pyruvic acid-induced growth inhibition. The two bacteria further enhance their collective competitiveness against other microbes by using arsenic as a weapon. Strain DT-2 reduces relatively non-toxic methylarsenate [MAs(V)] to highly toxic methylarsenite [MAs(III)], which kills or suppresses competitors, while strain BP-3 detoxifies MAs(III) by methylation to non-toxic dimethylarsenate [DMAs(V)]. These two arsenic transformations are enhanced when strains DT-2 and BP-3 are grown together. The two strains, along with their close relatives, widely co-occur in soils and their abundances increase with the soil arsenic concentration. Our results reveal that these bacterial types employ a two-tiered mutualism to ensure their collective metabolic activity and maintain their ecological competitive against other soil microbes. These findings shed light on the intricateness of bacterial interactions and their roles in ecosystem functioning.


Assuntos
Arsênio , Arsênio/metabolismo , Solo , Simbiose , Ecossistema , Ácido Pirúvico , Bactérias , Glucose
8.
NPJ Biofilms Microbiomes ; 9(1): 58, 2023 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-37608025

RESUMO

Droplet evaporation is a general process in unsaturated environments that results in micro-scale hydrodynamic flows which in turn determine the spatial distributions of microbial cells across surfaces. These spatial distributions can have significant effects on the development and functioning of surface-associated microbial communities, with consequences for important processes such as the spread of plasmids. Here, we experimentally quantified how evaporation-induced hydrodynamic processes modulate the initial deposition patterns of microbial cells (via the coffee ring effect and Marangoni convection) and how these patterns control the spread of an antibiotic resistance-encoding plasmid during surface-associated growth. We found that plasmid spread is a function of the initial density of cells deposited along the droplet periphery, which is a manifestation of the coffee ring effect. Using an individual-based model, we systematically linked how the different initial cell deposition patterns caused by the relative strengths of the coffee ring effect and Marangoni convection determine the extent of plasmid transfer during surface-associated growth. Our study demonstrates that evaporation-induced hydrodynamic processes that are common in nature can alter crucial ecological properties of surface-associated microbial communities and control the proliferation of plasmids, with consequences on the spread of antibiotic resistance and other plasmid-encoded traits.


Assuntos
Hidrodinâmica , Microbiota , Fenótipo , Plasmídeos/genética
9.
Infect Dis Ther ; 12(8): 1955-2003, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37653123

RESUMO

Vaccination in pregnancy using a tetanus toxoid, reduced dose diphtheria toxoid, and reduced dose acellular pertussis (Tdap) vaccine is important for prevention of severe pertussis disease in young infants. The objectives of this systematic literature review were to search for original research studies evaluating the vaccine effectiveness, immunogenicity, and safety of Adacel®/Adacel-Polio® used during pregnancy to prevent pertussis disease in young infants. Medical databases used included EMBASE, BIOSIS Previews, and Chemical Abstracts, with search terms related to pregnancy, vaccines/immunization, safety, pertussis, effectiveness/efficacy, and immune response; other potentially eligible reports were included where applicable. Search results were restricted to literature published from 1 January 1995 to 26 July 2021. A total of 2021 articles and 4 other reports were identified for primary review. A total of 49 publications qualified for inclusion after primary and secondary reviews. Effectiveness studies of Adacel or Adacel-Polio given in pregnancy consistently showed high levels of protection from pertussis disease in the newborn (vaccine effectiveness: 91-93%). In immunogenicity studies, the response in pregnant women was consistent with that of non-pregnant women. Infants of mothers vaccinated with Adacel or Adacel-Polio in pregnancy had higher anti-pertussis antibody levels at birth and at 2 months of age compared to infants born to women vaccinated with comparator vaccines, placebo, or those not vaccinated during pregnancy. There was evidence of a slightly decreased response to primary pertussis vaccination in infants of mothers vaccinated with Adacel or Adacel-Polio, but this was not thought to be clinically significant. In safety studies, Adacel or Adacel-Polio vaccination was well tolerated by pregnant woman and not associated with pregnancy, postpartum, or neonatal complications. In conclusion, Adacel or Adacel-Polio vaccination in pregnancy is highly effective in protecting young infants from pertussis disease, with a favorable safety profile for both pregnant women and their infants.

10.
Nat Commun ; 14(1): 3530, 2023 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-37316482

RESUMO

Plasmids are the main vector by which antibiotic resistance is transferred between bacterial cells within surface-associated communities. In this study, we ask whether there is an optimal time to administer antibiotics to minimize plasmid spread in new bacterial genotypes during community expansion across surfaces. We address this question using consortia of Pseudomonas stutzeri strains, where one is an antibiotic resistance-encoding plasmid donor and the other a potential recipient. We allowed the strains to co-expand across a surface and administered antibiotics at different times. We find that plasmid transfer and transconjugant proliferation have unimodal relationships with the timing of antibiotic administration, where they reach maxima at intermediate times. These unimodal relationships result from the interplay between the probabilities of plasmid transfer and loss. Our study provides mechanistic insights into the transfer and proliferation of antibiotic resistance-encoding plasmids within microbial communities and identifies the timing of antibiotic administration as an important determinant.


Assuntos
Antibacterianos , Microbiota , Antibacterianos/farmacologia , Resistência Microbiana a Medicamentos , Genótipo , Plasmídeos/genética
11.
Vaccine ; 41(18): 2968-2975, 2023 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-37032227

RESUMO

OBJECTIVE: To evaluate the effectiveness of the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine containing five pertussis components (Tdap5; Adacel®, Sanofi) when given during pregnancy at preventing pertussis in infants less than 2 months of age. METHODS: The US Centers for Disease Control and Prevention (CDC), in collaboration with the Emerging Infections Program (EIP) Network, undertook a case-control study evaluating the effectiveness of Tdap vaccination in pregnancy against pertussis in infants less than 2 months of age based on data collected by the EIP Network from 2011 through 2014. The dataset from the CDC/EIP Network study was used to conduct this product-specific vaccine effectiveness analysis of Tdap5 vaccination in pregnancy to prevent disease in young infants. The main outcome of interest was vaccine effectiveness in infants whose pregnant parents were vaccinated with Tdap5 between 27 and 36 weeks' gestation, in accordance with the ideal timing for Tdap vaccination in pregnancy recommended by the US Advisory Committee on Immunization Practices. Odd ratios (ORs) and 95 % confidence intervals (CIs) were estimated using conditional logistic regression, and vaccine effectiveness was calculated as (1-OR) × 100 %. RESULTS: There were 160 infant pertussis cases and 302 matched controls included in this Tdap5-specific study. Tdap5 effectiveness in preventing pertussis in infants whose pregnant parents were vaccinated between 27 and 36 weeks' gestation was 92.5 % (95 % CI, 38.5 %-99.1 %). Effectiveness of Tdap5 against pertussis-related hospitalization in infants whose pregnant parents were vaccinated between 27 and 36 weeks' gestation could not be calculated due to lack of discordance among matched cases and controls. Vaccination of the parents after pregnancy or less than 14 days before delivery did not protect infants from pertussis. CONCLUSIONS: Tdap5 vaccination in pregnancy between 27 and 36 weeks' gestation is highly effective at protecting young infants from pertussis. STUDY REGISTRATION: ClinicalTrials.gov, NCT05040802.


Assuntos
Vacinas contra Difteria, Tétano e Coqueluche Acelular , Difteria , Tétano , Coqueluche , Feminino , Humanos , Lactente , Gravidez , Estudos de Casos e Controles , Difteria/prevenção & controle , Tétano/prevenção & controle , Vacinação , Eficácia de Vacinas , Coqueluche/prevenção & controle
12.
Environ Technol ; 44(12): 1838-1849, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-34859742

RESUMO

Microalgal cell attaching and biofilm formation are critical in the application of microalgal biocathode, which severs as one of the hopeful candidates to an original cathode in bioelectrochemical systems. Many efforts have been put in biofilm formation and bioelectrochemical systems for years, but the predominant factors shaping microalgal biocathode formation are sketchy. We launched a pair of researches to investigate microalgal attachment and biofilm formation in the presence/absence of applied voltages using Chlamydomonas microsphaera as a model unicellular motile microalga. In this study, we presented how microalga attached and biofilm formed on a carbon felt surface without applied voltages and try to manifest the most important aspects in this process. Results showed that while nutrient sources did not directly regulate cell attachment onto the carbon felt, limited initial nutrient concentration nevertheless promoted cell attachment. Specifically, nutrient availability did not influence the early stage (20-60 min) of microalgal cell attachment but did significantly impact cell attachment during later stages (240-720 min). Further analysis revealed that nutrient availability-mediated chemotactic movements and zeta potential are crucial to facilitate the initial attachment and subsequent biofilm formation of C. microsphaera onto the surfaces, serving as an important factor controlling microalgal surface attachment. Our results demonstrate that nutrient availability is a dominant factor controlling microalgal surface attachment and subsequent biofilm formation processes. This study provides a mechanistic understanding of microalgal surface attachment and biofilm formation processes on carbon felts surfaces in the absence of applied voltages.


Assuntos
Chlamydomonas , Microalgas , Fibra de Carbono , Biofilmes , Carbono , Microalgas/metabolismo
13.
Curr Biol ; 32(24): 5285-5294.e4, 2022 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-36455559

RESUMO

The amount of bacterial diversity present on many surfaces is enormous; however, how these levels of diversity persist in the face of the purifying processes that occur as bacterial communities expand across space (referred to here as range expansion) remains enigmatic. We shed light on this apparent paradox by providing mechanistic evidence for a strong role of fungal hyphae-mediated dispersal on regulating bacterial diversity during range expansion. Using pairs of fluorescently labeled bacterial strains and a hyphae-forming fungal strain that expand together across a nutrient-amended surface, we show that a hyphal network increases the spatial intermixing and extent of range expansion of the bacterial strains. This is true regardless of the type of interaction (competition or resource cross-feeding) imposed between the bacterial strains. We further show that the underlying cause is that flagellar motility drives bacterial dispersal along the hyphal network, which counteracts the purifying effects of ecological drift at the expansion frontier. We finally demonstrate that hyphae-mediated spatial intermixing increases the conjugation-mediated spread of plasmid-encoded antibiotic resistance. In conclusion, fungal hyphae are important regulators of bacterial diversity and promote plasmid-mediated functional novelty during range expansion in an interaction-independent manner.


Assuntos
Bactérias , Hifas , Hifas/genética , Bactérias/genética , Plasmídeos/genética
14.
Hum Vaccin Immunother ; 18(5): 2073747, 2022 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-35653552

RESUMO

Vaccination against hepatitis B (HepB) provides long-term protection against infection. This is despite a reduction in HepB surface antibody (anti-HBs) concentrations over time to levels below the well-accepted correlate of protection of ≥10 mIU/mL. Continued evidence of immune memory and protection despite declined anti-HBs concentrations can be demonstrated by HepB virus surface antigen challenge studies. Long-term immune memory and protection against HepB infection has not been demonstrated previously for the pediatric hexavalent vaccine DTaP5-IPV-HepB-Hib. This phase 3, multicenter, single-group, open-label challenge study (NCT04490499; EudraCT: 2020-000126-26) evaluated immune memory against HepB infection in children who had received DTaP5-IPV-HepB-Hib at 2, 4, and 11-12 months of age, or at 2, 3, 4, and 12 months of age. At age 8-9 years, they were each challenged with 5 µg of monovalent HepB vaccine. Anti-HBs levels were measured on pre-challenge day 1 and post-challenge day 30. At baseline, 45.4% (93 of 205) had anti-HBs levels ≥10 mIU/mL. On post-challenge day 30, 99.5% (201 of 202) had anti-HBs levels ≥10 mIU/mL, regardless of initial vaccination schedule. Post-challenge, geometric mean concentrations increased 71-fold over baseline and 96.0% of children had a ≥4-fold rise in anti-HBs concentrations with similar results across both dosing schedules. The challenge dose was well tolerated. The robust anti-HBs responses after a single 5-µg dose of HepB vaccine confirm the persistence of a HepB immune memory and demonstrate that DTaP5-IPV-HepB-Hib provides long-term protection against HepB.


Assuntos
Vacinas Anti-Haemophilus , Haemophilus influenzae tipo b , Hepatite B , Criança , Pré-Escolar , Vacina contra Difteria, Tétano e Coqueluche , Hepatite B/prevenção & controle , Anticorpos Anti-Hepatite B , Vacinas contra Hepatite B , Humanos , Memória Imunológica , Lactente , Vacina Antipólio de Vírus Inativado , Vacinas Combinadas
15.
Microbiol Spectr ; 10(1): e0194421, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35171019

RESUMO

Microbes are social organisms that commonly live in sessile biofilms. Spatial patterns of populations within biofilms can be important determinants of community-level properties. Spatial intermixing emerging from microbial interaction is one of the best-studied characteristics of spatial patterns. The specific levels of spatial intermixing critically contribute to how the dynamics and functioning of such communities are governed. However, the precise factors that determine spatial patterns and intermixing remain unclear. Here, we investigated the spatial patterning and intermixing of an engineered synthetic consortium composed of two mutualistic Pseudomonas stutzeri strains that degrade salicylate via metabolic cross-feeding. We found that the consortium self-organizes across space to form a previously unreported spatial pattern (here referred to as a 'bubble-burst' pattern) that exhibits a low level of intermixing. Interestingly, when the genes encoding type IV pili were deleted from both strains, a highly intermixed spatial pattern developed and increased the productivity of the entire community. The intermixed pattern was maintained in a robust manner across a wide range of initial ratios between the two strains. Our findings show that the type IV pilus plays a role in mitigating spatial intermixing of different populations in surface-attached microbial communities, with consequences for governing community-level properties. These insights provide tangible clues for the engineering of synthetic microbial systems that perform highly in spatially structured environments. IMPORTANCE When growing on surfaces, multispecies microbial communities form biofilms that exhibit intriguing spatial patterns. These patterns can significantly affect the overall properties of the community, enabling otherwise impermissible metabolic functions to occur as well as driving the evolutionary and ecological processes acting on communities. The development of these patterns is affected by several drivers, including cell-cell interactions, nutrient levels, density of founding cells, and surface properties. The type IV pilus is commonly found to mediate surface-associated behaviors of microorganisms, but its role on pattern formation within microbial communities is unclear. Here, we report that in a cross-feeding consortium, the type IV pilus affects the spatial intermixing of interacting populations involved in pattern formation and ultimately influences overall community productivity and robustness. This novel insight assists our understanding of the ecological processes of surface-attached microbial communities and suggests a potential strategy for engineering high-performance synthetic microbial communities.


Assuntos
Fímbrias Bacterianas/fisiologia , Interações Microbianas , Pseudomonas stutzeri/fisiologia , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , Fímbrias Bacterianas/genética , Consórcios Microbianos , Pseudomonas stutzeri/genética , Salicilatos/metabolismo , Simbiose
16.
ISME J ; 16(5): 1453-1463, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35079136

RESUMO

Spatial self-organization is a hallmark of surface-associated microbial communities that is governed by local environmental conditions and further modified by interspecific interactions. Here, we hypothesize that spatial patterns of microbial cell-types can stabilize the composition of cross-feeding microbial communities under fluctuating environmental conditions. We tested this hypothesis by studying the growth and spatial self-organization of microbial co-cultures consisting of two metabolically interacting strains of the bacterium Pseudomonas stutzeri. We inoculated the co-cultures onto agar surfaces and allowed them to expand (i.e. range expansion) while fluctuating environmental conditions that alter the dependency between the two strains. We alternated between anoxic conditions that induce a mutualistic interaction and oxic conditions that induce a competitive interaction. We observed co-occurrence of both strains in rare and highly localized clusters (referred to as "spatial jackpot events") that persist during environmental fluctuations. To resolve the underlying mechanisms for the emergence of spatial jackpot events, we used a mechanistic agent-based mathematical model that resolves growth and dispersal at the scale relevant to individual cells. While co-culture composition varied with the strength of the mutualistic interaction and across environmental fluctuations, the model provides insights into the formation of spatially resolved substrate landscapes with localized niches that support the co-occurrence of the two strains and secure co-culture function. This study highlights that in addition to spatial patterns that emerge in response to environmental fluctuations, localized spatial jackpot events ensure persistence of strains across dynamic conditions.


Assuntos
Microbiota , Pseudomonas stutzeri , Bactérias , Modelos Teóricos
17.
ISME Commun ; 2(1): 77, 2022 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37938324

RESUMO

Multi-step substrate consumption pathways can promote microbial biodiversity via cross-feeding. If one cell type preferentially consumes a primary substrate rather than the subsequently formed intermediates, then other cell types can specialize in consuming the intermediates. While this mechanism for promoting biodiversity is established, predicting the long-term persistence of such cross-feeding interactions remains challenging. Under what conditions will the interaction (and thus biodiversity) persist or disappear? To address this question, we propagated co-cultures of two isogenic strains of the bacterium Pseudomonas stutzeri. One completely reduces nitrate to nitrogen gas but preferentially reduces nitrate rather than nitrite (referred to as the generalist), while the other only reduces nitrite to nitrogen gas (referred to as the specialist). We found that the two strains coexist via nitrite cross-feeding when grown together, but the initial ratio of specialist-to-generalist (rS/G) determines the long-term dynamics of the co-culture. Co-cultures with large initial rS/Gs converge to the same rS/G and persist thereafter. Co-cultures with small initial rS/Gs also converge to the same rS/G but then become increasingly dominated by the generalist. The likely cause of these different dynamics is that the initial rS/G determines the initial environment, which in turn determines the initial selection pressures and phenotypes acquired by the generalist. Our results demonstrate that initial community composition controls the long-term dynamics and persistence of a cross-feeding interaction, and is therefore an important factor for community development and for engineering communities to achieve desired outcomes.

18.
Bioelectrochemistry ; 143: 107989, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34735914

RESUMO

Cell attachment onto electrode-forming biocathodes is a promising alternative to expensive catalysts used for electricity production in bioelectrochemical systems (BESs). Though BESs have been extensively studied for decades, the processes, underlying mechanisms, and determinant driving forces of microalgal biocathode formation remain largely unknown. In this study, we employed a model unicellular motile microalga, Chlamydomonas microsphaera, to investigate the microalgal attachment processes onto the electrode surface of a BES and to identify the determinant factors. Results showed that the initial attachment of C. micrrosphaera cells is determined by the applied external voltage rather than nutrient availability and occurs via electrotaxis-mediated cell motility. The subsequent development of the C. microsphaera biofilm is then increasingly determined by nutrient availability. Our results revealed that, in the absence of an external voltage, nutrient availability remains a dominant factor controlling the fate of the microalgal surface attachment and subsequent biofilm formation processes. Thus, our results show that electrotactic and chemotactic movements are crucial to facilitate the initial attachment and subsequent biofilm formation of C. microsphaera onto the electrode surfaces of BES. This study provides new insights into the mechanisms of microalgal surface attachment and biofilm formation processes on microalgal biocathodes, which hold great promise for improving the electrochemical properties of cathodes.


Assuntos
Fontes de Energia Bioelétrica
19.
Clin Gerontol ; 45(5): 1155-1166, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33755524

RESUMO

OBJECTIVES: The goal of this study was to investigate diversity in stakeholders' perspectives on how best to maximize older adults' well-being when they use long-term services and supports (LTSS). METHODS: We used Q methodology, an exploratory method, to investigate preference patterns among a purposive sample of older adults, family members, and leadership professionals (n = 57). Participants categorized 52 items related to 9 domains of LTSS quality relevant to well-being into categories of importance. We used factors analysis and qualitative methods to identify groups of individuals who identified similar priorities. RESULTS: The analysis identified four shared viewpoints, each prioritizing different aspects of well-being: 1) physical health and safety; 2) independence; 3) emotional well-being; and 4) social engagement. Individual and contextual factors, including stakeholder role, care needs, and expectations for LTSS, appeared to influence participants' perspectives. CONCLUSIONS: Distinct viewpoints on how to maximize well-being when older adults use LTSS exist. Our results affirm the importance of person-centered care yet demonstrate that shared preference patterns LTSS exist. CLINICAL IMPLICATIONS: Engaging with older adults' values and preferences is critical to improving their experiences with LTSS. Better understanding common preference patterns could help providers deliver person-centered care more efficiently and effectively.


Assuntos
Família , Assistência de Longa Duração , Idoso , Humanos
20.
Pediatr Infect Dis J ; 40(12): 1122-1126, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34420008

RESUMO

BACKGROUND: Hypotonic-hyporesponsive episode (HHE) after whole cell pertussis vaccination is a known adverse event. Less is known about the risk of HHE after administration of acellular pertussis vaccines. METHODS: Using parental interviews, this study actively surveyed for HHE among infants after doses 1 and 2 of acellular pertussis vaccine. RESULTS: We interviewed the parents of 52,531 infants. HHE was reported at a rate of 22.8 per 100,000 doses (95% CI: 11.8-39.9) of acellular pertussis vaccine, approximately 45 episodes per 100,000 children. CONCLUSIONS: These rates are lower than HHE rates reported after whole cell pertussis vaccines and within the range of HHE rates reported in other studies of acellular pertussis vaccines.


Assuntos
Vacinas contra Difteria, Tétano e Coqueluche Acelular/efeitos adversos , Hipotonia Muscular/etiologia , Vacinação/efeitos adversos , Sistemas de Notificação de Reações Adversas a Medicamentos , Feminino , Humanos , Lactente , Masculino
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