Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 719
Filtrar
Mais filtros

Intervalo de ano de publicação
1.
Cell ; 175(5): 1380-1392.e14, 2018 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-30343895

RESUMO

ADP-ribosylation of proteins can profoundly impact their function and serves as an effective mechanism by which bacterial toxins impair eukaryotic cell processes. Here, we report the discovery that bacteria also employ ADP-ribosylating toxins against each other during interspecies competition. We demonstrate that one such toxin from Serratia proteamaculans interrupts the division of competing cells by modifying the essential bacterial tubulin-like protein, FtsZ, adjacent to its protomer interface, blocking its capacity to polymerize. The structure of the toxin in complex with its immunity determinant revealed two distinct modes of inhibition: active site occlusion and enzymatic removal of ADP-ribose modifications. We show that each is sufficient to support toxin immunity; however, the latter additionally provides unprecedented broad protection against non-cognate ADP-ribosylating effectors. Our findings reveal how an interbacterial arms race has produced a unique solution for safeguarding the integrity of bacterial cell division machinery against inactivating post-translational modifications.


Assuntos
ADP Ribose Transferases/metabolismo , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Proteínas do Citoesqueleto/metabolismo , N-Glicosil Hidrolases/metabolismo , ADP Ribose Transferases/química , ADP Ribose Transferases/genética , ADP-Ribosilação , Difosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/antagonistas & inibidores , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Domínio Catalítico , Proteínas do Citoesqueleto/antagonistas & inibidores , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/imunologia , Escherichia coli/metabolismo , Humanos , Mutagênese Sítio-Dirigida , N-Glicosil Hidrolases/química , N-Glicosil Hidrolases/genética , Estrutura Terciária de Proteína , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Alinhamento de Sequência , Serratia/metabolismo , Imagem com Lapso de Tempo
2.
Cell ; 168(1-2): 200-209.e12, 2017 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-28086091

RESUMO

Bacteria residing within biofilm communities can coordinate their behavior through cell-to-cell signaling. However, it remains unclear if these signals can also influence the behavior of distant cells that are not part of the community. Using a microfluidic approach, we find that potassium ion channel-mediated electrical signaling generated by a Bacillus subtilis biofilm can attract distant cells. Integration of experiments and mathematical modeling indicates that extracellular potassium emitted from the biofilm alters the membrane potential of distant cells, thereby directing their motility. This electrically mediated attraction appears to be a generic mechanism that enables cross-species interactions, as Pseudomonas aeruginosa cells also become attracted to the electrical signal released by the B. subtilis biofilm. Cells within a biofilm community can thus not only coordinate their own behavior but also influence the behavior of diverse bacteria at a distance through long-range electrical signaling. PAPERCLIP.


Assuntos
Bacillus subtilis/fisiologia , Biofilmes , Fenômenos Eletrofisiológicos , Pseudomonas aeruginosa/fisiologia , Biofilmes/classificação , Potenciais da Membrana , Técnicas Analíticas Microfluídicas , Modelos Biológicos , Potássio/metabolismo
3.
Appl Environ Microbiol ; 90(7): e0030924, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-38874336

RESUMO

In the last decade, advances in soil bacterial ecology have contributed to increasing agricultural production. Brazil is the world leading agriculture producer and leading soil biodiversity reservoir. Meanwhile, there is still a significant gap in the knowledge regarding the soil microscopic life and its interactions with agricultural practices, and the replacement of natural vegetation by agroecosystems is yet to be unfolded. Through high throughput DNA sequencing, scientists are now exploring the complexity of soil bacterial communities and their relationship with soil and environmental characteristics. This study aimed to investigate the progress of bacterial ecology studies in Brazil over the last 10 years, seeking to understand the effect of the conversion of natural vegetation in agricultural systems on the diversity and structure of the soil microbial communities. We conducted a systematic search for scientific publication databases. Our systematic search has matched 62 scientific articles from three different databases. Most of the studies were placed in southeastern and northern Brazil, with no records of studies about microbial ecology in 17 out of 27 Brazilian states. Out of the 26 studies that examined the effects of replacing natural vegetation with agroecosystems, most authors concluded that changes in soil pH and vegetation cover replacement were the primary drivers of shifts in microbial communities. Understanding the ecology of the bacteria inhabiting Brazilian soils in agroecosystems is paramount for developing more efficient soil management strategies and cleaner agricultural technologies.


Assuntos
Agricultura , Bactérias , Microbiota , Microbiologia do Solo , Bactérias/genética , Bactérias/classificação , Bactérias/isolamento & purificação , Brasil , Agricultura/métodos , Biodiversidade , Solo/química
4.
New Phytol ; 242(3): 1333-1347, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38515239

RESUMO

Warming and elevated CO2 (eCO2) are expected to facilitate vascular plant encroachment in peatlands. The rhizosphere, where microbial activity is fueled by root turnover and exudates, plays a crucial role in biogeochemical cycling, and will likely at least partially dictate the response of the belowground carbon cycle to climate changes. We leveraged the Spruce and Peatland Responses Under Changing Environments (SPRUCE) experiment, to explore the effects of a whole-ecosystem warming gradient (+0°C to 9°C) and eCO2 on vascular plant fine roots and their associated microbes. We combined trait-based approaches with the profiling of fungal and prokaryote communities in plant roots and rhizospheres, through amplicon sequencing. Warming promoted self-reliance for resource uptake in trees and shrubs, while saprophytic fungi and putative chemoorganoheterotrophic bacteria utilizing plant-derived carbon substrates were favored in the root zone. Conversely, eCO2 promoted associations between trees and ectomycorrhizal fungi. Trees mostly associated with short-distance exploration-type fungi that preferentially use labile soil N. Additionally, eCO2 decreased the relative abundance of saprotrophs in tree roots. Our results indicate that plant fine-root trait variation is a crucial mechanism through which vascular plants in peatlands respond to climate change via their influence on microbial communities that regulate biogeochemical cycles.


Assuntos
Microbiota , Micorrizas , Traqueófitas , Ecossistema , Dióxido de Carbono/farmacologia , Plantas , Árvores , Solo , Microbiologia do Solo , Raízes de Plantas
5.
Arch Microbiol ; 206(5): 213, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38616201

RESUMO

Mulberry bacterial wilt disease, caused by Ralstonia pseudosolanacearum, is a devastating soil-borne disease in the silk-mulberry-related industry. In this study, through high-throughput sequencing, we compared the rhizosphere bacterial composition of the mulberry-resistant cultivar (K10) and susceptible cultivar (G12), confirming Bacillus as a genus-level biomarker for K10. Next, twelve Bacillus spp. isolates, derived from the rhizosphere of K10, were screened for their antagonistic activity against R. pseudosolanacearum. The isolate showing strong antagonism was identified as B. velezensis K0T24 and selected for further analysis. The fermentation supernatant of B. velezensis K0T24 significantly inhibited the growth of R. pseudosolanacearum (82.47%) and the expression of its pathogenic genes. Using B. velezensis K0T24 in mulberry seedlings also increased defense enzyme activities and achieved a control efficacy of up to 55.17% against mulberry bacterial wilt disease. Collectively, our findings demonstrate the potential of B. velezensis K0T24 in suppressing mulberry bacterial wilt disease.


Assuntos
Bacillus , Infecções Bacterianas , Morus , Bactérias , Bacillus/genética
6.
Microb Ecol ; 87(1): 75, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38775958

RESUMO

The gut microbiome is a highly intricate ecosystem that exerts a pivotal influence on the host's physiology. Characterizing fish microbiomes is critical to understanding fish physiology and health, but little is known about the ecology and colonization dynamics of microorganisms inhabiting fish species. In this study, we investigated the bacterial communities of two small-bodied fish species, Cyprinella lutrensis (red shiner) and Notropis stramineus (sand shiner), two fish species where gut microbiomes have not been investigated previously and surrounding waters, collected from rivers in Nebraska, USA. Our study focused on evaluating microbial diversity in small-bodied fish and identifying autochthonous microbes present within these species irrespective of location to better understand bacterial community composition and possible roles of such bacterial species. Our results revealed that both red shiner and sand shiner exhibited gut bacterial communities dominated by typical bacterial phyla found in freshwater fish. The phylum Bacteroidota was minimally abundant in both species and significantly lower in relative abundance compared to the surrounding water microbial community. Furthermore, we found that the gut microbiomes of red shiner and sand shiner differed from the microbial community in the surrounding water, suggesting that these fish species contain host-associated bacterial species that may provide benefits to the host such as nutrient digestion and colonization resistance of environmental pathogens. The fish gut bacterial communities were sensitive to environmental conditions such as turbidity, dissolved oxygen, temperature, and total nitrogen. Our findings also show bacterial community differences between fish species; although they shared notable similarities in bacterial taxa at phyla level composition, ASV level analysis of bacterial taxa displayed compositional differences. These findings contribute to a better understanding of the gut bacterial composition of wild, freshwater, small-bodied fish and highlight the influence of intrinsic (host) and environmental factors on shaping the bacterial composition.


Assuntos
Bactérias , Cyprinidae , Microbioma Gastrointestinal , Rios , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/genética , Cyprinidae/microbiologia , Rios/microbiologia , RNA Ribossômico 16S/genética , Nebraska
7.
BMC Infect Dis ; 24(1): 590, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38886658

RESUMO

BACKGROUND: Urinary tract infection is one of the most common infections in humans, affecting women in more proportion. The bladder was considered sterile, but it has a urinary microbiome. Moreover, intracellular bacteria (IB) were observed in uroepithelial cells from children and women with urinary tract infections (UTIs). Here, we evaluated the presence of IB in urine from healthy people and patients with UTI symptoms. METHODS: Midstream urine was self-collected from 141 donors, 77 females and 64 males; 72 belonged to the asymptomatic group and 69 were symptomatic. IB was characterized by a culture-dependent technique and visualized by confocal microscopy. Urine was also subjected to the classical uroculture and isolated bacteria were identified by MALDI-TOF. RESULTS: One-hundred and fifteen uroculture were positive. A significant association was observed between the presence of symptoms and IB (P = 0.007). Moreover, a significant association between the presence of IB, symptoms and being female was observed (P = 0.03). From the cases with IB, Escherichia coli was the most frequent microorganism identified (34.7%), followed by Stenotrophomonas maltophilia (14.2%), Staphylococcus spp (14.2%), and Enterococcus faecalis (10.7%). Intracellular E. coli was associated with the symptomatic group (P = 0.02). Most of the intracellular Staphylococcus spp. were recovered from the asymptomatic group (P = 0.006). CONCLUSIONS: Intracellular bacteria are present in patients with UTI but also in asymptomatic people. Here, we report for the first time, the presence of S. maltophilia, Staphylococcus spp., and Enterobacter cloacae as intracellular bacteria in uroepithelial cells. These findings open new insights into the comprehension of urinary tract infections, urinary microbiome and future therapies. Uroculture as the gold standard could not be enough for an accurate diagnosis in recurrent or complicated cases.


Assuntos
Bactérias , Infecções Urinárias , Urotélio , Humanos , Feminino , Masculino , Infecções Urinárias/microbiologia , Adulto , Pessoa de Meia-Idade , Bactérias/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Urotélio/microbiologia , Células Epiteliais/microbiologia , Urina/microbiologia , Adulto Jovem , Idoso , Microbiota , Adolescente
8.
Environ Sci Technol ; 58(10): 4670-4679, 2024 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-38411077

RESUMO

Bacteria utilize electron conduction in their communities to drive their metabolism, which has led to the development of various environmental technologies, such as electrochemical microbial systems and anaerobic digestion. It is challenging to measure the conductivity among bacterial cells when they hardly form stable biofilms on electrodes. This makes it difficult to identify the biomolecules involved in electron conduction. In the present study, we aimed to identify c-type cytochromes involved in electron conduction in Shewanella oneidensis MR-1 and examine the molecular mechanisms. We established a colony-based bioelectronic system that quantifies bacterial electrical conductivity, without the need for biofilm formation on electrodes. This system enabled the quantification of the conductivity of gene deletion mutants that scarcely form biofilms on electrodes, demonstrating that c-type cytochromes, MtrC and OmcA, are involved in electron conduction. Furthermore, the use of colonies of gene deletion mutants demonstrated that flavins participate in electron conduction by binding to OmcA, providing insight into the electron conduction pathways at the molecular level. Furthermore, phenazine-based electron transfer in Pseudomonas aeruginosa PAO1 and flavin-based electron transfer in Bacillus subtilis 3610 were confirmed, indicating that this colony-based system can be used for various bacteria, including weak electricigens.


Assuntos
Flavinas , Shewanella , Eletroquímica , Flavinas/metabolismo , Elétrons , Citocromos/metabolismo , Transporte de Elétrons , Shewanella/química , Shewanella/genética , Shewanella/metabolismo
9.
Environ Res ; 243: 117886, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38081344

RESUMO

Water column mixing homogenizes thermal and chemical gradients which are known to define distribution of microbial communities and influence the prevailing biogeochemical processes. Little is however known about the effects of rapid water column mixing on the vertical distribution of microbial communities in stratified reservoirs. To address this knowledge gap, physicochemical properties and microbial community composition from 16 S rRNA amplicon sequencing were analyzed before and after mixing of vertically stratified water-column bioreactors. Our results showed that α-diversity of bacterial communities decreased from bottom to surface during periods of thermal stratification. After an experimental mixing event, bacterial community diversity experienced a significant decrease throughout the water column and network connectivity was disrupted, followed by slow recovery. Significant differences in composition were seen for both total (DNA) and active (RNA) bacterial communities when comparing surface and bottom layer during periods of stratification, and when comparing samples collected before mixing and after re-stratification. The dominant predicted community assembly processes for stratified conditions were deterministic while such processes were less important during recovery from episodic mixing. Water quality characteristics of stratified water were significantly correlated with bacterial community diversity and structure. Furthermore, structural equation modeling analyses showed that changes in sulfur may have the greatest direct effect on bacterial community composition. Our results imply that rapid vertical mixing caused by episodic weather extremes and hydrological operations may have a long-term effect on microbial communities and biogeochemical processes.


Assuntos
Bactérias , Microbiologia da Água , Bactérias/genética , Tempo (Meteorologia) , Temperatura , Qualidade da Água
10.
Environ Res ; 252(Pt 4): 119055, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38710429

RESUMO

Application of biochar and inoculation with specific microbial strains offer promising approaches for addressing atrazine contamination in agricultural soils. However, determining the optimal method necessitates a comprehensive understanding of their effects under similar conditions. This study aimed to evaluate the effectiveness of biochar and Paenarthrobacter sp. AT5, a bacterial strain known for its ability to degrade atrazine, in reducing atrazine-related risks to soybean crops and influencing bacterial communities. Both biochar and strain AT5 significantly improved atrazine degradation in both planted and unplanted soils, with the most substantial reduction observed in soils treated with strain AT5. Furthermore, bioaugmentation with strain AT5 outperformed biochar in enhancing soybean growth, photosynthetic pigments, and antioxidant defenses. While biochar promoted higher soil bacterial diversity compared to strain AT5, the latter selectively enriched specific bacterial populations. Additionally, soil inoculated with strain AT5 displayed a notable increase in the abundance of key genes associated with atrazine degradation (trzN, atzB, and atzC), surpassing the effects observed with biochar addition, thus highlighting its effectiveness in mitigating atrazine risks in soil.


Assuntos
Atrazina , Biodegradação Ambiental , Carvão Vegetal , Glycine max , Herbicidas , Microbiologia do Solo , Poluentes do Solo , Atrazina/toxicidade , Glycine max/microbiologia , Glycine max/efeitos dos fármacos , Poluentes do Solo/toxicidade , Herbicidas/toxicidade , Solo/química , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/metabolismo
11.
Environ Res ; 257: 119349, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-38844029

RESUMO

Integrated aquaculture wastewater treatment systems (IAWTSs) are widely used in treating aquaculture wastewater with the aeration-microalgae unit serving as an important component. In this study, we artificially constructed an IAWTS and applied two aeration-microalgae methods: ordinary aeration or ozone nanobubbles (ONBs) with microalgae (Nannochloropsis oculata). The impact of N.oculata and ONBs on the removal performance of nutrients and the underlying micro-ecological mechanisms were investigated using 16S rRNA gene amplicon sequencing. The results demonstrated that the combined use of ONBs and N.oculata exhibited superior purification effects with 78.25%, 76.59% and 86.71% removal of CODMn, TN and TP. N.oculata played a pivotal role as the primary element in wastewater purification, while ONBs influenced nutrient dynamics by affecting both N.oculata and bacterial communities. N.oculata actively shaped bacterial communities, with a specific focus on nitrogen and phosphorus cycling in the micro-environment remodeled by ONBs. Rare bacterial communities displayed heightened activity in response to the changes in N.oculata, ONBs, and nutrient levels. These findings provide a novel approach to improve the technological processes the IAWTS, contributing to the advancement of sustainable aquaculture practices by offering valuable insights into wastewater purification efficiency and micro-ecological mechanisms.


Assuntos
Aquicultura , Microalgas , Microbiota , Ozônio , Eliminação de Resíduos Líquidos , Águas Residuárias , Aquicultura/métodos , Águas Residuárias/química , Águas Residuárias/microbiologia , Microbiota/efeitos dos fármacos , Eliminação de Resíduos Líquidos/métodos , Fósforo/metabolismo , Nitrogênio/metabolismo
12.
Environ Res ; 249: 118337, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38325783

RESUMO

Microorganisms are integral to freshwater ecological functions and, reciprocally, their activity and diversity are shaped by the ecosystem state. Yet, the diversity of bacterial community and its driving factors at a large scale remain elusive. To bridge this knowledge gap, we delved into an analysis of 16S RNA gene sequences extracted from 929 water samples across China. Our analyses revealed that inland water bacterial communities showed a weak latitudinal diversity gradient. We found 530 bacterial genera with high relative abundance of hgcI clade. Among them, 29 core bacterial genera were identified, that is strongly linked to mean annual temperature and nutrient loadings. We also detected a non-linear response of bacterial network complexity to the increasing of human pressure. Mantel analysis suggested that MAT, HPI and P loading were the major factors driving bacterial communities in inland waters. The map of taxa abundance showed that the abundant CL500-29 marine group in eastern and southern China indicated high eutrophication risk. Our findings enhance our understanding of the diversity and large-scale biogeographic pattern of bacterial communities of inland waters and have important implications for microbial ecology.


Assuntos
Bactérias , RNA Ribossômico 16S , China , Bactérias/genética , Bactérias/classificação , Bactérias/isolamento & purificação , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/genética , Biodiversidade , Microbiologia da Água , Água Doce/microbiologia
13.
Environ Res ; 244: 118005, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38135101

RESUMO

Emerging contaminants, including antibiotics, antibiotic-resistant bacteria (ARB), and extracellular antibiotic resistance genes (eARGs), have been detected in large numbers in the aquatic environment. The effects of emerging contaminants on bacterial communities in marine sediments are not well studied. In this study, the effects of emerging contaminants (antibiotics, ARB, and eARGs) on the variations of bacterial populations in marine sediments of the Bohai Sea, Yellow Sea, East China Sea, and South China Sea were investigated. The results showed that the abundance of the host bacterial phylum Probacteria in the marine sediments of the Bohai Sea was the lowest among the four seas after exposure to different antibiotics, ARB, and eARGs. The inputs of exogenous antibiotics and resistance genes significantly affected the community function, resulting in significant differences in community abundance at the genus level. The abundance of Halomonas, Sulfitobacter, and Alcanivorax in the four sea areas displayed noteworthy differences in response to the addition of exogenous antibiotics and eARGs. These findings contribute to a more comprehensive understanding of the intricate interplay between emerging contaminants and the dynamics of bacterial communities in natural ecosystems.


Assuntos
Antagonistas de Receptores de Angiotensina , Ecossistema , Sedimentos Geológicos , Inibidores da Enzima Conversora de Angiotensina , Bactérias/genética , Genes Bacterianos , Resistência Microbiana a Medicamentos/genética , China , Antibacterianos/farmacologia
14.
J Water Health ; 22(3): 536-549, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38557569

RESUMO

Bacterial communities in drinking water provide a gauge to measure quality and confer insights into public health. In contrast to urban systems, water treatment in rural areas is not adequately monitored and could become a health risk. We performed 16S rRNA amplicon sequencing to analyze the microbiome present in the water treatment plants at two rural communities, one city, and the downstream water for human consumption in schools and reservoirs in the Andean highlands of Ecuador. We tested the effect of water treatment on the diversity and composition of bacterial communities. A set of physicochemical variables in the sampled water was evaluated and correlated with the structure of the observed bacterial communities. Predominant bacteria in the analyzed communities belonged to Proteobacteria and Actinobacteria. The Sphingobium genus, a chlorine resistance group, was particularly abundant. Of health concern in drinking water reservoirs were Fusobacteriaceae, Lachnospiraceae, and Ruminococcaceae; these families are associated with human and poultry fecal contamination. We propose the latter families as relevant biomarkers for establishing local standards for the monitoring of potable water systems in highlands of Ecuador. Our assessment of bacterial community composition in water systems in the Ecuadorian highlands provides a technical background to inform management decisions.


Assuntos
Água Potável , Humanos , Equador , RNA Ribossômico 16S/genética , Bactérias , Proteobactérias/genética , Microbiologia da Água
15.
Food Microbiol ; 119: 104448, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38225050

RESUMO

We aimed to evaluate the bacterial growth and diversity in vacuum-packed beef bags stored at different temperatures and to monitor blown-pack spoilage. We used culture-based methods and high-throughput sequencing to study the development of the main bacterial groups naturally present in beef stored at 4 and 15 °C for 28 days. The growth of sulfite-reducing clostridium (SRC) was impaired in beef bags stored at 4 °C; significant differences among SRC counts were observed in beef bags stored at 4 and 15 °C on days 14, 21, and 28 (P = 0.001). Blown pack was observed in most beef bags stored at 15 °C, from day 14 to day 28, but not in beef bags stored at 4 °C. A storage temperature of 4 °C was able to maintain a stable bacterial microbiota (most prevalent: Photobacterium, Hafnia-Obesumbacterium, and Lactococcus). Remarkable changes in microbial abundance occurred at 15 °C from day 14 to day 28, with a predominance of strict anaerobes (Bacteroides) and the presence of Clostridium spp. The relative frequencies of strict anaerobes and Clostridium were statistically higher in the beef bags stored at 15 °C (P < 0.001 and P = 0.004, respectively). The temperature influenced the microbial counts and relative abundance of spoilage bacteria, leading to blown pack spoilage.


Assuntos
Embalagem de Alimentos , Microbiota , Animais , Bovinos , Embalagem de Alimentos/métodos , Carne/microbiologia , Temperatura , Vácuo , Bactérias/genética , Clostridium , Microbiologia de Alimentos
16.
Proc Natl Acad Sci U S A ; 118(41)2021 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-34620708

RESUMO

Leaves and flowers are colonized by diverse bacteria that impact plant fitness and evolution. Although the structure of these microbial communities is becoming well-characterized, various aspects of their environmental origin and selection by plants remain uncertain, such as the relative proportion of soilborne bacteria in phyllosphere communities. Here, to address this issue and to provide experimental support for bacteria being filtered by flowers, we conducted common-garden experiments outside and under gnotobiotic conditions. We grew Arabidopsis thaliana in a soil substitute and added two microbial communities from natural soils. We estimated that at least 25% of the phyllosphere bacteria collected from the plants grown in the open environment were also detected in the controlled conditions, in which bacteria could reach leaves and flowers only from the soil. These taxa represented more than 40% of the communities based on amplicon sequencing. Unsupervised hierarchical clustering approaches supported the convergence of all floral microbiota, and 24 of the 28 bacteria responsible for this pattern belonged to the Burkholderiaceae family, which includes known plant pathogens and plant growth-promoting members. We anticipate that our study will foster future investigations regarding the routes used by soil microbes to reach leaves and flowers, the ubiquity of the environmental filtering of Burkholderiaceae across plant species and environments, and the potential functional effects of the accumulation of these bacteria in the reproductive organs of flowering plants.


Assuntos
Arabidopsis/microbiologia , Burkholderiaceae/crescimento & desenvolvimento , Burkholderiaceae/metabolismo , Flores/microbiologia , Folhas de Planta/microbiologia , Burkholderiaceae/classificação , Microbiota/fisiologia , RNA Ribossômico 16S/genética , Solo/química , Microbiologia do Solo
17.
Sensors (Basel) ; 24(2)2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38276359

RESUMO

The intrinsic fluorescence of bacterial samples has a proven potential for label-free bacterial characterization, monitoring bacterial metabolic functions, and as a mechanism for tracking the transport of relevant components through vesicles. The reduced scattering and axial confinement of the excitation offered by multiphoton imaging can be used to overcome some of the limitations of single-photon excitation (e.g., scattering and out-of-plane photobleaching) to the imaging of bacterial communities. In this work, we demonstrate in vivo multi-photon microscopy imaging of Streptomyces bacterial communities, based on the excitation of blue endogenous fluorophores, using an ultrafast Yb-fiber laser amplifier. Its parameters, such as the pulse energy, duration, wavelength, and repetition rate, enable in vivo multicolor imaging with a single source through the simultaneous two- and three-photon excitation of different fluorophores. Three-photon excitation at 1040 nm allows fluorophores with blue and green emission spectra to be addressed (and their corresponding ultraviolet and blue single-photon excitation wavelengths, respectively), and two-photon excitation at the same wavelength allows fluorophores with yellow, orange, or red emission spectra to be addressed (and their corresponding green, yellow, and orange single-photon excitation wavelengths). We demonstrate that three-photon excitation allows imaging over a depth range of more than 6 effective attenuation lengths to take place, corresponding to an 800 micrometer depth of imaging, in samples with a high density of fluorescent structures.


Assuntos
Corantes Fluorescentes , Fótons , Corantes Fluorescentes/química , Microscopia Confocal/métodos , Lasers , Luz , Microscopia de Fluorescência por Excitação Multifotônica/métodos
18.
J Environ Manage ; 365: 121651, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38955043

RESUMO

Hydraulic mixing of stratified reservoirs homogenizes physicochemical gradients and microbial communities. This has potential repercussions for microbial metabolism and water quality, not least in dams and hydraulically controlled waters. A better understanding of how key taxa respond to mixing of such stratified water bodies is needed to understand and predict the impact of hydraulic operations on microbial communities and nutrient dynamics in reservoirs. We studied taxa transitions between cyanobacteria and sulfur-transforming bacteria following mixing of stratified water columns in bioreactors and complemented the experimental approach with a biogeochemical model. Model predictions were consistent with experimental observations, suggesting that stable stratification of DO is restored within 24 h after episodic and complete mixing, at least in the absence of other more continuous disturbances. Subsequently, the concentration of S2- gradually return to pre-mixing states, with higher concentration at the surface and lower in the bottom waters, while the opposite pattern was seen for SO42-. The total abundance of sulfate-reducing bacteria and phototrophic sulfur bacteria increased markedly after 24h of mixing. The model further predicted that the rapid re-oxygenation of the entire water column by aeration will effectively suppress the water stratification and the growth of sulfur-transforming bacteria. Based on these results, we suggest that a reduction of thermocline depth by optimal flow regulation in reservoirs may also depress sulfur transforming bacteria and thereby constrain sulfur transformation processes and pollutant accumulation. The simulation of microbial nutrient transformation processes in vertically stratified waters can provide new insights about effective environmental management measures for reservoirs.


Assuntos
Bactérias , Bactérias/metabolismo , Cianobactérias , Qualidade da Água , Microbiologia da Água , Modelos Teóricos
19.
Proc Biol Sci ; 290(2002): 20230709, 2023 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-37403500

RESUMO

Fitness equalizing mechanisms, such as trade-offs, are recognized as one of the main factors promoting species coexistence in community ecology. However, they have rarely been explored in microbial communities. Although microbial communities are highly diverse, the coexistence of their multiple taxa is largely attributed to niche differences and high dispersal rates, following the principle 'everything is everywhere, but the environment selects'. We use a dynamical stochastic model based on the theory of island biogeography to study highly diverse bacterial communities over time across three different systems (soils, alpine lakes and shallow saline lakes). Assuming fitness equalization mechanisms, here we newly analytically derive colonization-persistence trade-offs, and report a signal of such trade-offs in natural bacterial communities. Moreover, we show that different subsets of species in the community drive this trade-off. Rare taxa, which are occasional and more likely to follow independent colonization/extinction dynamics, drive this trade-off in the aquatic communities, while the core sub-community did it in the soils. We conclude that equalizing mechanisms may be more important than previously recognized in bacterial communities. Our work also emphasizes the fundamental value of dynamical models for understanding temporal patterns and processes in highly diverse communities.


Assuntos
Ecossistema , Modelos Biológicos , Ecologia
20.
New Phytol ; 238(1): 383-392, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36564965

RESUMO

There is an urgent need to understand the coupled relationship between belowground microbes and aboveground plants in response to temperature under climate change. The metabolic theory of ecology (MTE) provides a way to predict the metabolic rate and species diversity, but the spatial scale dependence and connections between plants and microorganisms are still unclear. Here, we used two independent datasets to address this question. One is from comprehensive sampling of paddy fields targeting bacteria and microbial functional genes, and the other is a global metadata of spatial turnover for microorganisms (bacteria, fungi and archaea, n = 139) and plants (n = 206). Results showed that spatial turnover of bacterial communities and microbial functional genes increased with temperature and fitted MTE. Through meta-analysis, the temperature-dependent spatial scale pattern was further extended to the global scale, with the spatial turnover of microorganisms and plants being consistent with MTE. Belowground microorganisms and aboveground plants were closely linked with each other even when controlling for temperature, suggesting that factors other than shared relationships with temperature also contribute to their linkages. These results implied a broad application of MTE in biology and have important implications for predicting the ecological consequences of future climate warming.


Assuntos
Archaea , Bactérias , Temperatura , Bactérias/genética , Plantas/microbiologia , Fungos/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA