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1.
Nanomaterials (Basel) ; 14(7)2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38607144

RESUMO

Psoriasis, a chronic inflammatory skin disease induced by various factors, including genetic factors, immune factors, environmental factors, and psychological factors, is characterized by thickening of the epidermis, excessive proliferation of keratinocytes, abnormal differentiation, and an excessive inflammatory response. Traditional treatments for psoriasis still face challenges because of limited curative effects, notable side effects, and a tendency for recurrence. In contrast, topical therapy provides a favorable option for psoriasis treatment because of its noninvasive and self-administered method. In this study, gentiopicrin (Gen) is encapsulated in the liposomes to form a nanodrug, and then chitosan is covered on the nanodrug to assemble the nanodrug delivery system (CS@Gen), which is used as a topical agent for treating psoriasis. Then M5 (a mixture of five pro-inflammatory cytokines, i.e., IL-17A, IL-22, IL-1α, oncostatin M, and TNF-α)-induced HacaT cells and imiquimod-induced psoriasis mouse models are established, whose results show that CS@Gen induces apoptosis and inhibits the proliferation and cell migration of psoriasis keratinocytes. Additionally, the application of CS@Gen cream can significantly reduce epidermal thickness, diminish skin scaling, and improve other related mechanisms in mice affected by psoriasis. Meanwhile, the prepared CS@Gen can significantly reduce the expression levels of IL-17a, Cxcl2, S100a, Mki67, and other related inflammatory factors, resulting in indirectly inhibiting the inflammation of keratinocytes. In summary, the present study provides an ideal loading for an anti-inflammatory and immunomodulatory drug delivery system for the treatment of psoriasis.

2.
Biomacromolecules ; 25(4): 2635-2644, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38478586

RESUMO

Developing nonconjugated materials with large Stokes shifts is highly desired. In this work, three kinds of hyperbranched aggregation-induced emission (AIE) polymers with tunable n/π electronic effects were synthesized. HBPSi-CBD contains alkenyl groups in the backbone and possesses a promoted n-π* transition and red-shifted emission wavelength with a large Stokes shift of 186 nm. Experiments and theoretical simulations confirmed that the planar π electrons in the backbone are responsible for the red-shifted emission due to the strong through-space n···π interactions and restricted backbone motions. Additionally, the designed HBPSi-CBD could be utilized as an ROS scavenger after coupling with l-methionine. The HBPSi-Met exhibits remarkable ROS scavenging properties with a scavenging capacity of 77%. This work not only gains further insight into the structure-property relationship of nonconjugated hyperbranched AIE polymers but also provides a promising ROS-scavenging biomaterial for the treatment of ROS-related diseases.


Assuntos
Elétrons , Polímeros , Espécies Reativas de Oxigênio , Materiais Biocompatíveis
3.
Mar Pollut Bull ; 191: 114971, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37105054

RESUMO

The gate opening of estuarine dams discharge a large amount of freshwater into coastal zones during the summer monsoon in northeast Asia. We investigated seasonal and spatial variations in primary productivity (PP) and community structures of phytoplankton on a downstream macrotidal flat and examined the dam discharge effects. Our harmonic analysis of the PP revealed a clear seasonality with a unimodal peak in summer, possibly driven by high ammonium loading through internal recycling. External nitrate supply from the dam-water discharge promoted PP during July-August, generating conspicuous blooms near the discharging site. Phytoplankton community was characterized by a predominance of diatoms all year round and seasonal dominances from dinoflagellates, cryptophytes, and prasinophytes in spring to chlorophytes in summer, reflecting spatiotemporal patterns in ammonium and nitrate supply. Our findings provide new insights into the summer phytoplankton bloom linked to monsoonal rainfall in the shallow coastal seas along the Northeast Asian coast.


Assuntos
Diatomáceas , Água , Nitratos , Fitoplâncton/química , República da Coreia , Estações do Ano
4.
Chemosphere ; 307(Pt 2): 135829, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35948092

RESUMO

Coupling microalgae cultivation with wastewater treatment is a promising environmentally sustainable development strategy. However, toxics such as Bisphenol A (BPA) in wastewater damage microalgae cells and reduces bioresources production. Phytohormone regulation has the potential to solve this issue. However, phytohormone research is still in its infancy. In this work, 0.2 µM naphthyl acetic acid (NAA) significantly enhanced Chlorella vulgaris BPA detoxification by 127.3% and Chlorella biomass production by 46.4%. NAA helps Chlorella convert bisphenol A into small non-toxic intermediates by enhancing the expression of associated enzymes. Simultaneously, NAA promoted carbon fixation and photosynthetic metabolism. Activation of the mitogen-activated protein kinase (MAPK) pathway strengthened the downstream antioxidant system while improving photosynthesis and intracellular starch and lipid synthesis. Carbohydrates, pigment, and lipid production was significantly enhanced by 20.0%, 46.9%, and 21.8%, respectively. A new insight is provided into how phytohormones may increase microalgae in wastewater's bioresource transformation and toxicity resistance.


Assuntos
Chlorella vulgaris , Microalgas , Purificação da Água , Antioxidantes/metabolismo , Compostos Benzidrílicos , Biomassa , Carboidratos , Chlorella vulgaris/metabolismo , Lipídeos , Microalgas/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Ácidos Naftalenoacéticos/metabolismo , Fenóis , Reguladores de Crescimento de Plantas/metabolismo , Amido/metabolismo , Águas Residuárias
5.
Water Res ; 221: 118829, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35839592

RESUMO

Fungal bulking is caused by the evolution toward a fungi-dominant unbalanced sludge system, which is indeed the phenomenon of fungi competing against bacterial cells. We hypothesized that the cross-kingdom intercellular communication between fungi and bacteria was internal driving force that stimulated fungal bulking. In this study, we identified three signal molecules related to Penicillium fungi bulking under low-pH stress in an activated sludge reactor, which inspired us to propose a sludge bulking prevention strategy using the quorum quenching theory. When pH dropped from 7.0 to 4.5, the abundance of Penicillium increased from 12.5% to 44.8%. However, some functional bacterial genera, such as Nitrosomonas and Sphingopyxis, were washed out from the sludge. The production of quorum-sensing (QS) molecules N-Heptanoyl-L-homoserine lactone (C7-HSL), N-Dodecanoyl-L-homoserine lactone (C12-HSL), and N-Tetradecanoyl-L-homoserine lactone (C14-HSL) was regulated with sludge bulking; especially the response of the latter two was significantly negative to Penicillium blooming (P < 0.05). To test their roles, trace commercial C12-HSL and C14-HSL were added to Penicillium culture, successfully causing 8.3% and 30.2% inhibition of mycelial formation, respectively. They also contributed to the improvement of activated sludge settleability by 6.1% and 39.7%, respectively (represented by sludge volume index). The transcriptome technique further revealed the regulation of the expression of genes in |logFC| >1, involving signal transduction, mycelium synthesis, and metabolic pathways. Our study provided an innovative strategy for controlling fungal bulking from the perspective of microbial transboundary informatics.


Assuntos
Penicillium , Esgotos , Bactérias , Percepção de Quorum
6.
Environ Res ; 204(Pt A): 111823, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34400160

RESUMO

Fungal bulking is caused by fungi excessive growth and morphological changes, resulting from the evolution toward fungi dominant activated sludge. Communication across fungi and bacteria boundary that mediated by bacterial signal molecules (SMs) probably is the central induce caused fungal bulking occurrence. In this work, it intended to identify the bacterial SM that affected fungal bulking, and verified its roles in regulate the spore germination and hyphal growth. We found C12-HSL concentration decreased significantly from 12.36 to 3.38 ng/g-VSS (P < 0.05) when fungal sludge bulking happened, and filamentous Galactomyces's relatively abundant was correlatively enriched. To test the effects of this SM, trace commercial C12-HSL was added to pure cultured Galactomyces, in which spore germination rates decreased by 20 % and hyphal extension inhibited by 15 %. Ras1-cAMP-PKA and mitogen-activated protein kinase (MAPK) pathways of Galactomyces were responsible for signal C12-HSL transduction, which inhibited peroxisome biosynthesis, suppressed the biological activity of the actin cytoskeleton, and disrupted intercellular organelle transport. All these results showed C12-HSL was the functional SM that could suppress the development of fungal filamentous. This study provided a new insight into the sludge bulking mechanism from view of cross-kingdom communication.


Assuntos
Bactérias , Esgotos , 4-Butirolactona , Fungos , Transdução de Sinais
7.
Microorganisms ; 8(10)2020 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-32992637

RESUMO

Diffusible signal factor (DSF) is a type of cis unsaturated fatty acid, with a chemical structure of 11-methyl-2-dodecylene acid. DSF is widely conserved in a variety of Gram-negative bacterial pathogens and is involved in the regulation of pathogenic virulence. Quorum quenching (QQ) is a promising strategy for preventing and controlling quorum sensing (QS)-mediated bacterial infections by interfering with the QS system of pathogens. In this study, a novel DSF-degrading bacterium, Burkholderia anthina strain HN-8, was isolated and characterized for its degradation ability and potential biocontrol of black rot disease caused by Xanthomonas campestris pv. campestris (Xcc). The HN-8 strain exhibited superb DSF degradation activity and completely degraded 2 mM DSF within 48 h. In addition, we present the first evidence of bacterium having a metabolic pathway for the complete degradation and metabolism of DSF. Analysis of DSF metabolic products by gas chromatography-mass spectrometry led to the identification of dodecanal as the main intermediate product, revealing that DSF could be degraded via oxidation-reduction. Furthermore, application of strain HN-8 as a potent biocontrol agent was able to significantly reduce the severity of black rot disease in radishes and Chinese cabbage. Taken together, these results shed light on the QQ mechanisms of DSF, and they provide useful information showing the potential for the biocontrol of infectious diseases caused by DSF-dependent bacterial pathogens.

8.
Glob Chang Biol ; 24(11): 5426-5439, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30099832

RESUMO

Life history strategies such as multiyear life cycles, resting stages, and capital breeding allow species to inhabit regions with extreme and fluctuating environmental conditions. One example is the zooplankton species Calanus hyperboreus, whose life history is considered an adaptation to the short and unpredictable growth season in the central Arctic Ocean. This copepod is commonly described as a true Arctic endemic; however, by statistically analyzing compiled observational data, we show that abundances are relatively low and later stages and adults dominate in the central Arctic Ocean basins, indicating expatriation. Combining data analyses with individual-based modeling and energy requirement estimation, we further demonstrate that while C. hyperboreus can reach higher abundances in areas with greater food availability outside the central Arctic basins, the species' resilience to environmental fluctuations enables the life cycle to be completed in the central Arctic basins. Specifically, the energy level required to reach the first overwintering stage-a prerequisite for successful local production-is likely met in some-but not all-years. This fine balance between success and failure indicates that C. hyperboreus functions as a peripheral population in the central Arctic basins and its abundance will likely increase in areas with improved growth conditions in response to climate change. By illustrating a key Arctic species' resilience to extreme and fluctuating environmental conditions, the results of this study have implications for projections of future biogeography and food web dynamics in the Arctic Ocean, a region experiencing rapid warming and sea ice loss.


Assuntos
Distribuição Animal , Mudança Climática , Copépodes/fisiologia , Características de História de Vida , Animais , Regiões Árticas , Copépodes/crescimento & desenvolvimento , Cadeia Alimentar , Modelos Biológicos , Estações do Ano , Zooplâncton/crescimento & desenvolvimento , Zooplâncton/fisiologia
9.
J Environ Manage ; 212: 266-277, 2018 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-29448181

RESUMO

When beach water monitoring programs identify poor water quality, the causes are frequently unknown. We hypothesize that management policies play an important role in the frequency of fecal indicator bacteria (FIB) exceedances (enterococci and fecal coliform) at recreational beaches. To test this hypothesis we implemented an innovative approach utilizing large amounts of monitoring data (n > 150,000 measurements per FIB) to determine associations between the frequency of contaminant exceedances and beach management practices. The large FIB database was augmented with results from a survey designed to assess management policies for 316 beaches throughout the state of Florida. The FIB and survey data were analyzed using t-tests, ANOVA, factor analysis, and linear regression. Results show that beach geomorphology (beach type) was highly associated with exceedance of regulatory standards. Low enterococci exceedances were associated with open coast beaches (n = 211) that have sparse human densities, no homeless populations, low densities of dogs and birds, bird management policies, low densities of seaweed, beach renourishment, charge access fees, employ lifeguards, without nearby marinas, and those that manage storm water. Factor analysis and a linear regression confirmed beach type as the predominant factor with secondary influences from grooming activities (including seaweed densities and beach renourishment) and beach access (including charging fees, employing lifeguards, and without nearby marinas). Our results were observable primarily because of the very large public FIB database available for analyses; similar approaches can be adopted at other beaches. The findings of this research have important policy implications because the selected beach management practices that were associated with low levels of FIB can be implemented in other parts of the US and around the world to improve recreational beach water quality.


Assuntos
Praias , Recreação , Qualidade da Água , Monitoramento Ambiental , Fezes , Florida , Humanos , Microbiologia da Água
10.
Glob Chang Biol ; 24(1): e159-e170, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28869698

RESUMO

Dramatic changes have occurred in the Arctic Ocean over the past few decades, especially in terms of sea ice loss and ocean warming. Those environmental changes may modify the planktonic ecosystem with changes from lower to upper trophic levels. This study aimed to understand how the biogeographic distribution of a crucial endemic copepod species, Calanus glacialis, may respond to both abiotic (ocean temperature) and biotic (phytoplankton prey) drivers. A copepod individual-based model coupled to an ice-ocean-biogeochemical model was utilized to simulate temperature- and food-dependent life cycle development of C. glacialis annually from 1980 to 2014. Over the 35-year study period, the northern boundaries of modeled diapausing C. glacialis expanded poleward and the annual success rates of C. glacialis individuals attaining diapause in a circumpolar transition zone increased substantially. Those patterns could be explained by a lengthening growth season (during which time food is ample) and shortening critical development time (the period from the first feeding stage N3 to the diapausing stage C4). The biogeographic changes were further linked to large-scale oceanic processes, particularly diminishing sea ice cover, upper ocean warming, and increasing and prolonging food availability, which could have potential consequences to the entire Arctic shelf/slope marine ecosystems.


Assuntos
Copépodes/fisiologia , Ecossistema , Oceanos e Mares , Animais , Regiões Árticas , Mudança Climática , Camada de Gelo , Fitoplâncton , Estações do Ano , Temperatura
11.
Mar Pollut Bull ; 121(1-2): 160-167, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28595980

RESUMO

Large databases of fecal indicator bacteria (FIB) measurements are available for coastal waters. With the assistance of satellite imagery, we illustrated the power of assessing data for many sites by evaluating beach features such as geomorphology, distance from rivers and canals, presence of piers and causeways, and degree of urbanization coupled with the enterococci FIB database for the state of Florida. We found that beach geomorphology was the primary characteristic associated with enterococci levels that exceeded regulatory guidelines. Beaches in close proximity to marshes or within bays had higher enterococci exceedances in comparison to open coast beaches. For open coast beaches, greater enterococci exceedances were associated with nearby rivers and higher levels of urbanization. Piers and causeways had a minimal contribution, as their effect was often overwhelmed by beach geomorphology. Results can be used to understand the potential causes of elevated enterococci levels and to promote public health.


Assuntos
Praias , Enterococcus , Microbiologia da Água , Bactérias , Monitoramento Ambiental , Fezes , Florida
12.
Mar Pollut Bull ; 104(1-2): 54-60, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26892203

RESUMO

Many recreational beaches suffer from elevated levels of microorganisms, resulting in beach advisories and closures due to lack of compliance with Environmental Protection Agency guidelines. We conducted the first statewide beach water quality assessment by analyzing decadal records of fecal indicator bacteria (enterococci and fecal coliform) levels at 262 Florida beaches. The objectives were to depict synoptic patterns of beach water quality exceedance along the entire Florida shoreline and to evaluate their relationships with wave condition and geographic location. Percent exceedances based on enterococci and fecal coliform were negatively correlated with both long-term mean wave energy and beach slope. Also, Gulf of Mexico beaches exceeded the thresholds significantly more than Atlantic Ocean ones, perhaps partially due to the lower wave energy. A possible linkage between wave energy level and water quality is beach sand, a pervasive nonpoint source that tends to harbor more bacteria in the low-wave-energy environment.


Assuntos
Praias , Água do Mar/microbiologia , Microbiologia da Água , Qualidade da Água/normas , Oceano Atlântico , Bactérias , Enterococcus , Fezes/microbiologia , Florida , México , Recreação , Estados Unidos
13.
Zhonghua Jie He He Hu Xi Za Zhi ; 39(1): 41-6, 2016 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-26792055

RESUMO

OBJECTIVE: To investigate the clinical use of Macao predictive values of impulse oscillometry(IOS) for chronic obstructive pulmonary disease (COPD) in patients aged over 45 years. METHODS: We measured lung impedance with IOS and spirometry in healthy subjects (n=168) and patients with COPD (n=281) aging over 45 years. The spirometric parameters were compared with those of IOS calculated by Macao predictive equations with Lechtenboerger equations. RESULTS: Respiratory impedance (Zrs), respiratory resistance at 5 Hz (R5), R5-R20 in female COPD group were (0.72±0.28), (0.63±0.23)and(0.23±0.16) kPa·L(-1)·s(-1), respectively, and Fres was (22±7)Hz; while in male group, the value of each parameters was (0.56±0.21), (0.50±0.17) and(0.18±0.12) kPa·L(-1)·s(-1), Fres was(21±7)Hz, which were all greater than that of the healthy group(t value was 5.05, 4.30, 5.10, 6.05 and 8.27, 6.62, 12.68, 14.59, respectively; P value were all<0.01). Reactance at 5 Hz(X5) in the COPD group[(-0.30±0.21) kPa·L(-1)·s(-1) in female, (-0.26±0.16) kPa·L(-1)·s(-1) in male] was significantly lower than that in the healthy group[female group: X5=(-0.16±0.06) kPa·L(-1)·s(-1,) t value was -5.38; male group: X5=(-0.10±0.05) kPa·L(-1)·s(-1,) t value was -11.96, P value were all<0.01]. Zrs, R5, R5-R20 and Fres were negatively correlated with parameters (FEV1/FVC, FEV1%Pre) of spirometry, while X5 was positively correlated with them. Compared with the ROC areas under the curve(AUC), the AUC of Zrs(A/P2) (0.786 in female, 0.773 in male) was same as that of Zrs(A)(0.744 in female, 0.764 in male; χ(2) value was 4.96, 0.89, respectively, P value were all >0.05), the AUC of R5(A/P2)(0.754 in female, 0.741 in male) was larger than that of R5(A/P1) (both were 0.716; χ(2) value was 4.24, 6.38, respectively, P value were all <0.05). The AUC of X5(P2-A) was larger than that of X5(P1-A) in the male group, and it was same as in the female group. The first two AUC of IOS parameters were Fres and R5-R20. In the 2 groups, when Zrs (A/P2)% was larger than 130, R5(A/P2)% was larger than 130, X5(P2-A)was larger than 0.1, Fres was larger than 15 in male, 20 in female, their each Youden's index was 0.463, 0.398, 0.662 and 0.594, each accuracy was 84%, 71%, 81% and 82%, which were all greater than that of Lechtenboerger equations(66%, 63%, 80% and 50%). CONCLUSION: There are good correlations between spirometry and respiratory impendance measured by IOS in the diagnosis of COPD. The Macao predictive equations have higher sensitivity and specificity for diagnosing COPD.


Assuntos
Oscilometria , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Feminino , Volume Expiratório Forçado , Humanos , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Sensibilidade e Especificidade , Espirometria
14.
Mar Pollut Bull ; 94(1-2): 37-47, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25840869

RESUMO

Human health protection at recreational beaches requires accurate and timely information on microbiological conditions to issue advisories. The objective of this study was to develop a new numerical mass balance model for enterococci levels on nonpoint source beaches. The significant advantage of this model is its easy implementation, and it provides a detailed description of the cross-shore distribution of enterococci that is useful for beach management purposes. The performance of the balance model was evaluated by comparing predicted exceedances of a beach advisory threshold value to field data, and to a traditional regression model. Both the balance model and regression equation predicted approximately 70% the advisories correctly at the knee depth and over 90% at the waist depth. The balance model has the advantage over the regression equation in its ability to simulate spatiotemporal variations of microbial levels, and it is recommended for making more informed management decisions.


Assuntos
Praias/estatística & dados numéricos , Monitoramento Ambiental , Modelos Teóricos , Água do Mar/microbiologia , Microbiologia da Água , Enterococcus/crescimento & desenvolvimento , Meio Ambiente , Sedimentos Geológicos/microbiologia , Recreação
15.
Mar Pollut Bull ; 79(1-2): 114-22, 2014 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-24393380

RESUMO

Beach sands can sustain indigenous and introduced populations of enterococci. The objective of this study was to evaluate wave action in promoting the release of introduced bacteria. To accomplish this objective this study developed a method to assess attachment and identified conditions under which introduced bacteria are integrated into the sand. A new "shearing assay" showed that attachment of the introduced spike mimicked that of the natural sand when the spike was allowed to integrate into the sand for 24h at room temperature at a sand moisture content of 20%. Experiments in a wave flume showed that waves were capable of releasing about 60% of the total bacteria added. This suggests that for the range of wave conditions evaluated (height: 1.9-10.5 cm, period:1-2.7s), waves were incapable of releasing all of the bacteria. Further study is needed to evaluate bacteria attachment mechanisms.


Assuntos
Praias/estatística & dados numéricos , Enterococcus/crescimento & desenvolvimento , Monitoramento Ambiental , Sedimentos Geológicos/microbiologia , Ondas de Maré , Microbiologia da Água , Bactérias/crescimento & desenvolvimento , Enterococcus/classificação
16.
Water Res ; 48: 579-91, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24183401

RESUMO

Recolonization of enterococci, at a non-point source beach known to contain high background levels of bacteria, was studied after a full-scale beach renovation project. The renovation involved importation of new exogenous sand, in addition to infrastructure improvements. The study's objectives were to document changes in sand and water quality and to evaluate the relative contribution of different renovation activities towards these changes. These objectives were addressed: by measuring enterococci levels in the sand and fecal indicator bacteria levels (enterococci and fecal coliform) in the water, by documenting sediment characteristics (mineralogy and biofilm levels), and by estimating changes in observable enterococci loads. Analysis of enterococci levels on surface sand and within sediment depth cores were significantly higher prior to beach renovation (6.3-72 CFU/g for each sampling day) when compared to levels during and after beach renovation (0.8-12 CFU/g) (P < 0.01). During the renovation process, sand enterococci levels were frequently below detection limits (<0.1 CFU/g). For water, exceedances in the regulatory thresholds that would trigger a beach advisory decreased by 40% for enterococci and by 90% for fecal coliform. Factors that did not change significantly between pre- and post- renovation included the enterococci loads from animals (approx. 3 × 10(11) CFU per month). Factors that were observed to change between pre- and post- renovation activities included: the composition of the beach sand (64% versus 98% quartz, and a significant decrease in biofilm levels) and loads from direct stormwater inputs (reduction of 3 × 10(11) CFU per month). Overall, this study supports that beach renovation activities contributed to improved sand and water quality resulting in a 50% decrease of observable enterococci loads due to upgrades to the stormwater infrastructure. Of interest was that the change in the sand mineralogy also coincided with changes in biofilm levels. More work is needed to evaluate the relationships between beach sand mineralogy, biofilm characteristics, and the retention of fecal indicator bacteria in sand.


Assuntos
Contagem de Colônia Microbiana , Enterococcus/isolamento & purificação , Fezes/microbiologia , Microbiologia da Água , Biofilmes
17.
Water Res ; 46(7): 2237-46, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22365370

RESUMO

Fecal indicator microbes, such as enterococci, are often used to assess potential health risks caused by pathogens at recreational beaches. Microbe levels often vary based on collection time and sampling location. The primary goal of this study was to assess how spatial and temporal variations in sample collection, which are driven by environmental parameters, impact enterococci measurements and beach management decisions. A secondary goal was to assess whether enterococci levels can be predictive of the presence of Staphylococcus aureus, a skin pathogen. Over a ten-day period, hydrometeorologic data, hydrodynamic data, bather densities, enterococci levels, and S. aureus levels including methicillin-resistant S. aureus (MRSA) were measured in both water and sand. Samples were collected hourly for both water and sediment at knee-depth, and every 6 h for water at waist-depth, supratidal sand, intertidal sand, and waterline sand. Results showed that solar radiation, tides, and rainfall events were major environmental factors that impacted enterococci levels. S. aureus levels were associated with bathing load, but did not correlate with enterococci levels or any other measured parameters. The results imply that frequencies of advisories depend heavily upon sample collection policies due to spatial and temporal variation of enterococci levels in response to environmental parameters. Thus, sampling at different times of the day and at different depths can significantly impact beach management decisions. Additionally, the lack of correlation between S. aureus and enterococci suggests that use of fecal indicators may not accurately assess risk for some pathogens.


Assuntos
Praias/normas , Enterococcus , Sedimentos Geológicos/microbiologia , Prática de Saúde Pública/normas , Água do Mar/microbiologia , Staphylococcus aureus/isolamento & purificação , Densidade Demográfica , Chuva , Especificidade da Espécie , Fatores de Tempo , Movimentos da Água
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