RESUMO
INTRODUCTION: Metabolic syndrome (MetS) is one of the most important emerging pandemics of the 21st century and is associated with renal dysfunction in a significant number of subjects, the association of which is shown to be of greater significance in the South Asian population. AIMS AND OBJECTIVES: The prevalence of renal dysfunction in patients with MetS is the primary outcome. The secondary outcome is to assess the strength and significance of the association between the individual components of MetS and the presence of renal dysfunction. MATERIALS AND METHODS: This is a hospital-based cross-sectional observational study conducted for 2 years in a tertiary care hospital in India. A total of 100 diagnosed subjects of MetS were taken as cases and underwent relevant blood tests. Data were collected and analyzed in a Statistical Package for the Social Sciences (SPSS) v29 sheet. RESULTS: Over a period of 18 months, 100 subjects with MetS were documented, among which 66% had albuminuria, with microalbuminuria being 24% and the rest being macroalbuminuria. Among the same subjects, 30% had an estimated glomerular filtration rate (eGFR) <60 mL/minute/1.73m2. Waist circumference (WC) [measured by the National Institutes of Health (NIH) protocol] had the strongest association with increased albuminuria (r = 0.540; p-value < 0.001) as well as reduced eGFR (r = 0.460; p-value < 0.001). CONCLUSION: All the components of MetS, for example, increased WC, hypertension, increased fasting glucose, raised triglyceride (TG), and low high-density lipoprotein (HDL), have statistically significant correlations with increased urine albumin-to-creatinine ratio (ACR) and decreased eGFR, signifying glomerular injury and renal dysfunction, respectively.
Assuntos
Taxa de Filtração Glomerular , Síndrome Metabólica , Humanos , Síndrome Metabólica/epidemiologia , Síndrome Metabólica/fisiopatologia , Síndrome Metabólica/diagnóstico , Estudos Transversais , Feminino , Prevalência , Masculino , Pessoa de Meia-Idade , Índia/epidemiologia , Adulto , Albuminúria/epidemiologia , Circunferência da CinturaRESUMO
Biopolymers are an attractive environmentally friendly alternative to common synthetic polymers, whereas primarily proteins and polysaccharides are the biomacromolecules that are used for making the biopolymer. Due to the breadth of side chains of such biomacromolecules capable of participating in hydrogen bonding, proteins and polysaccharide biopolymers were also used for the making of proton-conductive biopolymers. Here, we introduce a new platform for combining the merits of both proteins and polysaccharides while using a glycosylated protein for making the biopolymer. We use mucin as our starting point, whereas being a waste of the food industry, it is a highly available and low-cost glycoprotein. We show how we can use different chemical strategies to target either the glycan part or specific amino acids for both crosslinking between the different glycoproteins, thus making a free-standing biopolymer, as well as for introducing superior proton conductivity properties to the formed biopolymer. The resultant proton-conductive soft biopolymer is an appealing candidate for any soft bioelectronic application.
Assuntos
Polissacarídeos , Prótons , Biopolímeros/química , Polissacarídeos/química , Polímeros , Proteínas , MucinasRESUMO
Microplastic (MP) pollution-an emerging environmental challenge of the 21st century-refers to accumulation of environmentally weathered polymer-based particles with potential environmental and health risks. Because of technical and practical challenges when using environmental MPs for risk assessment, most available data are generated using plastic models of limited environmental relevancy (i.e., with physicochemical characteristics inherently different from those of environmental MPs). In this study, we assess the effect of dominant weathering conditions-including thermal, photo-, and mechanical degradation-on surface and bulk characteristics of polystyrene (PS)-based single-use products. Further, we augment the environmental relevance of model-enabled risk assessment through the design of engineered MPs. A set of optimized laboratory-based weathering conditions demonstrated a synergetic effect on the PS-based plastic, which was fragmented into millions of 1-3 µm MP particles in under 16 h. The physicochemical properties of these engineered MPs were compared to those of their environmental counterpart and PS microbeads often used as MP models. The engineered MPs exhibit high environmental relevance with rough and oxidized surfaces and a heterogeneous fragmented morphology. Our results suggest that this top-down synthesis protocol combining major weathering mechanisms can fabricate improved, realistic, and reproducible PS-based plastic models with high levels of control over the particles' properties. Through increased environmental relevancy, our plastic model bolsters the field of risk assessment, enabling more reliable estimations of risk associated with an emerging pollutant of global concern.
Assuntos
Microplásticos , Poluentes Químicos da Água , Monitoramento Ambiental , Poluição Ambiental , Plásticos , Poliestirenos , Poluentes Químicos da Água/análiseRESUMO
Pseudomonas aeruginosa is a potent biofilm forming organism causing several diseases on host involving biofilm. Several natural and synthetic molecules have been explored towards inhibiting the biofilm formation of Pseudomonas aeruginosa. In the current report, the role of a natural molecule namely caffeine was examined against the biofilm forming ability of P. aeruginosa. We have observed that caffeine shows substantial antimicrobial activity against P. aeruginosa wherein the minimum inhibitory concentration (MIC) of caffeine was found to be 200 µg/mL. The antibiofilm activity of caffeine was determined by performing a series of experiments using its sub-MIC concentrations (40 and 80 µg/mL). The results revealed that caffeine can significantly inhibit the biofilm development of P. aeruginosa. Caffeine has been found to interfere with the quorum sensing of P. aeruginosa by targeting the swarming motility. Molecular docking analysis further indicated that caffeine can interact with the quorum sensing proteins namely LasR and LasI. Thus, the result indicated that caffeine could inhibit the formation of biofilm by interfering with the quorum sensing of the organism. Apart from biofilm inhibition, caffeine has also been found to reduce the secretion of virulence factors from Pseudomonas aeruginosa. Taken together, the results revealed that in addition to biofilm inhibition, caffeine can also decrease the spreading of virulence factors from Pseudomonas aeruginosa.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Cafeína/farmacologia , Pseudomonas aeruginosa/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Percepção de Quorum/efeitos dos fármacos , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Precious metals such as palladium (Pd) and platinum (Pt) are marvelous materials in the fields of electronic and catalysis, but they are tapering day by day. Zr(IV)-based metal-organic frameworks (MOFs) are competent for their recovery, notably in harsh environments, while the general powder form limits their practical application. Porous MOF-based membranes with ultraefficient metal ion permeation, strong stability, and high selectivity are, therefore, strikingly preferred. Herein, a set of polymeric fibrous membranes incorporated with the UiO-66 series are fabricated; their adsorption/desorption capabilities toward Pd(II) and Pt(IV) are evaluated from strongly acidic solutions; and the MOF-polymer compatibilities are investigated. Polyurethane (PU)/UiO-66-NH2 showed strong acid resistance and high chemical stability, which are attributable to strong π-π interactions between PU and MOF nanoparticles with a high configuration of energy. The as-fabricated MOF membranes show extremely good adsorption/desorption performances without ruptures/coalitions of nanofibers or leak of MOF nanoparticles, and successfully display the efficacy in a gravity-driven or even continuous-flow system with good recycle performance and selectivity. The as-fabricated MOF membranes set an example of potential MOF-polymer compatibility for practical applications.
RESUMO
Iron is an important element for growth and metabolism of all marine organisms, including bacteria. Most (99.9%) of iron in oceans are bound to organic ligands like siderophores and siderophore-like compounds. Distribution of bioavailable iron mainly depends on pH and temperature of the ocean. Due to global warming and ocean acidification, bioavailability of iron may alter and in turn effect the response of marine bacteria. In this study, we investigated the effect of growth conditions like pH, temperature, and iron (III) concentrations on growth and siderophore production in selected heterotrophic bacteria isolated from waters around Kerguelen Islands (KW) and Prydz Bay (PB). Microcosm experiments were carried out on two KW-isolates (Enterococcus casseliflavus and Psychrobacter piscatorii) and five PB-isolates (Pseudoalteromonas tetraodonis, Bacillus cereus, Psychrobacter pocilloporae, Micrococcus aloeverae, and Pseudomonas weihenstephanensis) which produced either hydroxamate-type or catecholate-type siderophores. Increasing iron concentrations (10 nM to 50 µM) increased the growth rate of all isolates while siderophore production (% siderophore) generally reduced at higher iron concentration. Siderophore production peaked at early log phase, probably in response to higher iron-demand. Temperature and pH experiments showed that most isolates produced more siderophore at 15 and 25 °C temperature and pH 8.5. These results reveal that in future ocean conditions (warmer and acidified waters), bacterial growth and siderophore production may get affected and thereby influencing iron uptake and associated biogeochemical processes.
Assuntos
Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Água do Mar/química , Água do Mar/microbiologia , Sideróforos/biossíntese , Microbiologia da Água , Bactérias/classificação , Disponibilidade Biológica , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Oceano Índico , Ferro/química , Ferro/metabolismo , Filogenia , RNA Ribossômico 16S/genética , Sideróforos/química , TemperaturaRESUMO
Intestinal malrotation and duplication of the inferior vena cava are rarely diagnosed in adult patients; however, incidence is likely underestimated as they are usually asymptomatic. These congenital malformations have been previously reported in the same patient twice but never with colonic obstruction or ischaemia. A 25-year-old female presented with nausea, vomiting, obstipation, and abdominal pain, and on computed tomography of the abdomen and pelvis was diagnosed with a caecal volvulus and pneumatosis coli associated with intestinal malrotation requiring emergency right hemicolectomy. Incidentally, the patient was noted to have duplication of the inferior vena cava, azygos continuation of the inferior vena cava, and splenic fragmentation. This constellation of symptoms has not been reported in the literature previously. The pattern of malformations follows that of polysplenia syndrome. Although rare, awareness of these malformations can be useful to clinicians.
RESUMO
Sedimentary processes are expected to play a crucial role in macronutrient cycling of the shallow Arabian Gulf. To investigate this aspect, sediment cores were collected from the shallow intertidal and subtidal expanses of the first Marine Protected Area (MPA) of Kuwait in the Northwestern Arabian Gulf (NAG). Porewater nutrient profiling and whole core incubation experiments were conducted to measure the nutrient fluxes, both with and without the addition of the nitrification inhibitor allylthiourea (ATU). The porewater data confirmed the potential of sediments to host multiple aerobic and anaerobic pathways of nutrient regeneration. The average (±SD) of net nutrient fluxes from several incubation experiments indicated that ammonium (NH4+) predominantly fluxed out of the sediment (3.81 ± 2.53 mmol m-2 d-1), followed by SiO44- (3.07 ± 1.21 mmol m-2 d-1). In contrast, the average PO43- flux was minimal, at only 0.06 ± 0.05 mmol m-2 d-1. Fluxes of NO3- (ranged from 0.07 ± 0.005 to 1.16 ± 0.35 mmol m-2 d-1) and NO2- (0.03 ± 0.003 to 0.71 ± 0.21 mmol m-2 d-1) were moderate, which either reduced or reversed in the presence of ATU (-0.001 ± 0.0001 to 0.01 ± 0.0001 mmol m-2 d-1 and -0.001 ± 0.0003 to 0.006 ± 0.001 mmol m-2 d-1 for NO3- and NO2- respectively). Thus, this study provides preliminary experimental evidence that nitrification can act as a source of NO3- and NO2- as well as contribute towards the relatively high concentrations of NO2- (>1 in the gulf waters.
Assuntos
Poluentes Químicos da Água , Água , Sedimentos Geológicos , Dióxido de Nitrogênio , Poluentes Químicos da Água/análise , Nutrientes , Nitrogênio/análiseRESUMO
Aeolian dust is an essential source of growth-limiting nutrients for marine phytoplankton. Despite being at the core of the Global Dust Belt, the response of the Arabian Gulf ecosystem to such atmospheric forcing is rarely documented. Here, the hydro-biological effect of mineral dust was studied in the northern Arabian Gulf (NAG) off Kuwait through monthly water sampling (December 2020 to December 2021), dust-storm follow-up sampling, and mineral dust and nutrient addition in-situ experiments. The multivariate analysis of oceanographic data revealed pronounced hydro-biological seasonality. The mineral dust deposition during two severe dust storm events in March and June 2021 showed a spatially varying effect of dust on coastal waters. The dust storms elevated the surface dissolved iron levels by several magnitudes, increased the dissolved inorganic nitrogen and phosphorous levels, changed their stoichiometry, and offset the hydrobiological seasonality. In the microcosms, dust input temporarily reduced phytoplankton phosphorous limitation in a dose-dependent manner when mesozooplankton (copepods) grazing was minimal. The microphytoplankton response to mineral dust inputs was comparable to that with nitrogen and phosphorous treatment. While Both treatments increased diatom size structure and biomass, the abundance of single-celled diatoms was comparatively higher in dust treatment. Multivariate analysis indicated that dust deposition alters the hydrographical properties of the surface ocean during dust storm events. The effects, though transient, were traceable for 3-16 days post-storm in coastal waters. The response of the summer phytoplankton to these changes, if delayed or muted, should be interpreted with caution given the summer water column stratification, the high nitrogen: phosphorous ratio and the low phosphorous solubility of aerosol dust, and the complex pelagic microbial food web interactions in the NAG. This study thus underlines the importance of a multivariate approach in documenting the ecological implications of Aeolian dust storms on marine environments closer to the dust source regions.
Assuntos
Diatomáceas , Fitoplâncton , Fitoplâncton/fisiologia , Ecossistema , Poeira/análise , Diatomáceas/fisiologia , Fósforo , Água , Minerais , Nitrogênio/análise , Água do Mar/químicaRESUMO
BACKGROUND: Leptospires lack many of the homologs for oxidative defense present in other bacteria, but do encode homologs of the Bacteriodes aerotolerance (Bat) proteins, which have been proposed to fulfill this function. Bat homologs have been identified in all families of the phylum Spirochaetes, yet a specific function for these proteins has not been experimentally demonstrated. RESULTS: We investigated the contribution of the Bat proteins in the model organism Leptospira biflexa for their potential contributions to growth rate, morphology and protection against oxidative challenges. A genetically engineered mutant strain in which all bat ORFs were deleted did not exhibit altered growth rate or morphology, relative to the wild-type strain. Nor could we demonstrate a protective role for the Bat proteins in coping with various oxidative stresses. Further, pre-exposing L. biflexa to sublethal levels of reactive oxygen species did not appear to induce a general oxidative stress response, in contrast to what has been shown in other bacterial species. Differential proteomic analysis of the wild-type and mutant strains detected changes in the abundance of a single protein only - HtpG, which is encoded by the gene immediately downstream of the bat loci. CONCLUSION: The data presented here do not support a protective role for the Leptospira Bat proteins in directly coping with oxidative stress as previously proposed. L. biflexa is relatively sensitive to reactive oxygen species such as superoxide and H2O2, suggesting that this spirochete lacks a strong, protective defense against oxidative damage despite being a strict aerobe.
Assuntos
Proteínas de Bactérias/metabolismo , Leptospira/fisiologia , Estresse Oxidativo , Estresse Fisiológico , Proteínas de Bactérias/genética , Deleção de Genes , Leptospira/genética , Leptospira/metabolismo , Proteoma/análiseRESUMO
A series of flash floods that swamped urban drainage systems in Kuwait in November-December 2018 drastically altered coastal hydrography. The phytoplankton responded quickly to the nutrient supply from land and reduced salinity despite elevated turbidity, as evident from rapid increases in chlorophyll a and net community production. Microphytoplankton was dominated by diatoms and the photosynthetic ciliate Myrionecta rubra. Both field observations and microcosm experiments suggested that although increased nutrient availability stimulates diatom growth, microzooplankton grazing controls their outbursts. This study revealed that in a hypersaline system similar to the northern Arabian Gulf, extreme events like flash floods have immediate but short-lived corollaries on coastal phytoplankton due to synergistic effects of bottom-up and top-down factors. The patterns are comparable to those reported from other tropical and sub-tropical systems.
Assuntos
Diatomáceas , Água do Mar , Clorofila A , Monitoramento Ambiental , Inundações , Fitoplâncton , Estações do AnoRESUMO
Persistent infection of a mammalian host by Borrelia burgdorferi, the spirochete that causes Lyme disease, requires specific downregulation of an immunogenic outer surface protein, OspC. Although OspC is an essential virulence factor needed by the spirochete to establish infection in the mammal, it represents a potent target for the host acquired immune response, and constitutive expression of OspC results in spirochete clearance. In this study, we demonstrate that a factor encoded on a linear plasmid of B. burgdorferi, lp17, can negatively regulate ospC transcription from the endogenous gene on the circular plasmid cp26 and from an ospC promoter-lacZ fusion on a shuttle vector. Furthermore, we have identified bbd18 as the gene on lp17 that is responsible for this effect. These data identify a novel component of ospC regulation and provide the basis for determining the molecular mechanisms of ospC repression in vivo.
Assuntos
Antígenos de Bactérias/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/metabolismo , Borrelia burgdorferi/metabolismo , Plasmídeos/genética , Antígenos de Bactérias/genética , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/genética , Borrelia burgdorferi/genética , Eletroforese em Gel de Poliacrilamida , Vetores Genéticos/genética , Immunoblotting , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
The conversion of nicotinamide to nicotinic acid by nicotinamidase enzymes is a critical step in maintaining NAD(+) homeostasis and contributes to numerous important biological processes in diverse organisms. In Borrelia burgdorferi, the nicotinamidase enzyme, PncA, is required for spirochaete survival throughout the infectious cycle. Mammals lack nicotinamidases and therefore PncA may serve as a therapeutic target for Lyme disease. Contrary to the in vivo importance of PncA, the current annotation for the pncA ORF suggests that the encoded protein may be inactive due to the absence of an N-terminal aspartic acid residue that is a conserved member of the catalytic triad of characterized PncA proteins. Herein, we have used genetic and biochemical strategies to determine the N-terminal sequence of B. burgdorferi PncA. Our data demonstrate that the PncA protein is 24 aa longer than the currently annotated sequence and that pncA translation is initiated from the rare, non-canonical initiation codon AUU. These findings are an important first step in understanding the catalytic function of this in vivo-essential protein.
Assuntos
Proteínas de Bactérias/genética , Borrelia burgdorferi/enzimologia , Doença de Lyme/microbiologia , Nicotinamidase/genética , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Sequência de Bases , Borrelia burgdorferi/química , Borrelia burgdorferi/genética , Códon , Feminino , Regulação Enzimológica da Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos C3H , Dados de Sequência Molecular , NAD/metabolismo , Nicotinamidase/química , Nicotinamidase/metabolismo , Iniciação Traducional da Cadeia Peptídica , Estrutura Terciária de Proteína , Alinhamento de SequênciaRESUMO
The rise of microplastic (MP) pollution in the environment has been bolstering concerns regarding MPs' unknown environmental fate, transport, and potential toxicity toward living forms. However, the use of real environmental plastics for risk assessment is often hindered due to technical and practical challenges such as plastics' heterogeneity and their wide size distribution in the environment. To overcome this issue, most available data in the field is generated using plastic models as surrogates for environmental samples. In this critical review, we describe the gaps in risk assessments drawn from these plastic models. Specifically, we compare physicochemical properties of real environmental plastic particles to synthesized polymeric micro-beads, one of the most commonly used plastic models in current literature. Several surface and bulk characteristics including size, surface chemistry, polymer type, and morphology are shown to not only be inherently different between environmental MP's and synthesized micro-beads, but also drive behavior in fate, transport, and toxicity assays. We highlight the importance of expressing real-world physicochemical characteristics in representative MP models and outline how current state-of-the-art models are limited in this regard. To address this issue, we suggest future areas of research such as combinations of mechanical, photochemical, and thermal degradation processes to simulate real-world weathering, all in an effort to increase realism of plastic modeling and allow more robust and reliable environmental MP risk assessment in the future.
RESUMO
BACKGROUND: Higher Peritoneal Cancer Index (PCI) requires more extensive surgery and maybe associated with more limited outcomes. The aim of this study in a high-volume centre in Australia was to analyse the outcomes in PCI 39 patients regarding short and long term outcomes in appendiceal tumours. METHODS: A retrospective analysis of prospectively maintained database of patients that underwent primary cytoreductive surgery (CRS) + hyperthermic intraperitoneal chemotherapy (HIPEC) with PCI 39 at St George Hospital, Sydney from 1996 to 2018. Patients with appendiceal tumours (inclusive of high and low grade) were analysed. Factors contributing to high grade (III/IV Clavien-Dindo) morbidity and mortality were assessed. RESULTS: Of the 1201 patients in the database, 58 patients had a PCI 39 from appendix tumours at their first operation. The overall survival rate at 1, 3 and 5 year was 91.2%, 79.5% and 62.9% respectively. The median survival was 87.2 months (96% CI 51.8-NR). The rate of major morbidity was 71%. The postoperative mortality incidence was 1.7%. The median hospital length of stay was 34 days (IQR:27-54 days). CONCLUSIONS: In an experienced centre CRS + HIPEC is safe in selected patients with PCI 39. Despite the high morbidity, the overall survival for appendiceal tumours appear considerably better than debulking surgery.
Assuntos
Neoplasias do Apêndice/patologia , Procedimentos Cirúrgicos de Citorredução , Quimioterapia Intraperitoneal Hipertérmica , Neoplasias Peritoneais/patologia , Neoplasias Peritoneais/terapia , Idoso , Neoplasias do Apêndice/cirurgia , Procedimentos Cirúrgicos de Citorredução/efeitos adversos , Feminino , Humanos , Estimativa de Kaplan-Meier , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Neoplasia Residual , Neoplasias Peritoneais/secundário , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Índice de Gravidade de Doença , Taxa de Sobrevida , Carga TumoralRESUMO
Albeit, all forms of tuberculosis (TB) are endemic in India, spinal intramedullary TB and tubercular longitudinally extensive transverse myelitis (LETM) is deemed extremely rare. With recent advances in the field of neurology, autoimmune astrocytopathy (neuromyelitis optica spectrum disorders, NMOSD), myelin-oligodendrocyte glycoprotein associated encephalomyelitis (MOG-EM), metabolic myelopathy, connective tissue diseases and viral infections have gained considerable focus in the list of differentials of LETM whereas tubercular association is often forgotten. This report presents a rare case of acute transverse myelopathy which unveiled previously undiagnosed pulmonary tuberculosis in an adult rural Indian male. The patient responded well to anti-tubercular therapy and corticosteroids. Exact pathogenesis of LETM in TB remains elusive. Association of TB with MOG-EM has been one of the recent hot-cakes. However, an ill-defined immune-inflammatory response to the infectious agent is the likely cause of tubercular LETM. Hence, the primary care physicians who are the first medical contacts of acute LETM cases and in most cases due to diagnostic dilemma there is an unavoidable delay in accurate diagnosis and initiation of therapy. Primary care doctors should nurture a high index of suspicion to diagnose this potentially lifetime-debilitating yet absolutely treatable clinical condition i.e. tubercular LETM.
RESUMO
Borrelia burgdorferi, the causative agent of Lyme disease, has a complex genome consisting of a linear chromosome and up to 21 linear and circular plasmids. These plasmids encode numerous proteins critical to the spirochete's infectious cycle and many hypothetical proteins whose functions and requirements are unknown. The conserved linear plasmid lp54 encodes several proteins important for survival in the mouse-tick infectious cycle, but the majority of the proteins are of unknown function and lack homologs outside the borreliae. In this study we adapted the Cre-lox recombination system to create large deletions in the B. burgdorferi genome. Using Cre-lox, we systematically investigated the contribution of 14 adjacent genes on the left arm of lp54 to the overall infectivity of B. burgdorferi. The deletion of the region of lp54 encompassing bba07 to bba14 had no significant effect on the infectious cycle of B. burgdorferi. The deletion of bba01 to bba07 resulted in a slight growth defect but did not significantly affect the ability of B. burgdorferi to complete the infectious cycle. This study demonstrated the utility of the Cre-lox system to efficiently explore gene requirements in B. burgdorferi and surprisingly revealed that a large number of the highly conserved proteins encoded on lp54 are not required to complete the infectious cycle.
Assuntos
Proteínas de Bactérias/fisiologia , Borrelia burgdorferi/patogenicidade , Ixodes/microbiologia , Plasmídeos , Recombinação Genética , Fatores de Virulência/fisiologia , Animais , Proteínas de Bactérias/genética , Borrelia burgdorferi/genética , Feminino , Integrases/metabolismo , Camundongos , Deleção de Sequência , Fatores de Virulência/genéticaRESUMO
This study aimed to select a high-performance cation-exchange resin (CER) and estimate its uptake of positively ionized tricyclic antidepressants (TCAs), i.e., amitriptyline (AMI), imipramine (IMI), clomipramine (CLO), and desipramine (DES), which are frequently used, and detected in wastewater treatment systems. For the selection of the resin, the one-point check test of AMI in distilled water was examined using several CERs. As a result, the strong-acid polystyrene CER, Dowex 50WX4-200, was selected on the basis of its outstanding uptake of AMI. The maximum adsorption capacities of Dowex 50WX4-200 for removal of the TCAs ranged from 2.53 ± 0.20 mmol/g to 3.76 ± 0.12 mmol/g, which are significantly higher when compared with those of previously reported adsorbents. This is likely because the combination of electrostatic and π-π interactions between the TCAs and Dowex 50WX4-200 may lead to high uptakes of the TCAs. Additionally, the removal efficiency of DES as a representative of the TCAs was tested in actual wastewater system containing activated sludge and miscellaneous cations. Consequently, the removal efficiencies of the DES in distilled water, aerobic wastewater, and filtered wastewater were 95.68%, 77.99%, and 56.66%, respectively. It is interesting to note that the activated sludge could also contribute to adsorption of the DES, leading to increased removability, while the cations present in the wastewater acted as competing ions, decreasing the removal efficiency.
Assuntos
Amitriptilina , Antidepressivos Tricíclicos , Adsorção , Cátions , ImipraminaRESUMO
In this study, banana peel (BP) and its derivatives after sequential extraction of biochemical components were evaluated for selective recovery of gold. In-depth instrumental characterizations including XPS, FTIR, XRD and HR-TEM were performed to understand the adsorption mechanisms. The biomass after lipid extraction, BP-L, demonstrated very good affinity and selectivity towards gold. In multi-metal systems containing 100 mg/L of Pt(IV), Au(III), Pd(II), Zn(II), Co(II), Ni(II) and Li(I), the selectivity coefficient increased from 978.45 in BP to 2034.70 in BP-L. Moreover, the equilibrium gold uptake was improved and reached 475.48 ± 3.08 mg/g owing to reduction-coupled adsorption mechanisms. The BP-L also showed improved gold nanoparticle formation properties that were pH-dependent. In a strategic adsorption-combined incineration process, metallic gold reaching 99.96% in purity was obtained. The BP and its derivative, BP-L have thus shown potentials for multiple applications in the areas of precious metal recovery and nanoscience.
Assuntos
Nanopartículas Metálicas , Musa , Adsorção , Ouro , IncineraçãoRESUMO
Dyes are colored compounds which are visible even at trace concentrations. Due to their recalcitrance and esthetic persistence, certain methods are unable to effectively eliminate them. So far, adsorptive treatment using activated carbons (ACs) is one of the most successful methods. In this study, we have employed orange peel (OP) as a cost-effective alternative to the expensive coal- and coir-based precursors to synthesize ACs for cationic methylene blue (MB) and anionic methyl orange (MO) dye adsorption. The pre-carbonized OP was activated via H2SO4, NaOH, KOH, ZnCl2, and H3PO4 to study the effects of activation reagents on dye removal efficiencies and mechanisms. Among several isotherm models employed to fit the adsorption data, the Langmuir and Sips models sufficiently estimated the maximum equilibrium uptakes close to the experimental values of 1012.10 ± 29.13, 339.82 ± 6.98, and 382.15 ± 8.62 mg/g, for ZnCl2-AC (MO), ZnCl2-AC (MB), and KOH-AC (MB), respectively. The adsorption mechanisms were suggested to involve electrostatic binding, pi-pi interactions, hydrogen bonding, and electron donor-acceptor reactions. Consequently, more than 99% removal efficiency was achieved from a laboratory organic wastewater sample bearing ~ 35 mg/L of MB. The results thus suggest that the synthesized ACs from agricultural waste have the tendencies to be applied to real dye wastewater treatment.