RESUMO
The B.1.617.2 (Delta) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in the state of Maharashtra in late 2020 and spread throughout India, outcompeting pre-existing lineages including B.1.617.1 (Kappa) and B.1.1.7 (Alpha)1. In vitro, B.1.617.2 is sixfold less sensitive to serum neutralizing antibodies from recovered individuals, and eightfold less sensitive to vaccine-elicited antibodies, compared with wild-type Wuhan-1 bearing D614G. Serum neutralizing titres against B.1.617.2 were lower in ChAdOx1 vaccinees than in BNT162b2 vaccinees. B.1.617.2 spike pseudotyped viruses exhibited compromised sensitivity to monoclonal antibodies to the receptor-binding domain and the amino-terminal domain. B.1.617.2 demonstrated higher replication efficiency than B.1.1.7 in both airway organoid and human airway epithelial systems, associated with B.1.617.2 spike being in a predominantly cleaved state compared with B.1.1.7 spike. The B.1.617.2 spike protein was able to mediate highly efficient syncytium formation that was less sensitive to inhibition by neutralizing antibody, compared with that of wild-type spike. We also observed that B.1.617.2 had higher replication and spike-mediated entry than B.1.617.1, potentially explaining the B.1.617.2 dominance. In an analysis of more than 130 SARS-CoV-2-infected health care workers across three centres in India during a period of mixed lineage circulation, we observed reduced ChAdOx1 vaccine effectiveness against B.1.617.2 relative to non-B.1.617.2, with the caveat of possible residual confounding. Compromised vaccine efficacy against the highly fit and immune-evasive B.1.617.2 Delta variant warrants continued infection control measures in the post-vaccination era.
Assuntos
Evasão da Resposta Imune , SARS-CoV-2/crescimento & desenvolvimento , SARS-CoV-2/imunologia , Replicação Viral/imunologia , Anticorpos Neutralizantes/imunologia , Vacinas contra COVID-19/imunologia , Fusão Celular , Linhagem Celular , Feminino , Pessoal de Saúde , Humanos , Índia , Cinética , Masculino , Glicoproteína da Espícula de Coronavírus/metabolismo , VacinaçãoRESUMO
During mitosis and meiosis, kinetochore, a conserved multi-protein complex, connects microtubule with the centromere and promotes segregation of the chromosomes. In budding yeast, central kinetochore complex named Ctf19 has been implicated in various functions and is believed to be made up of three biochemically distinct subcomplexes: COMA, Ctf3 and Iml3-Chl4. In this study, we aimed to identify whether Ctf3 and COMA subcomplexes have any unshared function at the kinetochore. Our data suggests that both these subcomplexes may work as a single functional unit without any unique functions, which we tested. Analysis of severity of the defects in the mutants suggests that COMA is epistatic to Ctf3 subcomplex. Interestingly, we noticed that these subcomplexes affect the organization of mitotic and meiotic kinetochores with subtle differences and they promote maintenance of Cse4 at the centromeres specifically during meiosis which is similar to the role of Mis6 (Ctf3 homolog) in fission yeast during mitosis. Interestingly, analysis of ctf3Δ and ctf19Δ mutants revealed a novel role of Ctf19 complex in regulation of SPB cohesion and duplication in meiosis.
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Centrômero/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Cinetocoros/fisiologia , Meiose , Complexos Multiproteicos/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/fisiologia , Polos do Fuso/metabolismo , Cinetocoros/metabolismo , Meiose/genética , Complexos Multiproteicos/metabolismo , Organismos Geneticamente Modificados , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/genética , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismoRESUMO
Meiosis is a specialized cell division process through which chromosome numbers are reduced by half for the generation of gametes. Kinetochore, a multiprotein complex that connects centromeres to microtubules, plays essential role in chromosome segregation. Ctf19 is the key central kinetochore protein that recruits all the other non-essential proteins of the Ctf19 complex in budding yeast. Earlier studies have shown the role of Ctf19 complex in enrichment of cohesin around the centromeres both during mitosis and meiosis, leading to sister chromatid cohesion and meiosis II disjunction. Here we show that Ctf19 is also essential for the proper execution of the meiosis I specific unique events, such as non-homologous centromere coupling, homologue pairing, chiasmata resolution and proper orientation of homologues and sister chromatids with respect to the spindle poles. Additionally, this investigation reveals that proper kinetochore function is required for faithful chromosome condensation in meiosis. Finally, this study suggests that absence of Ctf19 affects the integrity of meiotic kinetochore differently than that of the mitotic kinetochore. Consequently, absence of Ctf19 leads to gross chromosome missegregation during meiosis as compared with mitosis. Hence, this study reports for the first time the differential impact of a non-essential kinetochore protein on the mitotic and meiotic kinetochore ensembles and hence chromosome segregation.
Assuntos
Proteínas do Citoesqueleto/metabolismo , Cinetocoros/metabolismo , Substâncias Macromoleculares/metabolismo , Meiose , Multimerização Proteica , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Segregação de Cromossomos , Proteínas do Citoesqueleto/genética , Deleção de Genes , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genéticaRESUMO
Obesity and type 2 diabetes are prevalent metabolic diseases that have significant links to several chronic diseases, including cancer, diabetes, hypertension, and cardiovascular disease. Muscadine grape extracts have shown the potential to reduce adiposity and improve insulin sensitivity and glucose control. Thus, this study was designed to determine the potential of muscadine grape berries extract (Pineapple and Southern Home) for its antiobesity properties in 3T3-L1 cells as a model for obesity research. The current study's data indicated the total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydraziyl (DPPH) activity were higher in cultivar (CV) Southern Home, meanwhile, elevated the total flavonoid content (TFC) in Pineapple. Both extracts were safe across the tested range (0-5 mg/mL). A noticeable reduction in lipid accumulation was also found in extract-treated cells. In preadipocytes and adipocytes, the tested extracts showed significant alterations in various genes involved in glucose homeostasis and obesity. The most remarkable findings of the current study are the upregulation of two genes, Cntfr (+712.715-fold) and Hrh1 (+270.11-fold) in CV Pineapple extract-treated adipocytes 3T3-L1 and the high fold increase in Ramp3 induced by both Pineapple and Southern Home in pre-adipose cells. Furthermore, the tested extracts showed a potential to alter the mRNA of various genes, including Zfp91, B2m, Nr3c1, Insr, Atrn, Il6ra, Hsp90ab1, Sort1, and Npy1r. In conclusion, the data generated from the current study suggested that the two extracts under investigation are considered potential candidates for controlling insulin levels and managing obesity.
Assuntos
Células 3T3-L1 , Adipócitos , Fármacos Antiobesidade , Obesidade , Extratos Vegetais , Vitis , Animais , Camundongos , Extratos Vegetais/farmacologia , Fármacos Antiobesidade/farmacologia , Obesidade/metabolismo , Obesidade/tratamento farmacológico , Obesidade/genética , Vitis/química , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Diferenciação Celular/efeitos dos fármacos , Frutas/químicaRESUMO
We report the genomic features of Bradyrhizobium sp. strain SRS-191, which was isolated from a former nuclear legacy site in Aiken, South Carolina, USA. With a genome size of 7,621,400 bp, the strain harbored genes not only for environmentally beneficial traits (e.g., heavy metal resistance, nitrogen fixation, and aromatic biodegradation) but also for antimicrobial resistance.
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The centromere is a genetic locus, required for faithful chromosome segregation, where spindle fibers attach to the chromosome through kinetochore. Loss of centromere or formation of multiple centromeres on a single chromosome leads to chromosome missegregation or chromosome breakage, respectively, which are detrimental for fitness and survival of a cell. Therefore, understanding the mechanism of centromere locus determination on the chromosome and perpetuation of such a locus in subsequent generation (known as centromere identity) is very fundamental to combat conditions like aneuploidy, spontaneous abortion, developmental defects, cell lethality and cancer. Recent studies have come up with different models to explain centromere identity. However, the exact mechanism still remains elusive. It has been observed that most eukaryotic centromeres are determined epigenetically rather than by a DNA sequence. The epigenetic marks that are instrumental in determining centromere identity are the histone H3 variant, CENP-A and the specialized posttranslational modification of the core histones. Here we will review the recent studies on the factors responsible for generating unique centromeric chromatin and how it perpetuates during cell division giving the present-day models. We will further focus on the probable mechanism of de novo centromere formation with an example of neocentromere. As a matter of similitude, this review will include marking extrachromosomal chromatin to be served as a partitioning locus by deposition of CENP-A homolog in budding yeast.
Assuntos
Centrômero/metabolismo , Autoantígenos , Sequência de Bases , Divisão Celular , Proteína Centromérica A , Cromatina , Proteínas Cromossômicas não Histona , Segregação de Cromossomos , Eucariotos , Loci Gênicos , Histonas/genética , Histonas/metabolismo , Humanos , Cinetocoros/metabolismoRESUMO
The assessment of minimum inhibitory concentration (MIC) is a conventional technique used for the screening of microbial resistance against antibiotics, biocides, and contaminants such as heavy metals. However, as part of our ongoing work, we have observed biases associated with using traditional liquid MIC method to screen microbial heavy metal resistance, including both bacterial and fungal strains. Specifically, the addition of uranium into synthetic media causes immediate precipitation prior to the initiation of microbial growth, thus hampering the optical density measurements, and the obtained MIC values are thus flawed and inaccurate. To address this discrepancy, we report the optimization and development of a serial-dilution-based MIC method conducted on solid growth media supplemented with uranium, which is more accurate, relative to the testing of MICs performed in liquid cultures. Notably, we report on the efficacy of this method to screen not only bacteria that are resistant to uranium but also demonstrate the successful application to yeast and fungal isolates, for their ability to resist uranium, is more accurate and sensitive relative to the liquid method. We believe that this newly developed method to screen heavy metal resistance, such as uranium, is far superior to the existing liquid MIC method and propose replacing the liquid assay with the solid plate MIC reported herein.
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A mercury (Hg)-resistant Serratia sp. strain, SRS-8-S-2018, was isolated, followed by generation of its draft genome sequence, which indicated a genomic size of 5,323,630 bp composed of 5,261 coding sequences. A suite of genomic functions in strain SRS-8-S-2018 was identified, and these likely facilitate survival in a metalliferous soil habitat.
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The carriage of both, heavy metal and antibiotic resistance appears to be a common trait in bacterial communities native to long-term contaminated habitats, including the Savannah River Site (SRS). There is widespread soil contamination at the SRS; a United States Department of Energy (DOE) facility with long-term contamination from past industrial and nuclear weapons production activities. To further evaluate the genomic and metabolic traits that underpin metal and antibiotic resistance, a robust mercury (Hg) and uranium (U)-resistant strain- SRS-8-S-2018, was isolated. Minimum inhibitory concentration of this strain revealed resistance to Hg (10 µg/ml) and U (5 mM), the two main heavy metal contaminants at the SRS. Metabolic assessment of strain SRS-8-S-2018 using Biolog metabolic fingerprinting analysis revealed preference for carbohydrate utilization followed by polymers, amino acids, carboxy acids, and esters; this physiological activity diminished when Hg stress was provided at 1 and 3 µg/ml and completely ceased at 5 µg/ml Hg, indicating that continued release of Hg will have negative metabolic impacts to even those microorganisms that possess high resistance ability. Development of antibiotic resistance in strain SRS-8-S-2018 was evaluated at a functional level using phenomics, which confirmed broad resistance against 70.8% of the 48 antibiotics tested. Evolutionary and adaptive traits of strain SRS-8-S-2018 were further assessed using genomics, which revealed the strain to taxonomically affiliate with Serratia marcescens species, possessing a genome size of 5,323,630 bp, 5,261 proteins (CDS), 55 genes for transfer RNA (tRNA), and an average G + C content of 59.48. Comparative genomics with closest taxonomic relatives revealed 360 distinct genes in SRS-8-S-2018, with multiple functions related to both, antibiotic and heavy metal resistance, which likely facilitates the strain's survival in a metalliferous soil habitat. Comparisons drawn between the environmentally isolated Serratia SRS-8-S-2018 with 31 other strains revealed a closer functional association with medically relevant isolates suggesting that propensity of environmental Serratia isolates in acquiring virulence traits, as a function of long-term exposure to heavy metals, which is facilitating development, recruitment and proliferation of not only metal resistant genes (MRGs) but antibiotic resistant genes (ARGs), which can potentially trigger future bacterial pathogen outbreaks emanating from contaminated environmental habitats.
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Metagenomic assessment provides a comprehensive survey of soil microbiota; however, isolation and characterization of functionally relevant microbiota are required prior to their application(s), such as for metal remediation. Toward this end, we report the availability of a culture collection comprising uranium (U)-resistant microbial assemblages (CURMA) to the scientific community.
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The majority of environmental microbiomes are not amenable to cultivation under standard laboratory growth conditions and hence remain uncharacterized. For environmental applications, such as bioremediation, it is necessary to isolate microbes performing the desired function, which may not necessarily be the fast growing or the copiotroph microbiota. Toward this end, cultivation and isolation of microbial strains using diffusion chambers (DC) and/or microbial traps (MT) have both been recently demonstrated to be effective strategies because microbial enrichment is facilitated by soil nutrients and not by synthetically defined media, thus simulating their native habitat. In this study, DC/MT chambers were established using soils collected from two US Department of Energy (DOE) sites with long-term history of heavy metal contamination, including mercury (Hg). To characterize the contamination levels and nutrient status, soils were first analyzed for total mercury (THg), methylmercury (MeHg), total carbon (TC), total nitrogen (TN), and total phosphorus (TP). Multivariate statistical analysis on these measurements facilitated binning of soils under high, medium and low levels of contamination. Bacterial and fungal microbiomes that developed within the DC and MT chambers were evaluated using comparative metagenomics, revealing Chthoniobacter, Burkholderia and Bradyrhizobium spp., as the predominant bacteria while Penicillium, Thielavia, and Trichoderma predominated among fungi. Many of these core microbiomes were also retrieved as axenic isolates. Furthermore, canonical correspondence analysis (CCA) of biogeochemical measurements, metal concentrations and bacterial communities revealed a positive correlation of Chthoniobacter/Bradyrhizobium spp., to THg whereas Burkholderia spp., correlated with MeHg. Penicillium spp., correlated with THg whereas Trichoderma spp., and Aspergillus spp., correlated with MeHg, from the MT approach. This is the first metagenomics-based assessment, isolation and characterization of soil-borne bacterial and fungal communities colonizing the diffusion chambers (DC) and microbial traps (MT) established with long-term metal contaminated soils. Overall, this study provides proof-of-concept for the successful application of DC/MT based assessment of mercury resistant (HgR) microbiomes in legacy metal-contaminated soils, having complex contamination issues. Overall, this study brings out the significance of microbial communities and their relevance in context to heavy metal cycling for better stewardship and restoration of such historically contaminated systems.
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A largely understudied microbially mediated mercury (Hg) bioremediative pathway includes the volatilization of Hg2+ to Hg°. Therefore, studies on Hg resistant bacteria (HgR), isolated from historically long-term contaminated environments, can serve as models to understand mechanisms underpinning Hg cycling. Towards this end, a mercury resistant bacterial strain, identified as Stenotrophomonas sp., strain MA5, was isolated from Mill Branch on the Savannah River Site (SRS); an Hg-impacted ecosystem. Minimum inhibitory concentration (MIC) analysis showed Hg resistance of up to 20 µg/mL by MA5 with 95% of cells retaining viability. Microcosm studies showed that the strain depleted more than 90% of spiked Hg2+ within the first 24 h of growth and the detection of volatilized mercury indicated that the strain was able to reduce Hg2+ to Hg°. To understand molecular mechanisms of Hg volatilization, a draft whole genome sequence was obtained, annotated and analyzed, which revealed the presence of a transposon-derived mer operon (merRTPADE) in MA5, known to transport and reduce Hg2+ into Hg°. Based on the whole genome sequence of strain MA5, qRT-PCR assays were designed on merRTPADE, we found a ~40-fold higher transcription of merT, P, A, D and E when cells were exposed to 5 µg/mL Hg2+. Interestingly, strain MA5 increased cellular size as a function of increasing Hg concentrations, which is likely an evolutionary response mechanism to cope with Hg stress. Moreover, metal contaminated environments are shown to co-select for antibiotic resistance. When MA5 was screened for antibiotic resistance, broad resistance against penicillin, streptomycin, tetracycline, ampicillin, rifampicin, and erythromycin was found; this correlated with the presence of multiple gene determinants for antibiotic resistance within the whole genome sequence of MA5. Overall, this study provides an in-depth understanding of the underpinnings of Stenotrophomonas-mercury interactions that facilitate cellular survival in a contaminated soil habitat.
Assuntos
Mercúrio/toxicidade , Rios/microbiologia , Stenotrophomonas/efeitos dos fármacos , Stenotrophomonas/isolamento & purificação , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Genes Bacterianos , Mercúrio/isolamento & purificação , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Stenotrophomonas/genética , Stenotrophomonas/crescimento & desenvolvimento , Estresse Fisiológico/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacos , VolatilizaçãoRESUMO
A soilborne Stenotrophomonas sp. strain (MA5) that is resistant to mercury was isolated. A draft genome sequence-based analysis revealed a suite of gene determinants to resist mercury and other heavy metals, multidrug efflux, stress response, and membrane transport, and these provide cues to a suite of mechanisms that underpin cellular survival in contaminated soil.
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Halving of the genome during meiosis I is achieved as the homologous chromosomes move to the opposite spindle poles whereas the sister chromatids stay together and move to the same pole. This requires that the sister kinetochores should take a side-by-side orientation in order to connect to the microtubules emanating from the same pole. Factors that constrain sister kinetochores to adopt such orientation are therefore crucial to achieve reductional chromosome segregation in meiosis I. In budding yeast, a protein complex, known as monopolin, is involved in conjoining of the sister kinetochores and thus facilitates their binding to the microtubules from the same pole. In this study, we report Zip1, a synaptonemal complex component, as another factor that might help the sister kinetochores to take the side-by-side orientation and promote their mono-orientation on the meiosis I spindle. From our results, we propose that the localization of Zip1 at the centromere may provide an additional constraining factor that promotes monopolin to cross-link the sister kinetochores enabling them to mono-orient.
Assuntos
Cinetocoros/fisiologia , Meiose/fisiologia , Proteínas Nucleares/fisiologia , Proteínas de Saccharomyces cerevisiae/fisiologia , Saccharomycetales/fisiologia , Proteínas de Ciclo Celular/fisiologia , MutaçãoRESUMO
The budding yeast centrosome, often called the spindle pole body (SPB), nucleates microtubules for chromosome segregation during cell division. An appendage, called the half bridge, attaches to one side of the SPB and regulates SPB duplication and separation. Like DNA, the SPB is duplicated only once per cell cycle. During meiosis, however, after one round of DNA replication, two rounds of SPB duplication and separation are coupled with homologue segregation in meiosis I and sister-chromatid segregation in meiosis II. How SPB duplication and separation are regulated during meiosis remains to be elucidated, and whether regulation in meiosis differs from that in mitosis is unclear. Here we show that overproduction of the half-bridge component Kar1 leads to premature SPB separation during meiosis. Furthermore, excessive Kar1 induces SPB overduplication to form supernumerary SPBs, leading to chromosome missegregation and erroneous ascospore formation. Kar1--mediated SPB duplication bypasses the requirement of dephosphorylation of Sfi1, another half-bridge component previously identified as a licensing factor. Our results therefore reveal an unexpected role of Kar1 in licensing meiotic SPB duplication and suggest a unique mechanism of SPB regulation during budding yeast meiosis.
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Centrossomo/metabolismo , Meiose , Proteínas Nucleares/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomycetales/citologia , Saccharomycetales/metabolismo , Centrossomo/ultraestrutura , Prófase Meiótica I , Microtúbulos/metabolismo , Microtúbulos/ultraestrutura , Modelos Biológicos , Domínios Proteicos , Saccharomycetales/ultraestrutura , Corpos Polares do Fuso/metabolismo , Corpos Polares do Fuso/ultraestrutura , Esporos Fúngicos/metabolismoRESUMO
Two Burkholderia spp. (strains SRS-25 and SRS-46) were isolated from high concentrations of uranium (U) from the U.S. Department of Energy (DOE)-managed Savannah River Site (SRS). SRS contains soil gradients that remain co-contaminated by heavy metals from previous nuclear weapons production activities. Uranium (U) is one of the dominant contaminants within the SRS impacted soils, which can be microbially transformed into less toxic forms. We established microcosms containing strains SRS-25 and SRS-46 spiked with U and evaluated the microbially-mediated depletion with concomitant genomic and proteomic analysis. Both strains showed a rapid depletion of U; draft genome sequences revealed SRS-25 genome to be of approximately 8,152,324 bp, a G + C content of 66.5, containing a total 7604 coding sequences with 77 total RNA genes. Similarly, strain SRS-46 contained a genome size of 8,587,429 bp with a G + C content of 67.1, 7895 coding sequences, with 73 total RNA genes, respectively. An in-depth, genome-wide comparisons between strains 25, 46 and a previously isolated strain from our research (Burkholderia sp. strain SRS-W-2-2016), revealed a common pool of 3128 genes; many were found to be homologues to previously characterized metal resistance genes (e.g., for cadmium, cobalt, and zinc), as well as for transporter, stress/detoxification, cytochromes, and drug resistance functions. Furthermore, proteomic analysis of strains with or without U stress, revealed the increased expression of 34 proteins from strain SRS-25 and 52 proteins from strain SRS-46; similar to the genomic analyses, many of these proteins have previously been shown to function in stress response, DNA repair, protein biosynthesis and metabolism. Overall, this comparative proteogenomics study confirms the repertoire of metabolic and stress response functions likely rendering the ecological competitiveness to the isolated strains for colonization and survival in the heavy metals contaminated SRS soil habitat.
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Bacterial infection of implants can be controlled by selective trapping of bacteria, followed with consequent killing by targeted antibacterial agents. Herein, the role of various ZnO morphologies, viz. micro-rods (R), nanoparticles (NP), and micro-disks (D) on antibacterial efficacy of ZnO via release of Zn(2+) and H2O2 is assessed, both as isolated powders and via incorporating them in cytocompatible ultra high molecular weight polyethylene (UHMWPE). Though ZnO is antibacterial, interestingly, all ZnO morphologies elicited a supportive growth of gram-negative bacteria (Escherichia coli) in culture medium (until 28-35 µg/ml). But, all ZnO morphologies did elicit bactericidal effect on gram positive bacteria (Staphylococcus aureus or Staphylococcus epidermidis) both in culture medium (for 0-2.5 µg/ml) or when incorporated (5-20 wt.%) into UHMWPE. The bactericidal mechanisms were quantified for various ZnO morphologies via: (i) H2O2 production, (ii) Zn(2+) release, and (iii) the presence of surface oxygen vacancies. On one hand, where only ZnO(NP) elicited release of H2O2 in the absence of light, maximum Zn(2+) release was elicited by ZnO(D). Interestingly, when ZnO is incorporated as reinforcement (5-20 wt.%), its antibacterial action against E. coli was vividly observed due to selective proliferation of bacteria only on friendly UHMWPE matrix. Hence, luring bacteria on affable UHMWPE surface can be complemented with their targeted killing by ZnO present in composite.
Assuntos
Antibacterianos/química , Polietilenos/química , Óxido de Zinco/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Microscopia Eletrônica de Varredura , Peso Molecular , Tamanho da Partícula , Espectroscopia Fotoeletrônica , Espécies Reativas de Oxigênio/metabolismo , Espectrofotometria Atômica , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Zinco/análiseRESUMO
This study reports the unprecedented, novel and eco-friendly method for the synthesis of three-dimensional (3D) copper nanostructure having flower like morphology using leaf extract of Ficus benghalensis. The catalytic activity of copper nanoflowers (CuNFs) was investigated against methylene blue (MB) used as a modal dye pollutant. Scanning electron micrograph evidently designated 3D appearance of nanoflowers within a size range from 250 nm to 2.5 µm. Energy-dispersive X-ray spectra showed the presence of copper elements in the nanoflowers. Fourier-transform infrared spectra clearly demonstrated the presence of biomolecules which is responsible for the synthesis of CuNFs. The catalytic activity of the synthesised CuNFs was monitored by ultraviolet-visible spectroscopy. The MB was degraded by 72% in 85 min on addition of CuNFs and the rate constant (k) was found to be 0.77 × 10-3 s-1. This method adapted for synthesis of CuNFs offers a valuable contribution in the area of nanomaterial synthesis and in water research by suggesting a sustainable and an alternative route for removal of toxic solvents and waste materials.
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The advent of the tumescent technique in 1987 allowed for safe total corporal contouring as an ambulatory, single-session megaliposuction with the patient under regional anesthesia supplemented by local anesthetic only in selected areas. Safety and aesthetic issues define large-volume liposuction as having a 5,000-ml aspirate, mega-volume liposuction as having an 8,000-ml aspirate, and giganto-volume liposuction as having an aspirate of 12,000 ml or more. Clinically, a total volume comprising 5,000 ml of fat and wetting solution aspirated during the procedure qualifies for megaliposuction/large-volume liposuction. Between September 2000 and August 2005, 470 cases of liposuction were managed. In 296 (63%) of the 470 cases, the total volume of aspirate exceeded 5 l (range, 5,000-22,000 ml). Concurrent limited or total-block lipectomy was performed in 70 of 296 cases (23.6%). Regional anesthesia with conscious sedation was preferred, except where liposuction targeted areas above the subcostal region (the upper trunk, lateral chest, gynecomastia, breast, arms, and face), or when the patient so desired. Tumescent infiltration was achieved with hypotonic lactated Ringer's solution, adrenalin, triamcinalone, and hyalase in all cases during the last one year of the series. This approach has clinically shown less tissue edema in the postoperative period than with conventional physiologic saline used in place of the Ringer's lactate solution. The amount injected varied from 1,000 to 8,000 ml depending on the size, site, and area. Local anesthetic was included only for the terminal portion of the tumescent mixture, wherever the subcostal regions were infiltrated. The aspirate was restricted to the unstained white/yellow fat, and the amount of fat aspirated did not have any bearing on the amount of solution infiltrated. There were no major complications, and no blood transfusions were administered. The hospital stay ranged from 8 to 24 h for both liposuction and liposuction with a lipectomy. Serous discharge from access sites and serosanguinous fluid accumulation requiring drainage were necessitated in 32 of 296 cases (10.8%). Minor recontouring touch-ups were requested in 17 of 296 cases (5.7%). Early ambulation was encouraged for mobilization of third-space fluid shifts to expedite recovery and to prevent deep vein thrombosis. Follow-up evaluation ranged from 6 to 52 months, with 38 (12.8%) of 296 patients requesting further sessions for other new areas. Average weight reduction observed was 7 to 11.6 kg (approx. 4 to 10% of pre-operative body weight). Meticulous perioperative monitoring of systemic functions ensures safety in tumescent megaliposuction for the obese, and rewarding results are achieved in a single sitting.