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1.
Science ; 385(6713): 1077-1080, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39236185

RESUMO

There is extensive geologic evidence of ancient volcanic activity on the Moon, but it is unclear how long that volcanism persisted. Magma fountains produce volcanic glasses, which have previously been found in samples of the Moon's surface. We investigated ~3000 glass beads in lunar soil samples collected by the Chang'e-5 mission and identified three as having a volcanic origin on the basis of their textures, chemical compositions, and sulfur isotopes. Uranium-lead dating of the three volcanic glass beads shows that they formed 123 ± 15 million years ago. We measured high abundances of rare earth elements and thorium in these volcanic glass beads, which could indicate that such recent volcanism was related to local enrichment of heat-generating elements in the mantle sources of the magma.

2.
Planta ; 237(6): 1571-83, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23503782

RESUMO

Mitochondrial porins or voltage-dependent anion channels (VDAC) are the main route for solute transport through outer mitochondrial membranes (OMM). In mammals, hexokinase (HK) binds to VDAC, which allows the channeling of ATP synthesized by oxidative phosphorylation toward HK. In plants, although HK has been found associated with OMM, evidence for an interaction with VDAC is scarce. Thus, in this work, we studied the physical and functional interaction between these proteins in beetroot mitochondria. To observe a physical interaction between HK and VDAC, OMM presenting HK activity were prepared from purified mitochondria. Protein complexes were solubilized from OMM with mild detergents and separated by centrifugation in glycerol gradients. Both HK activity and immunodetected VDAC were found in small (9S-13S) and large (>40S) complexes. OMM proteins were also separated according to their hydropathy by serial phase partitioning with Triton X-114. Most of HK activity was found in hydrophobic fractions where VDAC was also present. These results indicated that HK could be bound to VDAC in beetroot mitochondria. The functional interaction of HK with VDAC was demonstrated by observing the effect of apyrase on HK-catalyzed glucose phosphorylation in intact mitochondria. Apyrase, which hydrolyzes freely soluble ATP, competed efficiently with hexokinase for ATP when it was produced outside mitochondria (with PEP and pyruvate kinase), but not when it was produced inside mitochondria by oxidative phosphorylation. These results suggest that HK closely interacts with VDAC in beetroot mitochondria, and that this interaction allows the channeling of respiratory ATP toward HK through VDAC.


Assuntos
Trifosfato de Adenosina/biossíntese , Beta vulgaris/enzimologia , Hexoquinase/metabolismo , Mitocôndrias/enzimologia , Fosforilação Oxidativa , Proteínas de Plantas/metabolismo , Canais de Ânion Dependentes de Voltagem/metabolismo , Sequência de Aminoácidos , Hexoquinase/química , Interações Hidrofóbicas e Hidrofílicas , Espectrometria de Massas , Membranas Mitocondriais/enzimologia , Proteínas Mitocondriais/química , Proteínas Mitocondriais/metabolismo , Dados de Sequência Molecular , Complexos Multiproteicos/metabolismo , Proteínas de Plantas/química , Ligação Proteica
3.
Am J Infect Control ; 48(9): 1028-1031, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-31924388

RESUMO

BACKGROUND: To evaluate risk factors for infection or colonization with carbapenem-resistant Enterobacteriaceae (CRE) to develop an algorithm for targeted CRE screening. METHODS: We conducted a case-control study of 50 CRE-positive cases and 100 CRE-negative controls to identify risk factors that were significant for CRE infection or colonization. The setting was at an acute care academic hospital. Patients who tested positive for CRE or other microbiological laboratory tests during the study period were included. We reviewed medical records of 50 patients who were CRE-positive and 100 matched controls who had a non-CRE culture at a similar anatomic site within the closest time period to the case's culture date. Risk factors were assessed using logistic regression with SAS 9.4, observing the 95% confidence interval (CI) to determine significance. RESULTS: Significant risk factors for CRE infection or colonization included the use of fluoroquinolones (odds ratio [OR], 3.75; 95% CI, 1.35, 10.38) and cephalosporins (OR, 2.37; 95% CI, 1.17, 4.86). In addition, undergoing an invasive procedure with a scope device was also a significant risk factor for our participants (OR, 4.57; 95% CI, 1.31, 16.02). Significance of these risk factors varied within the community-acquired and hospital-acquired cases. CONCLUSIONS: Our results suggest that exposure to certain antimicrobials and invasive procedures with a scope device (endoscopic retrograde cholangiopancreatography, duodenal endoscope) are risk factors for CRE. The findings of significant differences in antimicrobials received highlight the necessity to understand antimicrobial stewardship in the development of CRE colonization and infection. Along with antibiotics, inaccessibility to components within scope devices may be increasing the risk of CRE spread.


Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos , Infecções por Enterobacteriaceae , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Carbapenêmicos/farmacologia , Estudos de Casos e Controles , Infecções por Enterobacteriaceae/tratamento farmacológico , Infecções por Enterobacteriaceae/epidemiologia , Humanos , Fatores de Risco
4.
Am J Infect Control ; 48(1): 119-121, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31439371

RESUMO

In 2018, the Food and Drug Administration/Centers for Disease Control and Prevention revised protocols for surveillance sampling and cultures of duodenoscopes. We describe the recovery of the mold Curvularia from a duodenoscope processed according to the manufacturer's instructions using this revised sampling process. To our knowledge, this is the first time a mold has been recovered from a duodenoscope after following the Food and Drug Administration/Centers for Disease Control and Prevention protocol. This suggests that manufacturer's recommendation for scope reprocessing may be insufficient to adequately remove mold from these scopes.


Assuntos
Infecção Hospitalar/parasitologia , Curvularia/isolamento & purificação , Desinfecção/métodos , Duodenoscópios/parasitologia , Micoses/parasitologia , Desinfecção/normas , Contaminação de Equipamentos , Reutilização de Equipamento , Humanos
5.
J Am Chem Soc ; 131(37): 13369-74, 2009 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-19719166

RESUMO

The montmorillonite clay-catalyzed reactions of nucleotides generate oligomers as long as 50-mers. The extent of catalysis depends on the magnitude of the negative charge on the montmorillonite lattice and the number of cations associated with it. When cations in raw montmorillonites are replaced by sodium ions, the resulting Na(+)-montmorillonite does not catalyze oligomer formation because they saturate the interlayers between the platelets of montmorillonites, which blocks the binding of the activated monomers. Treating the montmorillonite with dilute hydrochloric acid replaces the cations on the raw montmorillonite with protons. The protonated montmorillonite, titrated to pH 6-7, serves as a catalyst for the formation of RNA oligomers. The titration does not add sufficient sodium ions to the interlayers of the montmorillonite platelets to prevent the activated monomer from entering. It was noted that noncatalytic montmorillonites have a higher negative charge on their platelets that is due mainly to the natural substitution of the tetravalent and trivalent elements in the montmorillonite lattice with trivalent and divalent metal ions, respectively. The larger negative charge on these montmorillonites was demonstrated by the almost 2-fold greater amounts of sodium hydroxide needed to titrate noncatalytic montmorillonites as compared to the catalytic montmorillonites. Adsorption isotherms established that the equilibrium binding is strongest for ImpA and weakest for ImpU. Of the 22 montmorillonites investigated, 12 were catalysts. This research provides insight into the mechanism of the catalytic process.


Assuntos
Bentonita/química , RNA/química , Catálise , Concentração de Íons de Hidrogênio , Metais Alcalinos/química , RNA/metabolismo , Titulometria
6.
Diagn Microbiol Infect Dis ; 79(3): 293-7, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24767683

RESUMO

We evaluated the accuracy and performance of the FilmArray Direct from Positive Blood Culture system (BCID) (BioFire Diagnostics, Salt Lake City, UT, USA) and the VITEK Mass Spectrometry System (Vitek MS; bioMerieux, Durham, NC, USA) to identify bacterial isolates from 161 positive blood culture bottles. The BCID uses multiplex PCR to identify 90-95% of common isolates to the genus or species/complex level as well as mecA, Van A/B, and bla(KPC) genes in approximately 1 hour. Of 151 monomicrobic isolates, the FilmArray correctly identified 48/49 (98%) to the genus and 84/84 (100%) to the species/complex level, while 18/151 (12%) gave no identification, as expected from the database. Mass spectrometry correctly identified 142/151 (94%) monomicrobic cultures to the genus level, 137/151 (91%) to the species level, with only 8/151(5%) giving no identification. Although mass spectrometry has a much larger database, the filtration system was cumbersome in contrast to the 3-5 minutes hands-on-time for the BCID.


Assuntos
Bacteriemia/diagnóstico , Bactérias/classificação , Bactérias/isolamento & purificação , Técnicas Bacteriológicas/métodos , Sangue/microbiologia , Espectrometria de Massas/métodos , Análise em Microsséries/métodos , Bactérias/química , Bactérias/genética , Humanos , Sensibilidade e Especificidade , Fatores de Tempo
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