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1.
Metallomics ; 15(8)2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37463796

RESUMO

As the second most abundant transition element and a crucial cofactor for many proteins, zinc is essential for the survival of all living organisms. To maintain required zinc levels and prevent toxic overload, cells and organisms have a collection of metal transport proteins for uptake and efflux of zinc. In bacteria, metal transport proteins are well defined for model organisms and many pathogens, but fewer studies have explored metal transport proteins, including those for zinc, in commensal bacteria from the gut microbiota. The healthy human gut microbiota comprises hundreds of species and among these, bacteria from the Lactobacillaceae family are well documented to have various beneficial effects on health. Furthermore, changes in dietary metal intake, such as for zinc and iron, are frequently correlated with changes in abundance of Lactobacillaceae. Few studies have explored zinc requirements and zinc homeostasis mechanisms in Lactobacillaceae, however. Here we applied a bioinformatics approach to identify and compare predicted zinc uptake and efflux proteins in several Lactobacillaceae genera of intestinal relevance. Few Lactobacillaceae had zinc transporters currently annotated in proteomes retrieved from the UniProt database, but protein sequence-based homology searches revealed that high-affinity ABC transporter genes are likely common, albeit with genus-specific domain features. P-type ATPase transporters are probably also common and some Lactobacillaceae genera code for predicted zinc efflux cation diffusion facilitators. This analysis confirms that Lactobacillaceae harbor genes for various zinc transporter homologs, and provides a foundation for systematic experimental studies to elucidate zinc homeostasis mechanisms in these bacteria.


Assuntos
Lactobacillaceae , Zinco , Humanos , Lactobacillaceae/metabolismo , Zinco/metabolismo , Metais/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Bactérias/metabolismo , Biologia Computacional
2.
Microbiol Spectr ; 10(1): e0100621, 2022 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-35080431

RESUMO

Lactobacillus is a genus of Gram-positive bacteria and comprises a major part of the lactic acid bacteria group that converts sugars to lactic acid. Lactobacillus species found in the gut microbiota are considered beneficial to human health and commonly used in probiotic formulations, but their molecular functions remain poorly defined. Microbes require metal ions for growth and function and must acquire them from the surrounding environment. Therefore, lactobacilli need to compete with other gut microbes for these nutrients, although their metal requirements are not well-understood. Indeed, the abundance of lactobacilli in the microbiota is frequently affected by dietary intake of essential metals like zinc, manganese, and iron, but few studies have investigated the role of metals, especially zinc, in the physiology and metabolism of Lactobacillus species. Here, we investigated metal uptake by quantifying total cellular metal contents and compared how transition metals affect the growth of two distinct Lactobacillus species, Lactobacillus plantarum ATCC 14917 and Lactobacillus acidophilus ATCC 4356. When grown in rich or metal-limited medium, both species took up more manganese, zinc, and iron compared with other transition metals measured. Distinct zinc-, manganese- and iron-dependent patterns were observed in the growth kinetics for these species and while certain levels of each metal promoted the growth kinetics of both Lactobacillus species, the effects depend significantly on the culture medium and growth conditions. IMPORTANCE The gastrointestinal tract contains trillions of microorganisms, which are central to human health. Lactobacilli are considered beneficial microbiota members and are often used in probiotics, but their molecular functions, and especially those which are metal-dependent, remain poorly defined. Abundance of lactobacilli in the microbiota is frequently affected by dietary intake of essential metals like manganese, zinc, and iron, but results are complex, sometimes contradictory, and poorly predictable. There is a significant need to understand how host diet and metabolism will affect the microbiota, given that changes in microbiota composition are linked with disease and infection. The significance of our research is in gaining insight to how metals distinctly affect individual Lactobacillus species, which could lead to novel therapeutics and improved medical treatment. Growth kinetics and quantification of metal contents highlights how distinct species can respond differently to varied metal availability and provide a foundation for future molecular and mechanistic studies.


Assuntos
Ferro/metabolismo , Lactobacillus acidophilus/crescimento & desenvolvimento , Lactobacillus acidophilus/metabolismo , Lactobacillus plantarum/crescimento & desenvolvimento , Lactobacillus plantarum/metabolismo , Manganês/metabolismo , Zinco/metabolismo , Cinética , Lactobacillus acidophilus/química , Lactobacillus plantarum/química
3.
Dental Press J Orthod ; 26(6): e212069, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34932713

RESUMO

OBJECTIVE: This study evaluated the force decay and design shape changes caused by stress relaxation in two different orthodontic cantilever configurations. METHODS: Eighty cantilevers made of 0.017 x 0.025-in beta-titanium wires were standardized in a passive position, using real scale templates, and randomly divided into two groups (n = 40): Type 1 and Type 2. Each group received a different design (Type 1 with three bends, and Type 2 with two bends), and both were divided in four subgroups (n = 10) according to the evaluation periods: G1 = 24h, G2 = 1 week, G3 = 4 weeks, and G4 = 8 weeks. Mechanical tests were performed immediately after preactivation and at the end of each period, to evaluate force decay. The cantilevers were also scanned and the angles of the bends were measured to assess shape changes. RESULTS: Cantilever forces decayed over time. Type 1 - G1 showed less force decay than Type 2 (10.83 cN vs 17.87 cN). Type 1 cantilevers showed significant force decay only when G4 was compared to G1 (9.05 cN), G2 (11.73 cN), and G3 (9.78 cN). Type 2 cantilevers presented differences when G1 was compared to G2 (9.57 cN) and G3 (7.89 cN). Regarding to the cantilever angle closest to the bracket insertion, Type 1 cantilevers showed significant decrease for G2 (1.58°) and G4 (1.52°). CONCLUSIONS: Cantilevers' design and proximity of the bends influenced force decay pattern overtime. Type 1 cantilevers presented more stable design at the first weeks than Type 2.


Assuntos
Ligas Dentárias , Fios Ortodônticos , Estresse Mecânico , Titânio
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