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1.
Appl Environ Microbiol ; 86(7)2020 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-31953343

RESUMO

In this study, the mineral-weathering bacterium Pseudomonas azotoformans F77, which was isolated from the soil of a debris flow area, was evaluated for its weathering activity under direct contact with biotite or without contact. Then, biotite-weathering behaviors of strain F77, mutants that had been created by deleting the gcd and adh genes (which are involved in gluconic acid metabolism and pilus formation, respectively), and the double mutant F77ΔgcdΔadh were compared. The relative gene expression levels of F77 and its mutants F77Δgcd and F77Δadh were also analyzed in the presence of biotite. Direct contact with biotite increased Fe and Al release from the mineral in the presence of F77. All strains had similar abilities to release Fe and Al from the mineral except for F77Δgcd and F77Δadh Mobilized Fe and Al concentrations were decreased by up to 72, 26, and 87% in the presence of F77Δgcd, F77Δadh, and F77ΔgcdΔadh, respectively, compared to levels observed in the presence of F77 during the mineral-weathering process. Gluconic acid production was decreased for F77Δgcd and F77ΔgcdΔadh, while decreased cell attachment on the mineral surface was observed for F77Δadh, compared to findings for F77. The F77 genes involved in pilus formation and gluconic acid metabolism showed increased expression levels in the presence of biotite. The results of this study showed important roles for the genes involved in gluconic acid metabolism and pilus formation in mineral weathering by F77 and demonstrated the distinctive effect of these genes on mineral weathering by F77.IMPORTANCE Bacteria play important roles in mineral weathering and soil formation, although the molecular mechanisms underlying the interactions between bacteria and silicate minerals are poorly understood. In this study, the interactions between biotite and the highly effective mineral-weathering bacterium P. azotoformans F77 were characterized. Our results showed that the genes involved in gluconic acid metabolism and pilus formation play important roles in mineral weathering by F77. The presence of biotite could promote the expression of these genes in F77, and a distinctive effect of these genes on mineral weathering by F77 was observed in this study. Our results provide new knowledge and promote better understanding regarding the interaction between silicate minerals and mineral-weathering bacteria, as well as the molecular mechanisms involved in these processes.


Assuntos
Silicatos de Alumínio/metabolismo , Compostos Ferrosos/metabolismo , Minerais/metabolismo , Pseudomonas/metabolismo , Microbiologia do Solo
2.
Appl Environ Microbiol ; 85(15)2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126945

RESUMO

Ectomycorrhizal (ECM) fungi, symbiotically associated with woody plants, markedly improve the uptake of mineral nutrients such as potassium (K) and phosphorus (P) by their host trees. Although it is well known that ECM fungi can obtain K and P from soil minerals through biological weathering, the mechanisms regulating this process are still poorly understood at the molecular level. Here, we investigated the transcriptional regulation of the ECM fungus Amanita pantherina in weathering K-containing feldspar and apatite using transcriptome sequencing (RNA-seq) and validated these results for differentially expressed genes using real-time quantitative PCR. The results showed that A. pantherina was able to improve relevant metabolic processes, such as promoting the biosynthesis of unsaturated fatty acids and steroids in the weathering of K-containing feldspar and apatite. The expression of genes encoding ion transporters was markedly enhanced during exposure to solid K-containing feldspar and apatite, and transcripts of the high-affinity K transporter ApHAK1, belonging to the HAK family, were significantly upregulated. The results also demonstrated that there was no upregulation of organic acid biosynthesis, reflecting the weak weathering capacity of the A. pantherina isolate used in this study, especially its inability to utilize P in apatite. Our findings suggest that under natural conditions in forests, some ECM fungi with low weathering potential of their own may instead enhance the uptake of mineral nutrients using their high-affinity ion transporter systems.IMPORTANCE In this study, we revealed the molecular mechanism and possible strategies of A. pantherina with weak weathering potential in the uptake of insoluble mineral nutrients by using transcriptome sequencing (RNA-seq) technology and found that ApHAK1, a K transporter gene of this fungus, plays a very important role in the acquisition of K and P. Ectomycorrhizal (ECM) fungi play critical roles in the uptake of woody plant nutrients in forests that are usually characterized by nutrient limitation and in maintaining the stability of forest ecosystems. However, the regulatory mechanisms of ECM fungi in acquiring nutrients from minerals/rocks are poorly understood. This study investigated the transcriptional regulation of A. pantherina weathering K-containing feldspar and apatite and improves the understanding of fungal-plant interactions in promoting plant nutrition enabling increased productivity in sustainable forestry.


Assuntos
Silicatos de Alumínio/metabolismo , Amanita/metabolismo , Apatitas/metabolismo , Micorrizas/metabolismo , Compostos de Potássio/metabolismo , Potássio/metabolismo , Amanita/genética , Perfilação da Expressão Gênica , Micorrizas/genética , Transcriptoma
3.
Biomacromolecules ; 20(2): 1056-1067, 2019 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-30608145

RESUMO

Probing the adsorption and lubrication behavior of lubricin, also known as proteoglycan 4 (PRG4), is important for understanding the ultralow friction of cartilage lubrication. Most previous research has focused on native lubricin either purified from synovial fluid or articular cartilage explant culture media. In this work, the adsorption behavior and lubrication mechanism of full-length recombinant human PRG4 (rhPRG4) on mica as well as the effect of adding hyaluronic acid (HA, a polysaccharide) were systematically investigated using a surface forces apparatus (SFA) technique. A low friction coefficient (µ ∼ 0.04) was measured when multilayer rhPRG4 (∼31 nm) was confined in between mica surfaces, even when the load increased to ∼1.2 MPa. Intriguingly, a previously unreported ultralow friction coefficient (µ < 0.005) was observed at a low sliding velocity ( v = 0.14 µm/s) with the applied load P reaching ∼3.6 MPa when a diluted rhPRG4 solution (∼90 µg/mL) was used. The distinct friction behavior is likely due to the smooth and more close-packed lubricin coating, as made evident by the atomic force microscope imaging. Adding HA onto multilayer rhPRG4-coated mica increased the friction coefficient µ to ∼0.1; however, the load bearing property increased, indicating potential synergistic effect between rhPRG4 and HA, which was further demonstrated by the weak adhesion observed when separating rhPRG4-coated mica and HA-coated aminopropyltriethoxysilane-mica (APTES-mica). Alternatively, adding premixed rhPRG4-HA on mica had a friction coefficient (µ ∼ 0.1) close to that of injecting concentrated rhPRG4 (∼450 µg/mL) with lower load sustainability. Our results provide fundamental insights into the adsorption and lubrication behavior of lubricin and its interaction with HA, with useful implications for the underlying mechanism of ultralow friction provided by synovial fluid.


Assuntos
Glicoproteínas/metabolismo , Ácido Hialurônico/metabolismo , Proteoglicanas/metabolismo , Proteínas Recombinantes/metabolismo , Adsorção , Silicatos de Alumínio/metabolismo , Cartilagem Articular/metabolismo , Fricção , Humanos , Lubrificação/métodos , Propriedades de Superfície , Líquido Sinovial/metabolismo
4.
J Appl Microbiol ; 126(1): 215-222, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30326179

RESUMO

AIM: Potassium (K) is one of the three major nutrients required of plant growth and muriate of potash (MoP) is the only recognized chemical fertilizer used in agriculture. In many countries, 100% of the applied MoP is imported costing huge revenue. Application of suitable potassium-solubilizing bacteria (KSB) as biofertilizer could be an integral part of K management in arable soil. The object of this study was to evaluate K-solubilizing ability of a ubiquitous micro-organism as KSB to supplement K in soil. METHODS AND RESULTS: Strain (O-5) was isolated from tea-growing soil and identified as Bacillus pseudomycoides. Phylogenetic analysis revealed that the nearest neighbours of B. pseudomycoides strain O-5 were Bacillus cereus, Bacillus thuringiensis and Bacillus toyonensis. Though the species was first identified in 1998 and is ubiquitous in soil, the role of this group of micro-organisms in nutrient cycling in soil has not been studied before. Strain solubilized 33·32 ± 2·40 µg K ml-1 in mica waste (MW; muscovite type mineral)-amended broth after 7 days incubation at 30 ± 1°C. In a soil microcosm study under laboratory condition, B. pseudomycoides strain O-5 increased K availability by 47·0 ± 7·1 mg kg-1 after 105 days incubation, while the strain released 104·9 ± 15·3 mg K kg-1 in MW-treated soil. In this study, application of isolated B. pseudomycoides with MW significantly increased K availability in soil, and that in turn facilitated K uptake by tea plants. CONCLUSION: Based on the data, it could be inferred that B. pseudomycoides could mobilize K from bound form in soil and can be utilized as K-solubilizing biofertilizer especially in combination with MW for supplementing K in soil. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacillus pseudomycoides strain O-5 has potential to be used as K-solubilizing biofertilizer in agriculture.


Assuntos
Silicatos de Alumínio/metabolismo , Bacillus/metabolismo , Camellia sinensis/metabolismo , Potássio/metabolismo , Agricultura , Silicatos de Alumínio/análise , Bacillus/classificação , Bacillus/genética , Bacillus/isolamento & purificação , Camellia sinensis/crescimento & desenvolvimento , Fertilizantes/análise , Índia , Filogenia , Solo/química , Microbiologia do Solo , Chá
5.
Mycologia ; 110(6): 1017-1032, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30481136

RESUMO

Mineral weathering plays an important role in poor-nutrient environments such as mine spoils and tailings. Ectomycorrhizal (ECM) fungi are able to enhance mineral weathering through different mechanisms, thereby increasing the availability of minerals and nutrients to plants. Six ECM fungi (Cadophora finlandia, Cenococcum geophilum, Hebeloma crustuliniforme, Lactarius aurantiosordidus, Paxillus involutes, and Tricholoma scalpturatum) were tested here for their tolerance to biotite-quartz-rich mine tailings. Either solid- or liquid-medium methods were used for in vitro selection of ECM fungi for their ability to grow on mine tailings. ECM fungi were selected based on their mycelial radial growth and metabolite production (ergosterol and low-molecular-mass organic acids, LMMOAs). We found a strong correlation between fungal ergosterol content and mycelial radial growth using the solid-medium method. However, the liquid-medium method was more appropriate for ergosterol synthesis and permitted direct measurement of organic acid production. We found that LMMOAs were exuded by ECM fungi, which solubilized mine tailings for their own growth and nutrition. Finally, we concluded that the ECM fungi C. finlandia and T. scalpturatum are the species most tolerant to tailings and could potentially improve the survival rate, growth, and health of white spruce seedlings planted on biotite mine spoils and tailings.


Assuntos
Silicatos de Alumínio/metabolismo , Biodegradação Ambiental , Biomassa , Meios de Cultura/química , Compostos Ferrosos/metabolismo , Micorrizas/crescimento & desenvolvimento , Micorrizas/metabolismo , Adaptação Fisiológica , Ergosterol/análise , Mineração , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Filogenia , Picea/microbiologia , Raízes de Plantas/microbiologia , Plântula/microbiologia
6.
J Vis Exp ; (136)2018 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-29939174

RESUMO

The mechanisms underpinning the deposition of fine-grained, organic-rich sediments are still largely debated. Specifically, the impact of the interaction of clay particles with reactive, planktonic cyanobacterial cells to the sedimentary record is under studied. This interaction is a potentially major contributor to shale depositional models. Within a lab setting, the flocculation and sedimentation rates of these materials can be examined and measured in a controlled environment. Here, we detail a protocol for measuring the sedimentation rate of cyanobacterial/clay mixtures. This methodology is demonstrated through the description of two sample experiments: the first uses kaolin (a dehydrated form of kaolinite) and Synechococcus sp. PCC 7002 (a marine coccoid cyanobacteria), and the second uses kaolin and Synechocystis sp. PCC 6803 (a freshwater coccoid cyanobacteria). Cyanobacterial cultures are mixed with varying amounts of clay within a specially designed tank apparatus optimized to allow continuous, real-time video and photographic recording. The sampling procedures are detailed as well as a post-collection protocol for precise measurement of chlorophyll a from which the concentration of cyanobacterial cells remaining in suspension can be determined. Through experimental replication, a profile is constructed that displays sedimentation rate.


Assuntos
Silicatos de Alumínio/metabolismo , Cianobactérias/patogenicidade , Silicatos de Alumínio/análise , Argila
7.
Food Chem Toxicol ; 114: 316-324, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29496528

RESUMO

Populations consuming aflatoxin (AF) and fumonisin (FN)-contaminated foods may be at increased risk for hepatocellular carcinoma (HCC) and developmental disorders; consequently, development of intervention strategies to reduce AF/FN-induced liver disease and adverse health effects in humans could be very useful. Calcium montmorillonite clay (NovaSil) has been shown to absorb AF in vitro, in multiple animal models, as well as in human studies. In the present study, we aimed to evaluate whether uniform particle size NovaSil (UPSN) possessed an ability to modulate the co-carcinogenic potentials of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) in F344 rats. Sequential treatment of FB1 following AFB1 synergistically induces preneoplastic alterations as well as liver damage, indicating that AFB1 acts as an initiator while FB1 as a promoter in the carcinogenesis model, confirming findings from previous studies. The enterosorbent agent UPSN clay at dose of up to 0.5% in diet was shown to be effective in modulating the toxicity and carcinogenicity of co-exposure to AFB1 and FB1, as demonstrated by significant reduction in number and size of hepatic GST-P+ foci, in alterations indicative of liver toxicity, and in levels of AFB1 and FB1 biomarkers.


Assuntos
Aflatoxina B1/toxicidade , Silicatos de Alumínio/administração & dosagem , Bentonita/administração & dosagem , Fumonisinas/toxicidade , Hepatopatias/tratamento farmacológico , Adsorção , Aflatoxina B1/química , Aflatoxina B1/metabolismo , Silicatos de Alumínio/química , Silicatos de Alumínio/metabolismo , Animais , Bentonita/química , Bentonita/metabolismo , Argila , Fumonisinas/química , Fumonisinas/metabolismo , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Hepatopatias/etiologia , Hepatopatias/metabolismo , Masculino , Ratos , Ratos Endogâmicos F344
8.
J Dairy Sci ; 101(4): 3008-3020, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29428756

RESUMO

The study was conducted to examine the effect of supplementing bentonite clay with or without a Saccharomyces cerevisiae fermentation product (SCFP; 19 g of NutriTek + 16 g of MetaShield, both from Diamond V, Cedar Rapids, IA) on the performance and health of dairy cows challenged with aflatoxin B1 (AFB1). Twenty-four lactating Holstein cows (64 ± 11 d in milk) were stratified by parity and milk production and randomly assigned to 1 of 4 treatment sequences. The experiment had a balanced 4 × 4 Latin square design with 6 replicate squares, four 33-d periods, and a 5-d washout interval between periods. Cows were fed a total mixed ration containing 36.1% corn silage, 8.3% alfalfa hay, and 55.6% concentrate (dry matter basis). Treatments were (1) control (no additives), (2) toxin (T; 1,725 µg of AFB1/head per day), (3) T + clay (CL; 200 g/head per day; top-dressed), and (4) CL+SCFP (CL+SCFP; 35 g/head per day; top-dressed). Cows were adapted to diets from d 1 to 25 (predosing period) and then orally dosed with AFB1 from d 26 to 30 (dosing period), and AFB1 was withdrawn from d 31 to 33 (withdrawal period). Milk samples were collected twice daily from d 21 to 33, and plasma was sampled on d 25 and 30 before the morning feeding. Transfer of ingested AFB1 into milk aflatoxin M1 (AFM1) was greater in T than in CL or CL+SCFP (1.65 vs. 1.01 and 0.94%, respectively) from d 26 to 30. The CL and CL+SCFP treatments reduced milk AFM1 concentration compared with T (0.45 and 0.40 vs. 0.75 µg/kg, respectively), and, unlike T, both CL and CL+SCFP lowered AFM1 concentrations below the US Food and Drug Administration action level (0.5 µg/kg). Milk yield tended to be greater during the dosing period in cows fed CL+SCFP compared with T (39.7 vs. 37.7 kg/d). Compared with that for T, plasma glutamic oxaloacetic transaminase concentration, indicative of aflatoxicosis and liver damage, was reduced by CL (85.9 vs. 95.2 U/L) and numerically reduced by CL+SCFP (87.9 vs. 95.2 U/L). Dietary CL and CL+SCFP reduced transfer of dietary AFB1 to milk and milk AFM1 concentration. Only CL prevented the increase in glutamic oxaloacetic transaminase concentration, and only CL+SCFP prevented the decrease in milk yield caused by AFB1 ingestion.


Assuntos
Aflatoxina B1/farmacologia , Silicatos de Alumínio/metabolismo , Bentonita/metabolismo , Bovinos/metabolismo , Leite/química , Saccharomyces cerevisiae/química , Silicatos de Alumínio/administração & dosagem , Ração Animal/análise , Animais , Bentonita/administração & dosagem , Bovinos/imunologia , Argila , Dieta/veterinária , Suplementos Nutricionais/análise , Feminino , Fermentação , Nível de Saúde , Lactação , Distribuição Aleatória
9.
J Agric Food Chem ; 66(11): 2925-2933, 2018 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-29470912

RESUMO

Natural halloysite (Al2Si2O5(OH)4· nH2O) nanotubes (HNT) are clay materials with hollow tubular structure and are widely applied in many fields. Many in vitro studies indicate that HNTs exhibit a high level of biocompatibility; however, the in vivo toxicity of HNTs remains unclear. In this study, the biodistribution and pulmonary toxicity of the purified HNTs in mice were investigated after intragastric administration for 30 days. HNTs have high stability in biological conditions. Oral administration of HNTs caused significant Al accumulation predominantly in the lung with relative slight effects on Si biodistribution. Oral administration of HNTs stimulated the growth of the mice at low dose (5 mg/kg BW) with no pulmonary toxicity but inhibited the mouse growth and resulted in oxidative stress and inflammation in lung at high dose (50 mg/kg BW). In addition, oral HNTs at high dose could be absorbed from the gastrointestinal tract and deposited in lung and could also induce pulmonary fibrosis.


Assuntos
Silicatos de Alumínio/metabolismo , Silicatos de Alumínio/toxicidade , Alumínio/toxicidade , Pulmão/efeitos dos fármacos , Camundongos/metabolismo , Nanotubos/toxicidade , Alumínio/metabolismo , Animais , Argila , Pulmão/metabolismo , Masculino , Camundongos/crescimento & desenvolvimento , Estresse Oxidativo , Distribuição Tecidual
10.
Fish Shellfish Immunol ; 75: 27-31, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29409931

RESUMO

The effect of Sodium Bentonite (SB) enriched diet on growth performance, innate immune response, and disease resistance in stinging catfish, Heteropneustes fossilis against Aeromonas hydrophila is reported. The infected fish fed with 5% SB had the maximum weight gain diet (PWG %) and specific growth rate (SGR %) were 26% and 29% when compared to 14% and 17% with 10% diet. Similarly the phagocytic activity increased significantly when infected fish were fed with 5% or 10% SB diets during the experimental period; the complement, respiratory burst and lysozyme activities were also significantly enhanced on weeks 2 and 4. The lower cumulative mortality (10% and 15%) was observed when the infected fish were fed with 5% and 10% SB diets for 30 days. The results suggest that the infected H. fossilis after administration of 5% and 10% SB enriched diets for 30 days had significantly improved growth performance, innate immunity, and disease resistance against A. hydrophilla. Hence, sodium bentonite can be used as a feed additive to stimulate immunity and for disease resistance in the effective production of economically valuable freshwater catfish, H. fossilis.


Assuntos
Silicatos de Alumínio/metabolismo , Bentonita/metabolismo , Peixes-Gato/crescimento & desenvolvimento , Peixes-Gato/imunologia , Resistência à Doença/imunologia , Doenças dos Peixes/imunologia , Imunidade Inata/efeitos dos fármacos , Aeromonas hydrophila/fisiologia , Silicatos de Alumínio/administração & dosagem , Ração Animal/análise , Animais , Bentonita/administração & dosagem , Peixes-Gato/metabolismo , Argila , Dieta/veterinária , Suplementos Nutricionais/análise , Resistência à Doença/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/imunologia
11.
Geobiology ; 16(1): 88-103, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29322690

RESUMO

Through the use of scanning transmission electron microscopy (STEM) combined with other complementary techniques (SEM, cryo-TEM, HRTEM, and EELS), we have studied the interaction of microorganisms inhabiting deep anoxic waters of acidic pit lakes with dissolved aluminum, silica, sulfate, and ferrous iron. These elements were close to saturation (Al, SiO2 ) or present at very high concentrations (0.12 m Fe(II), 0.12-0.22 m SO42- ) in the studied systems. The anaerobic conditions of these environments allowed investigation of geomicrobial interactions that are difficult to see in oxidized, Fe(III)-rich environments. Detailed chemical maps and through-cell line scans suggest both extra- and intracellular accumulation of Al, Si, S, and Fe(II) in rod-like cells and other structures (e.g., spherical particles and bacteriomorphs) of probable microbial origin. The bacterial rods showed external nanometric coatings of adsorbed Fe(II) and Al on the cell surface and cell interiors with significant presence of Al, Si, and S. These microbial cells coexist with spherical particles showing similar configuration (Fe(II) external coatings and [Al, Si, S]-rich cores). The Al:Si and Al:S ratios and the good Al-Si correlation in the cell interiors suggest the concurrent formation of two amorphous phases, namely a proto-aluminosilicate with imogolite-like composition and proto-hydrobasaluminite. In both cases, the mineralization appears to comprise two stages: a first stage of aluminosilicate and Al-hydroxysulfate precipitation within the cell or around cellular exudates, and a second stage of SO42- and Fe(II) adsorption on surface sites existing on the mineral phases in the case of (SO42- ) or on presumed organic molecules [in the case of Fe(II)]. These microbially related solids could have been formed by permineralization and mineral replacement of senescent microbial cells. However, these features could also denote biomineralization by active bacterial cells as a detoxification mechanism, a possibility which should be further explored. We discuss the significance of the observed Al/microbe and Si/microbe interactions and the implications for clay mineral formation at low pH.


Assuntos
Silicatos de Alumínio/metabolismo , Precipitação Química , Microbiologia da Água , Silicatos de Alumínio/química , Anaerobiose , Compostos Ferrosos/química , Concentração de Íons de Hidrogênio , Microbiota , Microscopia Eletrônica de Transmissão e Varredura , Solubilidade , Sulfatos/química
12.
Molecules ; 22(12)2017 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-29258162

RESUMO

Diatom biosilica may offer an interesting perspective in the search for sustainable solutions meeting the high demand for heterogeneous catalysts. Diatomaceous earth (diatomite), i.e., fossilized diatoms, is already used as adsorbent and carrier material. While diatomite is abundant and inexpensive, freshly harvested and cleaned diatom cell walls have other advantages, with respect to purity and uniformity. The present paper demonstrates an approach to modify diatoms both in vivo and in vitro to produce a porous aluminosilicate that is serving as a potential source for sustainable catalyst production. The obtained material was characterized at various processing stages with respect to morphology, elemental composition, surface area, and acidity. The cell walls appeared normal without morphological changes, while their aluminum content was raised from the molar ratio n(Al):n(Si) 1:600 up to 1:50. A specific surface area of 55 m²/g was measured. The acidity of the material increased from 149 to 320 µmol NH3/g by ion exchange, as determined by NH3 TPD. Finally, the biosilica was examined by an acid catalyzed test reaction, the alkylation of benzene. While the cleaned cell walls did not catalyze the reaction at all, and the ion exchanged material was catalytically active. This demonstrates that modified biosilica does indeed has potential as a basis for future catalytically active materials.


Assuntos
Silicatos de Alumínio/metabolismo , Diatomáceas/metabolismo , Biocatálise , Reatores Biológicos , Diatomáceas/ultraestrutura
13.
Drug Deliv ; 24(1): 1731-1739, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29124978

RESUMO

The present study aimed to develop the sustained-release oral dosage form of pelubiprofen (PEL) by using the blended mixture of 3-aminopropyl functionalized-magnesium phyllosilicate (aminoclay) and pH-independent polymers. The sustained-release solid dispersion (SRSD) was prepared by the solvent evaporation method and the optimal composition of SRSD was determined as the weight ratio of drug: Eudragit® RL PO: Eudragit® RS PO of 1:1:2 in the presence of 1% of aminoclay (SRSD(F6)). The dissolution profiles of SRSD(F6) were examined at different pHs and in the simulated intestinal fluids. The drug release from SRSD(F6) was limited at pH 1.2 and gradually increased at pH 6.8, resulting in the best fit to Higuchi equation. The sustained drug release from SRSD(F6) was also maintained in simulated intestinal fluid at fasted-state (FaSSIF) and fed-state (FeSSIF). The structural characteristics of SRSD(F6) were examined by using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR), indicating the change of drug crystallinity to an amorphous form. After oral administration in rats, SRSD(F6) exhibited the prolonged drug exposure in plasma. For both PEL and PEL-transOH (active metabolite), once a day dosing of SRSD(F6) achieved oral exposure (AUC) comparable to those from the multiple dosing (3 times a day) of untreated drug. In addition, the in vivo absorption of SRSD(F6) was well-correlated with the in vitro dissolution data, establishing a good level A in vitro/in vivo correlation. These results suggest that SRSD(F6) should be promising for the sustained-release of PEL, thereby reducing the dosing frequency.


Assuntos
Silicatos de Alumínio/química , Preparações de Ação Retardada/química , Fenilpropionatos/química , Polímeros/química , Silicatos de Alumínio/metabolismo , Animais , Varredura Diferencial de Calorimetria/métodos , Química Farmacêutica/métodos , Argila , Preparações de Ação Retardada/metabolismo , Portadores de Fármacos/química , Portadores de Fármacos/metabolismo , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Mucosa Intestinal/metabolismo , Masculino , Fenilpropionatos/metabolismo , Polímeros/metabolismo , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/metabolismo , Ratos , Ratos Sprague-Dawley , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Difração de Raios X/métodos
14.
Mar Pollut Bull ; 125(1-2): 186-191, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28821355

RESUMO

During the Deepwater Horizon (DwH) oil spill, interactions between oil, clay particles and marine snow lead to the formation of aggregates. Interactions between these components play an important, but yet not well understood, role in biodegradation of oil in the ocean water. The aim of this study is to explore the effect of these interactions on biodegradation of oil in the water. Laboratory experiments were performed, analyzing respiration and n-alkane and BTEX biodegradation in multiple conditions containing Corexit, alginate particles as marine snow, and kaolin clay. Two oil degrading bacterial pure cultures were added, Pseudomonas putida F1 and Rhodococcus qingshengii TUHH-12. Results show that the presence of alginate particles enhances oil biodegradation. The presence of Corexit alone or in combination with alginate particles and/or kaolin clay, hampers oil biodegradation. Kaolin clay and Corexit have a synergistic effect in increasing BTEX concentrations in the water and cause delay in oil biodegradation.


Assuntos
Poluição por Petróleo , Poluentes Químicos da Água/metabolismo , Alginatos , Alcanos/metabolismo , Silicatos de Alumínio/análise , Silicatos de Alumínio/metabolismo , Biodegradação Ambiental , Argila , Lipídeos/química , Poluição por Petróleo/análise , Pseudomonas putida/metabolismo , Rhodococcus/metabolismo , Tensoativos/química , Tensoativos/metabolismo , Microbiologia da Água , Poluentes Químicos da Água/análise
15.
J Agric Food Chem ; 65(31): 6564-6571, 2017 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-28712299

RESUMO

The efficacy of nanosilicate clay platelets (NSCP), exfoliated silicates from natural montmorillonites, as a feed additive for ameliorating fumonisin B1 (FB1) toxicosis was evaluated. Toxicological mechanisms by NSCP were examined through proteomic and biochemical analyses. Dietary supplementation with NSCP at a low level of 40 mg/kg of feed improved growth performances in chickens with respect to FB1 toxicosis. Other issues of ameliorated symptoms including serum and/or hepatic aspartate aminotransferase activity, oxidative stress indicators, and sphinganine/sphingosine ratio, a hallmark of FB1 toxicosis, were considered. Chickens with NSCP inclusion alone at 1000 mg/kg of feed exhibited no changes in hepatic histology, oxidative status, and serum parameters and even had a higher feed intake. Proteomic analysis with liver tissues identified 45 distinct proteins differentially affected by FB1 and/or NSCP, in which proteins involved in thiol metabolism and redox regulation, glycolysis, carcinogenesis, and detoxification by glutathione S-transferase were promoted by FB1, whereas NSCP caused differential changes of protein abundances related to methionine/cysteine and choline/glycine interconversion for glutathione synthesis, redox regulation by peroxiredoxin, toxin/metabolite delivery by albumin, glycolysis, tricarboxylic acid cycle, adenosine triphosphate (ATP) synthesis, and chaperon escort for endoplasmic reticulum stress relief. Functional analyses confirmed the enhancement of hepatic metabolic processes for ATP and NAD(P)H production to meet the need for detoxification, antioxidative defense, and toxin/metabolite clearance by FB1 or NSCP ingestion. On the basis of the amelioration of FB1 toxicosis, global profile of hepatic protein expressions, and validated toxicological mechanisms, NSCP were concluded as a safe and effective agent for FB1 detoxification.


Assuntos
Silicatos de Alumínio/metabolismo , Ração Animal/análise , Galinhas/metabolismo , Aditivos Alimentares/metabolismo , Fumonisinas/toxicidade , Micotoxinas/toxicidade , Silicatos/metabolismo , Silicatos de Alumínio/efeitos adversos , Animais , Galinhas/crescimento & desenvolvimento , Argila , Fumonisinas/metabolismo , Inativação Metabólica , Fígado/metabolismo , Micotoxinas/metabolismo , Estresse Oxidativo , Silicatos/efeitos adversos
16.
J Hazard Mater ; 334: 104-111, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28402894

RESUMO

Reductive dechlorination of carbon tetrachloride (CT) was investigated during bioreduction of iron-containing clay mineral (i.e., nontronite) by iron-reducing bacteria (Shewanella putrefaciens CN32 (CN32)). In the absence of CT, the production of Fe(II) significantly increased in nontronite suspension with CN32 in 124 d (11.1% of Fe(III) reduction), resulting in formation of new secondary Fe(II) mineral phase (i.e., vivianite (FeII3(PO4)2·8H2O)). In the presence of CT, an acceleration of CT dechlorination was observed after 13 d and it reached almost 68% of removal efficiency at 32 d in nontronite suspension with CN32, which was 1.8 times higher than that by CN32 alone (37%). Significant amounts of formate (30.1%) and CO (2.4%) were measured during the CT dechlorination in the nontronite suspension with CN32. Results obtained from Fe(II) measurement and X-ray diffraction (XRD) showed the acceleration of Fe(II) production after 13 d and the formation of vivianite in the range of 13-25 d, suggesting that the biogenic vivianite enhanced the CT dechlorination in this study. Experimental results from batch kinetic tests, Fe(II) measurements, XRD analysis, and by-product study suggested that the formation of vivianite can play a crucial role for the enhanced reductive dechlorination of CT in phosphorous enriched subsurface environments with iron-containing clay minerals.


Assuntos
Silicatos de Alumínio/metabolismo , Tetracloreto de Carbono/metabolismo , Shewanella putrefaciens/metabolismo , Argila , Compostos Férricos/metabolismo , Compostos Ferrosos/metabolismo , Halogenação , Oxirredução , Difração de Raios X
17.
J Basic Microbiol ; 57(4): 293-301, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28139058

RESUMO

Bacteria play important roles in mineral weathering and soil formation. However, little is known about the nutrition-related changes in mineral weathering potential and pattern of bacteria. In this study, mineral weathering behaviors of a novel mineral-weathering bacterium Chitinophaga jiangningensis JN53 were characterized in the presence of three contrasting biotite or potassium feldspar-added media. C. jiangningensis JN53 increased more Fe release from the minerals in the M-BHm (nutrition-poor medium) than in the SSKM (nutrition-rich medium) and BHm (nutrition-moderate medium), while C. jiangningensis JN53 released more Al from the minerals and Si from biotite in the SSKM. Similar Si release from potassium feldspar by C. jiangningensis JN53 was observed in the SSKM, BHm, and M-BHm. K releasing ability of C. jiangningensis JN53 was significantly higher in the biotite-added M-BHm. Highest and lowest growth of C. jiangningensis JN53 was observed in the SSKM and M-BHm, respectively. In the presence of the minerals, C. jiangningensis JN53 mainly produced gluconic acid in the SSKM and acetic acid in the BHm and M-BHm. C. jiangningensis JN53 also produced large amount of succinic acid in the biotite-added SSKM and oxalic acid in the potassium feldspar-added M-BHm. The results showed the growth, production of organic acids, and mineral weathering ability of C. jiangningensis JN53 in the three contrasting nutrition conditions. The results also suggested the change in the mineral weathering behaviors of C. jiangningensis JN53 under different levels of nutrition conditions.


Assuntos
Bacteroidetes/metabolismo , Minerais/metabolismo , Microbiologia do Solo , Ácido Acético/metabolismo , Alumínio/metabolismo , Silicatos de Alumínio/metabolismo , Silicatos de Alumínio/farmacologia , Bacteroidetes/efeitos dos fármacos , Bacteroidetes/crescimento & desenvolvimento , Meios de Cultura/química , Gluconatos/metabolismo , Ácido Oxálico/metabolismo , Compostos de Potássio/farmacologia , Silício/metabolismo , Ácido Succínico/metabolismo
18.
Chemosphere ; 174: 28-38, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28157606

RESUMO

Clay minerals are quite vital in biogeochemical processes but the effect of organo-clays in the microbial degradation of crude oil polycyclic aromatic hydrocarbons is not well understood. The role of organo-saponite and organo-montmorillonite in comparison with the unmodified clays in crude oil polycyclic aromatic hydrocarbons (PAHs) removal via adsorption and biodegradation was studied by carrying out microcosm experiments in aqueous clay/oil systems with a hydrocarbon degrading microbial community that is predominantly alcanivorax spp. Montmorillonite and saponite samples were treated with didecyldimethylammonium bromide to produce organo-montmorillonite and organo-saponite used in this study. Obtained results indicate that clays with high cation exchange capacity (CEC) such as montmorillonite produced organo-clay (organomontmorillonite) that was not stimulatory to biodegradation of crude oil polycyclic aromatic compounds, especially the low molecular weight (LMW) ones, such as dimethylnaphthalenes. It is suggested that interaction between the organic phase of the organo-clay and the crude oil PAHs which is hydrophobic in nature must have reduced the availability of the polycyclic aromatic hydrocarbons for biodegradation. Organo-saponite did not enhance the microbial degradation of dimethylnaphthalenes but enhanced the biodegradation of some other PAHs such as phenanthrene. The unmodified montmorillonite enhanced the microbial degradation of the PAHs and is most likely to have done so as a result of its high surface area that allows the accumulation of microbes and nutrients enhancing their contact.


Assuntos
Silicatos de Alumínio/metabolismo , Bactérias/metabolismo , Recuperação e Remediação Ambiental/métodos , Petróleo/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Silicatos de Alumínio/química , Biodegradação Ambiental , Argila , Interações Microbianas , Minerais/química , Minerais/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo
19.
Drug Dev Ind Pharm ; 43(3): 492-501, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27900918

RESUMO

The aim of this study was to determine the potential of gellan gum (GG) and halloysite (HS) dispersions at different mixing ratios and to investigate the potential of GG-HS dispersions in film formation. To this end, the dispersions and films were characterized. The dispersions formed films with large particles ranging from 3 to 4 µm in size, with a zeta potential of ∼-35 mV. The GG-HS films were fabricated using a solvent-casting technique, which generated films with a white opaque appearance and rough surface. The GG-HS films were formed via hydrogen bonding and electrostatic interactions at the inner cavity and outer surface, as confirmed by ATR-FTIR spectroscopy and X-ray diffractometry. The %water uptake and erosion of the GG-HS film decreased with increasing HS content, whereas both puncture strength and elongation were increased in the GG-HS ratios of 1:0.4 and 1:1.2. Moreover, addition of HS into the GG films could possibly decrease drug permeability coefficient when using higher HS ratio in acidic and neutral media. These results suggested that HS modifies the characteristics of the GG used to coat modified-release tablets.


Assuntos
Silicatos de Alumínio/química , Silicatos de Alumínio/metabolismo , Fenômenos Químicos , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/metabolismo , Argila , Avaliação Pré-Clínica de Medicamentos/métodos , Liberação Controlada de Fármacos , Tamanho da Partícula , Permeabilidade
20.
Fungal Biol ; 120(12): 1582-1599, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27890092

RESUMO

Fungi dissolve soil minerals by acidification and mechanical disruption. Dissolution may occur at the microscale (contact between fungus and mineral) and medium scale (entire mineral grains). Mineral weathering by fungi and other microorganisms is thought to be of significant global contribution, perhaps producing specific weathering signatures. We report fungal dissolution of phlogopite mica in experiments with three fungal strains (Alternaria tenuissima, Cladosporium cladosporioides, Stilbella sp.) on solid medium for 30 days at 21 °C and 96-100% relative humidity. The study used variable-pressure SEM-EDS equipped with charge contrast imaging. Statistical analysis of the results discriminated between the weathering activities of the three fungal species, which increased from Stilbella sp. to C. cladosporioides to A. tenuissima, in agreement with the respective decreasing pH in the media (6.4, 5.8, 5.2 ± 0.03). Phlogopite weathering features were irregular and variable, apparently not caused by direct contact with fungal hyphae. EDS values indicated two or more dissolution mechanisms, one of them suggesting cation rearrangement in the mica towards formation of Al-rich smectite. Intimate fungus-mineral interaction was observed, and the lack of observable dissolution traces from such contact interaction is interpreted as the result of effacing by the more intense acid leaching operating at larger scale.


Assuntos
Alternaria/metabolismo , Silicatos de Alumínio/metabolismo , Cladosporium/metabolismo , Microbiologia Ambiental , Hypocreales/metabolismo , Redes e Vias Metabólicas , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Temperatura
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