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1.
J Microbiol ; 57(9): 759-768, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31376108

RESUMO

The cultivation of microbial species remains a primary challenge in microbiology and obtaining pure cultures is essential for the study of microbial physiology and function. When isolating microorganisms from aquaculture environments, Vibrio are the most dominate isolates on the media that are commonly used. In order to expand our ability to study microbial species, an easy-operation and low-cost medium that can reduce the interference of Vibrio strains and increase the cultivability of other bacteria is urgently needed. We compared viable cell counts on conventional media (CM; including Marine Agar 2216 and LB media) and diluted media (DM; including 1/10-Marine Agar 2216, 1/10-LB). We also assessed the diversity of cultivable microorganisms under high and low nutrient conditions by a plate-wash strategy coupled with high-throughput sequencing of the V4 hypervariable region of the 16S rRNA gene. The results show that microbial communities from DM, especially 1/10-Marine Agar 2216, are more diverse than those obtained from CM. Vibrio isolates were reduced on DM. PICRUSt analysis revealed that nutrient composition is a significant contributor to the diversity and function of the cultivable microbial communities. Bacteria grown on CM possess more pathogenic characteristics, whereas DM favors the growth of bacteria that have multiple metabolic functions. Collectively, our data provide strong evidence that dilution of CM influences the cultivability of bacteria from aquaculture seawater. It also supports that DM can expand the range of microbial species that can be cultivated. This study also provides insights for media design in microbial cultivation from aquaculture systems.


Assuntos
Meios de Cultura/metabolismo , Água do Mar/microbiologia , Vibrio/crescimento & desenvolvimento , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Meios de Cultura/química , DNA Bacteriano/genética , Filogenia , RNA Ribossômico 16S/genética , Vibrio/genética , Vibrio/isolamento & purificação , Vibrio/metabolismo
2.
World J Microbiol Biotechnol ; 35(8): 130, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31385043

RESUMO

Bacterial biofilms (BFs) are membrane-like structures formed by the secretion of extracellular polymeric substances (EPS) by bacteria. The formation of BFs contributes to bacterial survival and drug resistance. When bacteria proliferate, they produce secondary metabolites that act as signaling molecules in bacterial communities that regulate intracellular and cell-to-cell communication. This communication can directly affect the physiological behavior of bacteria, including the production and emission of light (bioluminescence), the expression of virulence factors, the resistance to antibiotics, and the shift between planktonic and biofilm lifestyles. We review the major signaling molecules that regulate BF formation, with a focus on quorum-sensing systems (QS), cyclic diguanylate (c-di-GMP), two-component systems (TCS), and small RNA (sRNA). Understanding these processes will lead to new approaches for treating chronic diseases and preventing bacterial resistance.


Assuntos
Bactérias/crescimento & desenvolvimento , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Transdução de Sinais , Bactérias/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/metabolismo , Percepção de Quorum , RNA Bacteriano/metabolismo , Pequeno RNA não Traduzido/metabolismo
3.
World J Microbiol Biotechnol ; 35(9): 131, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432251

RESUMO

Cholesterol is a C27-sterol employed as starting material for the synthesis of valuable pharmaceutical steroids and precursors. The microbial transformations of cholesterol have been widely studied, since they are performed with high regio- and stereoselectivity and allow the production of steroidal compounds which are difficult to synthesize by classical chemical methods. In recent years, ongoing research is being conducted to discover novel biocatalysts and to develop biotechnological processes to improve existing biocatalysts and biotransformation reactions. The main objective of this review is to present the most remarkable advances in fungal and bacterial transformation of cholesterol, focusing on the different types of microbial reactions and biocatalysts, biotransformation products, and practical aspects related to sterol dispersion improvement, covering literature since 2000. It reviews the conversion of cholesterol by whole-cell biocatalysts and by purified enzymes that lead to various structural modifications, including side chain cleavage, hydroxylation, dehydrogenation/reduction, isomerization and esterification. Finally, approaches used to improve the poor solubility of cholesterol in aqueous media, such as the use of different sterol-solubilizing agents or two-phase conversion system, are also discussed.


Assuntos
Bactérias/metabolismo , Biotecnologia/métodos , Colesterol/metabolismo , Fungos/metabolismo , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Biotecnologia/tendências , Biotransformação , Enzimas/metabolismo , Fungos/genética , Fungos/crescimento & desenvolvimento
4.
Bioresour Technol ; 289: 121711, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323722

RESUMO

Transient anoxia due to the periodic anoxic/aerobic operation is beneficial for the nitrite-oxidizing bacteria (NOB) suppression. A continuous reactor of modified University of Cape Town process treating municipal wastewater was equipped with alternating anoxic/aerobic zones to maintain nitritation. Higher nitrite accumulation ratio in the oxic zones was achieved through transient anoxia and shorter aerobic actual hydraulic retention time (15 min), but it steeply deteriorated from above 95.0% to 21.0% after elevated temperature (25 °C). Batch experiments indicated that the existence of initial nitrite at the starting of aerobic phase promoted the recovery of NOB activity from transient anoxia and inhibited the activity of ammonium-oxidizing bacteria. Furthermore, a supplemental modeling further confirmed that the specific growth rates of NOB (µNOB) decreased at the anoxic phase and the recovery extent of µNOB after anoxic exposure have a positive correlation with the initial concentrations of nitrite, leading to the failure of maintaining nitritation.


Assuntos
Nitritos/metabolismo , Compostos de Amônio/metabolismo , Bactérias/crescimento & desenvolvimento , Reatores Biológicos/microbiologia , Águas Residuárias/microbiologia
5.
J Agric Food Chem ; 67(28): 7886-7897, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31283218

RESUMO

Hard, medium, and soft wheat proteins, based on gluten content, were studied for their important roles in nanometallic surface chemistry. In situ synthesis of Au nanoparticles (NPs) was followed to determine the surface adsorption behavior of wheat protein based on the gluten contents. A greater amount of gluten contents facilitated the nucleation to produce Au NPs. X-ray photoelectron spectroscopy (XPS) surface analysis clearly showed the surface adsorption of protein on nanometallic surfaces which was almost equally prevalent for the hard, medium, and soft wheat proteins. Wheat protein conjugated NPs were highly susceptible to phase transfer from aqueous to organic phase that was entirely related to the amount of gluten contents. The presence of higher gluten content in hard wheat protein readily enabled the hard wheat protein conjugated NPs to move across the aqueous-organic interface followed by medium and soft wheat protein conjugated NPs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS page) analysis allowed us to determine molar masses of nanometallic surface adsorbed protein fractions. Only two protein fractions of high molar masses (74 and 85 kDa) from SDS solubilized hard, medium, and soft wheat proteins preferred to adsorb on nanometallic surfaces out of more than 15 protein fractions of pure wheat protein. This made the surface adsorption of wheat protein highly selective and closely related to gluten content. Cetyltrimethylammonium bromide (CTAB) solubilized wheat protein conjugated NPs demonstrated their strong antimicrobial activities against both Gram negative and Gram positive bacteria making them suitable for their applications in food industry.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Glutens/química , Ouro/química , Nanopartículas Metálicas/química , Triticum/química , Adsorção , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Dureza
6.
Food Chem ; 298: 125068, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260977

RESUMO

In this work, 18 gluten-free flours (prepared from cereals, pseudocereals and legumes), differing in pigmentation, were screened for their phenolic profiles, cooked and, then, subjected to digestion and large intestinal fermentation in vitro. A combined targeted/untargeted metabolomic approach was used to elucidate the microbial biotransformation processes of polyphenols following digestion. This preliminary work demonstrated an increase in 3,5-dihydroxybenzoic acid (on average from 0.67 up to 1.30 µmol/g dry matter) throughout large intestinal fermentation of pseudocereals (esp. quinoa), due to their high alkylresorcinol contents. Isoflavones were converted into equol- or O-desmethylangolensin- derivatives, whereas anthocyanins were degraded into lower-molecular-weight phenolics (i.e., protocatechuic aldehyde and 4-hydroxybenzoic acid, with the latter exhibiting the highest increase over time). A decreasing trend was observed for antioxidant activities (i.e., FRAP and ORAC values) moving from digested to faecal fermented samples. These findings highlight that gluten-free flours are able to deliver bioaccessible polyphenols to the colon.


Assuntos
Farinha/análise , Intestino Grosso/microbiologia , Polifenóis/metabolismo , Animais , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Técnicas de Cultura Celular por Lotes , Cromatografia Líquida de Alta Pressão , Culinária , Fezes/microbiologia , Polifenóis/análise , Polifenóis/química , Espectrometria de Massas por Ionização por Electrospray , Suínos
7.
World J Microbiol Biotechnol ; 35(6): 90, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-31147784

RESUMO

The ability of plant growth promoting rhizobacteria (PGPR) for imparting abiotic stress tolerance to plants has been widely explored in recent years; however, the diversity and potential of these microbes have not been maximally exploited. In this study, we characterized four bacterial strains, namely, Pseudomonas aeruginosa PM389, Pseudomonas aeruginosa ZNP1, Bacillus endophyticus J13 and Bacillus tequilensis J12, for potential plant growth promoting (PGP) traits under osmotic-stress, induced by 25% polyethylene glycol (PEG) in the growth medium. Growth curve analysis was performed in LB medium with or without PEG, in order to understand the growth patterns of these bacteria under osmotic-stress. All strains were able to grow and proliferate under osmotic-stress, although their growth rate was slower than that under non-stressed conditions (LB without PEG). Bacterial secretions were analyzed for the presence of exopolysaccharides and phytohormones and it was observed that all four strains released these compounds into the media, both, under stressed and non-stressed conditions. In the Pseudomonas strains, osmotic stress caused a decrease in the levels of auxin (IAA) and cytokinin (tZ), but an increase in the levels of gibberellic acid. The Bacillus strains on the other hand showed a stress-induced increase in the levels of all three phytohormones. P. aeruginosa ZNP1 and B. endophyticus J13 exhibited increased EPS production under osmotic-stress. While osmotic stress caused a decrease in the levels of EPS in P. aeruginosa PM389, B. tequilensis J12 showed no change in EPS quantities released into the media under osmotic stress when compared to non-stressed conditions. Upon inoculating Arabidopsis thaliana seedlings with these strains individually, it was observed that all four strains were able to ameliorate the adverse effects of osmotic-stress (induced by 25% PEG in MS-Agar medium) in the plants, as evidenced by their enhanced fresh weight, dry weight and plant water content, as opposed to osmotic-stressed, non-inoculated plants.


Assuntos
Arabidopsis/microbiologia , Fenômenos Fisiológicos Bacterianos , Secas , Pressão Osmótica , Desenvolvimento Vegetal , Reguladores de Crescimento de Planta/metabolismo , Polissacarídeos Bacterianos/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Bacillus/crescimento & desenvolvimento , Bacillus/fisiologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Citocininas/metabolismo , Giberelinas/metabolismo , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/fisiologia , Rizosfera , Plântula/crescimento & desenvolvimento , Microbiologia do Solo , Estresse Fisiológico/fisiologia
9.
BMC Plant Biol ; 19(1): 284, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253081

RESUMO

BACKGROUND: Echinacea-endophyte interaction might affect plant secondary metabolites content and influence bacterial colonization specificity and plant growth, but the underlying mechanisms need deepening. An in vitro model, in which E. purpurea axenic plants as host species and E. angustifolia and Nicotiana tabacum as non-host species inoculated with single endophytes isolated from stem/leaf, root and rhizospheric soil, were used to investigate bacterial colonization. RESULTS: Colonization analysis showed that bacteria tended to reach tissues from which they were originally isolated (tissue-specificity) in host plants but not in non-host ones (species-specificity). Primary root elongation inhibition as well as the promotion of the growth of E. purpurea and E. angustifolia plants were observed and related to endophyte-produced indole-3-Acetic Acid. Bacteria-secreted substances affected plant physiology probably interacting with plant regulators. Plant metabolites played an important role in controlling the endophyte growth. CONCLUSIONS: The proposed in vitro infection model could be, generally used to identify novel bioactive compounds and/or to select specific endophytes contributing to the host metabolism properties.


Assuntos
Bactérias/crescimento & desenvolvimento , Echinacea/microbiologia , Endófitos/crescimento & desenvolvimento , Microbiologia do Solo , Echinacea/crescimento & desenvolvimento , Especificidade de Órgãos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/microbiologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Rizosfera , Tabaco/crescimento & desenvolvimento , Tabaco/microbiologia
10.
J Med Microbiol ; 68(8): 1159-1166, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31188093

RESUMO

PURPOSE: Burkholderia pseudomallei is a key pathogen causing bloodstream infections at Sihanouk Hospital Center of Hope, Phnom Penh, Cambodia. Here, visual instead of automated detection of growth of commercial blood culture bottles is done. The present study assessed the performance of this system. METHODOLOGY: Blood culture sets, consisting of paired adult aerobic and anaerobic bottles (bioMérieux, FA FAN 259791 and FN FAN 252793) were incubated in a standard incubator for 7 days after reception. Each day, the bottle growth indicator was visually inspected for colour change indicating growth. Blind subculture was performed from the aerobic bottle at day 3. RESULTS: From 2010 to 2015, 11  671 sets representing 10  389 suspected bloodstream infection episodes were documented. In 1058 (10.2  %) episodes, pathogens grew; they comprised Escherichia coli (31.7 %), Salmonella Paratyphi A (13.9 %), B. pseudomallei (8.5 %), Staphylococcus aureus (7.8 %) and Klebsiella pneumoniae (7.0 %). Blind subculture yielded 72 (4.1  %) pathogens, mostly (55/72, 76.4 %) B. pseudomallei. Cumulative proportions of growth at day 2 were as follows: E. coli: 85.0 %, Salmonella Paratyphi A: 85.0 %, K. pneumoniae: 76.3  % and S. aureus: 52.2  %; for B. pseudomallei, this was only 4.0  %, which increased to 70.1  % (70/99) at day 4 mainly by detection on blind subculture (55/99). Compared to the anaerobic bottles, aerobic bottles had a higher yield and a shorter time-to-detection, particularly for B. pseudomallei. CONCLUSIONS: Visual inspection for growth of commercial blood culture bottles in a low-resource setting provided satisfactory yield and time-to-detection. However, B. pseudomallei grew slowly and was mainly detected by blind subculture. The aerobic bottle outperformed the anaerobic bottle.


Assuntos
Bacteriemia/microbiologia , Hemocultura/métodos , Burkholderia pseudomallei/crescimento & desenvolvimento , Melioidose/diagnóstico , Aerobiose , Anaerobiose , Bacteriemia/diagnóstico , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Burkholderia pseudomallei/isolamento & purificação , Camboja , Recursos em Saúde , Humanos , Melioidose/microbiologia , Fatores de Tempo
11.
J Microbiol ; 57(9): 748-758, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31187413

RESUMO

Intrauterine growth restriction (IUGR) predisposes newborns to inflammatory and metabolic disturbance. Disequilibrium of gut microbiota in early life has been implicated in the incidence of inflammation and metabolic diseases in adulthood. This study aimed to investigate the difference in gut microbiota colonization, cytokines and plasma metabolome between IUGR and normal birth weight (NBW) piglets in early life. At birth, reduced (P < 0.05) body, jejunum, and ileum weights, as well as decreased (P < 0.05) small intestinal villi and increased (P < 0.05) ileal crypt depth were observed in IUGR piglets compared with their NBW counterparts. Imbalanced inflammatory and plasma metabolome profile was observed in IUGR piglets. Furthermore, altered metabolites were mainly involved in fatty acid metabolism and inflammatory response. At 12 h after birth and after suckling colostrum, reduced (P < 0.05) postnatal growth and the small intestinal maturation retardation (P < 0.05) continued in IUGR piglets in comparison with those in NBW littermates. Besides, the gut microbiota structure was significantly altered by IUGR. Importantly, the disruption of the inflammatory profile and metabolic status mainly involved the pro-inflammatory cytokines (IL-1ß and IFN-γ) and amino acid metabolism. Moreover, spearman correlation analysis showed that the increased abundance of Escherichia-Shigella and decreased abundance of Clostridium_sensu_stricto_1 in IUGR piglets was closely associated with the alterations of slaughter weight, intestinal morphology, inflammatory cytokines, and plasma metabolites. Collectively, IUGR significantly impairs small intestine structure, modifies gut microbiota colonization, and disturbs inflammatory and metabolic profiles during the first 12 h after birth. The unbalanced gut microbiota mediated by IUGR contributes to the development of inflammation and metabolic diseases.


Assuntos
Bactérias/crescimento & desenvolvimento , Retardo do Crescimento Fetal/veterinária , Microbioma Gastrointestinal , Plasma/química , Doenças dos Suínos/sangue , Doenças dos Suínos/imunologia , Animais , Animais Recém-Nascidos/sangue , Animais Recém-Nascidos/crescimento & desenvolvimento , Animais Recém-Nascidos/imunologia , Animais Recém-Nascidos/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Citocinas/sangue , Feminino , Retardo do Crescimento Fetal/sangue , Retardo do Crescimento Fetal/imunologia , Retardo do Crescimento Fetal/microbiologia , Mucosa Intestinal/anatomia & histologia , Mucosa Intestinal/crescimento & desenvolvimento , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Jejuno/anatomia & histologia , Jejuno/crescimento & desenvolvimento , Masculino , Tamanho do Órgão , Plasma/metabolismo , Gravidez , Suínos , Doenças dos Suínos/microbiologia , Doenças dos Suínos/fisiopatologia
12.
Microbiol Res ; 223-225: 1-12, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178042

RESUMO

Phosphorus (P) is an essential plant nutrient, but often limited in soils for plant uptake. A major economic constraint in the rice production is excessive use of chemical fertilizers to meet the P requirement. Bioaugmentation of phosphate solubilizing rhizobacteria (PSB) can be used as promising alternative. In the present study 11 mineral PSB were isolated from Basmati rice growing areas of Pakistan. In broth medium, PSB solubilized tricalcium phosphate (27-354 µg mL-1) with concomitant decrease in pH up to 3.6 due to the production of different organic acids, predominantly gluconic acid. Of these, 4 strains also have ability to mineralize phytate (245-412 µg mL-1). Principle component analysis showed that the gluconic acid producing PSB strains (Acinetobacter sp. MR5 and Pseudomonas sp. MR7) have pronounced effect on grain yield (up to 55%), plant P (up to 67%) and soil available P (up to 67%), with 20% reduced fertilization. For simultaneous validation of gluconic acid production by MR5 and MR7 through PCR, new specific primers were designed to amplify gcd, pqqE, pqqC genes responsible for glucose dehydrogenase (gcd) mediated phosphate solubilization. These findings for the first time demonstrated Acinetobacter soli as potent P solubilizer for rice and expands our knowledge about genus specific pqq and gcd primers. These two gcd containing PSB Acinetobacter sp. MR5 (DSM 106631) and Pseudomonas sp. MR7 (DSM 106634) submitted to German culture collection (DSMZ), serve as global valuable pool to significantly increase the P uptake, growth and yield of Basmati rice with decreased dependence on chemical fertilizer in P deficit agricultural soils.


Assuntos
Biofortificação , Glucose 1-Desidrogenase/genética , Oryza/crescimento & desenvolvimento , Fósforo/metabolismo , Acinetobacter/genética , Agricultura , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Bactérias/metabolismo , Proteínas de Bactérias/genética , Transporte Biológico , Meios de Cultura , Fertilizantes , Germinação , Gluconatos/metabolismo , Concentração de Íons de Hidrogênio , Paquistão , Fosfatos/metabolismo , Pseudomonas/genética , Sementes/crescimento & desenvolvimento , Solo/química , Microbiologia do Solo , Solubilidade
13.
Microbiol Res ; 223-225: 120-128, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178044

RESUMO

Plant growth-promoting bacteria have been highlighted by their potential for application in plant production, allowing the reduction of the use of fertilizers and pesticides, which is due to the ability to stimulate the growth of plants by nitrogen-fixation and production of phytohormones, such as indole-3-acetic acid (IAA). The objective of this study was to verify the potential of plant growth promotion of 25 wild isolates from the Agricultural Microbiology Culture Collection of the Federal University of Lavras (CCMA-UFLA) through the evaluation of the biological nitrogen-fixation capacity and the production of IAA. In addition, the growth of three selected strains inoculated on roots of strawberry seedlings in greenhouse conditions was evaluated. The experiment was conducted in a completely randomized design (CRD), with an 8 × 2 factorial schemes involving eight combinations of bacteria: alone, in pairs and threes, plus the control without inoculation. Two fertilizer levels were used (0% and 50% of nitrogen), totaling 16 treatments with eight replicates each. After 75 days, variables such as root length, root dry weight, aerial part length, aerial part dry weight, leaf number, total dry mass and ultrastructural analysis of the inoculated and uninoculated roots, were evaluated. The results showed that the strawberry crop responded positively to inoculation with the three bacteria combined Azospirillum brasilense (Ab-V5) + Burkholderia cepacia (CCMA 0056) + Enterobacter cloacae (CCMA 1285) compared to the uninoculated controls. More expressive responses in terms of plant growth were observed in relation to the combined inoculation of the three bacterial strains plus fertilizer application with 50% of nitrogen.


Assuntos
Fenômenos Fisiológicos Bacterianos , Fragaria/crescimento & desenvolvimento , Fragaria/microbiologia , Fixação de Nitrogênio , Desenvolvimento Vegetal , Azospirillum brasilense/fisiologia , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biomassa , Burkholderia cepacia/fisiologia , Enterobacter cloacae , Ácidos Indolacéticos/metabolismo , Nitrogênio , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/microbiologia , Raízes de Plantas/microbiologia , Plântula
14.
Chem Commun (Camb) ; 55(52): 7478-7481, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31184648

RESUMO

Facile chemical modification of mesoporous silica particles allows the production of gated reservoir systems capable of hydrophobicity-triggered release. Applied to the delivery of nutrients specifically to an oil phase, the systems developed have been shown to reliably assist the bacterial degradation of hydrocarbons. The gated system developed, made of C18 hydrocarbon chains, is demonstrated to be in a closed collapsed state in an aqueous environment, yet opens up through solvation by lipophilic alkanes and releases its content on contact with the oil phase.


Assuntos
Bactérias/crescimento & desenvolvimento , Nanopartículas/química , Poluição por Petróleo/prevenção & controle , Dióxido de Silício/química , Bactérias/metabolismo , Portadores de Fármacos/química , Hidrocarbonetos/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Marinobacter/crescimento & desenvolvimento , Marinobacter/metabolismo , Nutrientes/química , Porosidade
15.
BMC Complement Altern Med ; 19(1): 150, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31242939

RESUMO

BACKGROUND: Traditional medicine remedies are commonly used for treatment of diverse ailments including bacterial infections. The activity against resistant bacteria and safety of some remedies sold as anti-infective treatments in market places in Buea, Southwest Cameroon were investigated as potential alternative treatment to counter increasing antibiotic resistance. METHODS: Ten remedies were purchased, their components documented and microbial load estimated. Methanol extracts of the remedies were tested for antibacterial activity by disc diffusion and microdilution. Cytotoxicity was evaluated on monkey kidney epithelial cells (LLC-MK2) while acute oral toxicity was done in BALB/c mice for the bactericidal extract. Extracts were further analysed using phytochemical tests. RESULTS: All the remedies had microbial loads above the acceptable limit of 105 CFU/g. The highest activity was produced by extracts of four remedies (TP 1, 2, 4, 6a, 6b) against all clinical isolates among which three were active against four control strains. Zones of inhibition ranged from 8 to 27 mm. Two of the four extracts produced zones ≥20 mm against multidrug resistant clinical isolates of Citrobacter freundii and Escherichia coli but were less active compared to Gentamycin positive control (P < 0.0001-0.0014). The most active extracts also recorded minimum inhibitory concentrations of 1 to 4 mg/mL. One of them (TP2) was bactericidal against a clinical isolate of methicillin-resistant Staphylococcus aureus with a minimum bactericidal concentration of 8 mg/mL. Extracts of six remedies did not show cytotoxicity and no mortality or adverse effect was recorded in the acute oral toxicity test. Phytochemical screening showed the most active extracts contained relatively high amounts of alkaloids and flavonoids. CONCLUSION: Only four of the eight remedies tested showed activity against multidrug resistant bacteria suggesting some of these remedies may not be effective against bacterial infections. Production and handling methods should be improved and the product quality controlled to ensure biosecurity. The remedies which were both active and non-toxic should be further investigated including in vivo experiments to assess their efficacy.


Assuntos
Antibacterianos/farmacologia , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/toxicidade , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/microbiologia , Camarões , Farmacorresistência Bacteriana Múltipla , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Feminino , Humanos , Medicina Tradicional , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Compostos Fitoquímicos/química , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/toxicidade , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/toxicidade , Plantas Medicinais/microbiologia
16.
BMC Complement Altern Med ; 19(1): 146, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31227024

RESUMO

BACKGROUND: There is increasing interest in the pharmaceutical and food industries to substitute synthetic chemicals with naturally occurring compounds possessing bioactive properties. Plants are valuable sources of bioactive compounds. The present study investigates the chemical composition and antioxidant, antimicrobial, and anticancer activities of ethanolic extracts (EEs) and essential oils (EOs) from two species in the Lamiaceae family, Ocimum basilicum L. and Thymus algeriensis Boiss. & Reut., cultivated in the Algerian Saharan Atlas. METHODS: The total flavonoid contents of the plants' ethanolic extracts were determined by the aluminium chloride method, while the total phenols were determined using the Folin-Ciocalteu method. Essential oils were obtained by hydrodistillation of the aerial parts of the plants and were analysed by GC-MS. The free radical-scavenging ability and antioxidant potential of the plants' EEs and EOs were probed using the 2, 2-diphenyl-picrylhydrazyl radical-scavenging, ABTS radical-scavenging, ferric-reducing power and phosphomolybdenum assays. The antimicrobial activities were evaluated against several pathogens characteristic of gram-negative bacteria (three species), gram-positive bacteria (three species) and fungi (two species). The microdilution method was used to estimate the minimum inhibitory concentrations (MICs). The oils' anticancer potential against several cancer types was also studied using the MTT assay and reported as the toxic doses that resulted in a 50% reduction in cancer cell growth (LD50). RESULTS: Phenolic compounds in the EEs from both plants were analysed by HPLC and demonstrated a rich flavonoid content. Chemical analysis of the essential oil from Ocimum basilicum revealed 26 unique compounds, with linalool (52.1%) and linalyl acetate (19.1%) as the major compounds. A total of 29 compounds were identified in the essential oil from Thymus algeriensis, with α-terpinyl acetate (47.4%), neryl acetate (9.6%), and α-pinene (6.8%) as the major compounds. The ethanolic extracts and essential oils from both plants exhibited moderate antioxidant activities and moderate to weak antimicrobial activities. Furthermore, anticancer activities against the examined human cancer cell lines were associated with only the EOs from both plants, with LD50 values ranging between 300 and 1000 µg/mL. CONCLUSION: The results suggest that the bioactive compounds found in the ethanolic extracts and essential oils from Ocimum basilicum and Thymus algeriensis, with diverse antioxidant, antimicrobial and anticancer activities, may have beneficial applications in nutraceutical and pharmaceutical technologies.


Assuntos
Ocimum basilicum/química , Óleos Voláteis/química , Óleos Vegetais/química , Thymus (Planta)/química , Argélia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Linhagem Celular Tumoral , Sobrevivência Celular , Cromatografia Líquida de Alta Pressão , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Humanos , Fenol/química , Fenol/farmacologia , Óleos Vegetais/farmacologia
17.
Sci Total Environ ; 659: 1135-1145, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31096327

RESUMO

Aerated Constructed Wetlands are a state-of-the-art design that provides a different physical and chemical environment (compared to traditional passive wetland designs) for the wastewater treatment processes and, thus, may have different pathogen removal characteristics. In order to establish the fate of bacterial and viral indicators, a field study was carried out at a Sewage Treatment Works (STW) in the UK (serving 20,000 pe). The STW consists of primary and secondary sedimentation tanks and trickling filters (TF) as the biological stage. A large (1,160 m2) pilot aerated Vertical Flow Constructed Wetland (AVFCW) was constructed at the STW as tertiary stage receiving » of the total flow rate, i.e., 1250 m3/day. Effluent quality of the AVFCW complied with national and international standards for environmental discharge and reuse. For the first time, two sets of bacterial (Faecal coliforms, E.coli and intestinal enterococci) and viral indicators (Somatic coliphages, F-RNA specific bacteriophages and human-specific B. fragilis GB124 phages) were simultaneously investigated in an AVFCW and TF. High elimination rates were detected (up to 3.7 and 2.2 log reduction for bacteria indicators and phages, respectively) and strong correlations between the two sets were found. The superior efficiency of the aerated Constructed Wetlands in microbiological contamination removal compared to passive wetland systems was established for the first time, which may have implications for process selection for wastewater reuse. This field study therefore provides new evidence on the fate of bacteriophages and a first indication of their potential use for performance evaluation in TF and aerated Constructed Wetlands. It also demonstrates that the combination of TF with aerated constructed wetlands could be a novel and effective treatment scheme for new STW or for the upgrade of existing STW.


Assuntos
Bactérias/crescimento & desenvolvimento , Bacteriófagos/crescimento & desenvolvimento , Eliminação de Resíduos Líquidos/métodos , Microbiologia da Água , Áreas Alagadas , Monitoramento Ambiental , Humanos , Águas Residuárias/microbiologia , Águas Residuárias/virologia
18.
Food Chem ; 292: 336-345, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31054683

RESUMO

Biochemical effects of the water soluble fiber fraction of sugarcane bagasse (BSF) fermented in the colon was examined to evaluate its potential health promoting effects. A feeding experiment involving Fischer 344 rats, was conducted with 3 experimental diets containing, cellulose (CON), a commercial xylo-oligosaccharide (XYO) and BSF (BGS). Cumulative feed intake was significantly lower in XYO group while cecal weight was significantly higher. Acetic and propionic acid contents in the cecal content were significantly higher in the BGS and XYO, respectively. Total short chain fatty acid content was significantly higher in BGS and XYO resulting significantly lower cecal pH. Beneficial bacteria such as Bifidobacterium, Blautia, Akkermansia and Roseburia abundance was significantly higher in the XYO and BGS groups. Further, mucin and immunoglobulin-A contents were significantly higher in BGS group compared to CON group. Thus, BSF exhibited its ability to enhance the intestinal and systemic health upon fermentation in the colon.


Assuntos
Bactérias/metabolismo , Ceco/microbiologia , Fibras na Dieta/análise , Saccharum/metabolismo , Amônia/análise , Animais , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bifidobacterium/genética , Bifidobacterium/crescimento & desenvolvimento , Ceco/química , Ceco/metabolismo , Celulose/química , Cromatografia Líquida de Alta Pressão , DNA Bacteriano/química , DNA Bacteriano/metabolismo , Ácidos Graxos Voláteis/análise , Ácidos Graxos Voláteis/química , Masculino , Modelos Animais , Oligossacarídeos/química , Análise de Componente Principal , Ratos , Ratos Endogâmicos F344 , Água/química
19.
Microbes Environ ; 34(2): 191-198, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31080215

RESUMO

We investigated whether ectomycorrhizal (ECM) fungal species exhibit antibacterial activity towards culturable bacterial communities in mycorrhizospheres. Four hundred and thirty bacterial strains were isolated from the ECM root tips of Pinus densiflora and bulk soil, and 21 were co-cultured with six ECM fungal species. Three hundred and twenty-nine bacterial 16S rDNA sequences were identified in ECM roots (n=185) and bulk soil (n=144). Mycorrhizosphere isolates were dominated by Gram-negative Proteobacteria from 16 genera, including Burkholderia, Collimonas, Paraburkholderia, and Rhizobium. Paraburkholderia accounted for approximately 60%. In contrast, bulk soil isolates contained a high number of Gram-positive Firmicutes, particularly from Bacillus. Paraburkholderia accounted for ≤20% of the bacterial isolates from bulk soil, which was significantly lower than its percentage in ECM root tips. Co-cultures of six ECM fungal species with the 21 bacterial strains revealed that eight strains of three Gram-positive genera-Arthrobacter, Bacillus, and Lysinibacillus-were sensitive to the antibacterial activity of the fungi. In contrast, the Gram-negative strains, including five Paraburkholderia strains, two Burkholderia strains, and a Rhizobium sp., were not sensitive. The strength of fungal antibacterial activity varied in a species-dependent manner, but consistently affected Gram-positive bacteria. These results suggest that Gram-positive bacteria are excluded from the mycorrhizosphere by the antibacterial activity of ECM fungi, which develops specific soil bacterial communities in the mycorrhizosphere.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Microbiota , Micorrizas/metabolismo , Rizosfera , Antibacterianos/metabolismo , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Técnicas de Cocultura , Fungos/classificação , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Microbiota/efeitos dos fármacos , Microbiota/genética , Micélio/crescimento & desenvolvimento , Micorrizas/classificação , Micorrizas/crescimento & desenvolvimento , Pinus/microbiologia , Raízes de Plantas/microbiologia , Microbiologia do Solo
20.
J Basic Microbiol ; 59(7): 723-734, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31081547

RESUMO

In the present study, 12 indigenous diesel-oil-degrading bacteria were isolated from the petroleum-contaminated soils of the Changqing oil field (Xi'an, China). Measurement of the diesel-oil degradation rates of these strains by the gravimetric method revealed that they ranged from 42% to 66% within 2 weeks. The highest degradation rates were observed from strains CQ8-1 (66%), CQ8-2 (62.6%), and CQ11 (59%), which were identified as Bacillus thuringiensis, Ochrobactrum anthropi, and Bordetella bronchialis, respectively, based on their 16S rDNA sequences. Moreover, the physiological and biochemical properties of these three strains were analyzed by Gram staining, catalase, oxidase, and Voges-Proskauer tests. Transmission electron microscopy showed that all three strains were rod shaped with flagella. Gas chromatography and mass spectrometric analyses indicated that medium- and long-chain n-alkanes in diesel oil (C11-C29) were degraded to different degrees by B. thuringiensis, O. anthropi, and B. bronchialis, and the degradation rates gradually decreased as the carbon numbers increased. Overall, the results of this study indicate strains CQ8-1, CQ8-2, and CQ11 might be useful for environmentally friendly and cost-effective bioremediation of oil-contaminated soils.


Assuntos
Bactérias/classificação , Bactérias/metabolismo , Campos de Petróleo e Gás/microbiologia , Petróleo/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Alcanos/metabolismo , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Biodegradação Ambiental , China , DNA Bacteriano/genética , Flagelos , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
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