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1.
Insects ; 13(4)2022 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-35447768

RESUMO

The black soldier fly, Hermetia illucens (BSF, Diptera: Stratiomyidae) is an insect with high protein value and a potential feed agent for animals aimed for human consumption. The growth parameters of BSF larvae reared on four substrates-restaurant-waste, fruit-waste, fish-waste, and commercial tilapia food-for 41 days before processing for inclusion into Oreochromis niloticus (Perciformes: Cichlidae, Nile tilapia) commercial fry diets at 30% (70:30) were determined. On fly larvae, the food substrate based on restaurant waste yielded the greatest larval weight and length. BSF larvae fed a fish-waste diet showed the shortest developmental time. The fruit-waste diet induced the lowest weight and length in the fly larvae/pre-pupae (immature stage). The pre-pupal protein values were similar to commercial food. On fry-fish, the diets with pre-pupae grown on fish waste showed the greatest yields regarding weight (biomass), length, and nutritional content. These results suggest the BSF has the potential to be used in fish feed and provides an alternative for commercial cultivation.

2.
Molecules ; 26(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806654

RESUMO

Trypanosomatids are the causative agents of leishmaniasis and trypanosomiasis, which affect about 20 million people in the world's poorest countries, leading to 95,000 deaths per year. They are often associated with malnutrition, weak immune systems, low quality housing, and population migration. They are generally recognized as neglected tropical diseases. New drugs against these parasitic protozoa are urgently needed to counteract drug resistance, toxicity, and the high cost of commercially available drugs. Microbial bioprospecting for new molecules may play a crucial role in developing a new generation of antiparasitic drugs. This article reviews the current state of the available literature on chemically defined metabolites of microbial origin that have demonstrated antitrypanosomatid activity. In this review, bacterial and fungal metabolites are presented; they originate from a range of microorganisms, including cyanobacteria, heterotrophic bacteria, and filamentous fungi. We hope to provide a useful overview for future research to identify hits that may become the lead compounds needed to accelerate the discovery of new drugs against trypanosomatids.


Assuntos
Antiprotozoários/uso terapêutico , Bactérias/química , Fungos/química , Leishmaniose/tratamento farmacológico , Trypanosomatina/fisiologia , Tripanossomíase/tratamento farmacológico , Animais , Humanos , Leishmaniose/metabolismo , Tripanossomíase/metabolismo
3.
J Med Entomol ; 56(1): 261-267, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30239790

RESUMO

Culex quinquefasciatus Say (Diptera: Culicidae), an arboviral and filarial vector, is one of the most widespread mosquitoes in the world. The indiscriminate use of synthetic chemical insecticides has led to the development of resistance in mosquito populations worldwide. The effect of continuous exposure to crude extracts of Argemone mexicana, the Mexican poppy, on the development and growth stages of second-instar larvae of the mosquito was studied, along with qualitative chemical analysis of the different plant parts. Inhibition, mortality, and larval and pupal duration phases were assessed. Second-instar mosquito larvae were exposed to crude ethanol extracts of flowers, stems, and seeds. Flower extract exhibited the strongest larvicidal activity with LC50 and LC90 values after 24 h of exposure of 18.61 and 39.86 ppm, respectively, and 9.47 and 21.76 ppm after 48 h. Extracts from stem and seeds were significantly less effective. The flower extract registered a Growth Inhibition Index of 0.01 at 25 ppm, with stems and seeds registering 0.05 and 0.08, respectively, at 100 ppm (control group 1.02). Qualitative chemical analysis by thin-layer chromatography showed characteristic spots indicating the presence of alkaloids and flavonoids and phytochemical screening showed the presence of alkaloids, anthraquinones, flavonoids, tannins, and terpenoids in the various crude extracts. This is the first report of the effectiveness of an ethanol flower extract of A. mexicana on Cx. quinquefasciatus; it can be considered a promising alternative control for this mosquito species.


Assuntos
Argemone , Culex , Controle de Mosquitos , Extratos Vegetais , Animais , Feminino , Larva , Testes de Toxicidade
4.
Rev. chil. neuropsicol. (En línea) ; 13(1): 6-10, ago. 2018. ilus
Artigo em Espanhol | LILACS | ID: biblio-1099480

RESUMO

La memoria de trabajo (MT) ha servido de predictor para fenómenos como el desempeño escolar en matemáticas, el nivel de comprensión lectora y el aprendizaje de estudiantes con desarrollo atípico. Esto le ha llevado a tomar un rol clave en los estudios cognitivos. Debido a la importancia que ha tomado la MT, se vuelve relevante explorar modelos que expliquen este constructo de manera de acercar estas propuestas a los investigadores que se estén familiarizando con esta temática. El presente artículo presenta y compara el modelo multicomponencial de Baddeley y Hitch (1974) y sus actualizaciones posteriores (Baddeley, 2000, 2012, 2017) con el modelo integrado de atención y memoria de Cowan (1988, 1995, 2005). Desde la revisión detallada de ambas propuestas se realiza una comparación utilizando como criterios el rol de la memoria en el modelo, la equivalencia entre los componentes del modelo y la manera en la cual se propone se manipula la información. Los hallazgos de esta revisión muestran que aun cuando existen equivalencias de algunos de los elementos de ambas propuestas, los distintos énfasis de ambos modelos resultan en interpretaciones distintas de los sustentos empíricos y del funcionamiento de la MT en relación con los roles de la memoria a largo plazo y la atención.


Working Memory (MT) has served as a predictor for phenomena such as school performance in mathematics, reading comprehension and learning of students with atypical development. This has given it a key role in cognitive studies. Due to the importance that WM has taken, it becomes relevant to explore models that explain this construct to bring these proposals closer to researchers who are becoming familiar with this topic. The present article presents and compares the multicomponent model of Baddeley and Hitch (1974) and its subsequent updates (Baddeley, 2000, 2012, 2017) with the integrated attention and memory model of Cowan (1988, 1995, 2005). From the detailed review of both proposals a comparison is made using as criteria the role of memory in the model, the equivalence between the components of both models and the way in which the information is stored and accessed. The findings of this review show that although there are equivalences among some of the elements of both proposals, the different emphases of both models result in different interpretations of the empirical underpinnings and the functioning of WM in relation to the roles of the long-term memory and attention.


Assuntos
Humanos , Memória de Curto Prazo , Modelos Neurológicos , Atenção , Modelos Teóricos
5.
Artigo em Inglês | MEDLINE | ID: mdl-29439486

RESUMO

Cadmium is a major heavy metal found in polluted aquatic environments, mainly derived from industrial production processes. We evaluated the biosorption of solubilized Cd2+ using the extracellular polymeric substances (EPS) produced by Bacillus sp. MC3B-22 and Microbacterium sp. MC3B-10 (Microbactan); these bacteria were originally isolated from intertidal biofilms off the coast of Campeche, Mexico. EPS were incubated with different concentrations of cadmium in ultrapure water. Residual Cd2+ concentrations were determined by Inductive Coupled Plasma-Optic Emission Spectrometry and the maximum sorption capacity (Qmax) was calculated according to the Langmuir model. EPS were characterized by X-ray photoelectron spectroscopy (XPS) before and after sorption. The Qmax of Cd2+ was 97 mg g-1 for Microbactan and 141 mg g-1 for MC3B-22 EPS, these adsorption levels being significantly higher than previously reported for other microbial EPS. In addition, XPS analysis revealed changes in structure of EPS after biosorption and showed that amino functional groups contributed to the binding of Cd2+, unlike other studies that show the carbohydrate fraction is responsible for this activity. This work expands the current view of bacterial species capable of synthesizing EPS with biosorbent potential for cadmium and provides evidence that different chemical moieties, other than carbohydrates, participate in this process.


Assuntos
Biopolímeros/química , Cádmio/química , Poluentes Químicos da Água/química , Actinobacteria/metabolismo , Adsorção , Bacillus/metabolismo , Biofilmes , Biopolímeros/metabolismo , México
6.
Bioorg Med Chem Lett ; 27(15): 3490-3494, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28645659

RESUMO

We designed and synthesized five new 5-nitrothiazole-NSAID chimeras as analogues of nitazoxanide, using a DCC-activated amidation. Compounds 1-5 were tested in vitro against a panel of five protozoa: 2 amitochondriates (Giardia intestinalis, Trichomonas vaginalis) and 3 kinetoplastids (Leishmania mexicana, Leishmania amazonensis and Trypanosoma cruzi). All chimeras showed broad spectrum and potent antiprotozoal activities, with IC50 values ranging from the low micromolar to nanomolar order. Compounds 1-5 were even more active than metronidazole and nitazoxanide, two marketed first-line drugs against giardiasis. In particular, compound 4 (an indomethacin hybrid) was one of the most potent of the series, inhibiting G. intestinalis growth in vitro with an IC50 of 0.145µM. Compound 4 was 38-times more potent than metronidazole and 8-times more active than nitazoxanide. The in vivo giardicidal effect of 4 was evaluated in a CD-1 mouse model obtaining a median effective dose of 1.709µg/kg (3.53nmol/kg), a 321-fold and 1015-fold increase in effectiveness after intragastric administration over metronidazole and nitazoxanide, respectively. Compounds 1 and 3 (hybrids of ibuprofen and clofibric acid), showed potent giardicidal activities in the in vitro as well as in the in vivo assays after oral administration. Therefore, compounds 1-5 constitute promising drug candidates for further testing in experimental chemotherapy against giardiasis, trichomoniasis, leishmaniasis and even trypanosomiasis infections.


Assuntos
Antiprotozoários/química , Antiprotozoários/uso terapêutico , Giardia lamblia/efeitos dos fármacos , Giardíase/tratamento farmacológico , Tiazóis/química , Tiazóis/uso terapêutico , Animais , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Anti-Inflamatórios não Esteroides/uso terapêutico , Antiprotozoários/síntese química , Antiprotozoários/farmacologia , Desenho de Fármacos , Feminino , Humanos , Leishmania/efeitos dos fármacos , Camundongos , Nitrocompostos , Infecções por Protozoários/tratamento farmacológico , Tiazóis/síntese química , Tiazóis/farmacologia , Trichomonas vaginalis/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos
7.
Front Microbiol ; 7: 201, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26941725

RESUMO

Soil and rock surfaces support microbial communities involved in mineral weathering processes. Using selective isolation, fungi were obtained from limestone surfaces of Mayan monuments in the semi-arid climate at Yucatan, Mexico. A total of 101 isolates representing 53 different taxa were studied. Common fungi such as Fusarium, Pestalotiopsis, Trichoderma, and Penicillium were associated with surfaces and were, probably derived from airborne spores. In contrast, unusual fungi such as Rosellinia, Annulohypoxylon, and Xylaria were predominantly identified from mycelium particles of biofilm biomass. Simulating oligotrophic conditions, agar amended with CaCO3 was inoculated with fungi to test for carbonate activity. A substantial proportion of fungi, in particular those isolated from mycelium (59%), were capable of solubilizing calcium by means of organic acid release, notably oxalic acid as evidenced by ion chromatography. Contrary to our hypothesis, nutrient level was not a variable influencing the CaCO3 solubilization ability among isolates. Particularly active fungi (Annulohypoxylon stygium, Penicillium oxalicum, and Rosellinia sp.) were selected as models for bioweathering experiments with limestone-containing mesocosms to identify if other mineral phases, in addition to oxalates, were linked to bioweathering processes. Fungal biofilms were seen heavily covering the stone surface, while a biomineralized front was also observed at the stone-biofilm interface, where network of hyphae and mycogenic crystals was observed. X-ray diffraction analysis (XRD) identified calcite as the main phase, along with whewellite and wedellite. In addition, lower levels of citrate were detected by Attenuated Total Reflectance-Fourier-Transform Infrared Spectroscopy (ATR-FTIR). Overall, our results suggest that a diverse fungal community is associated with limestone surfaces insemi-arid climates. A subset of this community is geochemically active, excreting organic acids under quasi-oligotrophic conditions, suggesting that the high metabolic cost of exuding organic acids beneficial under nutrient limitation. Oxalic acid release may deteriorate or stabilize limestone surfaces, depending on microclimatic dynamics.

8.
Bioorg Med Chem ; 22(5): 1626-33, 2014 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-24529307

RESUMO

The 2-acylamino-5-nitro-1,3-thiazole derivatives (1-14) were prepared using a one step reaction. All compounds were tested in vitro against four neglected protozoan parasites (Giardia intestinalis, Trichomonas vaginalis, Leishmania amazonensis and Trypanosoma cruzi). Acetamide (9), valeroylamide (10), benzamide (12), methylcarbamate (13) and ethyloxamate (14) derivatives were the most active compounds against G. intestinalis and T. vaginalis, showing nanomolar inhibition. Compound 13 (IC50=10nM), was 536-times more active than metronidazole, and 121-fold more effective than nitazoxanide against G. intestinalis. Compound 14 was 29-times more active than metronidazole and 6.5-fold more potent than nitazoxanide against T. vaginalis. Ureic derivatives 2, 3 and 5 showed moderate activity against L. amazonensis. None of them were active against T. cruzi. Ligand efficiency indexes analysis revealed higher intrinsic quality of the most active 2-acylamino derivatives than nitazoxanide and metronidazole. In silico toxicity profile was also computed for the most active compounds. A very low in vitro mammalian cytotoxicity was obtained for 13 and 14, showing selectivity indexes (SI) of 246,300 and 141,500, respectively. Nitazoxanide showed an excellent leishmanicidal and trypanocidal effect, repurposing this drug as potential new antikinetoplastid parasite compound.


Assuntos
Antiprotozoários/farmacologia , Infecções por Protozoários/imunologia , Tiazóis/química , Animais , Desenho de Fármacos , Humanos
9.
Int J Mol Sci ; 14(9): 18959-72, 2013 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-24065097

RESUMO

A previously reported bacterial bioemulsifier, here termed microbactan, was further analyzed to characterize its lipid component, molecular weight, ionic character and toxicity, along with its bioemulsifying potential for hydrophobic substrates at a range of temperatures, salinities and pH values. Analyses showed that microbactan is a high molecular weight (700 kDa), non-ionic molecule. Gas chromatography of the lipid fraction revealed the presence of palmitic, stearic, and oleic acids; thus microbactan may be considered a glycolipoprotein. Microbactan emulsified aromatic hydrocarbons and oils to various extents; the highest emulsification index was recorded against motor oil (96%). The stability of the microbactan-motor oil emulsion model reached its highest level (94%) at 50 °C, pH 10 and 3.5% NaCl content. It was not toxic to Artemia salina nauplii. Microbactan is, therefore, a non-toxic and non-ionic bioemulsifier of high molecular weight with affinity for a range of oily substrates. Comparative phylogenetic assessment of the 16S rDNA gene of Microbacterium sp. MC3B-10 with genes derived from other marine Microbacterium species suggested that this genus is well represented in coastal zones. The chemical nature and stability of the bioemulsifier suggest its potential application in bioremediation of marine environments and in cosmetics.


Assuntos
Actinomycetales/metabolismo , Emulsificantes/metabolismo , Actinomycetales/classificação , Animais , Artemia/efeitos dos fármacos , Biodegradação Ambiental , Emulsificantes/química , Emulsificantes/toxicidade , Hidrocarbonetos Aromáticos/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Óleos/química , Ácido Oleico/química , Ácido Palmítico/química , Filogenia , Ácidos Esteáricos/química , Temperatura
10.
Electron. j. biotechnol ; Electron. j. biotechnol;15(4): 4-4, July 2012. ilus, tab
Artigo em Inglês | LILACS | ID: lil-646954

RESUMO

Background: Urban surface stones in Mexico City are exposed to a temperate climate and a range of atmospheric conditions ranging from mildly impacted to heavily polluted areas. In this study, we focused on the characterization of the cultivable fungal component of selected biological patinas in the surrounding area of Chapultepec castle, a historic monument in Mexico City. Thirty four representative fungal isolates selected based on distinctive differential macroscopic characteristics out of a total of 300 fungi, were characterized using morphological and molecular approaches. Results: This identification strategy based on the combination of phenotypic- and molecular-based methodologies allowed us to discriminate the fungal community in some cases down to the species level. Conclusions: The characterization of this mycoflora revealed the presence of a complex fungal community mainly represented by filamentous fungi belonging to the genera Fusarium, Trichoderma, Aspergillus, Cladosporium, Alternaria, Mucor, Penicillium, Pestalotiopsis, and the dimorphic fungus Aureobasidium, along with the yeast Rhodotorula. A specific distribution of fungi could be observed based on the type of biological patina analyzed.


Assuntos
Edifícios , Fungos/isolamento & purificação , Fungos/genética , Características do Solo , Área Urbana , DNA Fúngico/genética , Atmosfera , Técnicas de Cultura , Variação Genética , México , Fenótipo , Reação em Cadeia da Polimerase , Análise de Sequência de DNA
11.
Curr Opin Biotechnol ; 21(3): 346-52, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20202811

RESUMO

Microbial communities are ubiquitous in marine intertidal environments. These communities, which grow preferentially as biofilms on natural and artificial surfaces, carry out key processes contributing to the functioning of coastal environments and providing valuable services to human society, including carbon cycling, primary productivity, trophic linkage, and transfer and removal of pollutants. In addition, their surface-associated life style greatly influences the integrity and performance of marine infrastructure and archaeological heritage materials. The fluctuating conditions of the intertidal zone make it an extreme environment to which intertidal biofilm organisms must adapt at varying levels. This requirement has probably favored the development and spread of specific microorganisms with particular physiological and metabolic processes. These organisms may have potential biotechnological utility, in that they may provide novel secondary metabolites, biopolymers, lipids, and enzymes and even processes for the production of energy in a sustainable manner.


Assuntos
Biologia Marinha/métodos , Biofilmes/crescimento & desenvolvimento
12.
J Ind Microbiol Biotechnol ; 35(1): 9-15, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17909869

RESUMO

Marine biofilms are a virtually untapped source of bioactive molecules that may find application as novel antifoulants in the marine paint industry. This study aimed at determining the potential of marine biofilm bacteria to produce novel biomolecules with potential application as natural antifoulants. Nine representative strains were isolated from a range of surfaces and were grown in YEB medium and harvested during the late exponential growth phase. Bacterial biomass and spent culture medium were extracted with ethanol and ethyl acetate, respectively. Extracts were assayed for their antifouling activity using two tests: (1) antimicrobial well diffusion test against a common fouling bacterium, Halomonas marina, and (2) anti-crustacean activity test using Artemia salina. Our results showed that none of the ethanolic extracts (bacterial biomass) were active in either test. In contrast, most of the organic extracts had antimicrobial activity (88%) and were toxic towards A. salina (67%). Sequencing of full 16 S ribosomal DNA analysis showed that the isolates were related to Bacillus mojavensis and Bacillus firmus. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF-MS) profiling of ethyl acetate extracts of culture supernatants showed that these species produce the bioactive lipopeptides surfactin A, mycosubtilin and bacillomycin D.


Assuntos
Antibacterianos/farmacologia , Artemia/efeitos dos fármacos , Bacillus/isolamento & purificação , Bacillus/metabolismo , Biofilmes/efeitos dos fármacos , Halomonas/efeitos dos fármacos , Lipopeptídeos/farmacologia , Peptídeos Cíclicos/farmacologia , Água do Mar/microbiologia , Animais , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos , Bacillus/classificação , Bacillus/genética , Biofilmes/crescimento & desenvolvimento , Carbonato de Cálcio , Hydrocharitaceae/microbiologia , Lipopeptídeos/metabolismo , Lipoproteínas/metabolismo , Lipoproteínas/farmacologia , Dados de Sequência Molecular , Peptídeos/metabolismo , Peptídeos/farmacologia , Peptídeos Cíclicos/metabolismo , Filogenia , Folhas de Planta/microbiologia , Análise de Sequência de DNA , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
13.
Colomb. med ; 37(2,supl.1): 31-38, abr.-jun. 2006. tab
Artigo em Espanhol | LILACS | ID: lil-585781

RESUMO

Objetivo: Describir la prevalencia del síndrome del cuidador y las características psicosociales de los cuidadores de adultos mayores discapacitados. Materiales y métodos: Se realizó un estudio piloto de casos y controles en el Valle del Cauca durante el 2003-2004 para evaluar la funcionalidad familiar (APGAR familiar), la ansiedad y depresión (escala de Goldberg), la presencia de enfermedades (cuidadores y no cuidadores), y la prevalencia del síndrome del cuidador (escala de Zarit). Resultados: Se estudiaron 102 familias en su mayoría de nivel socioeconómico bajo (75.3%) con una discapacidad media de 4 años (rango 1-60 años). Se observó una mayor proporción de depresión (81.3% vs. 53.9%, p<0.01), una mayor proporción de ansiedad (85.2% vs. 45%, p<0.001), y una mayor proporción de disfunción familiar severa (26.5% vs. 10.8%) (p=0.004) en los cuidadores en relación con los no cuidadores. De los cuidadores principales 47% presentaron el síndrome del cuidador que se asociaba con ansiedad (96%, p=0.01) y con depresión (100%, p<0.0001); 85.3% de los cuidadores habían presentado enfermedades previas en comparación con 63.7% de los no cuidadores (p=0.0004). Conclusión: Los cuidadores de adultos mayores discapacitados presentan altos niveles de ansiedad, depresión, disfunción familiar y síndrome del cuidador con mayor predisposición a la morbilidad. Los resultados de este estudio identifican a los cuidadores de adultos mayores discapacitados como un grupo vulnerable con necesidades preventivas y terapéuticas.


Objective: To determine the profile of caregivers for disability old patients in home care and to investigate the psychosocial characteristics of caregivers. Materials and methods: A pilot case-control study was performed in the state of Valle del Cauca, Colombia during 2003-2004. Family function (family APGAR), anxiety and depression (Goldberg Scale), morbidity, and the prevalence of the syndrome of family caregivers (Zarit Scale) were assessed.Results: 102 families from low and middle socioeconomic status were studied. Median disability average was 4 years (range 1-60 years). A high proportion of depression (81.3% vs. 53.9%, p<0.01), anxiety (85.2% vs. 45%, p<0.001), and family dysfunction (26.5% vs. 10.8%) (p=0.004) was observed in caregivers; 48 (47%) caregivers had the syndrome and had high levels of anxiety (96%, p=0.01) as well as high levels of depression (100%, p<0.0001); 87 (85.3%) caregivers have had different pathologies in the precedent year in comparison with 65 (63.7%) not caregivers (p=0.0004). Conclussion: A caregivers syndrome was observed in 48 (47%) family members. The caregivers had high levels of anxiety, depression and family dysfunction associated to the syndrome and its morbidity. This study identified the caregivers of old disability people as a vulnerable group with high preventive and therapeutic necessities.


Assuntos
Idoso , Ansiedade , Cuidadores , Colômbia , Depressão , Pessoas com Deficiência , Família/psicologia , Estresse Psicológico
14.
Mar Biotechnol (NY) ; 8(1): 62-70, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16453199

RESUMO

Viable bacterial counts, chemical markers, phospholipid fatty acid analysis (PLFA), and Fourier-transformed infrared spectroscopy (FTIR), together with electrochemical methods, were used to study biofilm dynamics and its impact on the corrosion resistance of UNS S31603 stainless steels exposed to the Gulf of Mexico seawater. Biofilms progressively accumulated, peaking on day 20, but finally detached. The extracellular polysaccharide (EPS)/cellular biomass ratio remained low most of the time, but reached its highest level (4.2+/-1.9) also on day 20. Viable bacterial cells reached their highest abundance earlier (approximately 800 CFU/cm2), on day 15. Biofilms were seen covering the stainless steel surfaces heterogeneously and were composed mainly of gram-negative rods, presumably EPS-producing bacteria. Despite the different levels of biofilm biomass and attachment state, field-exposed steel coupons ennobled significantly and showed more active pitting potentials (approximately +500 mVSCE) than on the abiotic control (+650 mVSCE), where no significant ennoblement occurred. These results suggest that the heterogeneous distribution of biofilms, as opposed to the quantity of surface-associated biomass, promotes formation of differential aeration cells, and that this in turn contributes to the ennoblement of these steels.


Assuntos
Biofilmes/crescimento & desenvolvimento , Água do Mar/microbiologia , Aço Inoxidável/química , Biomassa , Contagem de Colônia Microbiana/métodos , Corrosão , Diatomáceas/ultraestrutura , Eletroquímica , Bacilos e Cocos Aeróbios Gram-Negativos/isolamento & purificação , Bacilos e Cocos Aeróbios Gram-Negativos/ultraestrutura , Microscopia Eletrônica de Varredura/métodos , Polissacarídeos Bacterianos/análise , Dinâmica Populacional , Água do Mar/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Fatores de Tempo , Clima Tropical
15.
Rev Latinoam Microbiol ; 48(2): 188-95, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17578091

RESUMO

Cyanobacterial biofilms are complex communities of microorganisms that cause damaging activity on historic monuments. A combined molecular approach shows that cyanobacteria belonging to the order Pleurocapsales are the main colonizers at the Mayan site of Uxmal, Mexico, confirming previous microscopic and culture-based reports. An important, previously unrecognized non-cyanobacterial community comprising Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes has also been found in Uxmal. Cyanobacterial communities in Palenque were composed of over 10 species, mainly coccoid forms. A novel PCR method designed to directly amplify DNA from uncultured cyanobacterial cells on historic buildings in Brazil indicated that the identified cyanobacteria sequenced corresponded to their appropriate morphological groups (as defined by both the bacterial and botanical codes). However, their homologies with deposited sequences were, in general, low. Terrestrial cyanobacteria from stone surfaces in Brazil, again mainly coccoid, formed a distinct population that differed from the better-studied aquatic members. Overall, results here show demonstrate that coccoid cyanobacteria are the main colonizers on Latin American monuments under tropical and subtropical conditions and the assessment of their potential deteriogenic activity requires the further development of rapid molecular techniques. Polyphasic studies are essential to increase our knowledge of the diversity of terrestrial biofilms and of global microbial diversity.


Assuntos
Biodiversidade , Cianobactérias , Biofilmes , Brasil , México
16.
Mol Biotechnol ; 30(1): 51-6, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15805576

RESUMO

A protocol is described for rapid DNA isolation from marine biofilm microorganisms embedded in large amounts of exopolysaccharides. The method is a modification of the hot phenol protocol used for plants tissues, where nonexpensive and easily available enzymes were used. The method is based on the incubation of biofilm biomass samples in an extraction buffer mixed with phenol preheated at 65 degrees C. The procedure can be completed in 2 h and up to 20 samples can be processed simultaneously with ease and DNA of excellent quality, as shown by successfully amplification of polymerase chain reaction (PCR) products. DNA was recovered from a range of intertidal marine biofilms with varying amounts of exopolysaccharides.


Assuntos
Bactérias/genética , Técnicas de Tipagem Bacteriana , Biofilmes , DNA Bacteriano/genética , Microbiologia da Água , Bactérias/classificação , Técnicas de Tipagem Bacteriana/métodos , Biofilmes/classificação , DNA Bacteriano/isolamento & purificação , Oceanos e Mares , Reação em Cadeia da Polimerase/métodos
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