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2.
Probiotics Antimicrob Proteins ; 12(2): 451-460, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-31111440

RESUMEN

The probiotic effect of Enterococcus faecalis-1 (isolated from healthy chickens) on growth performance, immune response, and modulation of the intestinal microbiota of broilers was assessed with a total of 100-day-old commercial Cobb chicks. The chicks were randomly divided into two equal groups. The control group received a basal diet, while the test group received a basal diet and was orally supplied with E. faecalis at a dose of 108 CFU/bird/day. Results showed that E. faecalis-1 supplement significantly (P < 0.05) improved the body weight and feed conversion ratio of treated broilers compared with the control ones. The mortality percentage was reduced in E. faecalis-1-supplemented group. The total IgY serum level was significantly (P < 0.05) increased in broilers receiving E. faecalis-1 supplement (7.1 ± 0.39) compared with the control group (5.8 ± 0.3), while the serum avidin level was significantly (P < 0.05) decreased in E. faecalis-1-supplemented broilers (76 ± 11.1). There was no significant change in the immune response towards avian influenza and Newcastle vaccines in both groups. The total Lactobacillus and Enterococcus counts were significantly (P < 0.05) higher in the cecal contents of broilers given E. faecalis-1 than those that received the control treatment. E. faecalis-1 supplement enhanced the enzyme activities, antioxidant system, and liver functions of treated broilers compared with those in the control group. Collectively, these results showed that E. faecalis-1 could promote growth performance and immunological status and convey beneficial modulation of the cecal microbiota in broilers.


Asunto(s)
Fenómenos Fisiológicos Nutricionales de los Animales , Pollos , Enterococcus faecalis , Microbioma Gastrointestinal , Inmunidad , Probióticos/administración & dosificación , Animales , Pollos/crecimiento & desarrollo , Pollos/inmunología
3.
Ann Anat ; 218: 190-198, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29704636

RESUMEN

Microglia represent the resident macrophages of the central nervous system (CNS). While it is clear that microglia recruitment is established by differentiation of primitive yolk sac (YS) macrophages and consecutive invasion of the brain, starting around E8 in rodents (Ginhoux et al., 2010), more recent studies suggest that a non-YS contribution to the microglia population should not entirely be dismissed (Swinnen et al., 2013; Xu et al., 2015). Therefore, we used Vav1-Cre+:dicer knock-out mice in order to study the effect of the post-YS hematopoiesis on the definitive microglial population in late prenatal (E16.5, E18.5) and early postnatal brains (P0, P1). Since Vav1 is thereby exclusively expressed in hematopoietic cells starting at E11, the depletion of the micro RNA processing enzyme dicer in Vav1-positive cells allows interfering with post-YS microglia recruitment. Using this approach, analysis of the number of Iba-1 positive microglia revealed a reduction of microglial numbers by 40% in knock-out mice at P1 compared to their individual control littermates. Noteworthy, immunolabeling for Ki-67 and active caspase 3 confirmed that the differences in the microglial numbers are not related to differential rates of proliferation or apoptosis. Therefore, our data demonstrates that interfering with the definitive hematopoiesis highly impacts on the microglial population, implicating an important role of post-YS hematopoiesis on microglial development and recruitment.


Asunto(s)
Encéfalo/embriología , Encéfalo/crecimiento & desarrollo , Macrófagos/fisiología , Microglía/fisiología , Proteínas Proto-Oncogénicas c-vav/genética , Saco Vitelino/citología , Animales , Apoptosis , Proteínas de Unión al Calcio/metabolismo , Recuento de Células , Proliferación Celular , ARN Helicasas DEAD-box/genética , Femenino , Hematopoyesis , Inmunohistoquímica , Ratones , Ratones Noqueados , Proteínas de Microfilamentos/metabolismo , Embarazo , Ribonucleasa III/genética
4.
Pharmacol Biochem Behav ; 161: 1-5, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28867606

RESUMEN

The FDA recently extended their regulatory authority to electronic cigarettes (ECs). Because the abuse liability of ECs is a leading concern of the FDA, animal models are urgently needed to identify factors that influence the relative abuse liability of these products. The ability of tobacco products to induce nicotine dependence, defined by the emergence of anhedonia and other symptoms of nicotine withdrawal following cessation of their use, contributes to tobacco abuse liability. The present study compared the severity of precipitated withdrawal during chronic infusion of nicotine alone or nicotine-dose equivalent concentrations of three different EC refill liquids in rats, as indicated by elevations in intracranial self-stimulation (ICSS) thresholds (anhedonia-like behavior). Because these EC liquids contain constituents that may enhance their abuse liability (e.g., minor alkaloids), we hypothesized that they would be associated with greater withdrawal effects than nicotine alone. Results indicated that the nicotinic acetylcholine receptor antagonist mecamylamine precipitated elevations in ICSS thresholds in rats receiving a chronic infusion of nicotine alone or EC liquids (3.2mg/kg/day, via osmotic pump). Magnitude of this effect did not differ between formulations. Our findings indicate that nicotine alone is the primary CNS determinant of the ability of ECs to engender dependence. Combined with our previous findings that nicotine alone and these EC liquids do not differ in other preclinical addiction models, these data suggest that product standards set by the FDA to reduce EC abuse liability should primarily target nicotine, other constituents with peripheral sensory effects (e.g. flavorants), and factors that influence product appeal (e.g., marketing).


Asunto(s)
Conducta Adictiva/psicología , Sistemas Electrónicos de Liberación de Nicotina/métodos , Nicotina/administración & dosificación , Nicotina/efectos adversos , Autoestimulación/efectos de los fármacos , Síndrome de Abstinencia a Sustancias/psicología , Animales , Estimulación Eléctrica/métodos , Bombas de Infusión Implantables , Infusiones Subcutáneas , Masculino , Haz Prosencefálico Medial/efectos de los fármacos , Haz Prosencefálico Medial/fisiología , Ratas , Ratas Sprague-Dawley , Autoestimulación/fisiología
5.
BMC Vet Res ; 13(1): 72, 2017 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-28320395

RESUMEN

BACKGROUND: Pulmonary capillary hemangiomatosis is a rare, vascular obstructive disorder that uniformly causes pulmonary arterial hypertension. Clinically, pulmonary capillary hemangiomatosis is indistinguishable from primary pulmonary arterial hypertension and histology is required for definitive diagnosis. The distinctive histologic feature of pulmonary capillary hemangiomatosis is non-malignant extensive proliferation of capillaries in the alveolar septae. Vasodilator treatment of humans with primary arterial hypertension due to pulmonary capillary hemangiomatosis can result in fatal acute pulmonary edema. Computed tomography is thus critical to discern pulmonary capillary hemangiomatosis from other causes of pulmonary arterial hypertension prior to vasodilator therapy. This is the first report of a vasoproliferative process resembling pulmonary capillary hemangiomatosis in the feline species. CASE PRESENTATION: A 15-year-old, male castrated, domestic shorthair cat presented for persistent labored breathing presumptively due to congestive heart failure despite treatment with diuretics for 7 days. Echocardiography showed evidence of hypertrophic cardiomyopathy with severe pulmonary hypertension; however, a normal sized left atrium was not consistent with congestive heart failure. Thoracic computed tomography was performed and showed evidence of diffuse ill-defined nodular ground glass opacities, enlarged pulmonary arteries, and filling defects consistent with pulmonary thromboembolism. The cat acutely decompensated after a single dose of sildenafil and was euthanized. Histopathology of the lungs showed severe multifocal alveolar capillary proliferation with respiratory bronchiolar infiltration, marked type II pneumocyte hyperplasia and multifocal pulmonary arterial thrombosis. CONCLUSION: This is the first description in a cat of a vasoproliferative disorder resembling pulmonary capillary hemangiomatosis complicated by multifocal pulmonary arterial thrombosis. Inspiratory and expiratory ventilator-driven breath holds with angiography revealed lesions predominantly characterized by ground glass opacification and vascular filling defects with absence of air trapping. The results from this report suggest that, as in humans, the cat can develop a pulmonary capillary hemangiomatosis-like disease in which vasodilator therapy to address pulmonary hypertension may lead to fatal pulmonary edema.


Asunto(s)
Enfermedades de los Gatos/diagnóstico , Hemangioma Capilar/veterinaria , Hipertensión Pulmonar/veterinaria , Animales , Capilares/patología , Cardiomiopatía Hipertrófica/diagnóstico , Cardiomiopatía Hipertrófica/veterinaria , Gatos , Diagnóstico Diferencial , Resultado Fatal , Hemangioma Capilar/diagnóstico , Hipertensión Pulmonar/diagnóstico , Pulmón/irrigación sanguínea , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/veterinaria , Masculino
6.
Biol Sport ; 33(1): 71-6, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26929473

RESUMEN

In this study, we tested the hypothesis that breathing hyperoxic air (FinO2 = 0.40) while exercising in a hot environment exerts negative effects on the total tissue level of haemoglobin concentration (tHb); core (Tcore) and skin (Tskin) temperatures; muscle activity; heart rate; blood concentration of lactate; pH; partial pressure of oxygen (PaO2) and carbon dioxide; arterial oxygen saturation (SaO2); and perceptual responses. Ten well-trained male athletes cycled at submaximal intensity at 21°C or 33°C in randomized order: first for 20 min while breathing normal air (FinO2 = 0.21) and then 10 min with FinO2 = 0.40 (HOX). At both temperatures, SaO2 and PaO2, but not tHb, were increased by HOX. Tskin and perception of exertion and thermal discomfort were higher at 33°C than 21°C (p < 0.01), but independent of FinO2. Tcore and muscle activity were the same under all conditions (p > 0.07). Blood lactate and heart rate were higher at 33°C than 21°C. In conclusion, during 30 min of submaximal cycling at 21°C or 33°C, Tcore, Tskin and Tbody, tHb, muscle activity and ratings of perceived exertion and thermal discomfort were the same under normoxic and hyperoxic conditions. Accordingly, breathing hyperoxic air (FinO2 = 0.40) did not affect thermoregulation under these conditions.

7.
Cell Death Dis ; 6: e1724, 2015 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-25880091

RESUMEN

This study aims at evaluating the combination of the tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL)-receptor 2 (TRAIL-R2)-specific antibody Drozitumab and the Smac mimetic BV6 in preclinical glioblastoma models. To this end, the effect of BV6 and/or Drozitumab on apoptosis induction and signaling pathways was analyzed in glioblastoma cell lines, primary glioblastoma cultures and glioblastoma stem-like cells. Here, we report that BV6 and Drozitumab synergistically induce apoptosis and reduce colony formation in several glioblastoma cell lines (combination index<0.1). Also, BV6 profoundly enhances Drozitumab-induced apoptosis in primary glioblastoma cultures and glioblastoma stem-like cells. Importantly, BV6 cooperates with Drozitumab to suppress tumor growth in two glioblastoma in vivo models including an orthotopic, intracranial mouse model, underlining the clinical relevance of these findings. Mechanistic studies reveal that BV6 and Drozitumab act in concert to trigger the formation of a cytosolic receptor-interacting protein (RIP) 1/Fas-associated via death domain (FADD)/caspase-8-containing complex and subsequent activation of caspase-8 and -3. BV6- and Drozitumab-induced apoptosis is blocked by the caspase inhibitor zVAD.fmk, pointing to caspase-dependent apoptosis. RNA interference-mediated silencing of RIP1 almost completely abolishes the BV6-conferred sensitization to Drozitumab-induced apoptosis, indicating that the synergism critically depends on RIP1 expression. In contrast, both necrostatin-1, a RIP1 kinase inhibitor, and Enbrel, a TNFα-blocking antibody, do not interfere with BV6/Drozitumab-induced apoptosis, demonstrating that apoptosis occurs independently of RIP1 kinase activity or an autocrine TNFα loop. In conclusion, the rational combination of BV6 and Drozitumab presents a promising approach to trigger apoptosis in glioblastoma, which warrants further investigation.


Asunto(s)
Anticuerpos Monoclonales/farmacología , Neoplasias Encefálicas/tratamiento farmacológico , Glioblastoma/tratamiento farmacológico , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismo , Animales , Anticuerpos Monoclonales Humanizados , Apoptosis/efectos de los fármacos , Neoplasias Encefálicas/enzimología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Proteína Reguladora de Apoptosis Similar a CASP8 y FADD/metabolismo , Línea Celular Tumoral , Glioblastoma/enzimología , Glioblastoma/genética , Glioblastoma/patología , Humanos , Ratones , Ratones Desnudos , Proteína Serina-Treonina Quinasas de Interacción con Receptores/genética , Transducción de Señal , Ensayos Antitumor por Modelo de Xenoinjerto
8.
Neuroscience ; 279: 139-54, 2014 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-25168731

RESUMEN

Inflammatory mechanisms were recently identified as contributors to delayed neuronal damage after ischemic stroke. However, therapeutic strategies are still lacking, probably related to the outstanding standardization on inflammatory cell recruitment emerging from predominantly artificial stroke models, and the uncertainty on functional properties of distinct subpopulations. Using a rodent model of stroke that closely reflects human embolic ischemia, this study was focused on the local recruitment of immunoreactive cells as well as their functional and regional characterization. Wistar rats underwent thromboembolic middle cerebral artery occlusion, followed by intravenous injection of the blood-brain barrier permeability marker fluorescein-conjugated albumin at 24h. One hour later, brain tissue was subjected to multi-parameter flow cytometry and Pappenheim staining to characterize cells invaded into the ischemia-affected hemisphere, compared to the contralateral side. Immunofluorescence labeling was applied to explore the distribution patterns of recruited cells and their spatial relationships with the vasculature. One day after ischemia onset, a 6.12-fold increase of neutrophils and a 5.43-fold increase of monocytes/macrophages was found in affected hemispheres, while these cells exhibited enhanced major histocompatibility complex class II expression and allocation with vessels exhibiting impaired blood-brain barrier integrity. Microglia remained numerically unaltered in ischemic hemispheres, but shifted to an activated phenotype indicated by CD45/CD86 expression and morphological changes toward an ameboid appearance in the bordering zone. Ischemia caused an increase of lymphoid cells in close vicinity to the affected vasculature, while further analyses allowed separation into natural killer cells, natural killer T cells, T cells (added by an unconventional CD11b(+)/CD3(+) population) and two subpopulations of B cells. Taken together, our study provides novel data on the local inflammatory response to experimental thromboembolic stroke. As concomitantly present neutrophils, monocytes/macrophages and lymphoid cells in the early stage after ischemia induction correspond to changes seen in human stroke, future stroke research should preferably use animal models with relevance for clinical translation.


Asunto(s)
Isquemia Encefálica/inmunología , Encéfalo/inmunología , Accidente Cerebrovascular/inmunología , Animales , Linfocitos B/fisiología , Barrera Hematoencefálica/inmunología , Barrera Hematoencefálica/fisiopatología , Permeabilidad Capilar/fisiología , Modelos Animales de Enfermedad , Infarto de la Arteria Cerebral Media , Células Asesinas Naturales/fisiología , Macrófagos/fisiología , Masculino , Microglía/fisiología , Monocitos/fisiología , Neutrófilos/fisiología , Distribución Aleatoria , Ratas Wistar , Linfocitos T/fisiología , Tromboembolia
9.
J Sports Med Phys Fitness ; 54(4): 475-80, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24721989

RESUMEN

AIM: This study aimed to quantify the cardiorespiratory, metabolic and hormonal responses of elite open-wheel indoor kart racers. METHODS: Ten male racers (age: 21±3 yrs; height: 1.92±0.06 m, body mass: 76.0±5.9 kg) participated in a racing tournament. Their peak oxygen uptake and heart rate were assessed by a ramp test (100 W, increase 30 W·min-1) in the laboratory. During the racing itself, the cardio-respiratory and accelerometer values were recorded and pre- and post-race levels of blood lactate and salivary cortisol were determined. RESULTS: The average peak values for all of the drivers with respect to oxygen uptake and heart rate were 4.5±0.8 L·min-1 (56.7±7.9 mL·min-1·kg-1) and 193±5 beats·min-1, respectively. Overall, 28.3±3.3 laps were completed during 30-min of racing. Acceleration forces for the entire test averaged 1.20±0.51 G (maximum: 3.30 G), declining from the first 10 min until the end of racing (P<0.03). The oxygen uptake (~20 mL·min-1·kg-1), heart rate (~133 beats·min-1), respiratory exchange ratio (~0.96) and ventilation (~70 L·min-1) observed indicated moderate cardio-respiratory responses. Blood lactate concentration was significantly higher after the race than before but remained at <2 mmol·L-1 (P<0.01; effect size: 1.62). CONCLUSION: There were no differences between salivary cortisol levels before and after the race (P<0.06; effect size: 0.49). Directly after the race, the drivers rated their perceived exertion on Borg's scale as 11.1±1.3. The present data revealed that the psycho-physical exertion associated with a 30-min open-wheel indoor kart race is moderate.


Asunto(s)
Frecuencia Cardíaca/fisiología , Hidrocortisona/análisis , Respiración , Saliva/química , Deportes/fisiología , Humanos , Ácido Láctico/sangre , Masculino , Consumo de Oxígeno/fisiología , Percepción , Esfuerzo Físico/fisiología , Estrés Psicológico , Adulto Joven
10.
Scand J Immunol ; 79(5): 299-304, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24498969

RESUMEN

Little is known about the bovine intestinal microbiota influence on systemic innate immune responses. The objective of the present study was to determine relationships between acute-phase proteins in blood serum of cows [C-reactive protein (CRP), LPS-binding protein (LBP) and haptoglobin (Hp)] and the faecal microbiota. Fifty-two healthy cows (2-8 years old) were investigated. Faecal bacteria were determent characterized by in situ hybridization with 16S/23S rRNA-targeted probes and by conventional culture methods. The population of Gram-negative faecal bacteria (Enterobacteriaceae) was correlated negatively with CRP and positively with LBP in blood plasma, independent of the method used. Similar results were observed with Clostridium perfringens. No correlation was found between the faecal population of intestinal bacteria and Hp levels in blood plasma. This datum indicates that intestinal bacteria, especially Enterobacteriaceae and C. perfringens, may influence the level of CRP and LBP in blood plasma. These findings can be very important for diagnostic evaluations of the intestinal microbiota and provide specific information about its regulation.


Asunto(s)
Proteínas de Fase Aguda/inmunología , Reacción de Fase Aguda/inmunología , Infecciones por Clostridium/inmunología , Clostridium perfringens/inmunología , Infecciones por Enterobacteriaceae/inmunología , Enterobacteriaceae/inmunología , Intestinos/inmunología , Microbiota/inmunología , Animales , Bovinos , Clostridium perfringens/genética , Enterobacteriaceae/genética , Heces/microbiología , Inmunidad Innata , Intestinos/microbiología , ARN Ribosómico 16S/genética
13.
Biomed Tech (Berl) ; 58 Suppl 12013 08.
Artículo en Inglés | MEDLINE | ID: mdl-24043041
14.
Analyst ; 138(20): 6154-62, 2013 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-23971072

RESUMEN

This article describes a novel bioluminescence assay for detecting the proteolytic activity of Botulinum NeuroToxins (BoNT) in complex matrices. The assay is capable of detecting traces of BoNT in blood samples as well as in food drinks. The assay was responsive to BoNT/A subtypes 1 to 5, and serotype E3 in buffered solutions. It was responsive to filtered Clostridium botulinum supernatants and BoNT/A1 in complex with neurotoxin associated proteins in bouillon and milk (3.8% fat) down to 400 fM after 4 h RT incubation and in bouillon at concentrations down to 120 fM after 21 h RT incubation. In combination with an immunocapture/enrichment step it could detect BoNT/A1 in citrated plasma at concentrations down to 30 fM (1.2 mouse LD50 per mL). The simplicity of the assay, combined with a demonstrated ability to lyophilize the reagents, demonstrates its usefulness for detection of BoNT in non-specialised analytical laboratories.


Asunto(s)
Toxinas Botulínicas Tipo A/análisis , Toxinas Botulínicas Tipo A/química , Mediciones Luminiscentes/métodos , Animales , Clostridium botulinum/química , Humanos , Ratones , Ratones Endogámicos BALB C , Estructura Secundaria de Proteína
15.
Open Orthop J ; 7: 25-32, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23407589

RESUMEN

OBJECTIVE: An appropriate measuring instrument for assessing if sports activity changes after a surgical treatment is not available yet. We hypothesised that the Heidelberg Sport Activity Score is a valid and adequate instrument for measuring sport activity in patients before and after operative treatment. DESIGN: This retrospective study presents a new score (Heidelberg Sports Activity Score - HAS) for measuring the sport activity in 11 selected sports. Validity, sensitivity and test-retest-reliability have been assessed. SETTING: The score includes importance of the sports for patients, impairment of the corresponding joint, and frequency and duration of the sporting activities undertaken. The HAS was validated using 3 criteria: external validation, internal comparison of groups and correlation with the Tegner Score. PATIENTS: A total of 655 patients were recruited for this study. The inclusion criterion was a planned or already received reconstruction (such as a high tibial osteotomy or implantation of a hip or knee prosthesis). The sport activity of these patients was evaluated before and after treatment. MAIN OUTCOME MEASUREMENT: The mean HAS was 32.1 points preoperatively and 37.0 postoperatively (p=0.017). RESULTS: A high correlation was found between the HAS and the Tegner Score (TS) (r=0.729; p=0.010). The Test-Retest- Reliability was performed within a time interval of 2 weeks and a significant correlation of r=0.752 was found (p<0.01). Sensitivity was analysed using a sample of patients before and after high tibial osteotomy. CONCLUSIONS: The HAS is a new, easy to use, effective and valid measuring instrument for the assessment of sports activity in patients before and after operative treatment.

16.
Eur J Histochem ; 57(4): e38, 2013 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-24441191

RESUMEN

While the concept of the Neurovascular Unit (NVU) is increasingly recognized for exploring mechanisms of tissue damage in ischemic stroke, immunohistochemical analyses are of interest to specifically visualize constituents like the endothelium. Changes in immunoreactivity have also been discussed to reflect functional aspects, e.g., the integrity of the blood-brain barrier (BBB). This study aimed to characterize the endothelial barrier antigen (EBA) as addressed by the antibody SMI-71 in a rat model of embolic stroke, considering FITC-albumin as BBB leakage marker and serum levels of BBB-associated matrix metalloproteinases (MMPs) to explore its functional significance. Five and 25 h after ischemia onset, regions with decreased BBB integrity exhibited a reduction in number and area of EBA-immunopositive vessels, while the stained area per vessel was not affected. Surprisingly, EBA content of remaining vessels tended to be increased in areas of BBB dysfunction. Analyses addressing this interrelation resulted in a significant and inverse correlation between the vessels' EBA content and degree of BBB permeability. In conclusion, these data provide evidence for a functional relationship between EBA-immunoreactivity and BBB dysfunction in experimental ischemic stroke. Further studies are required to explore the underlying mechanisms of altered EBA-immunoreactivity, which might help to identify novel neuroprotective strategies.


Asunto(s)
Antígenos de Superficie/inmunología , Barrera Hematoencefálica/fisiología , Accidente Cerebrovascular/inmunología , Animales , Isquemia Encefálica/complicaciones , Fluoresceína-5-Isotiocianato/análogos & derivados , Infarto de la Arteria Cerebral Media/inmunología , Masculino , Ratas , Ratas Wistar , Albúmina Sérica , Accidente Cerebrovascular/etiología
17.
Environ Microbiol ; 14(12): 3271-86, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23116231

RESUMEN

Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60°C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment.


Asunto(s)
Sedimentos Geológicos/microbiología , Microbiología del Suelo , Bacterias Reductoras del Azufre/metabolismo , Azufre/metabolismo , Erupciones Volcánicas/análisis , Azerbaiyán , Betaproteobacteria/clasificación , Betaproteobacteria/genética , Betaproteobacteria/metabolismo , Biodiversidad , ADN Ribosómico/aislamiento & purificación , Deltaproteobacteria/clasificación , Deltaproteobacteria/genética , Deltaproteobacteria/metabolismo , Desulfotomaculum/clasificación , Desulfotomaculum/genética , Desulfotomaculum/metabolismo , Ecosistema , Epsilonproteobacteria/clasificación , Epsilonproteobacteria/genética , Epsilonproteobacteria/metabolismo , Oxidación-Reducción , Filogenia , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/metabolismo
18.
Biomed Tech (Berl) ; 57 Suppl 12012 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-23096331
20.
Appl Microbiol Biotechnol ; 96(3): 841-9, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22968354

RESUMEN

Enzymatically catalyzed biofuel cells show unique specificity and promise high power densities, but suffer from a limited lifetime due to enzyme deactivation. In the present work, we demonstrate a novel concept to extend the lifetime of a laccase-catalyzed oxygen reduction cathode in which we decouple the electrode lifetime from the limited enzyme lifetime by a regular resupply of fresh enzymes. Thereto, the adsorption behavior of laccase from Trametes versicolor to buckypaper electrode material, as well as its time-dependent deactivation characteristics, has been investigated. Laccase shows a Langmuir-type adsorption to the carbon nanotube-based buckypaper electrodes, with a mean residence time of 2 days per molecule. In a citrate buffer of pH 5, laccase does not show any deactivation at room temperature for 2 days and exhibits a half-life of 9 days. In a long-term experiment, the laccase electrodes were operated at a constant galvanostatic load. The laccase-containing catholyte was periodically exchanged against a freshly prepared one every second day to provide sufficient active enzymes in the catholyte for the replacement of desorbed inactive enzymes. Compared to a corresponding control experiment without catholyte exchange, this procedure resulted in a 2.5 times longer cathode lifetime of 19 ± 9 days in which the electrode showed a potential above 0.744 V vs. normal hydrogen electrode at 110 µA cm(-2). This clearly indicates the successful exchange of molecules by desorption and re-adsorption and is a first step toward the realization of a self-regenerating enzymatic biofuel cell in which enzyme-producing microorganisms are integrated into the electrode to continuously resupply fresh enzymes.


Asunto(s)
Fuentes de Energía Bioeléctrica , Electrodos , Lacasa/metabolismo , Trametes/enzimología , Electricidad Estática , Factores de Tiempo
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