RESUMEN
As a lipopeptide (LP), surfactin exhibits properties, such as emulsifying and dispersing ability, which are useful in food industry. Discovery of new LP-producing strains from food sources is an important step towards possible application of surfactin in foods. A total of 211 spore-forming, Gram-positive, and catalase-positive bacterial strains were isolated from fermented African locust beans (iru) and palm oil mill effluents in a screening process and examined for their ability to produce surfactin. This was achieved by a combination of methods, which included microbiological and molecular classification of strains, along with chemical analysis of surfactin production. Altogether, 29 isolates, positive for oil spreading and emulsification assays, were further identified with 16S rDNA analysis. The strains belonged to nine species including less commonly reported strains of Lysinibacillus, Bacillus flexus, B. tequilensis, and B. aryabhattai. The surfactin production was quantitatively and qualitatively analysed by high-performance thin-layer chromatography and liquid chromatography-mass spectrometry (LC-MS). Confirmation of surfactin by MS was achieved in all the 29 strains. Highest surfactin production capability was found in B. subtilis IRB2-A1 with a titre of 1444·1 mg L-1 .
Asunto(s)
Bacillus , Péptidos Cíclicos , Bacillus/genética , Bacillus subtilis/genética , Cromatografía en Capa Delgada/métodos , Lipopéptidos , Espectrometría de Masas , Péptidos Cíclicos/químicaRESUMEN
The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft landed successfully on Mars and imaged the surface to characterize the surficial geology. Here we report on the geology and subsurface structure of the landing site to aid in situ geophysical investigations. InSight landed in a degraded impact crater in Elysium Planitia on a smooth sandy, granule- and pebble-rich surface with few rocks. Superposed impact craters are common and eolian bedforms are sparse. During landing, pulsed retrorockets modified the surface to reveal a near surface stratigraphy of surficial dust, over thin unconsolidated sand, underlain by a variable thickness duricrust, with poorly sorted, unconsolidated sand with rocks beneath. Impact, eolian, and mass wasting processes have dominantly modified the surface. Surface observations are consistent with expectations made from remote sensing data prior to landing indicating a surface composed of an impact-fragmented regolith overlying basaltic lava flows.
RESUMEN
Despite the numerous advantages of biosurfactants, such as low toxicity, biodegradability and high stability, these compounds are not widely used because of the high cost of production. Details about genetics, regulation and biosynthesis of rhamnolipids by Pseudomonas aeruginosa, are extremely important to the development of bioprocesses involving the synthesis of these compounds. The holding of such knowledge associated with the use of metabolic engineering tools allow modification of producing strains and the development of synthetic routes, with the purpose of increasing the production of rhamnolipids. Considering the need to obtain this know-how, this review provides information on the rhamnolipids, covering genetics, biosynthesis of hydrophobic and hydrophilic portions, and regulation, plus some future strategies that would contribute to the expansion of the production of this green surfactant.
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Glucolípidos/biosíntesis , Ingeniería Metabólica , Tensoactivos/química , Glucolípidos/química , Glucolípidos/genética , Interacciones Hidrofóbicas e Hidrofílicas , Industrias , Pseudomonas aeruginosa/químicaRESUMEN
BACKGROUND AND PURPOSE: It is assumed that ATP induces closure of the binding jaw of ligand-gated P2X receptors, which eventually results in the opening of the membrane channel and the flux of cations. Immobilization by cysteine mutagenesis of the binding jaw inhibited ATP-induced current responses, but did not allow discrimination between disturbances of binding, gating, subunit assembly or trafficking to the plasma membrane. EXPERIMENTAL APPROACH: A molecular model of the pain-relevant human (h)P2X3 receptor was used to identify amino acid pairs, which were located at the lips of the binding jaw and did not participate in agonist binding but strongly approached each other even in the absence of ATP. KEY RESULTS: A series of cysteine double mutant hP2X3 receptors, expressed in HEK293 cells or Xenopus laevis oocytes, exhibited depressed current responses to α,ß-methylene ATP (α,ß-meATP) due to the formation of spontaneous inter-subunit disulfide bonds. Reducing these bonds with dithiothreitol reversed the blockade of the α,ß-meATP transmembrane current. Amino-reactive fluorescence labelling of the His-tagged hP2X3 receptor and its mutants expressed in HEK293 or X. laevis oocytes demonstrated the formation of inter-subunit cross links in cysteine double mutants and, in addition, confirmed their correct trimeric assembly and cell surface expression. CONCLUSIONS AND IMPLICATIONS: In conclusion, spontaneous tightening of the binding jaw of the hP2X3 receptor by inter-subunit cross-linking of cysteine residues substituted at positions not directly involved in agonist binding inhibited agonist-evoked currents without interfering with binding, subunit assembly or trafficking.
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Adenosina Trifosfato/análogos & derivados , Modelos Moleculares , Agonistas del Receptor Purinérgico P2X/farmacología , Receptores Purinérgicos P2X3 , Adenosina Trifosfato/farmacología , Animales , Células HEK293 , Humanos , Activación del Canal Iónico , Mutación , Oocitos , Conformación Proteica , Receptores Purinérgicos P2X3/química , Receptores Purinérgicos P2X3/genética , Receptores Purinérgicos P2X3/fisiología , Xenopus laevisRESUMEN
The enzymatic conversion of an aggregate-forming substrate was kinetically analyzed and a model was applied for the prediction of reaction-time courses. An L-rhamnose molecule from a di-rhamnolipid is cleaved by Naringinase from Penicillium decumbens leading to a mono-rhamnolipid. Optimal reaction rates were found when both, substrate and product build large co-aggregates in a slightly acidic aqueous phase. On the other hand, reaction rates were independent of initial di-rhamnolipid concentration and this was interpreted by assuming that the reaction occurs in the aqueous phase according to Michaelis-Menten kinetics in combination with competitive L-rhamnose inhibition. Rhamnolipids were therefore assumed to be highly concentrated in aggregates, a second liquid phase, whereas diffusive rhamnolipid transport from and to the aqueous phase occurs due to the enzymatic reaction. Furthermore, ideal surfactant mixing between di- and mono-rhamnolipid was assumed for interpretation of the negative effect of the last on the reaction rate. A model was created that describes the system accordingly. The comparison of the experimental data, were in excellent agreement with the predicted values. The findings of this study may beneficially be adapted for any bioconversion involving aggregate-forming substrate and/or product being catalyzed by hydrophilic enzymes.
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Proteínas Fúngicas/metabolismo , Glucolípidos/metabolismo , Complejos Multienzimáticos/metabolismo , Penicillium/enzimología , beta-Glucosidasa/metabolismo , Emulsiones/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Modelos Teóricos , Ramnosa/metabolismo , Tensoactivos/farmacología , TemperaturaRESUMEN
AIMS: Pseudomonas aeruginosa LBI (Industrial Biotechnology Laboratory) was isolated from hydrocarbon-contaminated soil as a potential producer of biosurfactant and evaluated for hydrocarbon biodegradation. The emulsifying power and stability of the product was assessed in the laboratory, simulating water contamination with benzene, toluene, kerosene, diesel oil and crude oil at various concentrations. METHODS AND RESULTS: Bacteria were grown at 30 degrees C and shaken at 200 rpm for 168 h, with three repetitions. Surface tension, pH and biosurfactant stability were observed in the cell-free broth after 168 h of incubation. The strain was able to produce biosurfactant and grow in all the carbon sources under study, except benzene and toluene. When cultivated in 30% (w/v) diesel oil, the strain produced the highest quantities (9.9 g l(-1)) of biosurfactant. The biosurfactant was capable of emulsifying all the hydrocarbons tested. CONCLUSION: The results from the present study demonstrate that Ps. aeruginosa LBI can grow in diesel oil, kerosene, crude oil and oil sludge and the biosurfactant produced has potential applications in the bioremediation of hydrocarbon-contaminated sites. SIGNIFICANCE AND IMPACT OF THE STUDY: Pseudomonas aeruginosa LBI or the biosurfactant it produces can be used in the bioremediation of environmental pollution induced by industrial discharge or accidental hydrocarbon spills.
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Pseudomonas aeruginosa/metabolismo , Contaminantes del Suelo/química , Tensoactivos/química , Biodegradación Ambiental , Biotecnología/métodos , Hidrocarburos/química , Concentración de Iones de Hidrógeno , Petróleo/metabolismo , Pseudomonas aeruginosa/crecimiento & desarrollo , Microbiología del Suelo , Tensión SuperficialRESUMEN
In this study the kinetics of conversion of a low-soluble substrate by an immobilized enzyme was investigated with respect to the diffusion limitation within porous and non-porous carriers. Non-porous micro-magnetic beads in comparison to conventional porous supports like Eupergit and Sepharose were tested. Due to their small diameters and their magnetic properties, micro-magnetic beads are especially applicable in diffusion rate-controlled processes in biological suspensions. The enzymatic reaction studied was the conversion of emulsified dirhamnolipid by immobilized Naringinase from Penicillium decumbens to monorhamnolipid and L-rhamnose. Taking into account mass transfer phenomena, the variation of the reaction effectiveness factor with increasing enzyme loading was estimated and compared with experimental efficiencies utilizing different enzyme loaded immobilized preparations. For comparison, carrier activities were also determined with the model substrate p-nitro-phenyl-rhamnoside. Intrinsic enzyme activities were thereby evaluated for porous supports. Highest specific activities were obtained with the micro-magnetic beads. These non-porous micro-beads demonstrated to be the most suitable carrier for bioconversion of a low-soluble substrate like rhamnolipids, where mass diffusional resistances in the three-phase reaction process are completely overcome. However, the smaller particle surface available limited the specific activity obtained at high protein loadings.
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Enzimas Inmovilizadas/metabolismo , Magnetismo , Microesferas , Cromatografía Líquida de Alta Presión , Difusión , Enzimas Inmovilizadas/química , Glucolípidos/metabolismo , Cinética , Ramnosa/metabolismoRESUMEN
The performance of two detection techniques for body fluids, the Spectra-Physics(R) Revealtrade mark portable forensic laser system and the mercury-arc lamp Lumatec Superlite 400, was evaluated with various biological stains on different substrates. Serial dilutions of neat, 1/10, 1/100 and 1/1,000 using fluid semen, saliva, urine and blood were applied on glazed tiles, glass, PVC, wood, metal, stone, formica, carpet and cotton. Apart from the fact that blood traces were not detectable with the laser, both light sources showed comparable results regarding their detection capability. Clear advantages of the Lumatec Superlite 400, however, are its lower size, weight, purchase costs and the possibility to operate this light source by battery.
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Sangre , Medicina Legal/instrumentación , Saliva , Semen , Orina , Humanos , Rayos Láser , Masculino , Espectrometría de Fluorescencia/instrumentación , Propiedades de SuperficieRESUMEN
Economies grow by upgrading the products they produce and export. The technology, capital, institutions, and skills needed to make newer products are more easily adapted from some products than from others. Here, we study this network of relatedness between products, or "product space," finding that more-sophisticated products are located in a densely connected core whereas less-sophisticated products occupy a less-connected periphery. Empirically, countries move through the product space by developing goods close to those they currently produce. Most countries can reach the core only by traversing empirically infrequent distances, which may help explain why poor countries have trouble developing more competitive exports and fail to converge to the income levels of rich countries.
RESUMEN
The significance of both Purkinje cell numbers and various neuronal changes for the diagnosis and timing of hypoxic-induced brain lesions was investigated in tissue samples from the cerebellar cortex of 52 individuals with a history of acute or prolonged cerebral hypoxia/ischemia before death. Furthermore, the area of the Purkinje cell somata (PC size) was measured using an automatic image processing and analysis system (LEICA QWin). Significantly reduced numbers of Purkinje cells (<6 cells/unit length of 1 mm) and a decreased portion (<50%) of intact Purkinje cells could be detected in individuals with a period of resuscitation of at least 2 h after acute circulatory arrest. Average cell numbers of less than 4 cells/unit were found in individuals who suffered from diffuse brain swelling and were ventilated for at least 3 days, as well as in individuals who died of brain death. Moreover, the Purkinje cells in these cases exhibited shrunken somata compared to the controls. Specimens that were stored at room temperature up to 30 h after removal at autopsy showed no significant autolytic changes of the Purkinje cells. After 46 h, however, reduced Purkinje cell numbers and shrunken cell bodies were found.
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Cerebelo/patología , Hipoxia Encefálica/patología , Células de Purkinje/patología , Adulto , Anciano , Anciano de 80 o más Años , Autólisis/patología , Muerte Encefálica/patología , Edema Encefálico/patología , Reanimación Cardiopulmonar , Recuento de Células , Tamaño de la Célula , Niño , Preescolar , Femenino , Patologia Forense , Humanos , Masculino , Persona de Mediana Edad , Respiración Artificial , Factores de TiempoRESUMEN
The severity and duration of cognitive performance capacity deficits after intravenous administration of propofol were determined using the validated psychological test procedure syndrome short test (SKT), a simple reaction test and original driving licence exam questions. The test battery was performed before, immediately after, as well as 1 and 2 h after propofol administration in 23 persons. Immediately after propofol anaesthesia, six individuals had a slight performance loss, and four subjects showed mild deficits, consistent with medium organic neuropsychologic disorder or dementia. The status of the subjects rapidly changed for the better, and 2 h after propofol anaesthesia, only one person (4%) showed slight deficits of memory and attention. Therefore, it is suggested that patients refrain from any participation in road traffic for at least 2 h after propofol anaesthesia. Driving a car should not be admitted until an interval of 6 h has elapsed.
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Anestésicos Intravenosos/efectos adversos , Trastornos del Conocimiento/inducido químicamente , Propofol/efectos adversos , Adulto , Anciano , Anestésicos Intravenosos/administración & dosificación , Anestésicos Intravenosos/sangre , Atención/efectos de los fármacos , Conducción de Automóvil , Femenino , Toxicología Forense , Humanos , Inyecciones Intravenosas , Masculino , Trastornos de la Memoria/inducido químicamente , Persona de Mediana Edad , Pruebas Neuropsicológicas , Propofol/administración & dosificación , Propofol/sangre , Factores de TiempoRESUMEN
During a dispute, a boy was injured by a curtain rail which penetrated the skull in the left frontal region and led to severe brain injury. Despite intensive medical care, death occurred 10 days later due to malignant cerebral edema. With regard to the question whether the trauma resulted from throwing or pushing, some biomechanical aspects are discussed including individual morphologic findings as well as the kinetic energy required for penetrating the skull. According to the calculated data, we conclude that the velocity necessary for penetrating could be reached by throwing the curtain rail.
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Traumatismos Penetrantes de la Cabeza/patología , Fracturas Craneales/patología , Adolescente , Traumatismos Penetrantes de la Cabeza/etiología , Homicidio , Humanos , Masculino , Fracturas Craneales/etiologíaRESUMEN
This study investigated the value of both gross features and histological findings for grading of brain swelling. For this purpose, the grooving of the temporal gyri (unci) as well as the extension of the cones at the basal part of the cerebellum were measured in 42 brains obtained at autopsy. Furthermore, the distension of perivascular spaces in tissue samples from seven different regions of the brains was evaluated histologically, assisted by an automatic image processing and analysis system. In each individual, the normal range of brain weight was calculated on the basis of the body height, using the formulae by Röthig and Schaarschmidt. The difference between this calculated (normal) value and the brain weight evaluated at autopsy was considered as a reliable criterion for the grade of brain swelling. There was no statistical evidence of a positive correlation between the various parameters. Hence, it can be concluded that both gross section and histological findings are of minimal significance for grading of brain swelling.
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Edema Encefálico/patología , Encéfalo/patología , Patologia Forense/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Valores de ReferenciaRESUMEN
A previous healthy 35-year-old man was found dead in his truck. Shortly before death he merely complained of influenza-like symptoms. The histological examination revealed evidence of a massive accumulation of sickle cells in smaller blood vessels. After molecular genetic analysis, the preliminary diagnosis of "sickle cell disease" was finally changed to the diagnosis of a sickle cell trait. It is presumed that an epileptic attack which also has to be considered as a concurring cause of death, precipitated sickling of the erythrocytes and led to a fatal sickle cell crisis.
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Autopsia/métodos , Muerte Súbita/etiología , Muerte Súbita/patología , Rasgo Drepanocítico/complicaciones , Rasgo Drepanocítico/patología , Adulto , Humanos , Masculino , Rasgo Drepanocítico/genéticaRESUMEN
Neuronal apoptosis has been investigated in paraffin-embedded brain tissue from 103 individuals who had sustained blunt head injury by use of the in situ nick translation (ISNT) technique. In order to provide reliable data for a forensic wound age estimation, a quantitative morphometric analysis was performed. Apoptotic neuronal cells could be detected in a cortical contusion with a wound age of 45 min at the earliest and in the majority of the cases with postinfliction intervals up to 2 weeks, numerous ISNT-positive cells were found adjacent to the traumatically injured area. The presented data indicate that neuronal apoptosis peaks at about 1 day and persists for at least 22 weeks after blunt head injury. The time-dependent occurrence of apoptotic cells can contribute to a forensic timing of cortical contusions and complements other immunohistochemical parameters, especially in the early postinfliction interval.
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Apoptosis , Lesiones Encefálicas/patología , Traumatismos Cerrados de la Cabeza/patología , Neuronas/patología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Corteza Cerebral/lesiones , Corteza Cerebral/patología , Niño , Medicina Legal/métodos , Humanos , Etiquetado Corte-Fin in Situ , Persona de Mediana Edad , Factores de TiempoAsunto(s)
Quiste Dermoide/diagnóstico , Neoplasias de la Lengua/diagnóstico , Adulto , Quiste Dermoide/patología , Quiste Dermoide/cirugía , Diagnóstico Diferencial , Femenino , Humanos , Tomografía Computarizada por Rayos X , Lengua/patología , Lengua/cirugía , Neoplasias de la Lengua/patología , Neoplasias de la Lengua/cirugía , UltrasonografíaRESUMEN
BACKGROUND: Head and neck malignancies have a high rate of recurrences. Since the prognosis is often limited an early detection and therapy onset is essential for survival. This study surveys the relevance of regular colour-duplex echography examinations in the follow-up for detection and therapy of recurrent head and neck carcinomas. PATIENTS AND METHODS: In a prospective non-randomized study 43 patients were surveyed over a mean observation period of 28 (8-44) months. In addition to clinical and colour-duplex echography (CDS) examinations, computed tomography (CT) and positron-emission-tomography using 18fluorodeoxyglucose (PET) were performed. RESULTS: A recurrence was detected in 17/43 (39.5 %) patients. The median survival was 42 months. CDS was the most reliable procedure for the diagnosis of regional recurrences with an accuracy of 94.2 %. Sensitivity and specificity of CDS for the diagnosis of all recurrences was found to be 80 % and 78,6 % respectively. CT yielded identical results. In PET sensitivity was 82.4 % and specificity was found to be 88.4 %. In clinical examinations including panendoscopy sensitivity was 64.7 % only. In 7/17 recurrences a therapy was performed with curative intention. In 4 cases an early diagnosis by CDS contributed to a successful therapy. CONCLUSION: CDS is the imaging procedure of choice for the routine follow-up of head and neck cancer patients. In order to perform a comprehensive assessment of the head and neck region, for re-staging and to exclude second primary tumours additional (pan)endoscopy is necessary. CDS supports due to a high resolution and reliability an early therapy onset and a minimal invasive therapy. Thus, this procedure can significantly contribute to the successful treatment of recurrences in head and neck cancer.
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Carcinoma de Células Escamosas/diagnóstico , Recurrencia Local de Neoplasia/diagnóstico , Neoplasias de Oído, Nariz y Garganta/diagnóstico , Ultrasonografía Doppler en Color , Adenocarcinoma/diagnóstico , Adenocarcinoma/mortalidad , Adenocarcinoma/patología , Adenocarcinoma/terapia , Carcinoma Adenoide Quístico/diagnóstico , Carcinoma Adenoide Quístico/mortalidad , Carcinoma Adenoide Quístico/patología , Carcinoma Adenoide Quístico/terapia , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/patología , Carcinoma de Células Escamosas/terapia , Terapia Combinada , Fluorodesoxiglucosa F18 , Estudios de Seguimiento , Humanos , Leiomiosarcoma/diagnóstico , Leiomiosarcoma/mortalidad , Leiomiosarcoma/patología , Leiomiosarcoma/terapia , Metástasis Linfática , Recurrencia Local de Neoplasia/mortalidad , Recurrencia Local de Neoplasia/patología , Recurrencia Local de Neoplasia/terapia , Estadificación de Neoplasias , Neoplasias de Oído, Nariz y Garganta/mortalidad , Neoplasias de Oído, Nariz y Garganta/patología , Neoplasias de Oído, Nariz y Garganta/terapia , Sensibilidad y Especificidad , Tasa de Supervivencia , Tomografía Computarizada de Emisión , Tomografía Computarizada por Rayos XRESUMEN
This is the report of a 62-year-old man who committed suicide by drilling through his anterior chest wall with an electric power drill. Death was caused by pericardial tamponade combined with bleeding into the pleural cavity. The skin lesion at the left hemithorax was similar to a bullet entrance wound.
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Artículos Domésticos , Suicidio , Heridas Penetrantes , Taponamiento Cardíaco/etiología , Hemotórax/etiología , Humanos , Masculino , Persona de Mediana EdadRESUMEN
A case of death due to car fire is described where the carbonised skull of the cremated corpse showed an ovoid defect of the cranial bone. The question arose whether this formed fracture was caused by a gunshot. But the reconstruction of the cranial remains with detached parts of the tabula externa provided evidence that the suspicious defect was to be classified as an uncommon heat-induced post-mortem artefact.
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Incendios , Cambios Post Mortem , Cráneo/lesiones , Artefactos , Diagnóstico Diferencial , Medicina Legal , Humanos , Cráneo/patología , Heridas por Arma de Fuego/diagnóstico , Heridas por Arma de Fuego/patologíaRESUMEN
In a total of 104 individuals who had sustained traumatic brain injury (TBI), the course of glial immunoreactivity was investigated at the injured cortical area during the first 30 weeks after the trauma, in order to provide data for a forensic wound age estimation. Glial cells were stained with antibodies against the intermediate filament protein vimentin, the extracellular matrix protein tenascin and the serine protease inhibitor alpha1-antichymotrypsin (alpha1-ACT). Injury-induced glial staining reactions could be observed, at the earliest, after a post-infliction interval of 3.1 h for alpha1-ACT, 22 h for vimentin and 7 days for tenascin.