2,560 research outputs found
Using Green Fluorescent Protein to Correlate Temperature and Fluorescence Intensity into Bacterial Systems
The unique and stunning spectroscopic properties of Green Fluorescent Protein (GFP) from the jellyfish Aequorea victoria, not to mention of its remarkable structural stability, have made it one of the most widely studied and used molecular tool in medicine, biochemistry, and cell biology. Its high fluorescent quantum yield is due to its chromophore, structure responsible of emitting green visible light when excited at 395 nm. Although it is noteworthy that there is enormous available information of the wonderful luminescent properties of GFP, the fact is that there are features and properties unexplored yet, particulary about its capabilities as molecular reporter in several biological processes. In this work, we used recombinant DNA technology to express the protein in bacteria; prepared the bacterial system both in liquid and solid media, and assembled an experimental set to expose those media to a laser beam; thereby we excited the protein chromophore and used emission spectroscopy in order to observe variations in fluorescence when the bacterial system is exposed to different temperatures
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Cold temperature tolerance of the alien Indo-Pacific damselfish Neopomacentrus cyanomos from the Southern Gulf of Mexico
The abundance of the alien, Indo-Pacific damselfish Neopomacentrus cyanomos on an oil-loading platform in the southwest Gulf of Mexico indicates that widely distributed platforms could facilitate the expansion of its geo- graphic range across the western and northern fringes of the Gulf. From there it likely will spread to other areas of the Greater Caribbean. The lionfish example demonstrates that it eventually happens, and can do so rapidly. Reduced temperature effects on the physiology of this species were examined to better predict its survivability in the northern Gulf during winter, when sea surface temperatures fall as low as 15 °C along the coast. Overall, our results show that when the degree of experimental temperature decline was large and rapid, no compensation occurred and the stress response observed mostly reflected cellular processes that minimized damage. Integrated biomarker response values were significantly different between fish rapidly exposed to colder vs. warmer temperatures (declines of −4 °C each day, from 26 to 14 °C), reflected in higher values of blood metabolites and routine metabolic rates observed in fish exposed to 14 and 18 °C respectively, and lower activity of all enzymes, lower protein carbonylation, and higher oxidative damage to lipids in fish exposed to 14 °C. While the phy- siological proxies responded to minimize damage during the rapid-decrease experiment, the same proxies re- flected the consequences of compensation when fish were thermally challenged after a 45 days acclimation at 18 °C. In this case, lower values of blood metabolites and high antioxidant levels and indicators of damages underpinned its pejus lower range. Based on the results of the present work, it seems clear that low winter SSTs in the northern Gulf will slow down the colonization of the inshore area of N. cyanomos. We suggest that the use of physiological cellular stress markers on specimens acquired at the beginning of an invasion should be im- plemented in new standardized experimental protocols, including both rapid increases/decreases of temperature and post-acclimation temperature challenges, to assess the invasiveness potential of aquatic species such as this
Zaluzania montagnifolia: essential oil composition and biological properties
The chemical composition of the seasonal essential oils (2015-2016) from the leaves and flowers of Zaluzania montagnifolia is presented. The chemical content of those oils showed quantitative and qualitative differences. Germacrene D (19.9-29.8%), camphor (12.4- 19.4%) and β-caryophyllene (13.7-18.5%) were the most abundant volatiles in the leaves. The essential oils from the flowers contained high amounts of camphor (32.7-37.2%) limonene (19.8-24.9%) and germacrene D (3.2-7.3%). All the seasonal essential oils showed a potent in vitro inhibition against HMG-CoA reductase. The essential oils from flowers (IC50, 40.5-55.1 μg mL-1) showed better inhibition properties than those of leaves (IC50, 84.4-123.5 μg mL-1). Camphor (IC50, 72.5 μg mL-1) and borneol (IC50, 84.4 μg mL-1) exerted a non-competitive inhibition on the enzyme. Additionally, the hydrodistillates exhibited antibacterial activity against the phytopathogenic Pseudomonas syringae pv. tabaci TBR2004 (MIC, 62.7-76.5 μg mL-1) P. syringae pv. tomato DC3000 (MIC, 45.4-50.4 μg mL-1) and P. syringae pv.phaseolicola NPS3121 (MIC, 26.7-31.9 μg mL-1). Germacrene D (MIC, 35.4-66.2 μg mL-1) and β-caryophyllene (MIC, 36.5-54.2 μg mL-1) were the strongest anti-Pseudomonas syringae agents
La cueva de el Sidron (Borines, Piloña, Asturias) : primeros resultados
Se exponen los resultados preliminares de las excavaciones arqueológicas llevadas a
cabo en la Cueva de El Sidrón entre 2000 y 2002, de acuerdo con los tres objetivos
principales que conciernen al registro fósil humano: las caracterÃsticas antropológicas,
cómo y cuándo llegaron allà y la relación entre fósiles y cultura. Las primeras conclusiones
obtenidas son que los restos humanos pertenecen al Neandertal, que el registro
arqueológico corresponde a un tecno-complejo del PaleolÃtico Medio y que están en
posición secundaria.We expose the preliminary results ofthe archaeological excavations developed between
2000-2002 in Sidrón's Cave, according to the three main objectives that concern the
human fossil record: the anthropological characteristics, how and when they arrived
there and the relation between fossils and culture. We conclude preliminarily that the
record belongs to Horno Neanderthalensis, archeological remains to the Middle Paleolithic
techno-complex, and they are in a secondary [email protected]
Caracterización nutricional de salsas a base de Xoconostle (Opuntia oligacantha C. F. Först)
Se elaboraron salsas a base de Xoconostle Ulapa, de la variedad Opuntia oligacantha C. F. Först, de un huerto comercial establecido en el municipio de Tezontepec de Aldama, Hidalgo, utilizando ingredientes como chile seco cascabel y, ajos, se obtuvieron en plantaciones establecidas en Zacatecas, Zac., México. Las salsas fueron elaboradas bajo la norma NMX-F-377-1986. Se obtuvieron cuatro tratamientos; con dos formulaciones (asada y cosida) y dos tratamientos térmicos (marmita: 80°C durante 20 min y autoclave: 121°C durante 15 min); T1: Xoconostle cocido y tratamiento térmico en autoclave, T2: Xoconostle asado y tratamiento térmico en autoclave, T3: Xoconostle cocido y tratamiento térmico en marmita, T4: Xoconostle asado y tratamiento térmico en marmita. Las variables evaluaron fueron: pH, acidez titulable, color, grasas, carbohidratos, valor energético, cenizas humedad, proteÃna y fibra cruda. Para el análisis de resultados se utilizó el programa estadÃstico SAS, el diseño completamente al azar. Se realizó el análisis de varianza y la prueba de comparaciones múltiples de Tukey con una p≤0.05. El mayor contenido de sólidos solubles totales o °Bx, se encontró en la salsa de Xoconostle asada (A/m) y con tratamiento térmico en marmita y tratamiento térmico en autoclave (A/a), cenizas: en salsa de Xoconostle cocido y tratamiento térmico en autoclave (C/a); el mayor contenido de humedad en salsa cocida y tratamiento térmico en autoclave C/a y cocida y con tratamiento térmico en marmita (C/m), proteÃna en A/m y C/a; y el mayor contenido de fibra cruda lo presento C/a
The Atapuerca sites and the Ibeas hominids
The Atapuerca railway Trench and Ibeas sites near Burgos, Spain,
are cave fillings that include a series of deposits ranging from
below the Matuyama/Bruhnes reversal up to the end of Middle
Pleistocene. The lowest fossil-bearing bed in the Trench contains
an assemblage of large and small Mammals including Mimomys
savini, Pitymys gregaloides, Pliomys episcopalis, Crocuta crocuta,
Dama sp. and Megacerini; the uppermost assemblage includes
Canis lupus, Lynx spelaea, Panthera (Leo) fossilis, Felis sylvestris,
Equus caballus steinheimensis, E.c. germanicus, Pitymys subtenaneus,
Microtus arvalis agrestis, Pliomys lenki, and also Panthera
toscana, Dicerorhinus bemitoechus, Bison schoetensacki, which are
equally present in the lowest level. The biostratigraphic correlation
and dates of the sites are briefly discussed, as are the
paleoclimatic interpretation of the Trench sequences. Stone artifacts
are found in several layers; the earliest occurrences correspond
to the upper beds containing Mimomys savini. A set of
preserved human occupation floors has been excavated in the top
fossil-bearing beds. The stone-tool assemblages of the upper levels
are of upper-medial Acheulean to Charentian tradition. The rich
bone breccia SH, in the Cueva Mayor-Cueva del Silo, Ibeas de
Juarros, is a derived deposit, due to a mud flow that dispersed and
carried the skeletons of many carnivores and humans. The taxa
represented are: Vrsus deningeri (largely dominant), Panthera (Leo)
fossilis, Vulpes vulpes, Homo sapiens var. Several traits of both
mandibular and cranial remains are summarized. Preliminary attempts
at dating suggest that the Ibeas fossil man is older than the
Last Interglacial, or oxygen-isotope stage 5
Microstructure of an Extruded Third-Generation Snack Made from a Whole Blue Corn and Corn Starch Mixture
Blue corn is a potential material for expanded snack production. Whole blue corn meal was mixed with corn starch and processed by extrusion to produce a third-generation snack. Optimum extrusion conditions were calculated with the response surface methodology using expansion index (EI), penetration force (PF), specific mechanical energy (SME) and total anthocyanins content (TAC). Optimum conditions (zone 1, 67°C; cooking zone, 123°C; zone 3, 75°C; feed moisture, 24.6%) were used to extrude the mixture in a single-screw extruder, and EI,PF,SME and TAC of the expanded pellet were compared against predicted optimum values. Starch structural changes in pellets and expanded were analyzed with DSC, viscosity profiles, x-ray diffraction and SEM. Extruded pellet did not differ (p>0.05) from the predicted. However, TAC was lower (p<0.05) in the expanded pellet. Structural analyses showed damage starch granular structure during extrusion and pellet expansion. Blue corn is a promising material for production of third-generation snacks
La cueva de El Sidrón (Borines, Piloña, Asturias): primeros resultados
We expose the preliminary results of the archaeological excavations developed between 2000-2002 in Sidrón's Cave, according to the three main objectives that concern the human fossil record: the anthropological characteristics, how and when they arrived there and the relation between fossils and culture. We conclude preliminarily that the record belongs to Horno Neanderthalensis, archeological remains to the Middle Paleolithic techno-complex, and they are in a secondary position.Se exponen los resultados preliminares de las excavaciones arqueológicas llevadas a cabo en la Cueva de El Sidrón entre 2000 y 2002, de acuerdo con los tres objetivos principales que conciernen al registro fósil humano: las caracterÃsticas antropológicas, cómo y cuándo llegaron allà y la relación entre fósiles y cultura. Las primeras conclusiones obtenidas son que los restos humanos pertenecen al Neandertal, que el registro arqueológico corresponde a un tecno-complejo del PaleolÃtico Medio y que están en posición secundari
The first hominin of Europe
The earliest hominin occupation of Europe is one of the most debated topics in palaeoanthropology. However, the purportedly oldest of the Early Pleistocene sites in Eurasia lack precise age control and contain stone tools rather than human fossil remains(1-5). Here we report the discovery of a human mandible associated with an assemblage of Mode 1 lithic tools and faunal remains bearing traces of hominin processing, in stratigraphic level TE9 at the site of the Sima del Elefante, Atapuerca, Spain(6-8). Level TE9 has been dated to the Early Pleistocene ( approximately 1.2 - 1.1 Myr), based on a combination of palaeomagnetism, cosmogenic nuclides and biostratigraphy. The Sima del Elefante site thus emerges as the oldest, most accurately dated record of human occupation in Europe, to our knowledge. The study of the human mandible suggests that the first settlement of Western Europe could be related to an early demographic expansion out of Africa. The new evidence, with previous findings in other Atapuerca sites ( level TD6 from Gran Dolina(9-13)), also suggests that a speciation event occurred in this extreme area of the Eurasian continent during the Early Pleistocene, initiating the hominin lineage represented by the TE9 and TD6 hominins.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62855/1/nature06815.pd
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