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1.
Late Quaternary climate change,relict populations and present‐day refugia in the northern Atacama Desert: a case study from Quebrada La Higuera (18° S) 下载免费PDF全文
2.
C Balacco-Gabrieli S Salamanna E Giuliani G Mastrandrea M Latorre 《Bollettino della Società italiana di biologia sperimentale》1983,59(8):1172-1175
The Authors state the results of their research on the modification of the aqueous humor caused by the instillation of the Clonidina to the concentrations of 0,I25% in a group of ten rabbits. The results of these studies illustrate the variations of pH, the ocular tone, the concentration of lactic and ascorbic acid. In all the rabbits examined Clonidina was instillated in the RE while in the LE distilled water was instillated for the control. For two hours from the beginning of the experiment, every IO minutes measurements of the ocular tone in both eyes were taken. At the end of the two hours a sample of aqueous humor was taken from the RE and LE; It was found that: I) The drugs produced a very quick and prolonged decrease of the ocular tone. 2) There are no significant variations in the pH or in the concentration of lactic acid. 3) There was a notable reduction of the concentration of ascorbic acid. 相似文献
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Willy Carrasquel-Ursulaez Gustavo F. Contreras Romina V. Sepúlveda Daniel Aguayo Fernando González-Nilo Carlos González Ramón Latorre 《The Journal of general physiology》2015,145(1):61-74
Large-conductance Ca2+- and voltage-activated K+ channel (BK) open probability is enhanced by depolarization, increasing Ca2+ concentration, or both. These stimuli activate modular voltage and Ca2+ sensors that are allosterically coupled to channel gating. Here, we report a point mutation of a phenylalanine (F380A) in the S6 transmembrane helix that, in the absence of internal Ca2+, profoundly hinders channel opening while showing only minor effects on the voltage sensor active–resting equilibrium. Interpretation of these results using an allosteric model suggests that the F380A mutation greatly increases the free energy difference between open and closed states and uncouples Ca2+ binding from voltage sensor activation and voltage sensor activation from channel opening. However, the presence of a bulky and more hydrophobic amino acid in the F380 position (F380W) increases the intrinsic open–closed equilibrium, weakening the coupling between both sensors with the pore domain. Based on these functional experiments and molecular dynamics simulations, we propose that F380 interacts with another S6 hydrophobic residue (L377) in contiguous subunits. This pair forms a hydrophobic ring important in determining the open–closed equilibrium and, like an integration node, participates in the communication between sensors and between the sensors and pore. Moreover, because of its effects on open probabilities, the F380A mutant can be used for detailed voltage sensor experiments in the presence of permeant cations. 相似文献
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Ana Durb��n Juan J. Abell��n Nuria Jim��nez-Hern��ndez Marta Ponce Julio Ponce Teresa Sala Giuseppe D��Auria Amparo Latorre Andr��s Moya 《Microbial ecology》2011,61(1):123-133
Gut microbiota is the most complex bacterial community in the human body and its study may give important clues to the etiology of different intestinal diseases. Most studies carried out so far have used fecal samples, assuming that these samples have a similar distribution to the communities present throughout the colon. The present study was designed to test this assumption by comparing samples from the rectal mucosa and feces of nine healthy volunteers by sequencing libraries of 16S rRNA genes. At the family taxonomic level, where rarefaction curves indicate that the observed number of taxa is close to the expected one, we observe under different statistical analyses that fecal and mucosal samples cluster separately. The same is found at the level of species considering phylogenetic information. Consequently, it cannot be stated that both samples from a given individual are of similar composition. We believe that the evidence in support of this statement is strong and that it would not change by increasing the number of individuals and/or performing massive sequencing. We do not expect clinicians to stop using feces for research, but we think it is important to caution them on their potential lack of representativeness with respect to the bacterial biofilm on the rectal mucosa. 相似文献
8.
Castro Gabriel Vaisam Latorre Ana Frederica Sutter Korndorfer Fabíola Pozza de Carlos Back Lia Kubelka Lofgren Sara Emelie 《Biochemical genetics》2021,59(6):1666-1679
Biochemical Genetics - Obesity and overweight are worldwide public health problems with an evident genetic predisposition that is still poorly understood. In addition, great variability has been... 相似文献
9.
Yesenia Pacheco-Hernández Carlos Jonnathan Castro-Juárez Sergio Alberto Ramírez-García Ramiro Cruz-Durán Edmundo Lozoya-Gloria Nemesio Villa-Ruano 《Journal of Asia》2021,24(2):243-249
Preventive measures based in the control of insect vectors are considered as the best choice to decrease the incidence of insect-borne diseases. Herein we report on the volatile content of the leaf essential oils from Marina neglecta, a medicinal plant distributed in the tropical regions of southern Mexico. In order to investigate the chemical variation of the essential oils, a volatile screening was performed during the four seasons of the years 2016–2019. Simultaneously, their biological activity was tested on distinct life stages of Meccus pallidipennis, M. bassolsae, Aedes aegypti and A. albopictus. Essential oils were mainly constituted of β-pinene (>30%) β-caryophyllene (>25%) and germacrene D (>13%). Dorsal-abdomen application of essential oils on triatomines, revealed an efficient LC50 for nymphs of the stages I to III (4 µg/insect), nymphs of the stages IV to V (5–6 µg/insect), and adults (7–8 µg/insect). The LT50 for the stages I to III was between 6 and 8 h, whereas that for the stages IV to V and adults oscillated between 12 and 16 h and 22 to 26 h, respectively. Fumigation experiments performed on nymph V, demonstrated that 300 µg L?1 air produced 100% mortality after 72 h post-treatment. Among tested volatiles, β-pinene and β-caryophyllene produced a comparable mortality rate (p < 0.01) than that of essential oils in the stages assayed. Essential oils showed strong larvicidal (LC50, 24–36 µg mL?1) and adulticidal (35–48 µg mL?1) activities in mosquito species with an LT50 of 4.5 h and 25–35 min, respectively. The evaluation of β-pinene produced a significant mortality rate (p < 0.01) in larvae whereas germacrene D was the most effective volatile (p < 0.01) against adults of both mosquito species. According to our results, β-pinene was the most effective volatile against the four insect species evaluated and its effect was comparable to that of the essential oil. 相似文献
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This work is part of a series of aerobiological researches conducted in the city of Mar del Plata, Argentina. The annual,
seasonal and daily features of the pollen cloud were analyzed over 2 years, together with the effects of the meteorological
variables. Cupressaceae amounted to 75 and 54% of the annual total in each year, and it was analyzed separately due to its
proven overrepresentation. Eighty-five pollen types were registered during the 2 years, bearing a similar annual pattern (more
than 50% from August to November, December also being an important month). Arboreal pollen predominated between late winter
and spring (61 and 49% of the annual total), while non-arboreal pollen did so from late spring to summer. The observed seasonality
was significantly correlated with the monthly mean temperatures and associated with its effect on phenology. No significant
differences along the day were detected between years and 50% of the daily total was recorded between 1000 and 1600 hours.
The maximum concentration was registered at 1000 hours in spring and summer, but later in autumn and winter. Regarding the
hourly scale, the significant correlation of total pollen with temperature and wind speed was positive, albeit negative with
relative humidity. These effects are linked to airborne pollen release and transport. The role rainfall plays on airborne
pollen is discussed. To interpret the results, it is important to consider the time scale at which the aerobiological phenomenon
is analyzed. 相似文献