Papers by Carolina Castillo
Chronic kidney disease (CKD) remains a major epidemiological, clinical and biomedical challenge. ... more Chronic kidney disease (CKD) remains a major epidemiological, clinical and biomedical challenge. During CKD, renal tubular epithelial cells (TECs) suffer a persistent inflammatory and profibrotic response. Fatty acid oxidation (FAO), the main source of energy for TECs, is reduced in kidney fibrosis and contributes to its pathogenesis. To determine if FAO gain-of-function (FAO-GOF) could protect from fibrosis, we generated a conditional transgenic mouse model with overexpression of the fatty acid shuttling enzyme carnitine palmitoyl-transferase 1 A (CPT1A) in TECs. Cpt1a knock-in (CPT1A KI) mice subjected to three different models of renal fibrosis (unilateral ureteral obstruction, folic acid nephropathy-FAN and adenine induced nephrotoxicity) exhibited decreased expression of fibrotic markers, a blunted pro-inflammatory response and reduced epithelial cell damage and macrophage influx. Protection from fibrosis was also observed when Cpt1a overexpression was induced after FAN. FAO-GO...
MicroRNAs (miRNAs) regulate gene expression post-transcriptionally and control biological process... more MicroRNAs (miRNAs) regulate gene expression post-transcriptionally and control biological processes, including fibrogenesis. Kidney fibrosis remains a clinical challenge and miRNAs may represent a valid therapeutic avenue. We show that miR-9-5p protected from renal fibrosis in the mouse model of unilateral ureteral obstruction (UUO). This was reflected in reduced expression of fibrotic markers, decreased number of infiltrating monocytes/macrophages and diminished tubular epithelial cell injury and transforming growth factor-beta 1 (TGF-β1)-dependent de-differentiation in human kidney proximal tubular (HKC-8) cells. RNA sequencing (RNA-Seq) studies in the UUO model revealed that this protection was mediated by a global shift in the expression profile of genes related to key metabolic pathways, including mitochondrial dysfunction, oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO) and glycolysis, preventing their UUO-dependent down-regulation. Studies in human tubular epit...
Zootaxa, 2006
Napaeus lajaensis sp. nov. is the oldest Napaeus species found in the Canary Islands, with more t... more Napaeus lajaensis sp. nov. is the oldest Napaeus species found in the Canary Islands, with more than 130 ka. It is described from a Pleistocene aeolian deposit intercalated between two basaltic lava flows located at Mancha de La Laja (Tenerife Island). The new species is characterized mainly by the presence of two very prominent, spiral, semicylindrical ribs on the body whorl shell. The stratigraphic setting and taphonomic features of the land snail association to which N. lajaensis belongs, were also shown.
Futuristic Composites, 2018
The use of reinforcements from natural or animal sources has recently taken relevance because it ... more The use of reinforcements from natural or animal sources has recently taken relevance because it is a good way of obtaining improved polymers while reducing the environmental impact of the poultry industry, and at the same time, it allows to take advantage of the large amount of waste materials that is frequently considered useless. Styrene-butadiene copolymer (SBS) is used in a wide range of applications, for example, in shoes, adhesives, tires, plastic and asphalt modifiers, among others. However, SBS has limitations due to its mechanical and thermal properties; in some cases, it has been reinforced with particles in order to improve its thermomechanical behavior. Chicken feathers (CFs) represent a waste material from the poultry farming that has not been widely used in the polymer industry yet. Furthermore, in some cases, its final disposal management implies additional costs. CFs is mainly composed of keratin, a mix of proteins that have good mechanical and thermal properties. In the present work, CFs were milled and mixed with SBS with the aim of preparing SBS-CF composites. Composite materials were produced by means of a melt-mixing technique, and the effect of zinc oxide (ZnO) as coupling agent was evaluated. Three different concentrations of CFs at varying mixing speeds were tested with the aim of assessing their effect on the SBS-CF composites properties. The composites thermal properties were measured by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA), while their morphologic properties were evaluated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM).
RSC Adv., 2015
Nickel nanocomposites are obtained under solvothermal conditions by reduction of NiII on matrices... more Nickel nanocomposites are obtained under solvothermal conditions by reduction of NiII on matrices of polyethylene (Pe) and chitosan (Ch). The composites are weak magnets and are active as catalysts for the hydrogen transfer reaction for acetophenone.
Quaternary Research, 2011
The isotopic composition of land snail shells was analyzed to investigate environmental changes i... more The isotopic composition of land snail shells was analyzed to investigate environmental changes in the eastern Canary Islands (28–29°N) over the last ~ 50 ka. Shell δ13C values range from −8.9‰ to 3.8‰. At various times during the glacial interval (~ 15 to ~ 50 ka), moving average shell δ13C values were 3‰ higher than today, suggesting a larger proportion of C4 plants at those periods. Shell δ18O values range from −1.9‰ to 4.5‰, with moving average δ18O values exhibiting a noisy but long-term increase from 0.1‰ at ~ 50 ka to 1.6–1.8‰ during the LGM (~ 15–22 ka). Subsequently, the moving average δ18O values range from 0.0‰ at ~ 12 ka to 0.9‰ at present. Calculations using a published snail flux balance model for δ18O, constrained by regional temperatures and ocean δ18O values, suggest that relative humidity at the times of snail activity fluctuated but exhibited a long-term decline over the last ~ 50 ka, eventually resulting in the current semiarid conditions of the eastern Canary Is...
Paleobiology, 2008
The hypothesis of limiting similarity, which postulates that morphologically and/or ecologically ... more The hypothesis of limiting similarity, which postulates that morphologically and/or ecologically similar species will differ enough in shape, size, or other variables to minimize competition, has been controversial among ecologists and paleoecologists. Many studies have reported the occurrence of limiting similarity in modern environments or in time-averaged fossil deposits; however, empirical high-resolution time series demonstrating limiting similarity over longer time scales are lacking. We have integrated radiocarbon-calibrated amino acid dating techniques, stable isotope estimates, and morphometric data to test the hypothesis of limiting similarity in late Quaternary land snails from the Canary Islands over a period of 42,500 years. We tested for both ecological character displacement (two closely related species will differ in size in order to minimize competition in sympatry and these differences will be minimized in allopatry) and communitywide character displacement (overdi...
Palaeogeography, Palaeoclimatology, Palaeoecology, 1995
Lacustrine deposits, which form part of a continental unit cropping out in many localities of the... more Lacustrine deposits, which form part of a continental unit cropping out in many localities of the Jerez Basin (SW Spain), have for the first time been dated. These deposits are attributed to the lower part of the Dolomys subzone, the upper part of the MN 15 Neogene Mammal Unit (late Ruscinian). This continental unit unconformably overlies a marine unit. Since the isochrony of the unconformity is not precisely established, the biostratigraphic results and palaeomagnetic data give two possibilities in correlating the Dolomys subzone with the marine magnetobiostratigraphy: (1) it can be correlated with the C2Ar reversed-polarity chron, or (2) with the C2An.2r reversed-polarity subchron (or C2An.lr ?). Therefore, the lower boundary of the MN 15 would be at the base of the C2Ar or at the very top of the Early Pliocene, respectively. In any case, considering the magnetobiostratigraphy correlation carried out in other Pliocene continental basins of the southeastern Spain, the top of MN 15 seems to be within the Late Pliocene.
Lethaia, 2008
Quaternary aeolian deposits of the Canary Islands contain well-preserved terrestrial gastropods, ... more Quaternary aeolian deposits of the Canary Islands contain well-preserved terrestrial gastropods, providing a suitable setting for assessing the taphonomy and compositional fidelity of their fossil record over ~13 kyr. Nine beds (12, 513 shells) have been analysed in terms of multivariate taphonomic and palaeoecological variables, taxonomic composition, and the stratigraphic and palaeontological context. Shells are affected by carbonate coatings, colour loss and fragmentation. Shell preservation is size-specific: juveniles are less fragmented and show colour preservation more commonly than adults. In palaeosols, the adult shell density correlates negatively with the proportion of fragmented adults, negatively with the proportion of juveniles, and positively with the proportion of adults with coatings. High bioturbation intensity in palaeosols is associated with low shell fragmentation and high proportion of shells with coatings. These relationships imply that high adult density in palaeosols was driven by an increase in shell production rate (related to a decrease in predation rates on adults and a decrease in juvenile mortality) and a decrease in shell destruction rate (related to an increase in durability enhanced by carbonate precipitation). In dunes, the relationships between taphonomic alteration, shell density and bioturbation are insignificant. However, dune assemblages are characterized by a lower frequency of shells with coatings and higher rates of colour loss, indicating lower shell durability in dunes than in palaeosols. Additionally, nonrandom differences in the coating proportion among palaeosols imply substantial temporal variation in the rate of carbonate crust formation, reflecting long-term changes in bioturbation intensity that covaries positively with shell preservation. Dunes and palaeosols do not differ in species abundances despite differences in the degree of shell alteration, suggesting that both weakly and strongly altered assemblages offer data with a high compositional fidelity. Carbonate-rich terrestrial deposits originating in arid conditions can enhance the preservation of gastropods and result in fossil assemblages that are suitable for palaeoecological and palaeoenvironmental studies of terrestrial ecosystems. ᮀ Aeolian deposits, Canary Islands, land snail shell assemblages, Quantitative Taphonomy, Quaternary .
Chemical Geology, 2008
Stable isotopes of oxygen and carbon extracted from fossil land snail shells have been used incre... more Stable isotopes of oxygen and carbon extracted from fossil land snail shells have been used increasingly to interpret past environments. To evaluate the utility of this approach for low-latitude oceanic islands, populations of the modern helicid land snail Theba geminataa species also abundant in the Quaternary fossil record of the regionwere sampled at ten low altitude (b 300 m) sites from coastal areas of the eastern Canary Islands. The results include stable isotopes of (1) 17 aragonite shells of live-collected adult snails; (2) 17 body tissue samples from the same snail individuals; (3) 10 samples of carbonate sediments; (4) 69 plant tissue samples representing all 24 identified species; and (5) 7 rain water samples. The mean isotopic composition of the rain water is −5‰ (V-SMOW) for δD and −2‰ (V-SMOW) for δ 18 O, ranging from −11‰ to +2‰ (V-SMOW) and from −2.6‰ to −0.7‰ (V-SMOW), respectively. The local vegetation is heterogeneous, including C 3 , C 4 , and CAM plants. δ 13 C values vary from −13.0‰ to −29.0‰ (V-PDB) across plant species. Of the 24 species, five are C 4 , 15 are C 3 , and four are CAM plants. The δ 18 O values for shells represent a narrow range of values (from −0.3‰ to +2.5‰ [V-PDB]), which is consistent with the low climate seasonality typifying low-latitude oceanic settings. Hypothetical model of the expected δ 18 O value for shell aragonite precipitated in equilibrium suggests that the most negative δ 18 O shell represent the closest estimate for δ 18 O rain water. The δ 13 C values of shells range from −9.4‰ to +1.7‰ (V-PDB). The most positive δ 13 C values are attributed to a diet based on C 4 plants. The comparison of δ 13 C values of soft tissues and shells suggests that snails ingested notable amounts (from~20% up to~40%) of foreign carbonates. Consequently, fossil shells with the most negative δ 13 C values should be selected for radiocarbon dating in future geochronological studies of the region. The δ 13 C values of body tissues vary from −12.0‰ to −27.2‰ (V-PDB), indicating that land snails consumed C 3 and C 4 plants indiscriminately. The mean carbon isotopic composition, averaged across multiple fossil specimens, may thus provide a useful tool for reconstructing paleoclimates and paleoenvironments throughout the Quaternary history of the Canary Islands and other comparable low-latitude oceanic settings.
Journal of …, 2007
Napaeus lichenicola sp. nov. from Jandia, Fuerteventura Island, is described, the main difference... more Napaeus lichenicola sp. nov. from Jandia, Fuerteventura Island, is described, the main differences with the nearest species are discussed and data on distribution and conservation status are presented. The functional meaning of the epiphallar caecum and ...
Acta Crystallographica Section E Structure Reports Online, 2008
m778 Venegas-Yazigi et al. (C 10 H 10 N 3) 2 [ZnCl 4 ] Acta Cryst. (2008). E64, m777-m778 support... more m778 Venegas-Yazigi et al. (C 10 H 10 N 3) 2 [ZnCl 4 ] Acta Cryst. (2008). E64, m777-m778 supporting information sup-7
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Papers by Carolina Castillo