Telomere dynamics during hibernation in a tropical primate.

Hibernation is a widespread metabolic strategy among mammals for surviving periods of food scarcity. During hibernation, animals naturally alternate between metabolically depressed torpor bouts and energetically expensive arousals without ill effects. As a result, hibernators are promising models for investigating mechanisms that buffer against cellular stress, including telomere protection and restoration. In non-hibernators, telomeres, the protective structural ends of chromosomes, shorten with age and metabolic stress. In temperate hibernators, however, telomere shortening and elongation can occur in response to changing environmental conditions and associated metabolic state. We investigate telomere dynamics in a tropical hibernating primate, the fat-tailed dwarf lemur (Cheirogaleus medius). In captivity, these lemurs can hibernate when maintained under cold temperatures (11-15 °C) with limited food provisioning. We study telomere dynamics in eight fat-tailed dwarf lemurs at the Duke Lemur Center, USA, from samples collected before, during, and after the hibernation season and assayed via qPCR. Contrary to our predictions, we found that telomeres were maintained or even lengthened during hibernation, but shortened immediately thereafter. During hibernation, telomere lengthening was negatively correlated with time in euthermia. Although preliminary in scope, our findings suggest that there may be a preemptive, compensatory mechanism to maintain telomere integrity in dwarf lemurs during hibernation. Nevertheless, telomere shortening immediately afterward may broadly result in similar outcomes across seasons. Future studies could profitably investigate the mechanisms that offset telomere shortening within and outside of the hibernation season and whether those mechanisms are modulated by energy surplus or crises.

Of fruits and fats: high-sugar diets restore fatty acid profiles in the white adipose tissue of captive dwarf lemurs.

Fat-storing hibernators rely on fatty acids from white adipose tissue (WAT) as an energy source to sustain hibernation. Whereas arctic and temperate hibernators preferentially recruit dietary polyunsaturated fatty acids (PUFAs), tropical hibernators can rely on monounsaturated fatty acids that produce fewer lipid peroxides during oxidation. Nevertheless, compositional data on WAT from tropical hibernators are scant and questions remain regarding fat recruitment and metabolism under different environmental conditions. We analyse fatty acid profiles from the WAT of captive dwarf lemurs (Cheirogaleus medius) subjected to high-sugar or high-fat diets during fattening and cold or warm conditions during hibernation. Dwarf lemurs fed high-sugar (compared to high-fat) diets displayed WAT profiles more comparable to wild lemurs that fatten on fruits and better depleted their fat reserves during hibernation. One PUFA, linoleic acid, remained elevated before hibernation, potentially lingering from the diets provisioned prior to fattening. That dwarf lemurs preferentially recruit the PUFA linoleic acid from diets that are naturally low in availability could explain the discrepancy between captive and wild lemurs' WAT. While demonstrating that minor dietary changes can produce major changes in seasonal fat deposition and depletion, our results highlight the complex role for PUFA metabolism in the ecology of tropical hibernators.

Degradation of a series of fluorinated acrylates and methacrylates initiated by OH radicals at different temperatures.

Rate coefficients for the gas-phase reactions of OH radicals with a series of fluorinated acrylates and methacrylates: 2,2,2-trifluoroethylmethacrylate (k 1), 1,1,1,3,3,3-hexafluoroisopropylacrylate (k 2), 1,1,1,3,3,3-hexafluoroisopropylmethacrylate (k 3), and 2,2,2-trifluoroethylacrylate (k 4) have been measured for the first time as a function of temperature in the range 290-308 K. The kinetic data obtained were used to derive the following Arrhenius expressions (in units of cm3 per molecule per s): k 1 = (2.13 ± 0.68) × 10-18 exp[(4745 ± 206)/T], k 2 = (8.72 ± 0.68) × 10-15 exp[(2166 ± 205)/T], k 3 = (6.30 ± 0.51) × 10-17 exp[(3721 ± 153)/T] and k 4 = (3.93 ± 0.43) × 10-16 exp[(3140 ± 129)/T]. The experiments were performed at normal atmospheric pressure in synthetic air using a 1080 L photoreactor and coupled with FTIR analysis to monitor the decay of the substances of interest and the reference compounds. The obtained negative temperature dependencies are in agreement with a mechanism implying an initial addition of the OH radical to the double bond. Atmospheric implications are discussed with reference to the rate coefficients obtained as a function of the temperature.

Stable isotopes document resource partitioning and effects of forest disturbance on sympatric cheirogaleid lemurs.

The future of Madagascar's forests and their resident lemurs is precarious. Determining how species respond to forest fragmentation is essential for management efforts. We use stable isotope biogeochemistry to investigate how disturbance affects resource partitioning between two genera of cheirogaleid lemurs (Cheirogaleus and Microcebus) from three humid forest sites: continuous and fragmented forest at Tsinjoarivo, and selectively logged forest at Ranomafana. We test three hypotheses: (H1) cheirogaleids are unaffected by forest fragmentation, (H2) species respond individually to disturbance and may exploit novel resources in fragmented habitat, and (H3) species alter their behavior to rely on the same key resource in disturbed forest. We find significant isotopic differences among species and localities. Carbon data suggest that Microcebus feed lower in the canopy than Cheirogaleus at all three localities and that sympatric Cheirogaleus crossleyi and C. sibreei feed at different canopy heights in the fragmented forest. Microcbus have higher nitrogen isotope values than Cheirogaleus at all localities, indicating more faunivory. After accounting for baseline isotope values in plants, our results provide the most support for H3. We find similar isotopic variations among localities for both genera. Small differences in carbon among localities may reflect shifts in diet or habitat use. Elevated nitrogen values for cheirogaleid lemurs in fragments may reflect increased arthropod consumption or nutritional stress. These results suggest that cheirogaleids are affected by forest disturbance in Eastern Madagascar and stress the importance of accounting for baseline isotopic differences in plants in any work comparing localities.

Atmospheric photooxidation of fluoroacetates as a source of fluorocarboxylic acids.

A 1080 L environmental chamber with in situ FTIR spectroscopy detection was used to study the product distribution and the mechanism of the Cl-initiated photooxidation of a series of fluoroacetates. The gas-phase reactions of Cl atoms with ethyl trifluoroacetate (CF(3)C(O)OCH(2)CH(3)), methyl trifluoroacetate (CF(3)C(O)OCH(3)), and methyl difluoroacetate (CF(2)HC(O)OCH(3)) were investigated at 296 +/- 2 K and atmospheric pressure (approximately 760 Torr) of synthetic air. The fate of the fluoroalkoxy radicals formed in the reaction with Cl atoms mainly occurs through (i) an H-atom abstraction by reaction with O(2,) to produce the corresponding fluoroanhydride and (ii) an alpha-ester rearrangement via a five-membered ring intermediate to give the corresponding fluoroacetic acid. The yields of fluoroacids (CF(2)XC(O)OH, with X = H, F) obtained were as follows: 78 +/- 5, 23 +/- 2, and 30 +/- 5% for CF(3)C(O)OCH(2)CH(3), CF(3)C(O)OCH(3), and CF(2)HC(O)OCH(3,), respectively. Yields of

Síndrome de Wells. A propósito de dos casos / Well's syndrome

El síndrome de Wells o celulitis eosinofílica es una dermatosis inflamatoria caracterizada por placas edematosas, eritema-violáceas, infiltradas y discretamente pruriginosas. Con carácter autolimitado, desaparecen sin dejar secuelas en semanas o meses, y habitualmente presentan un curso recurrente. En ocasiones, se acompañan de manifestaciones sistémicas como fiebre o poliartralgias, siendo muy raro el compromiso simultáneo de otros órganos internos. En el 50 por ciento de los casos se acompañan de eosinofilia periférica, dato común pero no indispensable para el diagnóstico. La "figura en llama", cuadro histológico característico de este síndrome, no es patognomónico, ya que también está presente en diversas entidades que deben ser colocadas como diagnósticos diferenciales. Por tanto, la presencia concomitante de un cuadro clínico característico y hallazgos histopatológicos típicos es fundamental para el diagnóstico de celulitis eosinofílica. Se describen dos casos, en los que la realización de una historia clínica pormenorizada, con descripción detallada de las lesiones, complementada con el estudio histológico cutáneo, fue crucial para el diagnóstico de síndrome de Wells (AU)

Hurler-like phenotype: enzymatic diagnosis in dried blood spots on filter paper.

BACKGROUND: Clinical differentiation among mucopolysaccharidosis, oligosaccharidosis, and mucolipidosis II and III is difficult. We describe methods for the assay of 8 lysosomal enzymes in dried blood spots on filter paper that allow screening for 12 lysosomal storage diseases that present with a Hurler-like phenotype. METHODS: To test tubes containing 3-mm blood spots, we added elution liquid and fluorescent or radioactive substrate solution. After incubation at 37 degrees C, the reaction was terminated by the addition of a stop buffer. The amount of hydrolyzed product was compared with a calibrator to allow the quantification of enzyme activity. Sample stability was studied during storage for 21 days and during shipment of samples. We measured enzyme activities in 85 healthy controls (35 newborn, 50 adult), 57 patients suffering from 11 lysosomal storage diseases, and 46 obligate carriers. RESULTS: Intra- and interassay CVs were <9% and <15%, respectively. Mean activity losses during transportation or storage for up to 21 days at 4 degrees C were < or =27%. Enzyme activities in all patients were outside the ranges of values seen for carriers and controls. CONCLUSIONS: The described methodology distinguishes between patients and controls with samples that are sufficiently stable to be mailed to the testing laboratory.