Volatile profiles of human skin cell cultures in different degrees of senescence

It is known that skin releases volatile organic compounds to the environment, and also that its emission pattern changes with aging of the skin. It could be considered, that these compounds are intermediaries in cell metabolism, since many intermediaries of metabolic pathways have a volatile potential. In this work, a simple and non-destructive method consisting of SPME sampling and GC/MS analysis was developed to identify volatile organic emanations from cell cultures. This technique, applied to skin cells culture, indicates that the cells or cell metabolism produce several skin emissions. Chemometric analysis was performed in order to explore the relationship between a volatile profile and the senescence of cell cultures. Volatile profiles were different for cell cultures in different degrees of senescence, indicating that volatile compound patterns could be used to provide information about the age of skin cells.     

Naloxone influences ultrasonic calling in young mice

The ultrasonic calls produced by three day old mice when separated from the nest mother and siblings increase in number when naloxone is injected.     

Resprouting in the Mediterranean‐type shrub Erica australis afffected by soil resource availability

Abstract. Soil resource availability may affect plant regeneration by resprouting in disturbed environments directly, by affecting plant growth rates, or indirectly by determining allocation to storage in the resprouting organs. Allocation to storage may be higher in stressful, low resource‐supply soils, but under such conditions plant growth rates may be lower. These factors could act in opposite directions leading to poorly known effects on resprouting. This paper analyses the role played by soil resources in the production and growth of resprouts after removal of above‐ground plant tissues in the Mediterranean shrub Erica australis. At 13 sites, differing in substrate, we cut the base of the stems of six plants of E. australis and allowed them to resprout and grow for two years. Soils were chemically analysed and plant water potential measured during the summer at all sites to characterize soil resource availability. We used stepwise regression analysis to determine the relationships between the resprouting response [mean site values of the number of resprouts (RN), maximum length (RML) and biomass (RB)] and soil nutrient content and plant water potential at each site. During the first two years of resprouting there were statistically significant differences among sites in the variables characterizing the resprouting response. RML was always different among sites and had little relationship with lignotuber area. RN was less different among sites and was always positively correlated with lignotuber area. RB was different among sites after the two years of growth. During the first months of resprouting, RN and RML were highly and positively related to the water status of the plant during summer. At later dates soil fertility variables came into play, explaining significant amounts of variance of the resprouting variables. Soil extractable cations content was the main variable accounting for RML and RB. Our results indicate that resprout growth of E. australis is positively affected by high water availability at the beginning of the resprouting response and negatively so by high soil extractable cation content at later periods. Some of these factors had previously shown to be related, with an opposite sign, to the development of a relatively larger lignotuber. Indeed, RML and RB measured in the second year of resprouting were significantly and negatively correlated with some indices of biomass allocation to the lignotuber at each site. This indicates that sites favouring allocation to the resprouting organ may not favour resprout growth.     

Removal of naphthalene and phenanthrene using aerobic membrane bioreactor

The removal of polycyclic aromatic hydrocarbons by membrane bioreactor (MBR) under aerobic conditions had been studied using naphthalene (NAP) and phenanthrene (PHE) as model compounds. Three MBRs with submerged ultra-filtration hollow fiber membranes were operated applying different operational conditions during 6.5 months. Complete NAP and PHE removal was obtained applying loads of 7 gNAP kgTSS^?1 day^?1 and 0.5 gPHE kgTSS^?1 day^?1, while the organic loading rate was adjusted to 0.26 kgCOD kgTSS^?1 day^?1, with the biomass concentration being 6000 mgTSS L^?1, the hydraulic retention time (HRT) 8 h and the solids retention time (SRT) 30 days. Load increases, as well as HRT and SRT reductions, affected the NAP and PHE removals. Biodegradation was found to be the major NAP and PHE removal mechanism. There was no NAP accumulation in the biomass. Low PHE quantities remain sorbed in the biomass and the contribution of the sorption in the removal of this compound was estimated to be less than 0.01 %. The volatilization does not contribute to the PHE removal in MBRs, but the contribution of NAP volatilization can reach up to 0.6 % when HRT of 8 h is applied.     

A phylogenetic analysis of species in the Bufo crucifer group (Anura: Bufonidae), based on indolealkylamines and proteins from skin secretions

This research tested the utility of two classes of skin secretion compounds to the phylogeny of the Bufo crucifer group. Skin secretions from specimens of nine populations of B. crucifer group were obtained and submitted to qualitative analysis. We observed a clear difference in the composition of the skin secretion molecules obtained from the species of Bufo studied. Fifty-nine molecules, 16 indolealkylamines and 43 proteins, were used as characters, and 39 of these were parsimonious informative. The tree topology of the skin secretion combined data showed areas of congruence and conflict when compared to an mtDNA phylogeny of the B. crucifer group. We used the Templeton test to evaluate the heterogeneity between the skin secretion and mtDNA data. Although not recommended, we performed a combined analysis with the two partitions. The skin secretion characters from the species of Bufo studied have phylogenetic signal. These data are indicative, at least as a preliminary study, of the phylogenetic relationships among the B. crucifer group taxa.     

The roles of WRN and BLM RecQ helicases in the Alternative Lengthening of Telomeres

Approximately 10% of all cancers, but a higher proportion of sarcomas, use the recombination-based alternative lengthening of telomeres (ALT) to maintain telomeres. Two RecQ helicase genes, BLM and WRN, play important roles in homologous recombination repair and they have been implicated in telomeric recombination activity, but their precise roles in ALT are unclear. Using analysis of sequence variation present in human telomeres, we found that a WRN– ALT+ cell line lacks the class of complex telomere mutations attributed to inter-telomeric recombination in other ALT+ cell lines. This suggests that WRN facilitates inter-telomeric recombination when there are sequence differences between the donor and recipient molecules or that sister-telomere interactions are suppressed in the presence of WRN and this promotes inter-telomeric recombination. Depleting BLM in the WRN– ALT+ cell line increased the mutation frequency at telomeres and at the MS32 minisatellite, which is a marker of ALT. The absence of complex telomere mutations persisted in BLM-depleted clones, and there was a clear increase in sequence homogenization across the telomere and MS32 repeat arrays. These data indicate that BLM suppresses unequal sister chromatid interactions that result in excessive homogenization at MS32 and at telomeres in ALT+ cells.     

Degranulation and histamine release from murine mast cells sensitized with dengue virus-immune sera

Mice were immunized with dengue type 2 virus (DEN 2) under a schedule favoring the production of IgE antibody. The antibody obtained could sensitize peritoneal resident mast cells both in vitro and in vivo so that the sensitized cells were degranulated and released histamine on challenge with the DEN 2 antigen. It was also demonstrated that the antibody was cytophilic and heat-labile. The above observations suggest that the present experimental system can be used to detect anti-DEN 2 IgE antibody in mice.