Biocatalytic solutions to cyclomethicones problem in cosmetics

Silicones are polymers that have properties of great interest for cosmetic and personal care industry, especially D₄ (octamethylcyclotetrasiloxane) and D₅ (decamethylcyclopentasiloxane), generically named cyclomethicones. However, different studies show the hypothesis that the use of these products is harmful and, therefore, several countries have adopted legislative actions to limit their use in personal care and cosmetic products. Faced with this new situation, different cosmetic companies began to look for different alternatives to cyclomethicones, mainly: organomodified silicones or esters. The former are based on the addition of functional groups to the main chain of silicon and oxygen. The latter represent a totally different line, since their functional group is the ester, but they have properties similar to silicones. Esters, especially branched‐chain ones are currently the more promising alternative to replace cyclomethicones in cosmetic formulations. Nowadays, most of them are obtained by chemical reactions that require high temperatures and non‐selective /contaminant catalysts that lead to low‐quality final products. As an alternative, biocatalytic synthesis occurs always at mild operation conditions supplying ultra‐pure, odor, and colorless products with less wastes and side reactions. Therefore, biocatalysis is a valid and environmentally sustainable option for the synthesis of silicone‐substitute esters used in cosmetic formulations.     

昆虫抗药性与适合度

昆虫抗药性的产生常伴有适合度劣势(即适合度代价),即抗性个体常表现出发育速率较慢、存活率和生殖力较低。文章主要阐述害虫抗药性与生物适合度和适合度代价的关系以及适合度代价产生的机制、特性及影响因素。并从生态学角度论述害虫抗药性的进化,为探索抗性发展规律及害虫抗性治理提供理论依据。     

Nigrostriatal Modifications After Vanadium Inhalation: An Immunocytochemical and Cytological Approach

Vanadium (V) has increased in the air as a component of suspended particles originated from fuel combustion. In this report, a model of inhaled V in mice was implemented to identify the effect that V has in the corpus striatum and substantia nigra, structures with high concentrations of dopamine and scarce antioxidants burden. Mice inhaled 0.02 M V2O5 1 h twice a week and were sacrificed at points from 1 to 8 weeks after inhalation, perfused, and processed for Golgi method and for tyroxine hidroxylase (TH) inmunocytochemistry. Cytological analysis consisted in counting the number of dendritic spines in 20 medium-size spiny neurons and the number of TH immunoreactive neurons in the substatia nigra pars compacta. Dendritic spine density decreased drastically after V exposure; the same was observed with the TH-positive neurons, which decreased in a time-dependent mode. No previous morphological studies about V and nervous system have been reported. The decrease in spine density and in TH-positive neurons might have functional repercussions that should be studied because the trend of this element in the atmosphere is to increase.     

P2Y receptors activate MAPK/ERK through a pathway involving PI3K/PDK1/PKC-zeta in human vein endothelial cells.

AIMS: In this study we investigated the effects of P2 receptors in the regulation of mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) in human umbilical vein endothelial cells (HUVEC). METHODS: Cytosolic Ca(2+) concentration ([Ca(2+)](i)) was measured using fura-2/AM, and MAPK/ ERK phosphorylation using Western blot analysis. RESULTS: ATP, 2-meSATP, UTP and UDP cause a rapid and transitory increase in the phosphorylation of MAPK/ERK. In contrast, negligible response was seen for a,Beta-meATP, a general P2X receptors agonist. ATP-dependent activation of MAPK/ERK was prevented by pretreatment of HUVEC with pertussis toxin or MEK inhibitor PD98059. In addition, activation of the MAPK/ ERK cascade by ATP was blocked in cells pretreated with wortmannin and LY294002, but not by U73122, BAPTA or a Ca(2+)-free medium. Furthermore, an inhibition of ATP-dependent MAPK/ERK phosphorylation was observed in HUVEC pretreated with high doses of GF109203X or myristoylated PKC- zeta pseudosubstrate. Similar results were observed when cells were pretreated with the Src tyrosine kinase inhibitor PP2. However, ATP-stimulated MAPK/ERK activation was unaffected in cells pretreated with AG1478 or perillic acid. We also found that ATP stimulates both the phosphorylation of 3- phosphoinositide-dependent protein kinase-1 (PDK1) and its translocation to plasma membrane in a time-dependent manner. CONCLUSION: These observations suggest that the effects mediated by ATP in HUVEC occur via PTX-sensitive G-protein-coupled P2Y receptors through PI3K-dependent mechanisms, in which PDK1 and PKC-zeta are two key molecules within signal cascade leading to MAPK/ERK activation.     

d-β-Hydroxybutyrate Prevents Glutamate-Mediated Lipoperoxidation and Neuronal Damage Elicited during Glycolysis Inhibition In Vivo

Excitotoxic neuronal death mediated by over-activation of glutamate receptors has been implicated in ischemia, hypoglycemia and some neurodegenerative diseases. It involves oxidative stress and is highly facilitated during impairment of energy metabolism. We have shown previously that in vivo systemic glycolysis inhibition with iodoacetate (IOA), exacerbates glutamate excitotoxicity. We have now investigated whether this effect involves oxidative damage to membrane lipids, as evaluated by the presence of thiobarbituric acid-reactive substances. We have also tested whether the ketone body, d-β-hydroxybutyrate (d-BHB), prevents lipoperoxidation and tissue damage. Results show that glutamate intrastriatal injection in control rats transiently enhances lipoperoxidation, while in IOA-treated animals increased lipoperoxidation is sustained. Treatment with d-BHB significantly reduces striatal lesions and lipoperoxidation. Vitamin E also reduced neuronal damage and lipoperoxidation. Results suggest that glycolysis impairment favors a pro-oxidant condition and situates oxidative damage as an important mediator of in vivo induced excitotoxicity. Results provide evidence for the neuroprotective effect of d-BHB against glutamate toxicity.     

Missing link in the Southern Ocean: sampling the marine benthic fauna of remote Bouvet Island

Bouvet (Bouvetøya) is a geologically young and very remote island just south of the Polar Front. Here we report samples taken during the RV “Polarstern" cruise ANTXXI/2 on 3 days in November 2003 and January 2004. This work was part of SCAR’s EASIZ programme and intended, by providing data on the marine fauna of this “white gap" in the Atlantic sector of the Southern Ocean, to contribute to identifying the role of Bouvet in the faunal exchange between the Sub- and high Antarctic. While this goal demands extensive molecular analysis of the material sampled (future work), a checklist of the samples and data at hand widens the faunal and environmental inventory substantially. We suggest some preliminary conclusions on the relationship of Bouvet Island’s fauna with that of other regions, such as Magellanic South America, the Antarctic Peninsula, and the high Antarctic Weddell Sea, which have been sampled previously. There seem to be different connections for individual higher taxa rather than a generally valid consistent picture.     

Identification of differential gene expression in in vitro FSH treated pig granulosa cells using suppression subtractive hybridization

FSH, which binds to specific receptors on granulosa cells in mammals, plays a key role in folliculogenesis. Its biological activity involves stimulation of intercellular communication and upregulation of steroidogenesis, but the entire spectrum of the genes regulated by FSH has yet to be fully characterized.