Autophagy is an evolutionarily preserved degradation process of cytoplasmic cellular constituents and plays important physiological roles in human health and disease. It has been proposed that autophagy plays an important role both in tumor progression and in promotion of cancer cell death, although the molecular mechanisms responsible for this dual action of autophagy in cancer have not been elucidated. Pancreatic ductal adenocarcinoma is one of the most aggressive human malignancies with 2-3% five-year survival rate. Its poor prognosis has been attributed to the lack of specific symptoms and early detection tools, and its relatively refractory to traditional cytotoxic agents and radiotherapy. Experimental evidence pointed at autophagy as a pancreatic cancer cell mechanism to survive under adverse environmental conditions, or as a defective programmed cell death mechanism that favors pancreatic cancer cell resistance to treatment. Here, we consider several phenotypical alterations that have been related to increase or decrease the autophagic process in pancreatic tumor cells. We specially review autophagy as a cell death mechanism in response to chemotherapeutic drugs. 相似文献
A reduction of sleep time has become common over the last century, and growing evidence from both epidemiological and laboratory-based studies suggests sleep curtailment is a new risk factor for the development of obesity. On this basis, the present review examines the role of sleep curtailment in the metabolic and endocrine alterations, including decreased glucose tolerance and insulin sensitivity, increased evening concentrations of cortisol, increased levels of ghrelin, decreased levels of leptin and increased hunger and appetite. It will be discussed how sleep restriction may lead to increase in food intake and result in greater fatigue, which may favour decreased energy expenditure. Altogether, evidences point to a possible role of decreased sleep duration in the current epidemic of obesity and therefore present literature highlights the importance of getting enough good sleep for metabolic health. Many aspects still need to be clarified and intervention studies also need to be conducted. Copyright ? 2012 John Wiley & Sons, Ltd. 相似文献
Little is known about mate choice preferences outside Western, educated, industrialised, rich and democratic societies, even though these Western populations may be particularly unrepresentative of human populations. To our knowledge, this is the first study to test which facial cues contribute to African perceptions of African female attractiveness and also the first study to test the combined role of facial adiposity, skin colour (lightness, yellowness and redness), skin homogeneity and youthfulness in the facial attractiveness preferences of any population. Results show that youthfulness, skin colour, skin homogeneity and facial adiposity significantly and independently predict attractiveness in female African faces. Younger, thinner women with a lighter, yellower skin colour and a more homogenous skin tone are considered more attractive. These findings provide a more global perspective on human mate choice and point to a universal role for these four facial cues in female facial attractiveness. 相似文献
The innate immune response to Francisella tularensis is primarily mediated by TLR2, though the bacterial products that stimulate this receptor remain unknown. Here we report the identification of two Francisella lipoproteins, TUL4 and FTT1103, which activate TLR2. We demonstrate that TUL4 and FTT1103 stimulate chemokine production in human and mouse cells in a TLR2-dependent way. Using an assay that relies on chimeric TLR proteins, we show that TUL4 and FTT1103 stimulate exclusively the TLR2/TLR1 heterodimer. Our results also show that yet unidentified Francisella proteins, possibly unlipi-dated, have the ability to stimulate the TLR2/TLR6 heterodimer. Through domain-exchange analysis, we determined that an extended region that comprises LRR 9-17 in the extra-cellular portion of TLR1 mediates response to Francisella lipoproteins and triacylated lipopeptide. Substitution of the corresponding LRR of TLR6 with the LRR derived from TLR1 enables TLR6 to recognize TUL4, FTT1103, and triacylated lipopeptide. This study identifies for the first time specific Fran-cisella products capable of stimulating a proinflammatory response and the cellular receptors they trigger. 相似文献
A method for the screening of antioxidant activity is reported as a decolorization assay applicable to both lipophilic and hydrophilic antioxidants, including flavonoids, hydroxycinnamates, carotenoids, and plasma antioxidants. The pre-formed radical monocation of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS*+) is generated by oxidation of ABTS with potassium persulfate and is reduced in the presence of such hydrogen-donating antioxidants. The influences of both the concentration of antioxidant and duration of reaction on the inhibition of the radical cation absorption are taken into account when determining the antioxidant activity. This assay clearly improves the original TEAC assay (the ferryl myoglobin/ABTS assay) for the determination of antioxidant activity in a number of ways. First, the chemistry involves the direct generation of the ABTS radical monocation with no involvement of an intermediary radical. Second, it is a decolorization assay; thus the radical cation is pre-formed prior to addition of antioxidant test systems, rather than the generation of the radical taking place continually in the presence of the antioxidant. Hence the results obtained with the improved system may not always be directly comparable with those obtained using the original TEAC assay. Third, it is applicable to both aqueous and lipophilic systems. 相似文献
Parthenocarpy, or fruit development in the absence of fertilization, has been genetically engineered in eggplant and in other
horticultural species by using the DefH9-iaaM gene. The iaaM gene codes for tryptophan monoxygenase and confers auxin synthesis, while the DefH9 controlling regions drive expression of the gene specifically in the ovules and placenta. A previous greenhouse trial for
winter production of genetically engineered (GM) parthenocarpic eggplants demonstrated a significant increase (an average
of 33% increase) in fruit production concomitant with a reduction in cultivation costs. 相似文献
A novel method to prepare immobilized lipases derivatives is hereby proposed. Lipases are firstly adsorbed on supports having large internal surfaces covered by hydrophobic groups (e.g. polyacrylic resins covered by C18 moieties). Then, immobilized lipases are incubated in the presence of polyethyleneimine (PEI) at a pH value over the isoelectric point of the enzyme in order to cover the lipase surface with this polymer. In this way, we try to minimize all possible direct interactions between immobilized lipase and organic solvents when using these derivatives in anhydrous media.
Lipases from Rhizomucor miehie (RML) and Candida rugosa (CRL) were immobilized according to the proposed protocol. These derivatives were very active and very stable when catalyzing esterifications and transesterifications in anhydrous media. For example, RML derivatives exhibited a very high synthetic activity (more than 1000 Units/g immobilized biocatalyst) even when catalyzing the esterification of lauric acid with octanol at water activity values very close to zero. On the contrary, covalently immobilized derivatives exhibited a much lower synthetic activity under similar conditions (less than 10 Units/g of immobilized biocatalyst). Moreover, these new RML derivatives preserve 100% activity after incubation for 3 days in anhydrous butanone in the presence of molecular sieves. Under the same conditions, commercial immobilized RML lost more than 90% of activity in less than 10 min. 相似文献
The authors demonstrate possibilities of viral hepatitis diagnosis by means of fluorescent antisera labeled phiiTts. The antisera were obtained from the blood of convalescents after infectious hepatitis (with an uncomplicated course) on the 25th--30th day of the disease, and also from the placental gamma-globulin of persons who had had viral hepatitis (in the anamnesis). Both diagnostic preparations proved to be highly specific, although the first of them was somewhat more sensitive. Blood smears were stained with fluorescent antisera. The fluoresence was revealed in the cytoplasm of the white blood formed elements--lymphocytes and neutrophils; the nucleus was dark. Materials of this investigation permit experimental substantiation of a possibility of prolonged antigenemia in the blood leukocytes of patients suffering from viral hepatitis. 相似文献
We have studied the pattern of association between the season of conception and cytosolic low molecular weight phosphotyrosine
phosphatase (ACP1) genetic polymorphism in 329 consecutively newborn infants from the population of Penne and 361 consecutively
newborn infants from the population of Rome. In addition, 329 mothers were studied in the population of Penne. A concordant,
highly significant association was observed in the two populations between ACP1 parameters and the season of conception of
newborn infants. The total activity of ACP1 shows a minimum in infants conceived in January–February and a maximum in those
conceived at the end of the solar year. Analysis of the joint mother-newborn ACP1 distribution in relation to the season of
fertilisation has shown that among mothers carrying ACP1*A (the allele showing the lowest activity), the proportion of newborns
carrying this allele is higher in those conceived in the first months of the year than in those conceived subsequently. Since
ACP1 probably functions as a phosphotyrosine phosphatase and as a flavin mononucleotide phosphatase, low activity could enhance
the metabolic rate and would be advantageous in a cold environment. The cycle of variation of ACP1 in infants follows the
cycle of solar illumination. It is possible that individuals who have a genetic background allowing them to adapt easily and
readily to seasonal demand are more successful in reproducing themselves. The population of zygotes conceived in a given season
would therefore reproduce the pattern of gene combination more fit for that season.
Received: 15 June 1997 / Accepted: 31 July 1997 相似文献