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51.
Pim-1 kinase promotes inactivation of the pro-apoptotic Bad protein by phosphorylating it on the Ser112 gatekeeper site 总被引:8,自引:0,他引:8
Constitutive expression of the Pim-1 kinase prolongs survival of cytokine-deprived FDCP1 cells, partly via maintenance of Bcl-2 expression. Here, we show that Pim-1 colocalizes and physically interacts with the pro-apoptotic Bad protein and phosphorylates it in vitro on serine 112, which is a gatekeeper site for its inactivation. Furthermore, wild-type Pim-1, but not a kinase-deficient mutant, enhances phosphorylation of this site in FDCP1 cells and protects cells from the pro-apoptotic effects of Bad. Our results suggest that phosphorylation of Bad by Pim-1 is one of several mechanisms via which the Pim-1 kinase can enhance Bcl-2 activity and promote cell survival. 相似文献
52.
Rikkinen J 《Mycologia》2003,95(6):1032-1036
Two species of calicioid lichens (Ascomycota) are reported from Baltic amber dating back 55-35 million years ago. The fossils are very similar to some modern Calicium and Chaenotheca species, but because ascus characteristics and photobiont identities cannot be determined they are not assigned to any extant species. Calicioid lichens seem to show a conservative maintenance of morphological adaptations to successful ecological niches, as do several other groups of ascomycetes. The fossils demonstrate that distinguishing features in the morphology of both genera have remained unchanged for at least tens of millions of years. The palaeohabitat of the fossil lichens, viz. that of conifer trunks in a humid, mixed forest, is consistent with the habitat preferences of many modern Calicium and Chaenotheca species. 相似文献
53.
The aim of this work was to survey how processing parameters affect the crystal growth of beta-sitosterol in suspension. The process variables studied were the cooling temperature, stirring time and stirring rate during recrystallization. In addition, we investigated the effect a commonly used surfactant, polysorbate 80, has on crystal size distribution and the polymorphic form. This study describes the optimization of the crystallization process, with the object of preparing crystals as small as possible. Particle size distribution and habit were analyzed using optical microscopy, and the crystal structure was analyzed using X-ray diffractometry. The cooling temperature had a remarkable influence on the crystal size. Crystals with a median crystal length of approximately 23 microm were achieved with a low cooling temperature (<10 degrees C); however, a fairly large number of crystals over 50 microm appeared. Higher cooling temperatures (>30 degrees C) caused notable crystal growth both in length and width. Rapid (250 rpm), continuous stirring until the suspensions had cooled to room temperature created small, less than 50 micro m long (median <20 microm), needle-shaped crystals. The addition of surfactant slightly reduced the size of the initially large crystals. Both hemihydrate and monohydrate crystal forms occurred throughout, regardless of the processing parameters. By using an optimized process, it was possible to obtain a microcrystalline suspension, with a smooth texture. 相似文献
54.
The effect of the water table on nitrous oxide (N2O) fluxes from peat profiles representing boreal peatlands of differing nutrient status was studied in the laboratory. Lowering of the water table in peat monoliths taken from two natural waterlogged peatlands for 14 weeks in a greenhouse at 20 °C increased the fluxes of N2O, an effect that was enhanced further by incubation in the dark. Raising of the water table in monoliths from two drained and forested peatlands caused cessation of the N2O fluxes from the drained peats, which had previously been sources of N2O. It is known that N2O fluxes have increased in peatlands drained several decades ago. The results suggest that it is not necessary for the water table to be lowered for several years to change a boreal peatland from a N2O sink to a source of the gas. In addition to the draining of peatlands, climate change can be expected to lower ground water levels during the summertime in the boreal zone, and this could cause marked changes in N2O fluxes from boreal peatlands by enhancing the microbial processes involved in nitrogen transformations. 相似文献
55.
Risto Vesala Aleksi Rikkinen Petri Pellikka Jouko Rikkinen Laura Arppe 《Ecology and evolution》2022,12(3)
Fungus‐growing termites and their symbiotic Termitomyces fungi are critically important carbon and nutrient recyclers in arid and semiarid environments of sub‐Saharan Africa. A major proportion of plant litter produced in these ecosystems is decomposed within nest chambers of termite mounds, where temperature and humidity are kept optimal for the fungal symbionts. While fungus‐growing termites are generally believed to exploit a wide range of different plant substrates, the actual diets of most species remain elusive. We studied dietary niches of two Macrotermes species across the semiarid savanna landscape in the Tsavo Ecosystem, southern Kenya, based on carbon (C) and nitrogen (N) stable isotopes in Termitomyces fungus combs. We applied Bayesian mixing models to determine the proportion of grass and woody plant matter in the combs, these being the two major food sources available for Macrotermes species in the region. Our results showed that both termite species, and colonies cultivating different Termitomyces fungi, occupied broad and largely overlapping isotopic niches, indicating no dietary specialization. Including laser scanning derived vegetation cover estimates to the dietary mixing model revealed that the proportion of woody plant matter in fungus combs increased with increasing woody plant cover in the nest surroundings. Nitrogen content of fungus combs was positively correlated with woody plant cover around the mounds and negatively correlated with the proportion of grass matter in the comb. Considering the high N demand of large Macrotermes colonies, woody plant matter seems to thus represent a more profitable food source than grass. As grass is also utilized by grazing mammals, and the availability of grass matter typically fluctuates over the year, mixed woodland‐grasslands and bushlands seem to represent more favorable habitats for large Macrotermes colonies than open grasslands. 相似文献
56.
Pussinen PJ Jauhiainen M Vilkuna-Rautiainen T Sundvall J Vesanen M Mattila K Palosuo T Alfthan G Asikainen S 《Journal of lipid research》2004,45(1):139-147
Periodontitis, a consequence of persistent bacterial infection and chronic inflammation, has been suggested to predict coronary heart disease (CHD). The aim of this study was to investigate the impact of periodontitis on HDL structure and antiatherogenic function in cholesterol efflux in vitro. HDL was isolated from 30 patients (age 43.6 +/- 6.1 years, mean +/- SD) with periodontitis before and after (3.2 +/- 1.4 months) periodontal treatment. The capacity of HDL for cholesterol efflux from macrophages (RAW 264.7), HDL composition, and key proteins of HDL metabolism were determined. After periodontal treatment, phospholipid transfer protein (PLTP) activity was 6.2% (P<0.05) lower, and serum HDL cholesterol concentration, PLTP mass, and cholesteryl ester transfer protein activity were 10.7% (P<0.001), 7.1% (P=0.078), and 19.4% (P<0.001) higher, respectively. The mean HDL2/HDL3 ratio increased from 2.16 +/- 0.87 to 3.56 +/- 0.48 (P<0.05). HDL total phospholipid mass and sphingomyelin-phosphatidylcholine ratio were 7.4% (P<0.05) and 36.8% (P<0.001) higher, respectively. The HDL-mediated cholesterol efflux tended to be higher after periodontal treatment; interestingly, this increase was significant (P<0.05) among patients whose C-reactive protein decreased (53.7% reduction, P=0.015) and who were positive by PCR for Actinobacillus actinomycetemcomitans. These results suggest that periodontitis causes similar, but milder, changes in HDL metabolism than those that occur during the acute-phase response and that periodontitis may diminish the antiatherogenic potency of HDL, thus increasing the risk for CHD. 相似文献
57.
Cervera MF Heinämäki J Krogars K Jörgensen AC Karjalainen M Colarte AI Yliruusi J 《AAPS PharmSciTech》2004,5(1):109-114
The film-forming ability of chitosan and binary mixtures of chitosan and native amylose corn starch (Hylon VII) was evaluated
with free films prepared by a casting/solvent evaporation method. Unplasticized and plasticized free chitosan films in aqueous
acetic acid and respective films containing a mixture of chitosan and native amylose starch in acetic acid were prepared.
Glycerol, sorbitol, and i-erythritol were used as plasticizers. Solid-state and mechanical properties of the films were studied
by powder x-ray diffractometry (XPRD), differential scanning calorimetry (DSC), and a materials testing machine. The films
composed of a mixture of chitosan and native amylose starch in acetic acid were clear and colorless. A plasticizer concentration
of 20% wt/wt (of the polymer weight) ws sufficient to obtain flexible films with all samples tested. X-ray diffraction patterns
and DSC thermograms indicated an amorphous state of the films independent of the type of plasticizer used. In conclusion,
incorporation of native amylose com starch into chitosan films improves the consistency and the mechanical properties of the
films. 相似文献
58.
Drying is one of the standard unit operations in the pharmaceutical industry and it is important to become aware of the circumstances
that dominate during the process. The purpose of this study was to test microcapsulated thermochromic pigments as heat indicators
in a fluid bed drying process. The indicator powders were manually granulated with α-lactose monohydrate resulting in three
particle-size groups. Also, pellets were coated with the indicator powders. The granules and pellets were fluidized in fluid
bed dryer to observe the progress of the heat flow in the material and to study the heat indicator properties of the indicator
materials. A tristimulus colorimeter was used to measure CIELAB color values. Color indicator for heat detection can be utilized
to test if the heat-sensitive API would go through physical changes during the pharmaceutical drying process. Both the prepared
granules and pellets can be used as heat indicator in fluid bed drying process. The colored heat indicators give an opportunity
to learn new aspects of the process at real time and could be exploded, for example, for scaling-up studies. 相似文献
59.
Summary Laboratory measurements on the CO2 exchange and data on actual field temperatures and irradiation were used to compute (by simulation) an annual carbon budget for the Empetrum nigrum/Sphagnum fuscum community. A net fixation of 160 g CO2 m-2 was predicted for the growing season. This was already the figure at the beginning of July, after which no significant change occured. For one day in June (when CO2 exchange was most intense), estimates of c. 10 and 7 g CO2 m-2 for total photosynthesis and total respiration were derived, respectively. The annual net result is in accordance with earlier estimates of production and carbon accumulation in similar ecosystems, thereby partly validating the model. Radical changes in the annual peat production are to be expected, if the mean temperature changes even one or two Celsius degrees; an increase of 2° C resulted in an equilibrium in the carbon flow between bog and atmosphere (i.e. no net change in the carbon content of the bog). 相似文献
60.
Benjamin M. Kraemer Simon Hook Timo Huttula Pekka Kotilainen Catherine M. O’Reilly Anu Peltonen Pierre-Denis Plisnier Jouko Sarvala Rashid Tamatamah Yvonne Vadeboncoeur Bernhard Wehrli Peter B. McIntyre 《PloS one》2015,10(7)
Lake Tanganyika, the deepest and most voluminous lake in Africa, has warmed over the last century in response to climate change. Separate analyses of surface warming rates estimated from in situ instruments, satellites, and a paleolimnological temperature proxy (TEX86) disagree, leaving uncertainty about the thermal sensitivity of Lake Tanganyika to climate change. Here, we use a comprehensive database of in situ temperature data from the top 100 meters of the water column that span the lake’s seasonal range and lateral extent to demonstrate that long-term temperature trends in Lake Tanganyika depend strongly on depth, season, and latitude. The observed spatiotemporal variation in surface warming rates accounts for small differences between warming rate estimates from in situ instruments and satellite data. However, after accounting for spatiotemporal variation in temperature and warming rates, the TEX86 paleolimnological proxy yields lower surface temperatures (1.46 °C lower on average) and faster warming rates (by a factor of three) than in situ measurements. Based on the ecology of Thaumarchaeota (the microbes whose biomolecules are involved with generating the TEX86 proxy), we offer a reinterpretation of the TEX86 data from Lake Tanganyika as the temperature of the low-oxygen zone, rather than of the lake surface temperature as has been suggested previously. Our analyses provide a thorough accounting of spatiotemporal variation in warming rates, offering strong evidence that thermal and ecological shifts observed in this massive tropical lake over the last century are robust and in step with global climate change. 相似文献