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71.
Abstract

The distribution of macrophytic plant communities, defined by phytosociological numerical methods, in the irrigation system of the Lower river Po Plane was correlated with water characteristich. Water samples were collected periodically within phytocoena well-characterized from the phytosociological viewpoint. Nymphaeid-dominated communities (all. Nymphaeion) usually occur in deeper waters than elodeid- myriophyllid-, and ceratophyllid-dominated vegetation types (all. Potamogetonion). Hydrochemically, all of the studied waterbodies can be classified as rich in electrolytes and in bicarbonates. The distribution of phytocoena reflects a gradient in nutrient content: the Nymphoidetum peltatae characterizes waters moderately rich; the Myriophyllum spicatum community and the Trapetum natantis fairly rich; the Potamogetonetum pectinati and the Ceratophyllum demersum community very rich in nutrients.  相似文献   
72.
Abstract

Effect of light on the uptake, utilization and transport of sugars. — The effect of light on the uptake of saccharides, their incorporation into insoluble fractions and their transport by green tissues has been studied under conditions of complete inhibition of the photosynthetic assimilation of CO2. Such conditions were obtained by means of either an inhibitor of O2 evolution (CMU), or by running the experiment in CO2-free atmosphere. When Wolffia arryza plants are incubated with glucose-C14, light stimulates the incorporation of C14 into all fractions examined, and especially into the polysaccharides, like cellulose,' which are synthesized outside the chloroplasts.

Experiments with Elodea canadensis have shown that light stimulates the transport of glucose-C14 from the leaves to the stems, independently of the presence or absence of CO2 assimilation.

These experiments support the hypothesis that ATP synthesyzed in the light by chloroplasts can be utilized by green cells as an energy source for biosyntheses outside the plastids, as well as for other types of biological work, such as active uptake and transport.  相似文献   
73.
We used X-rays from a linear accelerator and from a low energy therapeutic source to calibrate the single cell gel electrophoresis (comet assay), a widely used method to measure DNA damage. γ-Rays from 60Co, with known efficiency in inducing DNA breakage, were used as reference. Human lymphocytes and one murine tumour cell line, F10-M3 cells, were irradiated under different experimental conditions. A similar relationship between radiation dose and induced DNA damage was obtained with γ- and X-rays. A calibration curve was constructed to convert the comet assay raw data into break frequency. The median levels of DNA breaks and oxidative damage in circulating lymphocytes from healthy volunteers were calculated to be 0.76 and 0.80 breaks/109 Da, respectively, (0.50 and 0.52 breaks/106 bp). The values of oxidative DNA damage were in the same order of magnitude as those found by others with HPLC methods.  相似文献   
74.
To solve novel problems, it is advantageous to abstract relevant information from past experience to transfer on related problems. To study whether macaque monkeys were able to transfer an abstract rule across cognitive domains, we trained two monkeys on a nonmatch-to-goal (NMTG) task. In the object version of the task (O-NMTG), the monkeys were required to choose between two object-like stimuli, which differed either only in shape or in shape and color. For each choice, they were required to switch from their previously chosen object-goal to a different one. After they reached a performance level of over 90% correct on the O-NMTG task, the monkeys were tested for rule transfer on a spatial version of the task (S-NMTG). To receive a reward, the monkeys had to switch from their previously chosen location to a different one. In both the O-NMTG and S-NMTG tasks, there were four potential choices, presented in pairs from trial-to-trial. We found that both monkeys transferred successfully the NMTG rule within the first testing session, showing effective transfer of the learned rule between two cognitive domains.  相似文献   
75.
Identification of driver mutations in lung adenocarcinoma has led to development of targeted agents that are already approved for clinical use or are in clinical trials. Therefore, the number of biomarkers that will be needed to assess is expected to rapidly increase. This calls for the implementation of methods probing the mutational status of multiple genes for inoperable cases, for which limited cytological or bioptic material is available. Cytology specimens from 38 lung adenocarcinomas were subjected to the simultaneous assessment of 504 mutational hotspots of 22 lung cancer-associated genes using 10 nanograms of DNA and Ion Torrent PGM next-generation sequencing. Thirty-six cases were successfully sequenced (95%). In 24/36 cases (67%) at least one mutated gene was observed, including EGFR, KRAS, PIK3CA, BRAF, TP53, PTEN, MET, SMAD4, FGFR3, STK11, MAP2K1. EGFR and KRAS mutations, respectively found in 6/36 (16%) and 10/36 (28%) cases, were mutually exclusive. Nine samples (25%) showed concurrent alterations in different genes. The next-generation sequencing test used is superior to current standard methodologies, as it interrogates multiple genes and requires limited amounts of DNA. Its applicability to routine cytology samples might allow a significant increase in the fraction of lung cancer patients eligible for personalized therapy.  相似文献   
76.
S-acylation, the covalent attachment of palmitate and other fatty acids on cysteine residues, is a reversible post-translational modification that exerts diverse effects on protein functions. S-acylation is catalyzed by protein acyltransferases (PAT), while deacylation requires acyl-protein thioesterases (APT), with numerous inhibitors for these enzymes having already been developed and characterized. Among these inhibitors, the palmitate analog 2-brompalmitate (2-BP) is the most commonly used to inhibit palmitoylation in cells. Nevertheless, previous results from our laboratory have suggested that 2-BP could affect protein deacylation. Here, we further investigated in vivo and in vitro the effect of 2-BP on the acylation/deacylation protein machinery, with it being observed that 2-BP, in addition to inhibiting PAT activity in vivo, also perturbed the acylation cycle of GAP-43 at the level of depalmitoylation and consequently affected its kinetics of membrane association. Furthermore, 2-BP was able to inhibit in vitro the enzymatic activities of human APT1 and APT2, the only two thioesterases shown to mediate protein deacylation, through an uncompetitive mechanism of action. In fact, APT1 and APT2 hydrolyzed both the monomeric form as well as the micellar state of the substrate palmitoyl-CoA. On the basis of the obtained results, as APTs can mediate deacylation on membrane bound and unbound substrates, this suggests that the access of APTs to the membrane interface is not a necessary requisite for deacylation. Moreover, as the enzymatic activity of APTs was inhibited by 2-BP treatment, then the kinetics analysis of protein acylation using 2-BP should be carefully interpreted, as this drug also inhibits protein deacylation.  相似文献   
77.
A large number of studies have analyzed social and sexual interactions between rodents in relation to neural activity. Computerized video analysis has been successfully used to detect numerous behaviors quickly and objectively; however, to date only 2D video recording has been used, which cannot determine the 3D locations of animals and encounters difficulties in tracking animals when they are overlapping, e.g., when mounting. To overcome these limitations, we developed a novel 3D video analysis system for examining social and sexual interactions in rats. A 3D image was reconstructed by integrating images captured by multiple depth cameras at different viewpoints. The 3D positions of body parts of the rats were then estimated by fitting skeleton models of the rats to the 3D images using a physics-based fitting algorithm, and various behaviors were recognized based on the spatio-temporal patterns of the 3D movements of the body parts. Comparisons between the data collected by the 3D system and those by visual inspection indicated that this system could precisely estimate the 3D positions of body parts for 2 rats during social and sexual interactions with few manual interventions, and could compute the traces of the 2 animals even during mounting. We then analyzed the effects of AM-251 (a cannabinoid CB1 receptor antagonist) on male rat sexual behavior, and found that AM-251 decreased movements and trunk height before sexual behavior, but increased the duration of head-head contact during sexual behavior. These results demonstrate that the use of this 3D system in behavioral studies could open the door to new approaches for investigating the neuroscience of social and sexual behavior.  相似文献   
78.
The hierarchical mating system among and within fruits of Jatropha curcas was investigated in a base population using five microsatellite loci, employing mixed mating and correlated mating models. Open-pollinated fruits were collected from 15 randomly selected seed trees, sampling seven fruits per tree for a total of 21 seeds from each tree. We detected multilocus genotypes identical to the mother tree in 13 % of offspring, implying the occurrence of apomixis in J. curcas. The presumed apomictic individuals were excluded from the analysis of the remaining results. Evidence of substantial selfing was provided by the average multilocus outcrossing rate (t m?=?0.683), showing that the species exhibits a mixed mating system. The outcrossing rate showed a large variation among seed trees, ranging from 0.21 to 1.0, indicating that the species is not self-incompatible. Significant differences were detected between the multilocus and the single locus outcrossing rates (t m???t s?=?0.347) that suggested mating among related individuals, possibly because of the presence of individuals from the same progeny (sibs) in the base population. The multilocus paternity correlation was extremely high for the population (r p(m)?=?0.999), indicating that the progenies were manly composed of full-sibs. As a consequence of selfing and a high paternity correlation, the co-ancestry coefficient within the progeny was higher (Θ?=?0.369) than expected for panmictic populations. Our results indicated that J. curcas produces seeds asexually by apomixis and sexually by a mixed mating system, combining selfing and outcrossing.  相似文献   
79.
The application of UV irradiation processes are successfully proposed for the first time in the fabrication of both of the two plastic electrodes in flexible dye solar cells (DSCs) and modules. For the realization of the photo‐electrode, a customized TiO2 paste formulation and UV processing method was developed which yields 134% (48%) performance enhancement with respect to the same (binder‐free) paste treated at 120 °C. UV treatment induces both complete removal of organic media and more efficient charge collection. Significantly, highly catalytic platinized flexible counter‐electrodes are also obtained via UV photo‐induced reduction of screen‐printed platinum precursor pastes based on hexachloroplatinic acid. Using both UV‐processed electrodes, a fully plastic DSC is fabricated with a conversion efficiency of 4.3% under 1 Sun (semitransparent) and 5.3% under 0.2 Sun (opaque). Performance is within 10% of the efficiency of a glass‐based DSC prepared with the same materials but with conventional high temperature processes. The material formulations and processes are simple, and easily up‐scaled over large areas, even directly and simultaneously applicable to the preparation of both the photo‐and counter‐electrode on the same substrate which enabled us to demonstrate the first module on plastic realized with a W series interconnection.  相似文献   
80.
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