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排序方式: 共有245条查询结果,搜索用时 15 毫秒
71.
Comparative cryptogam ecology: a review of bryophyte and lichen traits that drive biogeochemistry 总被引:2,自引:0,他引:2
BACKGROUND: Recent decades have seen a major surge in the study of interspecific variation in functional traits in comparative plant ecology, as a tool to understanding and predicting ecosystem functions and their responses to environmental change. However, this research has been biased almost exclusively towards vascular plants. Very little is known about the role and applicability of functional traits of non-vascular cryptogams, particularly bryophytes and lichens, with respect to biogeochemical cycling. Yet these organisms are paramount determinants of biogeochemistry in several biomes, particularly cold biomes and tropical rainforests, where they: (1) contribute substantially to above-ground biomass (lichens, bryophytes); (2) host nitrogen-fixing bacteria, providing major soil N input (lichens, bryophytes); (3) control soil chemistry and nutrition through the accumulation of recalcitrant polyphenols (bryophytes) and through their control over soil and vegetation hydrology and temperatures; (4) both promote erosion (rock weathering by lichens) and prevent it (biological crusts in deserts); (5) provide a staple food to mammals such as reindeer (lichens) and arthropodes, with important feedbacks to soils and biota; and (6) both facilitate and compete with vascular plants. APPROACH: Here we review current knowledge about interspecific variation in cryptogam traits with respect to biogeochemical cycling and discuss to what extent traits and measuring protocols needed for bryophytes and lichens correspond with those applied to vascular plants. We also propose and discuss several new or recently introduced traits that may help us understand and predict the control of cryptogams over several aspects of the biogeochemistry of ecosystems. CONCLUSIONS: Whilst many methodological challenges lie ahead, comparative cryptogam ecology has the potential to meet some of the important challenges of understanding and predicting the biogeochemical and climate consequences of large-scale environmental changes driving shifts in the cryptogam components of vegetation composition. 相似文献
72.
Sergey Novikov Pavel Krzhivitskii Sergey Kanaev Petr Krivorotko Nikolay Ilin Julia Melnik Nadejda Popova 《Reports of Practical Oncology and Radiotherapy》2019,24(6):688-694
PurposeTo evaluate the opportunities of single photon emission tomography/computerized tomography (SPECT-CT) for localization of axillary sentinel lymph nodes (ASLNs) and subsequent radiotherapy planning in women with early breast cancer.Material and methodsIndividual topography of ASLN was determined in 151 women with clinical T1-2N0M0 breast cancer. SPECT-CT visualization of ASLNs was initiated 120 min after intra-peritumoral injection of 99mTc-radiocolloids. Doses absorbed by virtual ASLNs after the whole breast irradiation with standard and extended tangential fields were calculated on a treatment planning station.ResultsSPECT-CT demonstrated a large variability of ASLN localization. They were detected in the central subgroup in 94 (61%) patients, in pectoral – in 77 (51%), and in interpectoral – in 4 (3%) patients. Sentinel lymph nodes “lying on the chest” were revealed in 35 (23%) cases.We found that with standard tangential fields coverage of ASLNs was obtained only in 20% of evaluated women. Extended tangential fields can effectively irradiate ASLNs localized in all axillary sub-regions with the exception of ASLNs “lying on the chest”.ConclusionSPECT-CT mapping of ASLNs in women with cT1-2N0M0 breast cancer reveals their variable localization. This information can be important for planning of radiation treatment in women that underwent breast conserving surgery without an axillary surgery. 相似文献
73.
74.
Smirnov VB Chesnokova EG Lopatina NG Voike E 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》2006,56(6):796-800
Neurophysiological characteristics of mushroom body neurons were examined by electrophysiological methods in mutants snow(laranja) and wild-type honey bees. Mutation snow(laranja) causes a drastic decrease in the activity of enzyme tryptophane oxygenase that results in deficiency of all kynurenines. It also modifies bioelectrical properties of neurons in the mushroom bodies. The duration of afterdepolarization in spikes recorded from calyx neurons and the amplitude of postsynaptic potentials in these neurons evoked by focal stimulation of antennal lobes were shown to be most dependent on the mutation and, consequently, on the content of endogenous kynurenines. A tendency to an increase in the frequency of spontaneous spikes was also observed. The effect of the mutation on neurophysiological characteristics under study was recessive, i.e. it was observed only in homozygous individuals. 相似文献
75.
N. G. Lopatina T. H. Zachepilo N. G. Kamyshev N. I. Chalisova 《Journal of Evolutionary Biochemistry and Physiology》2017,53(2):123-128
This study addresses the influence of combinations of two encoded amino acids with opposite, memory-inhibiting and memory-enhancing, effects on short-term and long-term memory formation in the honeybee. Experimentation was based on the classical proboscis extension response conditioning by a single-trial exposure to clove odor with a sucrose solution reward. The presence of the acquired conditioned response was tested 1 min (short-term memory) and 180 min (long-term memory) after the learning trial. The data obtained suggest a stimulatory (memory-enhancing) effect of the combination of two amino acids, individual effects of which are opposite. The stimulatory amino acid was present in the mixture in all the trials (8 combinations) at a subthreshold concentration, i.e. it did not influence memory formation. In some trials, the stimulatory effect of an amino acid mixture (for example, stimulatory aspartic acid combined with inhibitory lysine or serine) significantly exceeded that of a single stimulatory amino acid applied at a threshold concentration. Interestingly, the effect of amino acid combinations on memory formation in honeybees resembles their effect on cell proliferation in rat tissue explants of various origin. 相似文献
76.
Bill Shipley Michael Belluau Ingolf Kühn Nadejda A. Soudzilovskaia Michael Bahn Josep Penuelas Jens Kattge Lawren Sack Jeannine Cavender‐Bares Wim A. Ozinga Benjamin Blonder Peter M. van Bodegom Peter Manning Thomas Hickler Enio Sosinski Valério De Patta Pillar Vladimir Onipchenko Peter Poschlod 《植被学杂志》2017,28(5):1082-1095
77.
The open-field behaviour of rats selected for high and low active avoidance level was studied. The data obtained showed the correlated response of two selected lines for avoidance ability with the locomotor activity and emotional reactivity in the open-field situation. The line of a low avoidance value had the low activity level and high defecation score in comparison to the alternative one and to progenitory Krushinsky--Molodkina strain. The correspondence of learning ability and emotionality-motivation performance has been discussed. 相似文献
78.
E. S. Mil’ko M. O. Maksimovich L. I. Lopatina E. V. Porodenko 《Applied Biochemistry and Microbiology》2010,46(5):492-496
Growth of R-, S-, and M-dissociates of Rhodococcus rubropertinctus in mixed culture with R-, S-, and M-dissociates of Rhodococcus aeruginosa in comparison with rhodococcus monoculture cultivated on mineral nutrient medium with hexadecane has been studied. The amount
of cells in the stationary growth phase has increased 10–15 times in comparison with the monoculture, and pseudomonads which
dominated in population, in associations of M-dissociate of R. rubropertinctus with any dissociate of R. aeruginosa or two S-dissociates in the studied bacterial species. The emulsifying ability of the cells (maximal in R-dissociates), the
synthesis of surface active compounds in pseudomonads, which is maximal in M-dissociate had the main influence on the growth
of rhodococci on the nutrient medium with hydrocarbons. 相似文献
79.
80.
Korneeva NL Soung YH Kim HI Giordano A Rhoads RE Gram H Chung J 《Molecular cancer research : MCR》2010,8(12):1571-1578
It was previously shown that integrin α6β4 contributes to translation of cancer-related mRNAs such as VEGF via initiation factor eIF4E. In this study, we found that integrin α6β4 regulates the activity of eIF4E through the Ser/Thr kinase Mnk. Although a role for Mnk in various aspects of cancer progression has been established, a link between integrin and Mnk activity has not. Here we show that Mnk1 is a downstream effector of integrin α6β4 and mediates the α6β4 signaling, important for translational control. Integrin α6β4 signals through MEK and p38 MAPK to increase phosphorylation of Mnk1 and eIF4E. Inhibition of Mnk1 activity by CGP57380 or downregulation by shRNA blocks α6β4-dependent translation of VEGF mRNA. Our studies suggest that Mnk1 could be a therapeutic target in cancers where the integrin α6β4 level is high. 相似文献