Is an early calcium flux necessary to stimulate lymphocytes?

Concentrations of concanavalin A or the calcium ionophore A23187 that are optimal for the transformation of pig or mouse lymphocytes do not normally cause a measurable increase in calcium influx compared with unstimulated cells. If the cells are treated with the mitogens in conditions where a measurable increase in calcium influx occurs, no stimulation of the cells can occur while the flux is maintained. If an early influx of extracellular calcium is necessary for stimulation, then a much smaller increase in the total concentration of cellular calcium than reported previously is sufficient to allow the entry of lymphocytes into the cell cycle.     

Can sequencing shed light on cell cycling?

Every organism must have cells that can replicate indefinitely. Can the draft human genome sequence tell us how the cell cycle works and how it evolved? We studied two protein families--the cyclins and their partners the cyclin-dependent kinases (Cdks)--and a conserved regulatory circuit, the spindle checkpoint. Disappointingly, we discovered a few novel cyclins and no new Cdks or components of the spindle checkpoint, and could shed little light on the organization of the cell cycle.     

Can transgenic rice cause ecological risks through transgene escape?

Alien transgene escape from genetically engineered rice to non-transgenic varieties or close wild relatives (including weedy rice) may lead to unpredictable ecological risks. However, for transgene escape to occur three conditions need to be met: (i) spatially, transgenic rice and its non-transgenic counterparts or wild relatives should have sympatric distributions; (ii) temporally, the flowering time of transgenic rice and the non-transgenic varieties or wild relatives should overlap; and (iii) biologically, transgenic rice and its wild relative species should have such a sufficiently close relationship that their interspecific hybrids can have normal generative reproduction. This paper presents research data on the geographic distribution, flowering habits, interspecific hybridization, and gene flow of cultivated rice (Oryza sativa) and its closely related wild relatives containing the AA genome. The objective is to estimate the possibility of transgene escape to non-transgenic rice varieties and wild relatives of rice, which may result in unpredictable ecological risks.     

Can the memory of an object be enhanced by imagining its loss?

Previous investigations examining salient memories have demonstrated that personal memories that are important to individuals and contain emotional information are better remembered than neutral events.Using behavioral and brain-imaging experiments,the present studies explored whether the previous finding was applicable imagined loss.In a behavioral experiment,a free recall paradigm was used to compare the memory performance of individuals who imagined loss with that of individuals who imagined importance.The superior memory performance conferred by imagining loss was constrained to ordinary items of low to medium importance and did not generalize to vital items.Moreover,brain imaging evidence revealed that the activation in certain brain regions was stronger when participants were imagining the loss of ordinary items of low to medium importance compared to vital items.These brain regions included cognitive effort-related areas(such as the parietal cortex and middle prefrontal cortex) and areas related to emotional experiences and emotion-related memories(such as the amygdala,parahippocampal gyrus,and posterior cingulate gyrus).Our study provides a new way of exploring the superior memory performance when imagining loss and enriches the literature on memory enhancement by contributing to a deeper understanding of the psychological mechanisms related to the imagining of vital losses.     

What Physics Can We Learn from Integrated Stokes Parameter Measurements Made with Polarized Electrons?

IntroductionMuch of the basic physics of electron- atomscattering can be learned by looking at lightemitted by atoms excited during the scatteringprocess.Any beam of light can be completelycharacterized in terms of its Stokes parametersIP1,IP2 ,IP3,and I[1] . In a well- designedexperiment,the light' s intensity,I,is directlyproportional to the excitation cross section for thestate emitting the light. The polarizationparameters IPj give additional information aboutdifferentaspects of the e…     

Can the climate background of western North Pacific typhoon activity be predicted by climate model?

Based on the observation and reanalysis data through 1948-2004, the vertical shear of zonal wind, outgoing Iongwave radiation, and divergence fields in the lower and upper troposphere during summer are revealed to correlate significantly with the concurrent western North Pacific （WNP） typhoon frequency, and they therefore can be regarded as predictors for the WNP typhoon activity anomaly. After that, the 34-year （1970-2003） ensemble hindcast experiments are performed by the nine-level atmospheric general circulation model developed at the Institute of Atmospheric Physics Under the Chinese Academy of Sciences （IAP9L-AGCM）, aiming to investigate the numerical predictability of the summer vertical shear of zonal wind and divergence field in the lower troposphere. It is found that the temporal correlation coefficients between the hindcast and observation are 0.70 and 0.62 for the vertical shear of zonal wind and divergence field, respectively. This suggests that the model possesses a large potential skill for predicting the large-scale climate background closely related to the WNP typhoon activity, and the model is therefore capable of performing the real-time numerical prediction of the WNP typhoon activity anomaly to some extent.     

Can the occurrence of rare insertion/deletion polymor-phisms in human mtDNA be verified from phylogeny?

Owing to its maternal inheritance, absence of re-combination and high evolution rate, mtDNA has been widely used in unraveling the migration history of modern human and in medical genetics as well as in forensic prac-tice[1,2]. Compared with the Cambridge reference sequence (CRS) which was first sequenced in 1981[3] and the later revised CRS[4], insertions and deletions (indel) occur fre-quently in the mtDNA sequences available. Some of the indel polymorphisms are characteristic to mtDNA…     

Can other host species of cotton bollworm be non-Bt refuges to prolong the effectiveness of Bt-cotton?

The potential ecological risks ofBacillus thurigiensis (Bt) insecticides and Bt-crops have caused increasing concern since their commercial release in the field, among which pests’ resistance to Bt-crops is the major ecological risk. Refuge tactic, which can produce sensitive populations, has proved to be a key and sound resistance management strategy in USA and Australia; however, no tactics have been performed in China where Bt-cotton is mostly planted with other host crops of cotton bollworm. Genetic variation and gene flow among different host populations of the cotton bollwormHelicoverpa armigera were analyzed using PCR fingerprinting method. The results show that maize and castor-oil plant, as well as cotton can take effect as refuges to prevent resistance of cotton bollworm to Bt-cotton, while peanut and sesame are not as suitable for planting with Bt-cotton as refuges in the field as low gene flow was detected among populations on peanut, sesame and Bt cotton.     

Can Hybrid Synapse be Formed between Rat Spinal Motor Neurons and Major Pelvic Ganglion Neurons in vitro?

The purpose of this study is to determine whether synapses can be formed between spinal motor neurons (SMNs)and major pelvic ganglion (MPG) neurons of a rat in ...