Anesthetics and plants: no pain,no brain,and therefore no consciousness

Protoplasma - Plants have a rich variety of interactions with their environment, including adaptive responses mediated by electrical signaling. This has prompted claims that information processing...     

Kinesin motors: no strain, no gain

The processive movement of the dimeric motor protein kinesin 1 along microtubules requires communication between the two motor domains. Yildiz et al. (2008) now show that tension between the motor domains not only is necessary for normal processivity but also may be sufficient for motor motility under some conditions.     

When no pollen does not mean no trees

The question of what signal, if any, appears in the pollen record when trees are present in the vegetation without producing pollen or with no pollen being recorded, is addressed. Four scenarios are envisaged: (i) the number of trees in the landscape are very few and scattered, (ii) the trees are too young to produce pollen, (iii) climate conditions are unfavourable for the trees to produce pollen and (iv) the trees are cut or damaged so that they do not flower. Each of these is considered in terms of pollen accumulation rates (PARs) and present theories and models of pollen dispersal. Examples are provided for the forest limit areas of the northern boreal trees in Finnish Lapland using data of pollen deposition monitored by pollen traps and results from the high temporal resolution (near annual) analyses of peat profiles. The relevance of the results to questions such as finds of spruce macrofossils in the Swedish mountains, the 8200 cal b.p. cold event, the migration of species/vegetation succession, and widespread damage to trees are all considered. It is concluded that although these situations are sometimes ‘invisible’ or misrepresented when pollen assemblages are expressed in the traditional percentage manner, they are often revealed by PARs. The fact that the pollen assemblage reflects a much wider regional area than is often understood can strengthen signals which have a regional impact, such as those which are climate induced, but may obscure events which affect only a limited spatial area or occur as small patches in the landscape.Communicated by Pim van der Knaap     

Three wise centromere functions: see no error,hear no break,speak no delay

The main function of the centromere is to promote kinetochore assembly for spindle microtubule attachment. Two additional functions of the centromere, however, are becoming increasingly clear: facilitation of robust sister‐chromatid cohesion at pericentromeres and advancement of replication of centromeric regions. The combination of these three centromere functions ensures correct chromosome segregation during mitosis. Here, we review the mechanisms of the kinetochore–microtubule interaction, focusing on sister‐kinetochore bi‐orientation (or chromosome bi‐orientation). We also discuss the biological importance of robust pericentromeric cohesion and early centromere replication, as well as the mechanisms orchestrating these two functions at the microtubule attachment site.     

Knowing no fear

People with brain injuries involving the amygdala are often poor at recognizing facial expressions of fear, but the extent to which this impairment compromises other signals of the emotion of fear has not been clearly established. We investigated N.M., a person with bilateral amygdala damage and a left thalamic lesion, who was impaired at recognizing fear from facial expressions. N.M. showed an equivalent deficit affecting fear recognition from body postures and emotional sounds. His deficit of fear recognition was not linked to evidence of any problem in recognizing anger (a common feature in other reports), but for his everyday experience of emotion N.M. reported reduced anger and fear compared with neurologically normal controls. These findings show a specific deficit compromising the recognition of the emotion of fear from a wide range of social signals, and suggest a possible relationship of this type of impairment with alterations of emotional experience.