Tag Archives: Science Week

The evolutionary secrets of garden flowers described at Birkbeck’s Science Week

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This post was contributed by Tony Boniface – a member of the University of the Third Age.

Science Week logo

Science Week logo

On 3 July, Dr Martin Ingrouille, of Birkbeck’s Department of Biological Sciences, began his talk by pointing out that Darwin had studied plants for 40 years and had published books on pollination. However, Darwin knew nothing of genes and chromosomes and could not explain the rapid origin of flowering plants in the Cretaceous period.

Dr Ingrouille continued by emphasising that garden plants are sterile and exotic plants without their natural pollinators. They have been selected for showiness, many being artificial hybrids. He referred to Goethe, who stressed the essential unity of floral parts, which have all evolved from leaves.

Dr Ingrouille explained how genetic control, in its simplest form, consists of three classes of genes: A, B and C. Class A genes control sepals and petals, class B genes control petals and stamens, and class C genes control stamens and carpels. Mutations of these genes result in parts being converted into others.

Floral evolution in plants could have been the result of duplication of basic genes allowing one to perform its normal function while the other could give rise to a novel structure or function. New plant species have often arisen by chromosome doubling in a sterile hybrid as seen in the formation of Primula kewensis.

Dr Ingrouille then explained how much insight into plant evolution arose from the work of John Gerard (gardener to William Cecil), John Ray (author of the first modern text book of botany) and the Jussieus family (three generations of gardeners to the king of France). These people put plants into groups that were the first natural classification of the angiosperms.

Now DNA sequencing has resulted in a detailed understanding of the phylogeny or evolutionary history of these plants in which many of the families have survived such as the umbellifers and legumes but some such as the figwort family have been split. The result was the arrangement of the plants into two main groups namely the Eudicots, with three  grooves on their pollen grains, and the Basal Angiosperms, with only one groove. Within the Eudicots are the Core Eudicots including the Rosids and the Asterids whilst the Monocots are within the Basal Angiosperms. The first ancestor was Amborella trichopoda, a weedy shrub from New Caledonia in the Pacific – a place Dr Ingrouille hopes to visit on his retirement.

Dr Ingrouille finished  by urging his audience – all members of the University of the Third Age (a movement for retired and semi-retired people to come together and learn together) – to examine their garden plants in detail to look for the variations, which suggest their origins.

Exploring the hidden complexities of routine behaviour at Birkbeck’s Science Week

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This post was contributed by Guy Collender, Communications Manager, Birkbeck’s Department of External Relations.

Dr Richard Cooper

Dr Richard Cooper at Birkbeck’s Science Week

How often do you forget to attach the relevant document when you are sending emails? When was the last time you accidentally put the coffee in the fridge instead of the milk? Or, more alarmingly, when did you last leave the nozzle of the petrol pump in your car when you drove off from the petrol station? (Yes, believe it or not, there is ample photographic evidence to prove the last point).

Such errors, made during routine tasks, were the centre of attention at a fascinating lecture, entitled The hidden complexities of routine behaviour, during Birkbeck’s Science Week. Dr Richard Cooper explained why it is important to understand routine behaviour, why mistakes are made during everyday tasks, and the implications for the rehabilitation of brain-damaged patients.

Benefits of routine behaviour
The presentation on 3 July began with a description of routine behaviour and its advantages. Dr Cooper, of Birkbeck’s Department of Psychological Sciences, defined routine tasks, such as dressing, grooming, preparing meals, and cleaning, as frequently performed tasks carried out in a stable and predictable environment. By automatically performing various stages in a routine task, people do not have to plan every action on a moment-by-moment basis. This, as Dr Cooper showed, saves the mental exertion associated with constant planning, and enables the brain to think about other things when performing routine tasks.

Difficulties associated with routine tasks
However, routine tasks are prone to error, especially following an interruption, and these mistakes may have “catastrophic consequences”, including vehicle collisions and industrial accidents. Dr Cooper said: “Routine behaviour is not something we can take for granted.”

The lecture continued with a list of different types of errors made while performing routine tasks. These include omission errors (leaving out a vital task), perseverative errors (repeating an action even though the goal has been achieved), and substitution errors (mixing up objects).

Dr Cooper showed how people with brain injuries are much more prone to making these mistakes. He said: “Neurological patients can have a much more difficult time.” They can suffer from a range of problems, including anarchic hand syndrome (where one hand performs involuntary movements), frontal apraxia (which leads to patients making sequential errors and substitution errors on a minute-by-minute basis), or ideational apraxia (which leads to the right action, but wrong place – such as trying to light the wrong end of a candle).

Devising solutions
Dr Cooper also referred to studies of brain-damaged patients in rehabilitation clinics and their performance of routine tasks in a controlled environment. He said: “Re-learning must focus on rote learning of the precise procedure, with no variation. Home environments should be designed to minimise distractions.”

Dr Cooper also hinted at future developments in this field as smart devices might be able to monitor the performance of routine tasks for certain errors. Hopefully the latest technology will be able to help reduce everyday problems in the years ahead.

Mindfulness Meditation Training

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This post was contributed by Lucia Magis-Weinberg, who is doing her PhD under the supervision of Dr Dumontheil and Dr Custers, investigating how motivation impacts adolescents’ executive functions (which include self-regulation and attention). Learn more about Dr Dumontheils’ research. Follow us on Twitter @idumontheil and @luciamawe. 

PsychologyInhale. Exhale. Focus your attention on the present moment. Mindfulness meditation (MM) is a type of awareness that involves focusing on moment to moment experiences in a non-judgmental and non-reactive way. MM was adopted from the Buddhist tradition, and was originally implemented in Western medicine for the treatment of chronic intractable pain. In adults, it has been shown to improve people’s ability to manage attention, regulate emotion, well-being, and ameliorate anxiety and depression. It even boosts immune function. But can these benefits be extended to other age groups?

This was discussed as part of the Birkbeck Science Week by Dr Iroise Dumontheil from the Department of Psychological Sciences, who talked about her ongoing research on the effects of mindfulness meditation training (MMT) in adolescence. The teenage years are characterised by continued improvements in self-regulation, the ability to exert voluntary control on thought, emotion and action. A deficit in self-regulation results in impaired impulse control and increased sensation seeking and risk taking. Furthermore, adolescents can struggle with the regulation of emotions. Failures in self-regulation can have a bigger impact in decisions and behaviour in the teenage years than later in life, as is evident by the alarmingly high rates of death by accidents and violence, two preventable issues, in the second decade of life. Around 75% of mental disorders have an onset before the age of 24. All of these issues could benefit from enhancing the ability of adolescents to self-regulate. Can MMT be one of the ways? Dr Dumontheil’s ongoing research, conducted in collaboration with UCL and the University of Minnesota, is starting to address this question and is motivated by the impact that interventions could have on adolescent well-being.

There is some initial promise from early research in the adolescent population. It has been shown that MMT is feasible in adolescence, particularly because it could be done in schools. MMT seems to benefit performance in tasks that involve a negative emotional component (being less distracted by angry faces, for example). Additionally, there is evidence that anxiety is decreased. The positive effects of MMT on increased attentional control are similar to those seen previously in adult studies.

Currently, Dr Dumontheil is looking at changes in brain function in response to an 8-week MMT with fMRI, a neuroimaging technique. In adults, it has been shown previously that MMT reinforces self- regulation by targeting the ability to control thought and action (associated with increased activity in the prefrontal regions of the brain) and lessening the influence of anxiety, stress and immediate reactivity (associated with decreased activity in the amygdala). Preliminary data from Dr Dumontheil’s research show changes in the brain regions that control attention.

As was noted by attendees of the lecture, there are very interesting questions yet to be explored, such as gender differences in the response to MMT and whether variants of the standard MMT may be more successful in adolescents and children. While research in psychology and neuroscience shed light on this interesting phenomenon, let’s reorient our attention to our present moment for now. Inhale. Exhale.

Science Week: Structures of sodium channels

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This post was contributed by Dr Clare Sansom, of Birkbeck’s Department of Biological Sciences.

The structures of sodium channels and what they can teach us about human health, particularly rare neurological diseases, were explained during Science Week.

Professor Bonnie Wallace, of Birkbeck’s Department of Biological Sciences, delivered the fascinating and accessible lecture on 18 April. She has been at Birkbeck for about twenty years and now directs the department’s impressive research work on the structural biology of membrane ion channels.  Membrane proteins are ubiquitous, are responsible for the transport of both chemicals and signals into and out of cells, and form some of the most important drug targets. They are also, as Professor Wallace made very clear in her talk, some of the most challenging of all proteins for structural biologists to examine.

All cell membranes are semi-permeable, which means that some substances can pass across them easily while others are excluded. Ions, which are charged, are generally excluded by the hydrophobic (“water hating”) membranes. This could be something of a problem, as ion transport into and out of cells is an essential physiological process. Ion channels are evolution’s solution to this problem: proteins embedded in membranes that allow ions to selectively enter and leave cells.

Much of Professor Wallace’s work over the last 10 years has focused on the structures of voltage gated sodium channels. These open to allow sodium ions to enter cells, and close to prevent them from doing so, in response to changes in potential across the membrane, and they are found throughout nature. Small molecules can bind to these channels, holding them either open or closed; some of these are severely toxic, but others are important drugs for cardiac arrhythmias, epilepsy, and pain.

It took over ten years for Professor Wallace and her group to isolate the gene, clone and purify the protein, obtain crystals and finally solve the structure of the channel pore. The structure was finally solved using the powerful X-rays generated at Diamond, the UK’s only synchrotron radiation source located near Harwell in Oxfordshire.

Different structural forms
These channels exist in three different structural forms: “open”, “closed” and “inactivated”. Many years before the detailed structures were solved Professor Wallace and her group had used a biophysical technique, circular dichroism (CD) spectroscopy, to examine the conformational changes that occurred when mammalian and bacterial channels switched from one state to the other. As always, however, the full atomic-crystal structures yielded very much more information.

Professor Wallace and her group were the first to solve the structure of an open form of the channel which showed the “top” part of this structure, towards the extracellular membrane surface, has a hydrophobic surface, and an internal selectivity filter which allows sodium ions in while keeping others, including potassium and calcium ions, out.  The lower part, on the extracellular surface, is where the ions exit. This open structure could be compared with the published structure of closed form of the channel, and showed that the upper portion containing the selectivity filter was virtually unchanged The conformational change associated with opening and closing the channel occurs at the internal or cytoplasmic side of the protein. When the pore closes, a small turning motion of the “bottom” part of the helical bundle causes the bottom ends of the pore to come together and the diameter of the pore to shrink; the resulting channel is too small for sodium ions to pass through, so any inside the pore become trapped there.

Two subunits of the bacterial sodium channel pore in the “open” conformation, shown as a ribbon structure

Two subunits of the bacterial sodium channel pore in the “open” conformation, shown as a ribbon structure

Bacterial  voltage gated sodium channels have a domain at the C-terminal end of the molecule that is necessary for channel activity but that was not visible in any of the crystal structures. Professor Wallace and her group looked at this part of the molecule using a particularly powerful form of CD spectroscopy called synchrotron radiation CD spectroscopy that she had pioneered, and showed that each subunit had an extremely flexible protein chain separating the pore from a C-terminal helix. Using this information, the group have proposed a novel mechanism for channel opening in which the conformational change in the pore is enabled by these helices oscillating up and down.

Two subunits of the bacterial sodium channel pore in the “open” conformation, shown as a ribbon structure

Two subunits of the bacterial sodium channel pore in the “open” conformation, shown as a ribbon structure

Implications for health
The final part of Professor Wallace’s talk was devoted to the role of sodium channels in health and disease, and as a drug target. A few unfortunate individuals have mutations in a type of channel that is involved in the response to painful stimuli. If this channel is jammed open, patients experience a constant, burning pain termed erythromelalgia, most commonly in their hands and feet. Professor Wallace showed that an equivalent mutation from phenylalanine to valine at the base of one of the protein subunits could cause the channel to open just enough for ions to pass through. There are also people in whom these channels are jammed in the closed position or are missing altogether, and they feel no pain, even if they walk on hot coals. It may one day be possible for drugs based on our knowledge of these structures to be designed to ease both these conditions.