Jump to content

NinaMS

Members
  • Posts

    7
  • Joined

  • Last visited

Everything posted by NinaMS

  1. Only further evidence will tell whether the links that J Matysik has made between the protective effect described and ultra fast electron transfer in photosynthesis or the suggestions that this effect might support both photosynthesis and magnetoreception by Iannis K Kominis are more than speculation. It is one avenue that is being explored, among the many avenues being explored in quantum biology. Until one is proven correct they are all speculation. That is why I started my first post with 'could'? If you still unable to see how the posting might connect to the title of this thread, then I haven't got anything else to add. Perhaps any posting discussing an area that isn't widely accepted within the scientific community should be moved to the speculation section of this website. If that was the case I would accept that this thread should be within that grouping. However, from what I have seen from the posts on this forum there are plenty of discussions with less substance than this one, and they would all need to be moved across for the sake of consistency. Thank you.
  2. Yes you are right, but the field of quantum biology is seeking to demonstrate that that quantum mechanics plays an important role in biological processes and evolution. My posting attempts to support this approach. I cant sum up the implications of quantum biology in a sentence or two, so if you are interested in finding out more I would recommended www.nature.com/nphys/journal/v9/n1/full/nphys2474.html or http://richannel.org/jim-al-khalili--quantum-life-how-physics-can-revolutionise-biology
  3. My argument back is that nature will take the same basic mechanisms and generate complexity from this through evolutionary strategies. You asked for a simplified explanation, so I have set this out below. Photosynthesis and magnetoreception (in species that are able to navigate using the Earth’s magnetic field) are the focuses of study in quantum biology. There is a good introduction to quantum biology at www.nature.com/nphys/journal/v9/n1/full/nphys2474.html Quantum coherence in photosynthesis has been evidenced (actually measured) and is thought to be supporting ultra-fast charge separation. There are plenty of scientific papers exploring this (published on the internet and generally available) but there has been no agreement on what has been behind this effect. Magnetoreception has also been demonstrated in a number of species, and there are many peer reviewed papers out there that have explored the theory that magnetoreception is based on quantum mechanics. However, there been no actual measurement of quantum coherence in magnetoreception as yet. There are two main theories of what might trigger a quantum version of magnetoreception, one which involves a light dependent flavoprotein called cryptochrome and the generation of radical pairs. In the case of the cryptochrome theory, a short-lived radical pair (magnetically sensitive chemical intermediates formed by photoexcitation of cryptochrome proteins) would interconvert coherently between its electronic singlet and triplet states in such a way that the yields of its reaction products would be influenced by weak magnetic fields. What the above posting describes are findings in photosynthesis of a radical pair mechanism resulting in reduced triplet product yield and that this could be connected to the quantum mechanical effects found in photosynthesis. The solid state photo CIDNP effect is thought to be based on a radical pair mechanism - and this effect potentially offers bacteria and plants a form of protection from damaging oxidative stress. The findings that the solid state photo CIDNP effect is also present in Escherichia coli photolyase, and the bluelight photoreceptor phototropin LOV1-C57S, and the possibility it may be present in cryptochrome (both photolyases and cryptochromes are from the same 'family'), may mean that the same quantum effect is supporting both quantum mechanics in photosynthesis and magnetoreception. The finding that cysteine residues may be involved a newly discovered protective/quenching effect in the green sulphur bacteria (which has already demonstrated the solid state photo CIDNP effect) is of interest as it could through more light on the above. The cysteine mediated mechanism could be a completely different protective effect from that of the solid state photo CIDNP effect - but there is also the possibility the two could be related. In mutant plant cryptochrome it has been found that cysteine can act as a gatekeeper for proton transfer and it has been concludes that the formation of the flavin anion radical as the photoproduct is a consequence of a blockage of proton transfer by cysteine. A Hense 2015. These cysteine mediated effect also shows a possible role for cysteine residues in the redox activity of the pigment-protein complex. Generally the coupling between circadian rhythms and the metabolism/redox is recognised within biology, although a relatively new development. Such an effect could support the concept of environmentally assisted quantum transport (ENAQT) which is thought to take place in the FMO complex of the green sulphur bacteria). The idea behind ENAQT is that optimally efficient networks are not purely quantum, but assisted by interaction with a 'noisy' classical environment. A coupled redox - circadian system could potentially offer this combination. I hope that makes more sense to you - if you click into the links in the first posting, you will find the accompanying theory and evidence from these fields.
  4. G S Orf et al 2016 recently found evidence for a cysteine-mediated mechanism of excitation energy regulation in a photosynthetic antenna complex (of the green sulphur bacteria). Further findings on the specific cysteines identified in the G S Orf study highlight a possible role for cysteine residues in the redox activity of the pigment-protein complex. R Saer 2016. By specific and reversible oxidation of redox-sensitive cysteines, many biological processes sense and respond to signals from the intracellular redox environment. M Putker 2016. Other studies such as Marais 2015 have explored protective effects in other bacteria which have yet to be properly explained. These relate to a reduction in triplet product yield in reaction centres due to weak magnetic fields. Such solid state photo CIDNP effects have previously been found in the green sulphur bacteria. Roy et al 2007. They have also been found in Rhodobacter Sphaeroides (K Schulten 1977, K Schulten et al 2002, Daviso 2008, Prakash et al 2005, Y Liu et al 2005, Zysmilich and McDermott 1994 and 1996, Matysik et al 2000, Prakash et al 2005 and 2006, Daviso et al 2008) and Spinach (Alia et al 2004, Diller at al 2007, Matysik et al 2000, Diller et al 2005 and 2007). Full references for these studies are given by J Matysik 2009. Indications of long-lived quantum coherence have been found in the green sulphur bacteria, rhodobacter sphaeroides, and spinach. And it is interesting that there has been the suggestion that there could be a link between the conditions of occurrence of photo-CIDNP in Reaction Centres and the conditions of the unsurpassed efficient light-induced electron transfer in reaction centres. This has been explored in various papers by J Matysik e.g Jeschke and Matysik 2003, J Matysik 2009), I F Cespedes-Camacho and J Matysik 2014. There is evidence for the strong correlation between the degree of electronic coherence and efficient and ultrafast charge separation. E Romero 2014. And if a solid state photo CIDNP effect is a quantum mechanism supporting ultrafast charge separation in photosynthesis, there may be wider implications, as there are similar ultra-fast dynamics in bond isomerization in sensory photoreceptors and repairing DNA damage. C Tan 2015. It has also been speculated that solid-state photo CIDNP effect at earth field also plays a role in the magnetoreception of biological systems....Studies have found that the 'solid-state photo-CIDNP' effect allows for signal enhancement of factors of several 10000 s. Such strong signal enhancement allows for example selectively observing photosynthetic cofactors forming radical-pairs at nanomolar concentrations in membranes, cells, and even in entire plants. W Xian Jie 2016 and G Jeskchke 2011. Both the effect in photosynthesis and in magnetoreception may be drawing on radical pairs, and - A magnetic-field effect has been demonstrated on the photochemical yield of a flavin-tryptophan radical pair in Escherichia coli photolyase. K B Henbest 2008. - An effect has been observed a mutant of the bluelight photoreceptor phototropin (LOV1-C57S from Chlamydomonas reinhardtii). S S Themarath 2010. It may be of interest that in flavo-proteins (mutated in order to remove a cysteine residue next to the chromophore), it is possible to form a spin-correlated radical pair. Denis V. Sosnovsky. 2016. It has been thought that solid-state photo-CIDNP effect has required high magnetic fields and cyclic electron transfer, but does the paper by G S Orf offer a new perspective? Could a mechanism initially developed as a protection against damage from reactive oxygen species, become utilised (through evolution) for other purposes (e.g perhaps supporting ultra-fast electron transfer). This type of approach could also be matched with the concept of environmentally assisted quantum transport - as a redox mediated system (using flavoproteins, etc) could potentially be coupled to a circadian system. Redox-circadian coupling is being found throughout biology e.g M Putker 2016, K Nishio 2015, N B Milev 2015, A Stangherlin 2013. N P Hoyle 2015. Circadian rhythms feature in almost every aspect of photosynthesis, and cryptochrome (in Arabidopsis, Drosophila, and mouse) provide the most direct path by which redox status can interact with the core components of the transcription–translation feedback loop (TTFL). Lisa Wulund 2015. Sorry I should have also included the following in the above post. The observation of the solid-state photo-CIDNP effect in phototropin has been shown that this effect is not limited to natural photosynthetic systems. In the same way that photo-CIDNP MAS NMR has provided detailed insights into photosynthetic electron transport in RCs, it is anticipated in a variety of applications in mechanistic studies of other photoactive proteins. It may be possible to characterize the photoinduced electron transfer process in cryptochrome in detail. W Xiao-Jie12016.
  5. ​Potentially circadian medicine offers a holistic way of bringing together a number of symptoms that may on first sight seem unrelated. Disruptions in circadian systems can negatively affect sleep quality, alertness, cognitive performance, motor control, metabolism, etc. Increasingly it is being recognised that this approach can be applied to specific learning difficulties. A growing body of research has identified significant sleep problems in children with autism. Disturbed sleep–wake patterns and abnormal hormone profiles in children with autism suggest an underlying impairment of the circadian timing system. G Glickman 2010. Z Yang 2015 Sylvie Tordjman (et al Feb 2015) proposes a central role of rhythmicity and synchrony of rhythms in typical child development and offers an integrative approach, which considers autism as a disorder of biological and behavioral rhythms. Similar observations have been made in relation to ADHD. It is not clear how sleep disturbances come to be so common in ADHD, but one putative mechanism is through the circadian timekeeping system. A N Cogan 2016. I Paclt 2011. It would also be interesting to explore whether this approach could be applied to dyslexia. Common problems with dyslexia include with tendencies to 'zone out' and lose track of time. They also include: 1. Problems with writing and motor skills It has been found that there are circadian rhythms in handwriting. I Jasper 2009. Dyslexia has also been associated with dyspraxia, differences in eye movement and binocular vision/depth perception. There are circadian rhythms of motor function, including rapid eye movement. S W Wurts 2000. L Zhou 2014. A link between motor dysfunction and circadian rhythms has also been associated with autism Sylvie Tordjman (et al Feb 2015). And in an animal model, it was recently shown that circadian disturbances that exist before parkinson's onset dramatically worsen motor and learning deficits brought on by the disease. Differences in gamma oscillations have also been detected in dyslexia (e.g K Lehongre - ‎2013 ) and a number of other neuro-conditions. Interestingly gamma oscillations have been very closely associated with rapid eye movements called microsaccades. Invasive recordings in a number of animal species suggest that these oscillations play a key role in such diverse processes as visual feature integration, attentional selection, episodic memory and working memory maintenance. K Wieczorek 2015. The presence of gamma-band activity in many LFP measurements under stimulation led to the idea that gamma-band oscillations serve as a ‘clock’ signal for the purpose of temporally encoding information (Hopfield, 1995; Buzsaki and Chrobak, 1995; Jefferys et al., 1996; Buzsaki and Draguhn, 2004; Buzsaki, 2006; Bartos et al., 2007; Fries et al., 2007; Hopfield, 2004). The ‘clock’ theory of gamma combined with the pervasiveness of gamma oscillations have given rise to the theory that the brain uses gamma oscillations to synchronize different regions of the brain for the purpose of ‘binding’ information about a stimulus (Gray and Singer, 1989; Singer and Gray, 1995). 2. Problems with the rhythms of speech and learning language Scientists have identified that dyslexics have problems with the rhythms of speech. ' children with dyslexia often find it difficult to count the number of syllables in spoken words or to determine whether words rhyme. These differences are seen across languages with different writing systems and they indicate that the dyslexic brain has trouble processing the way that sounds in spoken language are structured' M Huss 2011. It has been found that generally, there are optimal times in the day for learning other languages (suggesting circadian rhythms influence language learning) Kees De Bot 2015, and may influence language performance. J Rosenberg 2009. It is also speculated that there may be differences in dyslexia and other specific learning difficulties in circadian driven mechanisms which protect the ear from noise. During the day a hormone called brain-derived-neurotrophic factor (BDNF) is distributed into the ears. This hormone protects the auditory nerves from damage. It provides a layer of insulation to protect the ears from harmful noises that are more likely during waking or day hours. This mechanism is based on circadian rhythms. 3. Problems with memory (particularly sequential task information) The presence of circadian variations in gene expression and synaptic plasticity in hippocampal cells, as well as in learning and memory formation, indicates an inherent link between cellular activities and behaviors of the whole animal. However, the mechanism by which the activity of a group of pacemaker cells is translated into behavioral responses is still poorly understood. X Mou 2016.B L Smarr 2014 4. Sleep Problems Some adult dyslexics report sleep dysfunction. http://community.dys...exics-and-sleep. This could be due to stress, but a recent study has connected sleep disorder and development dyslexia. Acta Paediatr. 2016 This could potentially be related to melatonin. It should not be assumed that it is due to underproduction of melatonin, as dyslexic people report high levels of tiredness and vivid dreams which are more symptomatic of over production of melatonin. However, it has also been reported that dyslexia is a 'changeable' conditions, and this condition may fluctuate. 5. The perceived benefits of different lighting and fish oils for people with dyslexia. It has been suggested that dyslexic people can find their symptoms mitigated by filtering out certain types of light (including blue), although the research on this has been inconclusive. Circadian rhythms can be entrained by various means including nutrition, temperature, but also lighting. For example it has been found that in the general population blue light improves performance generally due to circadian rhythms. J Sharples 2007 . However dyslexics may be over sensitive to blue light because of differences in circadian rhythms. These may be because of differences in retinal receptors e.g G S Grosser 1998. 'Recently, a new class of intrinsically photosensitive retinal ganglion cells (IPRGCs) has been discovered. These connect to the body’s internal clock, which controls diurnal rhythms. Thus, the function of its input from the melanopsin-containing retinal ganglion cells is not to mediate conscious vision but to synchronise the SCN to seasonally varying day length.... it has been reported that 'Many children with visual reading difficulties have disturbed sleep patterns Their parents are often surprised that the blue filters seem to improve their child’s sleeping. Likewise, many such children complain of headaches when they try to read. Migraine headaches are known to be accompanied by disturbed sleep rhythms. Hence, we now have many anecdotal reports that successful treatment of reading difficulties with blue filters is accompanied by fewer headaches, and we are now following this up more systematically'. J Stein 2014. Recent research in animal models suggests PUFA-deficient diet lessens the melatonin rhythm, weakens endogenous functioning of the circadian clock, and plays a role in nocturnal sleep disturbances as described in attention deficit/hyperactivity disorder. The circadian clock plays a role in regulation of plasma and tissue lipids, including triglycerides, cholesterol and free fatty acids. 6. Related immunological Issues Immunological disorders are frequently found in people with specific learning difficulties. The human immune response also follows a circadian cycle (Levy et al.,1991) and most immune cells express circadian clocks and present a wide array of genes expressed with a 24 hr rhythm, and alterations in circadian rhythms lead to disturbed immune responses. N Labrecque 2015 Some Possible Solutions Please note that I am not a medical professional or chronobiologist. I am however dyslexic and so interested in a holistic approach to understanding this condition. 'If it is' found that dyslexia and other specific learning difficulties are related to circadian rhythms then there are some possible solutions. Melatonin treatments are not a simple answer and there is limited evidence of their effect on people with specific learning difficulties. Over production of melatonin can also have serious side effects. There are however various ways of naturally entraining the circadian clock e.g through light exposure, temperature, nutrition (K Peukuri 2011). Due to the link between circadian rhythms and the metabolism, chrononutrition is emerging as a key form of intervention is addressing circadian dysfunction (e.g J D Johnston 2016). There can also be consideration of equipment that effect circadian rhythms such as blue screens on computers and mobile phones, and use of stimulants such as coffee. It will also be important for educators to recognise the influence of circadian rhythms in the learning environment (and recognising these may be different for some students).
  6. I should have also mentioned in the above post, that there are underground/ocean based species which appear to have weak circadian rhythms (including in the metabolism) and do not have very long lifespans. The Mexican blind cave fish is one of these, so the weak circadian clock in itself could not be the full explanation for differences in ageing. However there are still findings of interest in relation to the blind cave fish. They stored up high fat reserves, and yet they are a healthy and relatively long lived species. Research also shows that although the blind cavefish has a circadian clock when kept in an environment of daily cycles of light and dark, this is repressed in cave environments. The expression level of Period 1 is very low and not oscillating and there is a significantly raised expression of per 2. There is also a higher expression of DNA repair genes, and a greater ability to repair DNA damage. Current results point to an internal timing process in the blind cave fish - perhaps related to the feeding patterns of the blind cave fish. When food does become available to the blind cave fish - perhaps once a year, - the fish are able to eat without limit and store as much fat as they can.
  7. The biosphere is dominated by dark, largely “arrhythmic” habitats, and most of life lives away from the direct effects of the sun...studies of species that live away from the sun are a very small fraction of chronobiological research. Perhaps unsurprisingly, when I have then looked at some studies on long lived species in such environments, I have found that a number have hard to quantify circadian rhythms. The long lived eusocial naked mole rats shows attenuated or no circadian clock rhythms, and although circadian rhythms have been described in the nematode Caenorhabditis elegans at the behavioral level, these rhythms appear to be relatively non-robust. As is widely known cancer is rare (although not unknown) in the naked mole-rat and C. elegans rarely acquires the kinds of tumours that can be readily observed in other animals. I looked more widely and found that the very long lived proteid proteus anguinus, an obligate cave-dweller, shows no apparent daily rhythm of activity or resting metabolic rate. In addition, recent sequencing of the long lived Hydra magnipapillata has reveal that it has lost both Clock and Cycle. but still displays a photoperiodic behaviour in response to life cycles. Tumors have been found in Hydra, but these tumors affect only female Hydra polyps and resemble ovarian cancers in humans. I would need to collect a lot more evidence on various species before arriving at a solid hypothesis, but I would be interested to know what research has already been undertaken on any links between circadian rhythms and longer lived species. A lack of a robust circadian clock can offer species benefits (e.g major energy saving benefits (30-40%) in the case of the blind cave fish), if they do not have to adapt their foraging to daily cycles. Species living away from the light can also survive without circadian regulated anti-oxidant processes that respond to strong sunlight. This also made me think what might be the implications of a weakly coupled circadian-redox system in longer lived species. Recent findings strongly suggest that the circadian clockwork is involved in cellular programmes that regulate endogenous ROS and protect the organism. Evidence seems to support the conclusion that the responses to ROS are mediated both through the regular function of the molecular clockwork and the involvement of the TTFL (transcription–translation feedback loops producing oscillations with a period of approximately 24 hours) genes in extra-circadian pathways. In addition, Redox signals are important regulators of cellular homeostasis and recently, it has become apparent that the cellular redox state oscillates in vivo and in vitro, with a period of about one day (circadian). Oxidation–reduction cycles of peroxiredoxin proteins are thought to constitute a universal marker for circadian rhythms in all domains of life. And they may not be unique in their ability to undergo redox oscillations since many other proteins are susceptible to oxidation of their cysteine residues by peroxide. The redox-circadian coupling might also potentially be found in SIRT 1. SIRT1 is involved in both aging and circadian-clock regulation. SIRT1 can stimulate the expression of antioxidants via the FoxO pathways, and recent studies have demonstrated that an increased level of ROS can both directly and indirectly control the activity of SIRT1 enzyme. For instance, ROS can inhibit SIRT1 activity by evoking oxidative modifications on its cysteine residues. There are also implications for morphogenesis. Circadian rhythms permeate mammalian cell biology, and significant proportions of gene expression and metabolism are circadian regulated with a commensurate impact upon biological function. So it should not be surprising that from cell division to signal transduction from inflammation to neuronal long-term potentiation circadian rhythms modulate cellular activity to support anticipated demand. And increasingly evident is that metabolic homeostasis at the systems level relies on accurate and collaborative circadian timing within individual cells and tissues of the body. S A Brown (2014) has provided an overview of the molecular mechanisms involved in circadian clocks and then discuss how such mechanisms can influence stem cell biology and hence tissue development, homeostasis and regeneration. Studies have shown that clock genes can indeed directly influence stem and progenitor cell fate. Circadian clock genes have recently been found to modulate human bone marrow mesenchymal stem cell differentiation, migration, and cell cycle. H Boucher 2016. A number of studies have suggested strong links between circadian rhythms and cancer. In rodent studies exploring how cancer in one organ spreads to others, it was found that lung adenocarcinoma sends signals to the liver through an inflammatory response, which rewires the circadian mechanisms that manage metabolic pathways. Sassone-Corsi 2016. So could a weaker circadian-redox coupling result in a slower metabolism (one where redox/the metabolism is not oscillating on a 24 hr cycle) and slower ageing in some species (particularly those that do not live in direct sunlight) and perhaps resistance to cancer. There may be a number of associated factors beyond weak circadian rhythms including low body temperature,calorie restriction, oxygen restriction, neoteny, etc, which are also found in some of the longest lived species. It might be possible explore some of the ideas raised in this posting by looking at aging and rejuvenation in bacterial populations. E Coli is not thought to have circadian rhythms, although a clock can be transplanted into the bacteria. It would be interesting to see if there are any differences in the 'ageing' (cell division) process between e-coli with - and without - a clock. So models such as the naked mole rat might potentially be less useful for understanding how to slow ageing in humans than species such as relatively long lived species that live in daylight including the caribou and elephant, which have an extended clock (e.g with the caribou's clock mainly being seasonal, and the elephant foraging both day and night). For those dwelling above ground there may have been an evolutionary need to develop a strong link between circadian rhythms and the metabolism (i.e nutrition, photosynthesis, respiration, etc), responding to more extreme changes in light and temperature, supporting migration, and stress resistance to biotic and abiotic cues. In such species the loss of robust circadian rhythms may result in accelerated ageing.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.