Good morning all, I hope that you have had an excellent Break, and are ready for the second half of our term! We will begin our third unit of the semester with consideration of the cardiac and pulmonary systems. There is much in our upcoming chapters that will be familiar (we all have some inherent understanding of how these systems function) and important (cardiovascular pathology is a leading contributor to human morbidity and mortality). Health science research and news is dominated by several major fields, including cancer, infectious disease, and cardiopulmonary health, for they are at the forefront of what ails us. One critical feature of our cardiac and pulmonary function is its malleability - we have real power to change how these systems perform, through our habits. Lack of exercise and poor lifestyle choices (in terms of diet, tobacco use, alcohol/drugs) plague too many of us, and a large component of the pharmaceutical industry is geared toward making medications that influence our cardiovascular and pulmonary health. But, we already hold the power to improve our condition, through exercise. Exertion is a form of physiological stress, and (within reason), it is a useful stress - our tissues respond to extra use with improved effectiveness. But, the temptation to simply 'pop a pill', or the lack of available time for exercise, makes it difficult for most of us to meet fitness goals (such as 150 min of moderate exercise per week). Are these options equivalent? Here's a link to a recent study that makes this type of comparison: are medications or exercise better for treating/managing high blood pressure and body fat stores? https://www.nytimes.com/2019/03/13/well/move/exercise-vs-drugs-to-treat-high-blood-pressure-and-reduce-fat.html This study reports benefits from both medications and from exercise, and highlights some of the difficulties in making these comparisons (such as ensuring equivalent samples, and quantifying exercise uniformly). They also note that exercise is more easily accessible - no appointments or prescriptions are necessary (although anyone beginning a new exercise program is advised to seek medical consult, first). Remember, though, that there are health benefits to exercise that extend beyond individual physiological systems, and that many of the benefits are somewhat intangible (improved mood, improved decision-making, social benefits). Studies like this are good reminders that we too easily forget the power of exercise, and the power we already hold to improve our own health. Perhaps Nike put it best in their advertisements from a few years ago: just do it. See you on Tuesday - Dr. Nealen
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Good morning all, I'm sure that you have heard recent news about gene editing that was performed on two human embryos by a Chinese scientist, in an attempt to introduce resistance to HIV infection. His efforts only came to light after the children were born, and have been roundly criticized as 'crossing the bridge too soon' - there seems to have been little or no oversight of his work, and most geneticists agree that it is too early for us to consider human genome editing, before we better understand the risks, and the opportunities, it poses. But, calls for a moratorium on this type of work are not universal - some believe that the time is now to proceed, and that the potential risks of waiting are greater than the potential for doing harm. Others say that this is simply scientific progress - messy, risky, but in the end, advancing our knowledge and capabilities. That this debate is prominent in the science literature is a sign that this is truly the cutting-edge of research and its application. I'm sure that we haven't heard the last on this issue, and I also am sure that in your lifetimes there will be increasing opportunity to perform exactly this kind of genome editing. Think about children you might have in the future - would you edit their genomes to improve their health? Or to make them smarter? Or kinder? What if you could only choose one of these characteristics? What if improving one caused reductions in another? There is still much to learn, and much to discuss... https://www.sciencemag.org/news/2019/03/new-call-ban-gene-edited-babies-divides-biologists?utm_campaign=news_weekly_2019-03-15&et_rid=17390186&et_cid=2717665 Hope that you all have had a great Break, and are ready for the second half of our semester! I have been taking care of our planaria, and they are almost ready for your evaluation. Travel safely back to campus - see you on Wednesday. Dr. Nealen Good morning everyone, As I scan the science news each day, I often read articles that are interesting, and potentially useful. Less frequently do I encounter news reports that make me say 'wow!". Here is a link to a news report about a recent study that did, for it potentially changes something that has been fixed for perhaps a billion years. You've heard much about DNA in your lecture and our lab, and you know the basics of its structure: two twisted strands of a sugar-phosphate backbone, with paired nucleotides along their length. You also know that the nucleotides in use are four only (A, C, G, and T) and that they pair in only two possibilities (A-T, C-G). Recently, scientists have created synthetic DNA molecules that have not four, but eight different nucleotides (by adding synthetic nucleotides Z, P, S, and B). There are LOTS of potential implications from this - from the spread of artificial DNA, to the possibility of new life forms, and the potential therapeutic uses of new forms of DNA. One of the more intriguing possibilities is the expanded possibility for use of DNA as a storage molecule. Computer scientists and bioengineers have long been testing methods for using DNA as a way to store digital information (after all, evolution has refined DNA structure/function for a long time, to the point at which it is highly efficient and reliable). Having additional base pairs is akin to adding letters to our alphabet - it makes the number of words or combinations of bases much, much greater, and it dramatically raises the density of data which could be stored by a molecule of DNA.. There are lots of details to work out, but this is a scientific breakthrough that will be a top contender for 'science advance of the year', if not the decade - and you can say that you are well-informed about it! https://www.the-scientist.com/news-opinion/dnas-coding-power-doubled-65499 Hope that your Break is a good one! Dr. Nealen Good morning everyone, In our recent chapters, we have been considering aspects of nervous system structure and function. During our discussions, we noted that the cerebral cortex of the forebrain is responsible for our "higher" functions, including emotion, reasoning, and planning. Many would argue that these are uniquely human, or at least developed to a higher degree in humans than in any other animal. Chief among these "higher" functions is that of consciousness. Consciousness has been described as a form of "meta-awareness" (literally, being aware that we are aware). While there are many aspects of neural function that we still do not understand, the neural basis for consciousness is generally agreed to be the most challenging. In fact, consciousness is often described as "the hard problem" of neuroscience, which is a way of saying that it is so poorly understood that we do not really know even how to begin study of it, let alone explanation of it. As our tools and our thinking are refined, however, more and more investigators are willing to study consciousness. In doing so, they often invoke aid from philosophers and psychologists, for not only is consciousness the ultimate emergent property, it cannot be isolated from itself - we are consciously trying to study consciousness, and that has significant implications for our approaches and our interpretations. I'm passing along here a link to a recent news article describing (perhaps) a new way of thinking about consciousness, and the study of it. It describes the work of a number of the most prominent neuroscientists working today (including Giulio Tononi, Cristof Koch, and Stanislas Dehaene). This article describes some of the modern techniques used to study consciousness, and also presents some specific models for how consciousness may occur. In doing so, it also offers some specific predictions that might be tested, which will allow us to evaluate which models may, or may not, be plausible. If you are interested in the "brain-mind" problem, as it is called, you might enjoy this article. https://www.quantamagazine.org/neuroscience-readies-for-a-showdown-over-consciousness-ideas-20190306/ Hope that your Break is a good one! Dr. Nealen Good morning all, As I scan the science news each day, I often read articles that are interesting, and potentially useful. Less frequently do I encounter news reports that make me say 'wow!". Here is one that did. You will recall from our sensory systems chapter that the photoreceptors in our eyes exist in several forms, and that each form is able to interact with light of some defined frequency range. Together, they give us our vision in the range of light frequencies known as "visual light". Many other organisms can detect light frequencies outside of our visual range, including infrared and ultraviolet. This news report describes a recent advance that marries technology and neuroscience (two of my favorite topics). Here, scientists have developed molecules that act as intermediates between the light entering the eye and the light striking the photoreceptors. These molecules harvest light of one frequency, and emit it at another (the phenomenon of fluorescence). In this case, they have been designed to harvest a light frequency normally unavailable to us (and to mice), and to then emit it at a frequency to which our photoreceptors are sensitive. The effect is to allow vision under light frequencies which are not normally useful to us. As the article notes, these experiments only have been performed in mice, to date. But, you can be sure that human applications are coming. I think that they will have to build-in some sort of kill-switch, first - a way to get rid of the molecules should they prove problematic. My guess is that they are already working on it... Wow! https://www.sciencedaily.com/releases/2019/02/190228141412.htm Have a great rest of the weekend - Dr. Nealen Hello everyone, In science education, we like to categorize - things are either "this way", or "that way". Simplifying the variety and pointing out the differences is a proven way to aid understanding, and "boiling things down" to their general features is usually also scientifically accurate - except when it isn't. In our labs this term, we have talked about meiosis and chromosomes, how chromosomes are paired to give us our genotype, how genotype determines what gametes can be passed on, and how our alleles direct our phenotype. Much of those discussions, as is typical, are of a 'this-of-that' format - we either have this genotype or that one, this phenotype or that one. But exceptions to these general rules are interesting, and often enlightening. Several weeks ago I sent you a news story about a bird that was spotted in Erie, PA that appeared to be a gynandromorph - a genetic mosaic of both male and female tissues. Gynandromorphs are rare, and form when something other than the normal pattern of gamete combinations, chromosome sorting, and cell division occurs during early embryonic formation. This week, there is news of another, even rarer genetic variant, this time in humans: a semi-identical pair of twins. You are already familiar with identical twins, which form when a fertilized zygote splits into two genetically-equal cells that develop into separate individuals. Identical twins share 100% of their DNA. You also know about fraternal twins, formed when two (separate) fertilized eggs, rather than one, develop at the same time. Fraternal twins share 50% of their DNA (on average), just like any two siblings born at different times from the same parents. In this, case we have something different. Semi-identical (sesquizygotic) twins form when a single female egg is fertilized by not one, but two, male sperm. This early embryo divides and begins to develop into not one fetus, but two fetuses. These fetuses develop at the same time and are born as twins. In this case, though, they are predicted to share 75% of their DNA, because they share 100% of their mother's DNA and only 50% (on average) of their fathers DNA, which together average 75%. In the case reported here, the twins share a slightly higher value (89%). It is likely that this unusual pattern of fertilization actually happens with some frequency, but that the early embryos do not typically survive. This chance occurrence will give geneticists a new data point in their ability to test hypotheses of genes and relatedness - no longer are all twins in their databases either 50% or 100% related, now there is a known 3rd possibility. https://www.bbc.com/news/health-47371431 Have a great weekend - Dr. Nealen Good morning all, Our lab topics remain at the forefront of science news: this week, Japanese scientists announced a new stem cell therapy for treatment of spinal cord injuries. In lab this past week, we considered both stem cells as well as genes related to the spinal column - together, these are evidence that very basic studies of individual genes can often lead to useful results! And, we will talk more about this specific kind of stem cells (induced pluripotent stem cells) in an upcoming lab... https://www.the-scientist.com/news-opinion/japan-approves-ips-cell-therapy-trial-for-spinal-cord-injury-65484 Have a great weekend - Dr. Nealen Split and continuous sleep in teens impact cognition and glucose levels differently -- ScienceDaily2/23/2019 Good morning, to all of you early birds - We all probably have trouble fitting everything into our busy schedules, and sometimes our sleep is shortchanged. Do you get enough sleep? Is one long bout of sleep better than two shorter bouts? Why do we need to sleep, anyway? These are just a few of the many interesting questions about sleep, and scientists are tackling them, one small step at a time. One recent study (link below) suggests that, if you can't get a full 9 hrs of overnight sleep, having an early nap followed by a relatively short overnight sleep may, in fact, not be so bad. https://www.sciencedaily.com/releases/2019/02/190222101312.htm Have a great weekend - Dr. Nealen Good morning all, In our last lecture, we discussed the characteristics of neurons, and how they use electricity (specifically, changes in membrane potential) to send information to their targets. Many of our BIOL 240 lab sections this week explored this concept via EEGs (electroencephalograms), which are recordings of skin potentials that occur due to changes in brain electrical activity. I also mentioned in lecture that many of our pharmaceuticals are designed to chemically influence neural function. You may also know that electrical manipulation of the bran is not far behind. Scientists have known about the electrical properties of nervous tissue for many decades, and in recent years, we have been able to apply this knowledge to stimulate the brain. Rather than using electrodes to measure the electricity coming from the brain, what if we use them to apply electricity to it? As you would expect, we can cause neurons to become activated by passing electrical current over them. There are many different forms of neural stimulation possible, from very local applications to nearly whole-brain methods. Increasingly, we are getting better at using small-scale, focal stimulation to apply electricity at select locations, in order to change the function of circuits in that area. Below is a link to a recent report of one such use of this method. Think about all of the different aspects of our behavior, emotions, and performance that are controlled neurally. What if we could adjust them, with a battery? https://www.sciencenews.org/article/brain-electric-implants-treat-depression-closer-reality Have a great weekend - Dr. Nealen Good morning all, In our labs these past two weeks, we have explored the shuffling of chromosomes that occurs during meiosis, and how the alleles of the genes on the chromosomes get sorted into gametes, which then combine to give offspring unique genotypes (sets of chromosomes and alleles) and phenotypes (physical features). Some of our examples this week included our 'sex chromosomes', the X and the Y, which combine to give us female (XX) or male (XY) characteristics. When we discussed the phenomenon of nondisjunction, we noted that sometimes things don't quite work according to plan, and that unusual chromosome numbers occur. How about when unusual chromosome combinations occur? You may have seen a news story recently abut an unusual bird (spotted in Erie, PA) that appeared to be male on one side of its body and female on the other. This is likely to be a gynandromorph, an individual that has male chromosomes (genotype) and characteristics (phenotype) on one side, and female genotype and phenotype on the other side. A few examples of gynandromorphy have been reported in animals over the years. They appear relatively normal (as male and female organs are generally the same), but their ability to mate and breed is likely very low (as male and female mating behaviors and reproductive structures are very different, of course). This individual was spotted because, in this species (the Northern cardinal), male and female phenotypes are very obviously different in color (dimorphic). In most bird species, you can't tell females and males apart, as they look the same (monomorphic). It makes me wonder: how many gynandromorphs are out there, and we just don't know about them? And, does this occur in humans? https://www.nationalgeographic.com/animals/2019/01/half-male-half-female-cardinal-pennsylvania/ Have a great weekend - Dr. Nealen |
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