AuthorObakeng Jona, PhD Candidate (Chemical Engineering), University of Cape Town We often hear the words “bacteria” or “germs” and immediately associate these with diseases, dirt or many other ill-connotated ideas. It is rare that we come across their usage in good context. In fact, it is scientifically incorrect to regard all microorganisms as “bad” or detrimental to human health. There are “good” and “bad” microorganisms. Yes, some microorganisms are beneficial to your health! And these distinct microorganisms are found in abundance all around us – literally. Not only are they in our surroundings, but they are also found in everyday food such as cheese, yogurt and milk to name a few. It turns out, you also have gazillions of microorganisms in and on you (even after taking that shower!). The collective makeup of the microorganisms in and on the human body is special and referred to as the human microbiota. This microbiota is so special that it is often regarded as an organ in its own right, as it plays an important role in the human body. It is estimated that the number of microorganisms comprising the microbiota outnumbers human somatic cells by a factor of ten; that is, for every human body cell there are about ten microorganisms which belong to the community of cells making up the human microbiota. These microorganisms secrete biologically active chemicals that interact with the human body, and thus contribute to its health and immunity. In fact, some of these microorganisms are antagonistic towards pathogens (disease-causing microorganisms) and are regarded as probiotic microorganisms (beneficial or offering health benefits to the host). A fetus is said to be essentially sterile and devoid of any other cells apart from those which make up our organs. It is only after birth that our skin, oral cavity and gut are colonized by an astounding number of bacteria, viruses, archaea and fungi, which all constitute what is referred to as the microbiome. The microbiome is a collection of microorganisms of the microbiota, including their genomes. Note that the microbiome is different from the microbiota, which is solely the collection or make up of the microorganisms in a particular site or region of the body. The microbiome is known to be paramount in contributing to the digestion of food and general human health. A dysfunction or shift in the human microbiome is often linked to disease, examples include common ailments such as diabetes, bacterial vaginosis, diarrhoea and antibiotic-resistant infections. This microbiome-health relationship has given rise to an area of research where the human microbiome is increasingly being used as a biological indicator and detection technique for diseases. Alongside the use of the human microbiome as a health indicator, biotherapeutics (drug therapy products where the active substance is extracted or produced from a biological source) in the form of probiotics, are an emerging means of treating ailments which are characterized by a change in the microbiome. The probiotics intend to mediate and restore the human microbiome in cases where there may be a shift in the makeup of this microbial community. When probiotic microorganisms are administered in adequate amounts, they can confer health benefits to the human body. The use of probiotics to treat ailments form a new and exciting research field, one where traditional pharmaceutical approaches to combat disease are integrated with biotherapeutic routes, which assists the body to restore itself. These probiotics are not available only as capsules, which one can purchase for a particular function, but they also exist in food items such as cheese, yogurt and milk as stated earlier. The microorganisms do not only help in the fermentation processes of these food items, they also aid in boosting the human microbiota when the foods are consumed. So perhaps it is indeed a good idea to have germs in our yogurt and cheese! ___________________________________________________________ Johnson, D.E. 2018. Biotherapeutics: Challenges and opportunities for predictive toxicology of monoclonal antibodies. International Journal of Molecular Sciences. 19(11):1–14. DOI: 10.3390/ijms19113685. Morgan, X.C. & Huttenhower, C. 2012. Chapter 12: Human Microbiome Analysis. PLoS Computational Biology. 8(12). DOI: 10.1371/journal.pcbi.1002808. Reid, G., Gadir, A.A. & Dhir, R. 2019. Probiotics: Reiterating What They Are and What They Are Not. Frontiers in Microbiology. 10. DOI: 10.3389/fmicb.2019.00424. Turnbaugh, P.J., Ley, R.E., Hamady, M., Fraser-Liggett, C.M., Knight, R. & Gordon, J.I. 2007. The Human Microbiome Project. Nature. 449(7164):804–810. DOI: 10.1038/nature06244. Images obtained from the ISAPP consumer website : https://isappscience.org/for-consumers/infographics/
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AuthorNtokozo Zwane, Software Engineer, Rapid7 How did this blog end up on your computer? Your answer is likely something along the lines of, “I clicked the link and my browser fetched the page from the internet and loaded it up for me”. Hopefully, by the end of this short post, we will demystify the entire process, by digging into what the internet is, where to find it and how to break it. You have probably heard the internet being referred to as ‘the cloud’, but this analogy doesn’t accurately capture what it looks like in reality. A more realistic image of what the internet is would be to think of it as a really long wire - an actual physical wire. Multiple devices are then able to communicate to each other by simply connecting (directly or indirectly) to this wire. Computers that are connected directly to the wire are called servers. This is typically where files for websites are stored. In the case of this blog, it is currently stored on a server just outside Wichita, in the United States. Unlike servers, your computer or phone connects to the wire indirectly through an internet service provider (ISP). Each country would have a number of national ISPs (e.g Telkom, Afrihost, rain or eir broadband). The national ISPs are able to connect directly to servers within their home country. In order to reach a server in a different country, your country’s national ISPs need to connect to the ISPs in the country where that server is found. ISPs act like mediators, since they have the necessary infrastructure to communicate with other servers and ISPs that are connected to the wire. This means you do not have to manually connect to each server or ISP yourself. Now back to the server near Wichita that this blog is sitting on. How does it land up on the screen in front of you? Since there are billions of computers, servers and ISPs (we’ll just call these devices) connected to the wire, there needs to be a process to ensure that information travels between the correct devices. The first step is to give each and every device a unique identifier - much like your government ID number. This is the device’s IP address, and at each intersection point of the wire, exists a special type of device that figures out where to send information based on this identifier, this is called a router. IP addresses are hard to remember, and it would be really inconvenient if you had to type in 199.34.228.53 every time you wanted to visit this blog. Instead of using the IP address, we give them friendly names that are easier to consume by humans, such as takealot.co.za and twitter.com. For this blog, the IP address 199.34.228.53 is given the name, reazwane.weebly.com. Bringing this all together, when you came over here through the following link/url reazwane.weebly.com/science-for-a-lay, the first step was your browser looking up the IP address that the url belongs to. Once that was established, it sent a message to the server to ask it for this blog page. This message was then carried along the different components of the wire, and the routers directed it to the correct destination. Once the server near Wichita received your message, it interpreted it and replied with the information you asked for. The blog post was then sent (in tiny chunks) back to your browser. The crux of this all working is that all these different components need to use the same language (protocol) to communicate with each other. A group of computers that communicates together using a common protocol is a called network. The term internet is formed by inter-, meaning between, and net, short for network. It is a global network of computers that speak a common language, connected by the wire - a long physical wire, 1.2 million km of which sits at the bottom of the ocean to enable intercontinental communication.
So next time you really want to break the internet, grab a wetsuit and some wire cutters ;). AuthorReabetswe Zwane, PhD student (Computational Chemistry), Dublin City University, Solid State Pharmaceutical Centre What are the characteristics of your favourite chocolate? Is it its lustre, the snap when you break it, the balance between sweetness and bitterness or its ability to melt in your mouth? To understand what gives a particular chocolate its characteristics, and what separates a luxury chocolate from a regular one, you would need to know a little bit more about the the raw materials, the manufacturing steps and the chemistry of chocolate. Further processing of the cacao beans via roasting gives you cocoa, which is sweeter and has less nutrients. Chocolate is made up of different cocoa bean derivatives that include cocoa liquor, cocoa solids and cocoa butter. Cocoa liquor is a paste made from ground cocoa beans, from which the cocoa butter (fat) and the cocoa solids are extracted via heavy pressing. The proportionate mixture of these derivatives, and other ingredients such as sugar, milk and flavors, gives a particular chocolate its uniqueness. Conching and tempering One of the most important steps in chocolate making is the slow mixing, or conching, of the different ingredients to create an evenly smooth chocolate mixture and develop flavour, and the subsequent tempering step, where the chocolate mixture undergoes controlled heating and cooling. The conching of chocolate can take up to 36 hours and the longer the mixing process is, the smoother the chocolate. The repeated heating of the chocolate paste and the subsequent cooling leads to a glossy and shiny chocolate with an audible snap. More importantly, when the chocolate is allowed to cool, it leads to the formation of a particular stable chocolate crystal. During the cooling process, chocolate can crystallize into one of six different crystal forms, depending on the temperature to which the chocolate mixture was heated to. The different crystal forms are known as polymorphs (i.e. many forms) and they arise from the differences in the packing arrangement of the fat molecules in the structure of chocolate. The phenomenon is known as polymorphism in chemistry. The different chocolate polymorphs have different properties, such as softness, lustre and how easily it melts. Of the known chocolate polymorphs, “polymorph V” has the most desirable properties – it is shiny, smooth yet firm and it melts in the mouth – and is the crystalline form that most chocolate-makers aim for. Polymorph V is able to melt in the mouth because of its melting temperature, 34 °C, which is just below the body temperature. Storage and packaging of chocolate
Keeping chocolate in the cupboard for several months allows polymorph V to turn into another form, polymorph VI. You can tell the formation of polymorph VI by its hardness, its slowness to melt in the mouth and a whitish coating on the surface of the chocolate. Polymorph VI can also be formed from polymorph V if chocolate is left in the sun or a car trunk, provided it is allowed to melt above its melting temperature and then cooled again. That is why melted chocolate does not have the same texture and shine once it is cool again. To combat this transformation, you need to store chocolate in the fridge. The packaging of the chocolate is also important for protecting it from moisture, heat and light. Beyond the science, chocolate making is also an art. The characteristics of your favourite chocolate boil down to a conglomeration of texture and appearance, mostly influenced by the science, but also the distinctiveness of its taste, driven by the art. Implications of polymorphism on drugs The same chemistry of polymorphism applies to tablets in your medicine cabinet. The reason that your pill container says ‘store in a cool, dry place’ is to keep the drug from transforming from one polymorph to another, among other reasons. Proper packaging of the drug is just as important for chocolate as it is for your drugs. That is why it is important to keep your tablets in their original container and throw out expired tablets. In my line of research, polymorphism poses a challenge in the development stages of drugs. Since different polymorphs of the same drug can have different properties, it is imperative to monitor the drug at different stages of development for any changes in its structure. It is especially important because polymorphic transformation can be induced by pressure during the handling of drugs. The results can be disastrous if a polymorph with unwanted and undesirable properties emerges during and after development stages. Such was the case for the HIV drug, Ritonavir. Ritonavir, like chocolate and many drugs, can also exist as different polymorphs. When it was marketed in 1996, polymorph I was the only form known to exist, but it was soon discovered that polymorph I changed to the more stable polymorph II, which the body had difficulty absorbing. The drug had to be temporarily withdrawn from the market as a result. Despite all of this, the discovery of new polymorphs can also be an opportunity to identify interesting properties in drugs and specialty materials for the combat of disease and for solving many of the problems we face in today's society. |
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