A triplet of bases (3 bases) forms a codon. Each codon codes for a particular amino acid. Amino acids in turn link to form proteins. Therefore DNA and RNA regulate protein synthesis. The genetic code is the codons within DNA and RNA, composed of triplets of bases which eventually lead to protein synthesis.
A polypeptide is formed by amino acids liking together through peptide bonds. There are 20 different amino acids so a wide range of polypeptides are possible. Genes store the information required for making polypeptides. The information is stored in a coded form by the use of triplets of bases which form codons. The sequence of bases in a gene codes for the sequence of amino acids in a polypeptide. The information in the genes is decoded during transcription and translation leading to protein synthesis.
Chemokines are a family of small peptides, subdivided into classes based upon the core cysteine motifs that form disulphide bonds to fold the molecule; CC chemokines has two adjacent cysteines whilst in CXC chemokines, there is an intervening amino acid. A single chemokine, CX3CL1 has three intervening amino acids. Chemokine receptors are classified accordingly, CCR, CXCR and CX3CR families. The large majority of receptor that control chemotaxis fall into the class of G protein coupled receptors (GPCRs). Agonist occupation of GPCRs stimulates a change in conformation of the receptor, which couples the receptor to a so-called G-protein and promotes the exchange of GDP for GTP on the α-subunit. The GTP-bound α-subunit dissociates from the βγ-subunit; the free subunits then regulate effector enzymes positively or negatively, ultimately leading to a biological response, in this case, directed cell migration. As reviewed by , macrophages are remarkably adapted to respond to a wide range of different signals coupled to GPCRs, with very high levels of expression of many of the downstream signaling and feedback control mechanisms. Expression of specific chemokine receptors (e.g. CCR2 and CX3CR1) on different populations of monocytes provides a mechanism for their differential recruitment in response to different signals.
Monocytes are recruited into tissues in response to a very wide range of different stimuli. Where a pathogen is involved, they are commonly preceded by neutrophils, which release a range of toxic agents designed to kill extracellular pathogens. The macrophage then has the task of clearing both the dead pathogens and the dead neutrophils. To enter a tissue, the monocyte in peripheral blood must adhere to the vessel wall, cross the endothelial cell barrier, and then migrate towards the stimulus; a process known as chemotaxis. The process of recruitment of neutrophils and macrophages involves the resident macrophages which act as sentinels. They responds to local stimuli by producing cytokines that make the endothelial cells more sticky (through the increased expression of cell adhesion molecules such as P-selectin) and so-called chemokines, that promote the directed migration of inflammatory cells. Monocytes may also migrate towards increasing concentrations of molecules that produced by microorganisms themselves, by damaged tissues, or by the activation of the complement or clotting cascades which release bioactive peptides such as C5a. One example of a microbial chemoattractant is N-formyl-methionyl peptides; which are unique to bacteria because this is the initiating amino acid at the N terminus of all bacterial proteins.
In the Markstein laboratory we use the fruit fly Drosophila melanogaster to learn about the stem cell features of cancer cells. Fruit flies may seem like a strange model system to study cancer because fruit flies do not normally get cancer. However, in the laboratory, fruit flies have become one of the most powerful genetic systems to learn about the biology of cancer. For example, most of the major genetic pathways known to cause cancer in humans were first identified in the fruit fly. Two examples are the RAS pathway which is mutated in 30% of all human cancers and the NOTCH pathway which is mutated in most cases of childhood and adult leukemia.
Another major advance happened in the late 20th century: the ability to analyze DNA. was discovered in 1953. In 1973, . In 2003, . was accomplished in 2005, for orangutans in 2011, and for in 2012. The comparisons of human and great ape DNA have yielded many insights, but the science of DNA analysis is still young. What has yielded far more immediately relevant information has been studying human DNA. The have been identified. Hundreds of falsely convicted Americans have been released from prison, and nearly 20 from , due to Human DNA testing has provided startling insights into humanity's past. For instance, in Europe it appears that after the ice sheets receded 16,000 to 13,000 years ago, , and for all the bloody history of Europe over the millennia since then, there have not really been mass population replacements in Europe by invasion, migration, genocide, and the like. Europeans just endlessly fought each other and honed the talents that helped them conquer humanity. There were , but other than hunter-gatherers being displaced or absorbed by the more numerous agriculturalists, there do not appear to be many population replacements. In 2010, suggested that male farmers from the Fertile Crescent founded the paternal line for most European men as they mated with the local women. DNA testing has demonstrated that all of today’s humans are , of whom a few hundred and conquered Earth. The , as well as genomes of other extinct species, and for a brief, exuberant moment, some scientists thought that , -style. Although dinosaur DNA is unrecoverable, organic dinosaur remains been recovered, and even some proteins have been sequenced, which probably no scientist believed possible in the 1980s.
The significance of proteins to the continuation of our biological systems is undeniable, and a study of how to quantify proteins seems an appropriate introduction to our studies of biology.
George Henderson, your comments are very interesting!! Since 2011 I have struggled with a severe reaction to benzoates (including benzoic acid) when applied to my skin (lotion, serums, deodorant, etc). I DO take alpha lipoic acid, and am wondering if that is interfering with the glycine process to get it out of my system. Bone broth and supplemental glycine does help, but each accidental exposure is worse than before, and I have to go off of benzoate foods for a few weeks. My theory is that when applied to the skin, the glycination process in the liver is by-passed. ?? I have a bachelor’s in biology and a master’s in counseling, so my science background is less than sufficient to help me figure this out on my own. The recent episode was the result of a well-intentioned massage therapist trying a new lotion without mentioning the change to me. The resulty was general lethargy, cognitive sluggishness, and then the telltale severe (SEVERE) eye irritation. I am beyond retirement age and must continue to work full time. I work with teenage kids and would like to not be the counselor with the “ugly eyes.” The trouble I’m having is the food lists I find are not consistent, and I would like a good list that truly omits the problem foods. Can you help? Also, what do you think about the supplements we take with hopes of them being life-enhancing, but interfering with this process of eliminating the benzoates before they cause problems? Sorry for this confusing comment. I am heading to a spa to spend a few hours in a sauna so that I can feel better. By the way, at the spa there is a mugwort infusion for the women to splash on themselves, as mugwort is said to be good for females. Well, being female, I tried it. Within 20 minutes, my eyes were itching and I knew I was on my way back to hell. Hurried home and googled mugwort, only to find that it is high in benzoic acid. If you have any help for me I would deeply appreciate it. Thank you very much!
Our lab's primary interest is understanding how plants reproduce to make seeds. While this is an important problem, since plant reproduction feeds the world and maintains an ecological balance, the process involves fascinating biology. Unlike animal sperm, plant sperm cannot swim â how does it travel to find its mate, the egg, for fertilization? Our research depends on experimental approaches ranging from molecular biology, genetics, cell biology and biochemistry, not unlike research in other systems ranging from bacteria to animals, normal development or development into the diseased states. Projects for high school students will range from generating genetically transformed plants to study expression of genes that are important for reproduction, and to dissect their functions, to biochemical approaches to produce and characterize the structures and functions of these proteins. Students will have the opportunity to learn how genetically modified plants are produced, work with molecular genotyping methods by polymerase chain reactionism, and produce and large amounts of proteins to study their biochemical properties. The Cheung lab can host 2 students.
Plants and animals frequently engage microbes in mutualistic interactions, some of which have significant impacts on our society and the ecosystem. Because such interactions are complex by nature, we are using one well-studied system as an example to probe the molecular mechanisms needed to establish symbiotic relationships in general. Legumes (beans, peas, etc.) play hosts to a class of bacteria that can convert nitrogen in the atmosphere into plant food. This nitrogen-fixing symbiosis is of great importance to sustainable development, and also has medical implications for human health. Potential projects include discovering novel genes required for this symbiosis, and the effects of specific host proteins on the microbial partner. The Wang lab can host 4 students.
Expressed genes include those that aretranscribed and translated all the way to proteins, and those that aretranscribed into RNA but not translated into protein (e.g., transfer andribosomal RNAs).