09 OCTUBRE, 2010El mapa de las rutas metabólicas… Animado!
Gastó cientos de ATP escribiendo: David Castro
¿Qué es una ruta o vía metabólica? De manera sencilla, es el flujo de reacciones que sigue un determinado compuesto al ingresar a la célula, de esta manera, se transforma en una molécula más compleja (biosíntesis o anabolismo) o en una más sencilla (degradación o catabolismo).
el Dr, Donald Nicholson, el mismo que creó este mapa de las rutas metabólicas que les acabo de poner, ha desarrollado unos mapas animados. A sus 80 años y con la ayuda de una computadora ha desarrollado los “Animaps”.
Hepaptitis B virus (HBV) likes liver cells (hepatocytes). In fact, it likes them so much it won’t grow anywhere else. The reason for this close connection is because the receptor this virus needs to infect cells is only found on hepatocytes. In a new study, scientists have finally identifed what that receptor is: sodium taurocholate cotransporting polypeptide (NTCP).
HIV (human immunodeficiency virus) infection has now become endemic worldwide and AIDS ranks fourth among the world's top killers of mankind. A rapid and accurate HIV testing assay is a pre-requisite for practical applicability of diagnostic tests. The aim of this present study was to design peptide cocktail as an antigen and to develop ELISA test for HIV-1/2 antibody detection, with enhanced sensitivity and specificity. A novel peptide stretch V3-I, covering immunodominant epitope corresponding to V3 hypervariable loop of gp120 antigens of selected Indian isolates, has been studied and incorporated in an antigenic cocktail of gp36, gp41, and rp24 of HIV-1/2.
Inhibiting the growth of tumor vasculature represents one of the relevant strategies against tumor progression. Between all the different pro-angiogenic molecular targets, plasma membrane glycosphingolipids have been under-investigated.
Antibodies (immunoglobulins) are glycoproteins naturally produced in response to invading foreign particles (antigens) such as micro-organisms and viruses. They play a critical role in the immune system’s defense against infection and disease.
Another helpful bit of Mycoplasma information – everyone doing cell culture should know this stuff!
Let’s say you have a sample where you need a high degree of confidence that it is Mycoplasma free. For example, you may have treated a culture for Mycoplasma and you want to see if there are viable organisms still left before you proceed to an important assay. What do you do?
Enrichment is a useful resource to keep in mind when you are dealing with an important sample. In this context, enrichment (also known as co-cultivation) refers to taking medium from your culture and inoculating it onto a cell line that is known to support the rapid growth of a broad number of Mycoplasma species. You then test the enriched cell line to see if Mycoplasma can be detected using your preferred test method. This approach increases the sensitivity of many of the test methods out there, allowing you to get more informative results.
If you are tempted to give enrichment a try, then the link above is well worth visiting. This paper from scientists at the Food and Drug Administration looks in detail at enrichment – what cell lines are best to use, what species can be detected as a result.
Just something to keep in mind – you never know when it might be useful....
Medscape Autoantibodies Found in 10% of Adult-Onset Diabetes Patients Medscape These included GADA in 8.8%, insulinoma-associated antigen-2 autoantibodies in 2.3%, and zinc-transporter 8 autoantibodies in 1.8%.
Almost 30 years ago, Harold J. Morowitz, who was then at Yale, set forth a bold plan for molecular biology. He outlined a campaign to study one of the smallest single-celled organisms, a bacterium of the genus Mycoplasma. The first step would be to decipher its complete genetic sequence, which in turn would reveal the amino acid sequences of all the proteins in the cell. In the 1980s reading an entire genome was not the routine task it is today, but Morowitz argued that the analysis should be possible if the genome was small enough. He calculated the information content of mycoplasma DNA to be about 160,000 bits, then added: Alternatively, this much DNA will code for about 600 proteins—which suggests that the logic of life can be written in 600 steps. Completely understanding the operations of a prokaryotic cell is a visualizable concept, one that is within the range of the possible.
There was one more intriguing element to Morowitz’s plan: At 600 steps, a computer model is feasible, and every experiment that can be carried out in the laboratory can also be carried out on the computer. The extent to which these match measures the completeness of the paradigm of molecular biology.
Looking back on these proposals from the modern era of industrial-scale genomics and proteomics, there’s no doubt that Morowitz was right about the feasibility of collecting sequence data. On the other hand, the challenges of writing down “the logic of life” in 600 steps and “completely understanding” a living cell still look fairly daunting. And what about the computer program that would simulate a living cell well enough to match experiments carried out on real organisms?
As it happens, a computer program with exactly that goal was published last summer by Markus W. Covert of Stanford University and eight coworkers. The program, called the WholeCell simulation, describes the full life cycle of Mycoplasma genitalium, a bacterium from the genus that Morowitz had suggested. Included in the model are all the major processes of life: transcription of DNA into RNA, translation of RNA into protein, metabolism of nutrients to produce energy and structural constituents, replication of the genome, and ultimately reproduction by cell fission. The outputs of the simulation do seem to match experimental results. So the question has to be faced: Are we on the threshold of “completing” molecular biology?
This thought-provoking blog from Scientific American talks about cell line authentication and the need to characterize cells - not just from fear of contamination, but also to understand better the material you are working with.
The viewpoints expressed in this blog are not always supported by the science in this field - for example, you could easily get the impression that authentication becomes steadily more unreliable as a cell line is handled. For the method used to authenticate human cell lines, STR profiling, publications show that this is not the case for the vast majority of cell lines studied. The same can be said for the method often used to authenticate non-human cell lines, DNA barcoding, which will remain consistent across an entire species.
I also do not agree with the final comment that it's OK for scientists to be responsible for authentication. To me, this is exactly why the problem has not been addressed. It's all too easy for a busy lab to put off authentication testing, or simply not know that it's a necessary part of good cell culture practice.
But the bottom line - curiosity not fear - makes sense to me. The more you know, the better, when it comes to any kind of science. Authenticating a cell line is just part of the work you should do to understand the cells you are working with, and what they can teach you about the natural world.
En "Los productos naturales ¡Vaya Timo!" JM Mulet nos habla del desarrollo del probiótico destinado a los celiacos, el porqué de su desarrollo, cómo fue desarrollado y cómo va a ser comercializado. Un estupendo trabajo de lectura obligada para los alumnos de Microbiología Industrial
How do you work out what Mycoplasma test method is best for your samples? This article (see above link) answers that question for pharma labs. If you are in a research lab, my answer is: assess the quality of the method and use that in your decision. Price and quality may be poles apart.
Just because everyone should know this information, here are the three questions I use to assess quality for Mycoplasma test methods.
Question One – how sensitive? Every kit or test lab should be able to give you an objective measure of their method’s sensitivity. Sensitivity is usually measured in cfu/mL (colony forming units per mL), or ng/mL with a PCR kit. The lower the number detected, the more sensitive that method should be. Compare the different test kits on the market and you will immediately see there are some large differences.
Question Two – how many species? There are many different Mycoplasma species, one reason why testing can be difficult. Your test method should at least be able to detect the six species that commonly appear in cell cultures. But the more the better.
Question Three – can you detect your own control? If you test for Mycoplasma routinely, it won’t be long before you find a positive sample. Aliquot the medium from that sample into a set of tubes and freeze it (in its own box) at -80C to give yourself a set of positive controls. Alternatively, if you are looking at a PCR-based method, purchase DNA from one or more of the common species. Of course most kits on the market include a control, but that’s only one species. Your own sample will give an even better idea of how good the method truly is.
FEI Unveils Broad Correlative Microscopy Solution Set for Cell BiologistsNASDAQHILLSBORO, Ore., Nov. 26, 2012 (GLOBE NEWSWIRE) -- FEI (Nasdaq:FEIC) today announced a suite of solutions for correlative light and electron microscopy (CLEM).