Mitochondria, often thought of as powerhouses of the cell, are fascinating eukaryotic organelles with a double-layered membrane and their own genome. Mitochondrial DNA (Mt DNA) is typically about 16570 bases, circular, highly compact, haploid and contains 37 genes, all of which are essential for normal mitochondrial function. Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation, a process that uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell’s main energy currency. The remaining genes code for transfer RNA (tRNA) and ribosomal RNA (rRNA) which are necessary for translating messenger RNA transcribed from nuclear DNA, into protein molecules.
Identification of a crime perpetrator on the basis of DNA fingerprinting is not as easy as some of the CSI shows on television make it out to be. A sample such as blood stain, touch sample or body fluid retrieved at a crime scene is often a challenge for DNA analysts. In many instances, the samples are limited in quantity, found in dirty conditions, exposed to harsh environmental factors and are mixtures of more than one DNA—human and/or non-human. One of the most important aspects of the workflow to successfully obtain a DNA fingerprint profile is accurate quantification of human amplifiable DNA. The more information gleaned from the sample, the better equipped the DNA analyst is to determine the best course of action for obtaining a usable short tandem repeat (STR) profile from challenging samples. Therefore, Promega has developed the PowerQuant™ System, a probe-based 4-target, 5-dye real-time PCR method to a) determine human and male DNA concentrations in a sample, b) detect possible PCR inhibitors c) identify possible mixtures and d) measure DNA integrity. Continue reading “PowerQuant System: Tool for informed casework sample processing decisions”
A person needs to browse through any health related journal, magazine or website to find new and novel ways to reduce weight. While the options range from bariatric surgery to good old “eat-less-exercise-more” concepts, it is intriguing how the more weight a person gains, the harder it is to shed the extra calories. Losing weight is an uphill battle for majority of us. And that got me thinking about how much our biology cooperates while we try to lose weight. I came across these two elegant studies that explain why this is indeed an uphill battle. Continue reading “Biology of Overeating and the Weight-Gain Cycle”
When my son was about 2 years old, he commented that the jingles “Twinkle twinkle little star” and “alphabet song” had the same musical notation. While I do not think I am tone deaf and I do appreciate music, I had not made the connection in all these years. Music appreciation is perhaps one of the most subjective and controversial topics. For some people, appreciating music involves understanding the technical nuances and critically evaluating artist’s mastery over the art, and for some of us, it is about simply enjoying the patterns and rhythms. While one might claim that they enjoy all kinds of music, for most of us, only certain kinds of music elicit a deeper appreciation, emotive experience and pleasure. Our music preferences are molded by exposure, cultural diversities and to some extent, mood. Music is extremely varied, and listing the kinds of music could fill pages. Arguing one kind of music is better than other is as like saying one color is better than the other.
It is hard to undermine the role of cleanliness in disease prevention, both internally and externally. Within our body, the lymphatic system plays an important role in clearing the intercellular passages of large and potentially harmful toxic molecules and recirculate back into the blood stream. This enables the transport of these molecules to liver for inactivation and subsequent removal from the body. Therefore, lymphatic system prevents build-up of soluble proteins in the interstitial space. Typically, more metabolically active a cell is, more intricate is the lymphatic vasculature around it. This observation was in contrast to our scientific knowledge a few years ago, when we believed that due to the presence of the blood-brain barrier, there was no lymphatic system active in the brain. The brain, as we know, is highly active metabolically and the removal of harmful solutes and proteins from the neuronal vicinity is of utmost urgency. For a long time it was believed that cerebrospinal fluid (CSF), while coursing through the brain also removed cellular metabolite by products, apart from carrying nutrients to brain tissue, through a process known as diffusion. This is a rather slow process and it did not very well explain how large molecules such as proteins were removed from the interstitial place.
Recently, using two-photon imaging technique in live mice, scientists at Rochester discovered (1) that there is another vasculature functioning in the brain which circulates CSF to every corner of the brain much more efficiently, through bulk flow or convection. Continue reading “A Clean Brain Is a Healthy Brain”
Marijuana is a highly controversial substance with roughly an equal number of supporters and opponents of its use for medicinal purposes. Marijuana is a dry, shredded mix of flowers, stems, seeds and leaves of the Hemp plant Cannabis sativa. New studies reporting the efficacy of medicinal marijuana in clinical conditions surface on a fairly regular basis, with the latest being a reported treatment for seizures. This constant influx of new information shows how little we know about the substance and how it works in the human body. So what do we know about this substance? While many psychoactive drugs clearly fall into the category of either stimulant, depressant or hallucinogen, Cannabis exhibits a mix of all properties, perhaps leaning the most towards hallucinogenic or psychedelic, though with other effects quite pronounced as well. Continue reading “Elevating “bliss” the natural way”
While the forensic and general communities continue to argue about the merits of the recent Supreme Court ruling on collection of samples from arrestees prior to conviction, I am fascinated by the technology that make this question relevant. The conventional way of generating a DNA profile from a sample by STR (short tandem repeat) analysis is a long process involving a series of steps that require sophisticated expensive equipment, trained personnel and, more importantly, time. The actual process of DNA analysis consists of a) sample collection, b) DNA extraction, c) PCR amplification using 16 or more unique fluorescently labeled primer sets d) capillary electrophoresis to size labeled DNA amplicons, e) software analysis to size DNA fragments and allele calls based on migration of allelic ladder fragments, and f) comparison to known profiles in the database. This entire workflow can typically take days or even weeks, and therefore it is not surprising that we see newspaper reports of backlogs of criminal and other property cases. With these time ranges, the sample collected at a site would be of no practical use to most ongoing investigations. Continue reading “Rapid DNA Technology: Establishing your Identity in Less than Two Hours”
Researchers working with immortalized cell lines would readily agree when I state that it is almost impossible to look at cells under the microscope and identify them by name. There are phenotypic traits, however they do change with change in media composition, passage number and in response to growth factors. I remember the pretty arborizations my neuroblastoma cell line SH-SY5Y exhibited in response to nerve growth factor treatment. Thus physical appearance is not a distinguishing feature. Currently, in many labs, researchers typically use more than one cell line, and more than likely, share the same lab space to passage cells and the same incubator to grow the cells. In such scenarios, it is not difficult to imagine that cell lines might get mislabeled or cross-contaminated. For example HeLa cells, one of the fastest growing cell lines have been shown to invade and overtake other cell lines.
Misidentification of cell lines has deep and severe implications. A review of cell lines used to study esophageal adenocarcinoma found that a large number of the cell lines were actually derived from lung or gastric cancers. Unfortunately, by the time this error was discovered, data from these cell line studies were already being used for clinical trials and other advanced studies and publications. Moreover, the cell lines were being to screen and design and test specific cancer drugs which ended up in flawed clinical trials. Continue reading ““Fingerprinting” Your Cell Lines”
It is not difficult to appreciate why a keen sense of smell is important to well-being and to general living. While it signals the presence of delicious (or stale) food before we can even see or taste it, it has obvious great survival value to be able to alert living beings of danger such as certain poisons, leaking gas or fire. Humans are known to identify about 10,000 different types of odors. Of course dogs have vastly improved and keener sense of smell than human beings.
When odorant molecules (molecules that we can smell) reach the nostril, they dissolve in the mucus and bind to olfactory receptors present on the cilia of each sensory neuron. This binding activates a G-protein coupled cascade involving adenylyl cyclase. This causes the release of cyclic AMP and opening of cAMP-dependent sodium channels. Influx of sodium causes the membrane to depolarize and activate an action potential for propagation of the signal to the brain where it is analyzed and decoded(1). This seems pretty straightforward until one realizes the sheer magnitude of smells we are able to identify using this mechanism. Continue reading “Chromatography and “Air Traffic Control” Interplay Direct Olfactory Function”
When I first came across an article about methylene blue being protective against neuronal death, I was intrigued. I had always associated methylene blue (sometimes confused with methyl blue—an entirely different molecule) with staining nucleic acids or proteins following membrane transfer or with staining bacteria or its use as a redox indicator. It turns out that methylene blue (MB) has an extremely wide range of applications: commercial (dye in the textile / paper industry), laboratory (supravital dye, redox indicator) and an amazingly large plethora of clinical and therapeutic (early Alzheimer’s disease, mild cognitive impairment) applications(1). In fact, MB is an FDA-grandfathered antidote for the treatment of methemoglobinemia, a condition characterized by elevated levels of oxidized form of hemoglobin that interferes with its ability to release oxygen to the tissues.
By clicking “Accept All”, you consent to the use of ALL the cookies. However you may visit Cookie Settings to provide a controlled consent.
If you are located in the EEA, the United Kingdom, or Switzerland, you can change your settings at any time by clicking Manage Cookie Consent in the footer of our website.
Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously.
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Advertisement".
This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
6 months 2 days
This cookie is set by the provider Media.net. This cookie is used to check the status whether the user has accepted the cookie consent box. It also helps in not showing the cookie consent box upon re-entry to the website.
This cookie is used to store the language preferences of a user to serve up content in that stored language the next time user visit the website.
Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc.
This cookie is associated with Sitecore content and personalization. This cookie is used to identify the repeat visit from a single user. Sitecore will send a persistent session cookie to the web client.
This domain of this cookie is owned by Vimeo. This cookie is used by vimeo to collect tracking information. It sets a unique ID to embed videos to the website.
1 month 18 hours 24 minutes
This cookie is used to calculate unique devices accessing the website.
This cookie is installed by Google Analytics. The cookie is used to calculate visitor, session, campaign data and keep track of site usage for the site's analytics report. The cookies store information anonymously and assign a randomly generated number to identify unique visitors.
This cookie is installed by Google Analytics. The cookie is used to store information of how visitors use a website and helps in creating an analytics report of how the website is doing. The data collected including the number visitors, the source where they have come from, and the pages visted in an anonymous form.
Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. These cookies track visitors across websites and collect information to provide customized ads.
1 year 24 days
Used by Google DoubleClick and stores information about how the user uses the website and any other advertisement before visiting the website. This is used to present users with ads that are relevant to them according to the user profile.
This cookie is set by doubleclick.net. The purpose of the cookie is to determine if the user's browser supports cookies.
5 months 27 days
This cookie is set by Youtube. Used to track the information of the embedded YouTube videos on a website.
Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors.
This cookies is set by Youtube and is used to track the views of embedded videos.
This is a pattern type cookie set by Google Analytics, where the pattern element on the name contains the unique identity number of the account or website it relates to. It appears to be a variation of the _gat cookie which is used to limit the amount of data recorded by Google on high traffic volume websites.