New Step In Genetic Modification Of Plants

Researchers discover role of cytokinin in agrobacterium-mediated plant modification.

Among various methods to modify the genetic make-up of plants agrobacterium tumifaciens is considered the best. It is a soil borne bacterium directed at gene addition. Plant transformation is insertion of new genetic material to the plant’s body. This used to be difficult because many economically important plants are recalcitrant to it as they lack certain gene elements. But according to a recent report published in Science, researchers now have successfully transformed a model plant, Arabidopsis, through agrobacterium-mediated transformation process.

Scientists at Purdue University in a one-of-its-kind study identified certain genes called MTF1. When inactivated, these increase the attachment of different strains of this same bacteria to the plant roots. Cytokinins from Agrobacterium tumefaciens decrease the expression of MTF1 through activation of the cytokinin response regulator ARR3, but the altered MTF1 produces cell molecules which perform cell attachment or adhesion. This means the bacterium now has improved property of attaching to plant cell walls and injecting their DNA.

Thus, by promoting bacterial attachment and transformation of resistant plants and increasing such processes in susceptible plants, treating roots with cytokinins may help engineer crops with improved features or yield.

References:

Photo: Flickr,  Max Mayorov

Sardesai N, Lee LY, Chen H, Yi H, Olbricht GR, Stirnberg A, Jeffries J, Xiong K, Doerge RW, & Gelvin SB (2013). Cytokinins Secreted by Agrobacterium Promote Transformation by Repressing a Plant Myb Transcription Factor. Science signaling, 6 (302) PMID: 24255177

gene, modification, transformation, plant, cytokinin, agrobacterium, MTF1, DNA, resistance, crops

Discovered Link Between Itch And Pain

Finally: a new relieve for that itchy feeling.

When you have an itch on the skin, what is the first thing you do? Obviously, our first immediate and natural response would be to scratch the spot of the itch with our fingernails. But, do you have any idea what is happening under your skin when you have an itch?

Itchy feelings are caused by a hundred different things. Pruritus or chronic itching is an unpleasant sensation on the skin that generally provokes in us the desire to rub or scratch the area in order to obtain relief. But that is not the only option. New research published in The Journal of Clinical Investigation explains how chronic itching is different from other types.

The main characteristic distinguishing chronic itching from normal itch is that the former incorporates not just the itch neurons but also neurons that are responsible for causing pain. Normal itch, on the other hand, involves a fixed pathway that transmits only the itch signals.

Chronic itch thus causes pain as well as discomfort. The study mentioned above, conducted on mice, revealed that BRAF protein may play a role in turning itch genes on and off. BRAF gene and its protein were already known to be involved in pain response. The new findings suggest that targeting the BRAF pathways could help in treating chronic itch too. Although chronic itch and pain are different, it seems that one pathway does lead to the other.

Scientists at Washington University School of Medicine in St. Louis speculate that the remarkable discovery may help develop efficient treatment strategies to target groups of neurons that play a role in inducing both itch as well as pain. Furthermore, there are many pathways leading from BRAF that could be potential hotspots for developing anti-itch therapies and drug discovery.

Reference

Photo: Flickr

Source: Zhau ZQ, Huo FQ, Jeffry J, Hampton L, Demehri S, Kim S, Liu XY, Barry DM, Wan L, Liu ZC, Li H, Turkoz A, Ma K, Cornelius LA, Kopan R, Battey JF, Zhong J, Chen ZF (2013). Chronic itch development in sensory neurons requires BRAF signaling pathways The Journal of Clinical Investigation DOI: 10.1172/JCI70528

Candida Albicans- A Friend Or Foe?

Candida’s ability to cause infection has been identified.

Almost everyone has this fungus in their gut-Candida albicans! Though it lives in almost 80% of the human population, its quantities are kept under control by friendly gut bacterias. Affected are generally those people who have a relatively weak immune system, like HIV-infected patients, cancer chemotherapy recipients, or that are suffering from other severe illnesses. A study published in TheJournal of Biological Chemistry reported that it is now to target the fungal component, which is responsible for causing the dreaded disease.

The major roadblock has always been finding drug targets to control the fungal infection, because fungi are quite closely related to us. This means that if we consume an anti-fungal drug in order to kill the fungus, it might also adversely affect us. Keeping this in mind, research groups at John Hopkins University and Harvard Medical School have identified vacuoles as cellular organelles that play an important role in this process.

Vacuoles are meant to destroy cellular waste due to their acidic nature. The researchers discovered that acidification of vacuoles was important for fungal virulence. The research team focused on V-ATPase, an enzyme responsible for making many compartments of the cell, including the vacuoles, acidic.

Instead of taking whole enzymes into consideration, they homed in on just one of the enzymes components, known as subunit, which comes in many versions due to gene duplication. After inactivating many versions of subunit, they confirmed one subunit involved in imparting acidity as well as virulence to the vacuoles. Now unable to acidify the vacuole, the fungus could no longer form the tentacle-like filaments that characterize its deadly form.

This new discovery has opened many paths in the area of drug discovery. The study reveals a vulnerability that could be exploited using drugs known to alter the pH of the vacuole, rendering Candida harmless, posing little risk to infected patients.

Photo: Flickr, zabozrut
Source :

Patenaude C, Zhang Y, Cormack B, Köhler J, & Rao R (2013). Essential Role for Vacuolar Acidification in Candida albicans Virulence. The Journal of biological chemistry, 288 (36), 26256-64 PMID: 23884420

Human Gut Micro Flora Gives an Index of Obesity

Research shows that less intestinal bacteria is associated with susceptibility to obesity.

With easy access to energy-rich junk food and modern living with a sedentary lifestyle, more and more people are becoming slaves to excessive fat consumption. Yet being a couch potato is dangerous for our health. Studies on the human genome variation show there are significant differences in the genome of bacteria that live in our intestine. The latest research published in Nature reveals that the bacterial population in the intestine varies significantly from obese to thin bodies. This indicates that people with fewer bacterial species in their intestine are more likely to develop complications, such as cardiovascular diseases and diabetes.

An international consortium, including the VIB scientists Falk Hildebrand, Gwen Falony and Jeroen Raes in Brussels, examined the intestinal flora of 292 volunteers from the Ethical Committees of the Capital Region of Denmark before participation in the study. All individuals were examined after an overnight fast with blood sampling and physical body parameter measurements like height, weight, skin fold thickness and bodily circumference at the waist, hip, and chest. Faeces samples were collected from all volunteers and frozen immediately; DNA was extracted from it and sequenced to know the arrangement of genes on DNA. Then gene frequency matching was done to match the intestinal genes to those in the gut bacterial catalogue.

The results were interesting. Two groups were distinguished on the basis of their intestinal flora: People having rich intestinal gut micro flora and people with less bacterial species. Clearly the two groups behaved differently in function. The latter was more susceptible to developing obesity-related conditions and chronic inflammation.  Therefore, it can be inferred that it is not only weight gain and dietary habits that play an important role in the development of medical complications in obese people, but different bacterial species that make up the gut microflora as well.

Reference : Emmanuelle Le Chatelier, Trine Nielsen, Junjie Qin, Edi Prifti, Falk Hildebrand, Gwen Falony, Mathieu Almeida, Manimozhiyan Arumugam, Jean-Michel Batto, Sean Kennedy, Pierre Leonard, Junhua Li, Kristoffer Burgdorf, Niels Grarup, Torben Jørgensen, Ivan Br (2013). Richness of human gut microbiome correlates with metabolic markersNature DOI: 10.1038/nature12506

Researchers Discover New Strategy to Prevent Influenza Infection

Research shows microRNA based strategy to fight against viral pathogens.

H5N1, also called “Influenza A virus,” has the potential to cause catastrophic pandemics. This virus circulates in birds as a pathogen of the digestive and respiratory tracts but, on occasion, gains the capacity to jump to other species and establish respiratory infections in mammals. According to a new study published in Nature Biotechnology, scientists have developed a strategy by which healthy molecules in human lung cells catch these bugs and kill them before they get a chance to infect the human host.

Researchers at Icahn School of Medicine at Mount Sinai have used a microRNA based mechanism to help the body fight against these invading viral pathogens. MicroRNAs are small non-coding RNA molecules that help regulate gene expression. This process involves recognizing a foreign viral particle, creation of small inhibitory RNA (siRNA) molecules and cleavage of virus by siRNAs.  Generally, humans have these small inhibitory siRNA but only to maintain cell health and not for killing such virus. Dr. tenOever and Garcia-Sastre along with scientists from University of Maryland have discovered that altering the viral genome leads to viral genome disruption in the same way as plants do. So, they discovered a unique miR-192 that is found only in human and mouse lung cells but not in ferrets. By addition of multiple binding site of miR-192 onto the H1N5 genome, lung cells completely destroyed the virus in the mice model. Researchers showed that this approach also works well with other influenza A viruses.

This finding is unique in a way that it can be applied to any virus provided humans have a miRNA for the same. Knowledge generated from this study will help resolve concerns that led to a controversy worldwide for research in H1N5 virus.

Reference:
Langlois, RA, Albrecht, RA, Kimble, B, Sutton, T, Shapiro, JS, Finch, C, Angel, M, Chua, MA, Gonzalez-Reiche, AS, Xu, K, Perez, D, García-Sastre, A, & tenOever, BR (2013). MicroRNA-based strategy to mitigate the risk of gain-of-function influenza studies. Nature Biotechnology DOI: 10.1038/nbt.2666

Sensors for Rapid Detection of Proteins Developed

Chemists have developed nano sensors for detecting multiple proteins in tiny samples.

Could you ever imagine that one day testing a protein in your tiny sample would be so easy, just like performing a pregnancy strip test at home. Yes, this is made possible by a group of chemists from Johannes Gutenberg University Mainz (JGU). They have developed a new method for multiple protein analysis that is, in principle, capable of identifying hundreds or even thousands of different proteins. It could be used to detect the presence of viruses and identify their type in tiny samples. The method is quite efficient, quick and cost-effective which means it may find application in medicine, water monitoring, environment technology, food analysis, etc.

The procedure involves taking of a small drop of sample which can be blood, saliva or any body fluid on a small test strip. The test strips consist of glass capillary tubes that basically have gold nano-particles as sensor elements on their internal surfaces. Because the test sample is very small so nano sized sensors are to be used in order to identify many proteins. The nano-particles are prepared using specific DNA strands which have affinity to the foreign proteins. Thus, when a protein locks with one of these special DNA strands, the corresponding nano-particle changes its color. This change is then detected by a spectrometer. This is a very simple method by which multiple proteins can be identified simultaneously in a fluid-flow containing randomly placed nano-rods, reported by researchers from JGU’s Institute of Physical Chemistry.

The study published in Nano Letters can be very useful for detecting various flu viruses that infects people world-wide. Also, it will be used in detection of various kinds of toxin in environment or food, particularly milk or baby food as well as in identifying  doping cases.

Reference:
Rosman C, Prasad J, Neiser A, Henkel A, Edgar J, & Sönnichsen C (2013). Multiplexed Plasmon Sensor for Rapid Label-Free Analyte Detection. Nano letters PMID: 23789876