A completely new structure heats water and turns it into steam. Continue reading →
If this can be scaled up, it could find some real uses.
A completely new structure heats water and turns it into steam. Continue reading →
If this can be scaled up, it could find some real uses.
Bacterial infections usually announce themselves with pain and fever but often can be defeated with antibiotics — and then there are those that are sneaky and hard to beat. Now, scientists have built a new weapon against such pathogens in the form of tiny DNA pyramids. Published in the journal ACS Applied Materials & Interfaces, their study found the nanopyramids can flag bacteria and kill more of them than medicine alone.
Medicine using nanoparticles to carry a drug holds a lot of promise. But the structural carriers for the drugs can cause health problems.
While they have not used this in a human being, these researchers did say that using this DNA pyramid to carry an antibiotic substantially enhanced the killing ability of the drug.
With grilling season upon us, many backyard cooks are turning to more healthful alternatives to their savored but fatty hot dogs. But low fat can sometimes mean low satisfaction. Now researchers are reporting new progress toward addressing the texture problem in low-fat wieners that are made with olive oil rather than pork fat. Their study was published in ACS’ Journal of Agricultural and Food Chemistry.
Removing the pig fat from hotdogs usually makes them less tasty. Here researchers found that they could use olive oil, maintain the taste and reduce calories by 30%.
With over 100 diseases that can attack soybean crops, why would charcoal rot rise to the top of the most wanted list? University of Illinois scientists cite the earth’s changing climate as one reason that more research is needed on the fungus that causes charcoal rot.
One of the arguments from denialists is that climate change will not be so bad because plants like carbon dioxide. While this is debatable, what is not often discussed is how much better some plant diseases will do.
Here we have a fungus that likes warm, dry weather. And that also infects 500 other plants, including corn and sorghum, besides soybeans. And it loves salty conditions.
So a resistant plant must be one that is heat-, drought -, and salt-tolerant in order to beat the fungus.
Also, in contrast to other disease, charcoal rot not only kills the plant, it lives off the dead tissue. So, it can thrive living off the leftovers from other pathogens that can only use living plants.
At the moment, no soybean plant is completely immune to this fungus. So these researchers are trying to develop varieties that are able to fight off the fungus.
But those varieties also still need to be highly productive. Not an easy task.
Working with a gene that plays a critical role in HIV infection, University of Maryland researchers have discovered that some human genes have an alternate set of operating instructions written into their protein-making machinery. The alternate instructions can quickly alter the proteins’ contents, functions and ability to survive.
Ribosomes read messenger RNA (mRNA) three nucleotides at a time. But every once in a while it stutters, skips one nucleotide, before starting again.
This causes a frameshift usually resulting in nonsense, producing proteins that are not useful. The protein and the mRNA are then rapidly degraded and things start over again.
So what these researchers found is that the cell actually has a system that directly causes frameshifts, actually controlling protein production by creating nonsense.
How it does this is by using another small RNA – a microRNA or miRNA – that sticks to the mRNA and causes a frameshift at a specific location. The mRNA and resulting proteirn are then targeted for rapid degradation.
So this serves as a negative control loop, decreasing the amount of a specific protein in a cell.
Just another control mechanism in a cell – purposefully inserting errors.
There’s no denying that the process of giving birth is an unforgettable experience for those involved but now it seems the labor of love could also be important for programming an infants development. Researchers from the Karolinska Institutet (Sweden) drop some knowledge about the mechanosensitive nature of DNA methylation and show that birth via Caesarean Section (CS) skips the profiles established in blood (hematopoietic) stem cells during labor.
Here’s the scoop:
- Blood stem cells (CD34+) from infants delivered by CS are more globally methylated (+2%) than their ‘vaginal peers’.
- A locus-specific analysis identified 343 differentially methylated regions (DMRs) showing a difference of 10% or more.
- The majority of these DMRs in infants (76%) are hypermethylated after vaginal delivery.
- Interestingly, in these infants, the degree of DNA methylation in 3 loci correlates to the duration of labor.
- DMRs modulate immune system function and metabolism and almost seem to parallel a computer boot up sequence.
Author Mikael Norman shares that “During a vaginal delivery, the fetus is exposed to an increased level of stress, which in a positive way will prepare the unborn baby for life outside the uterus. This activation of the fetus’ defense systems doesn’t occur when a cesarean section is performed before labor begins, which in turn could be a possible cause for the noticed differences between the groups.” So, when it comes down to it, this report suggests that vaginal birth helps give babies an epigenetically programmed ‘jump start’ upon entry into the real world that a CS bypasses, which can lead to some health burdens later in life.
Very intriguing that there are different methylation patterns in the DNA of infants depending on whether they went through the stress of a vaginal birth vs the less stressful caesarean.
Now to see if this results in any physical differences.
by Wei Wei, Huhu Xin, Bhaskar Roy, Junbiao Dai, Yungen Miao, Guanjun Gao
We report the establishment of an efficient and heritable gene mutagenesis method in the silkworm Bombyx mori using modified type II clustered regularly interspaced short palindromic repeats (CRISPR) with an associated protein (Cas9) system. Using four loci Bm-ok, BmKMO, BmTH, and Bmtan as candidates, we proved that genome alterations at specific sites could be induced by direct microinjection of specific guide RNA and Cas9-mRNA into silkworm embryos. Mutation frequencies of 16.7–35.0% were observed in the injected generation, and DNA fragments deletions were also noted. Bm-ok mosaic mutants were used to test for mutant heritability due to the easily determined translucent epidermal phenotype of Bm-ok-disrupted cells. Two crossing strategies were used. In the first, injected Bm-ok moths were crossed with wild-type moths, and a 28.6% frequency of germline mutation transmission was observed. In the second strategy, two Bm-ok mosaic mutant moths were crossed with each other, and 93.6% of the offsprings appeared mutations in both alleles of Bm-ok gene (compound heterozygous). In summary, the CRISPR/Cas9 system can act as a highly specific and heritable gene-editing tool in Bombyx mori.
Truthfully, it is pretty amazing that they can make changes in the genome that are carried through the germline and are inherited.
GMO insects may not be far away.
HIV, the virus that causes AIDS, does its damage by decimating immune cells. But it also lies dormant in some cells, creating a reservoir that can restart an active infection long after the active virus has been cleared by treatments. This is apparently what happened to a child from Mississippi who was thought to have been cured of infection following antiviral treatments.
Researchers may now have found one of the reasons that it’s so hard to clear out these reservoirs of infected cells. As part of the infection process, HIV normally inserts a copy of itself into a cell’s chromosomes. By chance, some of these insertions cause the cell to grow faster, ensuring that more copies of the virus are around to cause trouble.
The researchers, who are all based in Seattle, took a pretty simple approach to discover this: they sampled cells from HIV patients who were receiving long-term antiviral treatment, looking for the sites of HIV insertion. In these patients, viral replication was suppressed by the drugs, often for periods of over a decade. Therefore, any viruses researchers found were from those cells that had quiescent viruses inserted into their genome.
In some ways, HIV works like a tumor. Cancer cells have mutations that often affect cell growth. When we try and hit this with chemotherapy, tumor cells with a selective advantage that allows them to survive will continue to grow.
HIV inserts randomly into a cell’s DNA, sometimes close to a gene. If that gene happens to be one of the growth genes , the HIV will alter the cell’s metabolism much as cancer mutations do.
So, even when drugs are used to control the HIV, the cells with HIV insertions next to growth genes still manage to survive.
It is not just enough to have drugs that stop HIV from replicating We may have to figure out how to deal with specific insertion points and how to deal with those cells.
The Denisovans, relatives of the Neanderthals who inhabited Asia before modern humans arrived, are known only from a scattering of small bones and a wealth of DNA data. So far, all of that originates from a single Siberian cave (called Denisova, naturally). Like the Neanderthals, the Denisovans interbred with those modern humans once they arrived. But the modern populations who have the most Denisovan DNA are far from Siberia, occupying southern Asia and some Pacific islands.
Now, a tiny fragment of Denisovan DNA has also been found in a group that’s much closer to Siberia: the Tibetans. And all indications are that it helps them adapt to the extreme elevations of the Tibetan plateau.
Large parts of that plateau are 4,000 meters (2.5 miles) above sea level. The populations native to the area have lower infant mortality and higher birth weights than people who have relocated to the area. In addition, the Tibetans have acclimated to the altitude without relying on increased red blood cell counts, which is how most other people respond after spending time at altitude. Higher red blood cell counts mean a more viscous blood, which creates its own health hazard, so this difference is also likely to be very advantageous.
This explains some really interesting aspects of what has been called a great example of natural selection in human beings. The Tibetans gained this trait in less than 3000 years.The ability to survive at high altitude shows just how dramatically the environment has shaped human genomes.
And now we know that those genes came from non-human sources.
Kind of cool what DNA sequencing is now showing us about our human heritage. Just small amounts of ancient DNA from species we crossbred with still have an impact today.
The Tibetans are healthy at an air pressure that is 60% of what it is at sea level. I wonder just how low the air pressure could go for them to live? The Nepalese sherpas also have the relevant Denisovan genes and are able to survive altitudes on Mt. Everest that others require oxygen to survive. But people in the Andes have a different set of genes.
So I wonder what would happen if someone from Tibet has children with someone from the Andes? Would the children have the abilities to survive at even higher altitudes? And Ethiopians have a completely different set of genetic mutations from Andean or Tibetan sources..
The Armstrong limit is about 19,000 meters or about 12 miles, the point at which water boils at human body temperature. Even the most dense portion of the Martian atmosphere is 6 times less than this. So we would need to do extensive terraforming to raise the air pressure. But would these Tibetans be a likely group to make the first Martian settlers to live unencumbered by pressure suits?
Scientists have identified a potential Achilles’ heel for Salmonella – the bacteria’s reliance on a single food source to remain fit in the inflamed intestine
The nutrient – fructose-asparagine – is required for Salmonella to provoke what we call food poisoning. Blocking this nutrient may help alleviate 42,000 incidents a year.
Salmonella can be 10,000 times less fit if it does not have access to this nutrient. A surprising result but something that may well help us dealign with this illness.
Suddenly, a chemical attack kills most of your neighbors. As other types of microorganisms arrive and begin to take over the vacated niches, they alter the milieu so that you’re washed out in a sudden stream propelled by a blast of gas. How can your few surviving colleagues back in the colon re-establish the peaceful old community?
An infusion of feces from another body can reboot a healthy microbiome in the large intestine (colon), in a biological gentrification of sorts that’s been well studied and much discussed. Now, Vincent B. Young and his team from the University of Michigan and the Essentia Institute of Rural Health in Duluth report in the May/June issue of mBio the biological functions that “fecal microbiota transplantation” (FMT) alters to restore the neighborhood of the colon.
A really nice article about a recent report on the use of fecal transplants to deal with C. diff infections. These can be very difficult to treat and can be life-threatening.
Looks like the treatment works, something we expected. But there is a ton of data regarding bacterial metabolism and such that helps inform why and how to move forward.
Stanley Miller, the chemist whose landmark experiment published in 1953 showed how some of the molecules of life could have formed on a young Earth, left behind boxes of experimental samples that he never analyzed. The first-ever analysis of some of Miller’s old samples has revealed another way that important molecules could have formed on early Earth.
I wish I had been smart enough to use Miller’s ideas on my organic chemistry exams. The ones that said synthesize an amino acid starting from carbon, oxygen and ammonia, for example.
“Put the ingredients in a vessel and apple electricity to a spark gap for 2 weeks. Isoalte the amino acid.”
The answer for almost any organic compound could have been the same.
This is really interesting work but it would appear that the levels of amino acids are quite small. One needs a way to concentrate them so they can become useful for life.
Still a great story here.