A)Why are some E. coli deadly while others live peacefully within our bodies?
E. coli outbreaks hospitalize people and cause food recalls pretty much annually in the United States. This year is no different.
Obviously some E. coli can be deadly for people. But not all strains of these bacteria make you sick. In fact, you have a variety of strains of E. coli in your intestines right now – including one that’s busy making the antioxidant vitamin K, crucial for your and its survival.
Scientists like me often characterize E. coli by the sugar coat they display on their cell surface. A molecule called a lipopolysaccharide is the anchor that displays a collection of sugars to their environment.
These sugars help the bacteria stick to surfaces and reveal their identity to your immune system. Human cells do this, too – your blood type is defined by sugars displayed on your blood cells, for instance.
The sugars E. coli display vary from strain to strain. Some sugar coats are associated with strains living symbiotically in your stomach – E. coli HS, UTI89 and CFT073 are some of the most commonly found to be helpful. Others are associated with illness – like E. coli O104:H4, also called enterohemorrhagic E. coli (EHEC), which caused a major outbreak in Europe in 2011. According to the CDC, this latest outbreak is due to E. coliO157:H7 – a strain that’s caused at least one food-borne outbreak in the U.S. each year since 2006.
The letters and numbers that name a strain serve as a code for which sugars are present. While the sugars bacteria display aren’t what makes you sick, they’re quickly and easily detectable and help scientists and doctors differentiate whether a present strain will generate toxins that can make you ill.
Bacteria rely on what researchers term virulence factors: molecules that aid their survival while undermining your immune system. Both the EHEC and O157 strains of E. coli are able to make a virulence factor called a Shiga toxin. Shiga toxins were discovered first in Shigella dysenteriae, the bacterium that causes dysentery. Later researchers discovered that the EHEC and O157 strains of E. colihad gained the gene for Shiga toxinsfrom the dysentery bacterium through a process called horizontal gene transfer.
When bacteria reach a critical mass in your body after you eat a contaminated food, they secrete these toxins as part of their strategy for finding a new host. The toxins enter the cells of your intestines, causing symptoms including low-grade fever, stomach cramps, diarrhea (often bloody) and vomiting.
It’s virulence factors like these that are to blame for human illnesses and that give E. coli a bad name – even if all strains don’t deserve it.
B)Your genome may have already been hacked
On April 25, California law enforcement announced the possible captureof a long-sought serial killer. Shortly after, it was reported that police had used public DNA databases to determine his identity.
This extraordinary event highlights that when you send off a cheek swab to one of the private genome companies, you may sacrifice not just your own privacy but that of your family and your ancestors.
In a time of widespread anxiety over the misuse of social media, Americans should also be concerned over who has access to their genetic information.
For-profit genome testing companies like 23andMe make money, in part, by selling anonymized genomic data. Many people may not realize that re-identifying genomes – that is, identifying an individual from their genetic profile – is a relatively straightforward process. In one study, researchers could re-identify five of 10 people, as well as their families.
Humans share about 99 percent of their DNA bases with one another. The few differences that exist are often sufficient to figure out who’s related to whom.
The genome has been something of a disappointment medically. Physicians generally can’t do much with the information that a given patient has, say, a 3 percent greater risk of dementia. But those data are potentially very useful to insurance companies and employers trying lower their risk.
The Genetic Information Nondiscrimination Act, a federal law passed in 2008, prevents insurance companies and employers from forcing people to undergo genetic testing. But it doesn’t necessarily prevent bad actors from using dark-web databases and advanced analytics to give themselves a commercial edge.
There have been no reports yet of companies doing this. But we live in an age in which it seems the possible becomes probable on an almost daily basis.
The financial services industry offers a cautionary tale for the customers of the genome industry. Banks are highly regulated and supposed to provide state-of-the-art protection, yet they have been hacked.
Compared to financial institutions, genome companies are lightly regulated. Eventually one or more of them will be hacked or even caught selling “risk profiling” services to third parties.
With respect to police and prosecutors, the situation is somewhat different. In the end, they must submit their work to the courts. It’s possible that setting up a fake account on an ancestor DNA website, as the California police reportedly did, constitutes unreasonable search and seizure.
Given the large financial rewards and the behavior of other industries, millions of American families should likely consider their genomic privacy as already compromised. If the genome of one of your relatives is in one of these databases, then essentially so is yours.
In the uncommon circumstance that a whole family has not one member who has yet to send off a cheek swab, that family might want to consider opting out of this whole thing until society sorts out risks, benefits and privacy protections.
Most people, however, will have to wait and hope they will not be harmed by a genomic revolution that has provided them with little benefit.
C)No Sex Required: Body Cells Transfer Genetic Info Directly Into Sperm Cells, Amazing Study Finds
A revolutionary new study reveals that the core tenet of classical genetics is patently false, and by implication: what we do in this life — our diet, our mindset, our chemical exposures — can directly impact the DNA and health of future generations.
In classical genetics, Mendelian laws specify that the inheritance of traits passed from one generation to the next can only occur through sexual reproduction as information is passed down through the chromosomes of a species’ germline cells (egg and sperm), and never through somatic (bodily) cells. Genetic change, according to this deeply entrenched view, can take hundreds, thousands and even millions of generations to manifest.
The new study, however, has uncovered a novel mechanism through which somatic-to-germline transmission of genetic information is made possible. Mice grafted with human melanoma tumor cells genetically manipulated to express genes for a fluorescent tracer enzyme (EGFP-encoding plasmid) were found to release information-containing molecules containing the EGFP tracer into the animals’ blood; since EGFP is a non-human and non-murine expressed tracer, there was little doubt that the observed phenomenon was real. These EGFP trackable molecules included exosomes (small nanoparticles produced by all eukaryotic cells (including plants and animals), which contain RNA and DNA molecules), which were verified to deliver RNAs to mature sperm cells (spermatozoa) and remain stored there. The authors of the study pointed out that RNA of this kind has been found in mouse models to behave as a “transgenerational determinant of inheritable epigenetic variations and that spermatozoal RNA can carry and deliver information that cause phenotypic variations in the progeny.”
The researchers concluded that their study’s findings strongly suggest, “exosomes are the carriers of a flow of information from somatic cells to gametes,” and that their “results indicate that somatic RNA is transferred to sperm cells, which can therefore act as the final recipients of somatic cell-derived information.”
Breaking Through Weismann’s Genetic Barrier
These findings overturn the so-called Weismann barrier, a principle proposed by the German evolutionary biologist August Weismann (1834 – 1914), that states hereditary information can only move from genes to body cells, and not the other way around, which has long been considered a nail in the coffin of the Lamarkian concept that an organism can pass on characteristics it has acquired during its lifetime to its offspring.
Over the past decade, however, the seeming impenetrability of the Weismann barrier has increasingly been called into question, due to a growing body of evidence that epigenetic patterns of gene expression (e.g. histone modifications, gene silencing via methylation) can be transferred across generations without requiring changes in the primary DNA sequences of our genomes; as well as the discovery that certain viruses contain the enzyme reverse transcriptase, which is capable of inscribing RNA-based information directly into our DNA, including germline cells, as is the case for endogenous retroviruses, which are believed responsible for about 5% of the nucleotide sequences in our genome. Nonetheless, as the authors of the new study point out, until their study, “no instance of transmission of DNA- or RNA-mediated information from somatic to germ cells has been reported as yet.”
The researchers further expanded on the implications of their findings:
“Work from our and other laboratories indicates that spermatozoa act as vectors not only of their own genome, but also of foreign genetic information, based on their spontaneous ability to take up exogenous DNA and RNA molecules that are then delivered to oocytes at fertilization with the ensuing generation of phenotypically modified animals –. In cases in which this has been thoroughly investigated, the sperm-delivered sequences have been seen to remain extrachromosomal and to be sexually transmitted to the next generation in a non-Mendelian fashion . The modes of genetic information delivery in this process are closely reminiscent of those operating in RNA-mediated paramutation inheritance, whereby RNA is the determinant of inheritable epigenetic variations , . In conclusion, this work reveals that a flow of information can be transferred from the soma to the germline, escaping the principle of the Weismann barrier  which postulates that somatically acquired genetic variations cannot be transferred to the germline.”
The implications of research on exosome-mediated information transfer are wide ranging. First, if your somatic cells, which are continually affected by your nutritional, environmental, lifestyle and even mind-body processes, can transfer genetic information through exosomes to the DNA within your germline cells, then your moment-to-moment decisions, behaviors, experiences, toxin and toxicant exposures, could theoretically affect the biological ‘destinies’ of your offspring, and their offspring, stretching on into the distant future.
Exosome research also opens up promising possibilities in the realm of nutrigenomics and ‘food as medicine.’ A recent study found common plant foods, e.g. ginger, grapefruit, grapes, produce exosomes that, following digestion, enter human blood undegraded and subsequently down-regulate inflammatory pathways in the human body in a manner confirming some of their traditional folkloric medicinal uses. If the somatic cells within our body are capable through extrachromosomal processes of modulating fundamental genetic processes within the germline cells, or, furthermore, if foods that we eat are also capable of acting as vectors of gene-regulatory information, truly the old reductionist, mechanistic, unilinear models of genetics must be abandoned in favor of a view that accounts for the vital importance of all our decisions, nutritional factors, environmental exposures, etc., in determining the course, not only of our bodily health, but the health of countless future generations as well.
Job title: (f)PHELLOW OF SOPHIA
Favorite quote: "ITS TIME FOR KOSMOPOLITANS(=HELLINES) TO FLY IN SPACE."
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Places lived: EN THE HIGHLANDS OF KOSMOS THROUGH THE DARKNESS OF AMENTHE