Expanding the Plague Family Tree: Yersinia pestis in the Neolithic

Yersinia pestis. See page for author [Public domain], via Wikimedia Commons

In recent years, scientists have been able to refine their molecular tools to resurrect ancient DNA from human graves and determine that yes, Yersinia pestis was the causative agent for the Black Death in the 14th century and the Plague of Justinian in the 6th century.  As more and more human graves have been uncovered, their DNA has revealed many secrets that scientists even ten years ago were unable to discover. With the ability to sequence entire genomes of bacteria that died with their hosts hundreds and even thousands of years ago, researchers are exploring the rise and possible spread of Y. pestis. Each new member sequence adds to the Y. pestis family tree, pinpointing the origin of this bacteria as it diverged from its ancestor Y. pseudotuberculosis. Peering into the past, scientists have been able to track down a strain of Y. pestis from individuals in a Swedish passage grave that is basal to known strains and that the authors of a Cell article suggest has interesting implications.

This pathogenic journey into history started by analyzing ancient DNA data sets from the teeth of individuals present in a communal passage grave in Gökhem parish, located in western Sweden, for any disease-causing microbial sequences that might be present. Y. pestis was flagged in one 20-year-old female dated 4,867–5,040 years ago. The bacterial sequences from this individual, named Gok2, were more closely aligned with Y. pestis than the Y. pseudotuberculosis reference genome. Continue reading “Expanding the Plague Family Tree: Yersinia pestis in the Neolithic”

Black-Footed Ferrets: Back from the Brink

Bff = black footed ferret
Giving some love to a BFF (Black-Footed Ferret).

Today is Valentine’s Day (February 14) and our thoughts turn to doing something special for a significant other (so),  a best friend (bf) or best friend forever (bff).  In this blog we consider doing something special for a bff, but the bff at focus here is not human.

This bff is the black-footed ferret.

That’s correct—we’re talking about the weasel-like critter with the black mask, black tail tip and black feet. This small, wiry animal, with the help of some particularly dedicated humans, has had an amazing come-back story since the 1970s, when these ferrets were believed to be extinct.

About the BFF (Black-Footed Ferret)
The black-footed ferret, Mustela nigripes, is a member of the family Mustelidae, which includes mink, badger, marten, fisher, polecat and wolverine (of course domestic ferrets are also members of this family). Like mink and other members of the mustelidae, bff are long, slender animals that average 18 to 24 inches in length. Black-footed ferrets weigh 1½ –2½ lbs. Female ferrets are “jills”, males are “hobs” and juvenile ferrets are “kits”. The average life span of a black-footed ferret in the wild is 1–3 years. Continue reading “Black-Footed Ferrets: Back from the Brink”

All You Need is Pla (for Pneumonic Plague)

Yersinia pestis. By Mrs Robinson at bg.wikipedia (Transferred from bg.wikipedia) [Public domain], from Wikimedia Commons.
Writing about Yersinia pestis or the Black Death, has earned me a reputation among Promega Connections bloggers. I am interested in what researchers have been able to piece together about the causative agent of ancient plagues, what modern research shows about how Y. pestis spreads in the body and the continuing reservoirs in modern times, resulting in publication of eight blog posts on the subject. Understanding Y. pestis bacterium is of continuing interest to researchers. How did Yersinia pestis evolve from the humble Yersinia pseudotuberculosis, a pathogen that causes gastrointestinal distress, into a virulent pneumonic plague that is a global killer? One strategy for answering this question is to look at the genomic tree of Y. pestis and trace which strains had what characteristics. In a recent Nature Communications article, Zimbler et al. explored the role of the plasmid pPCP1 in Y. pestis evolution and the signature protease Pla it expresses. Continue reading “All You Need is Pla (for Pneumonic Plague)”

Tracking the Progression of Plague Using Bioluminescence

Sequencing Yersinia pestis, the bacterium that caused the Black Plague in Europe during 1348–50, is an amazing accomplishment. Y. pestis infection still occurs sporatically and causes fatalities despite the Age of Antibiotics. Even with animal models, there are questions remaining about the progression of infection. Nham et al. used in vivo imaging to examine the course of infection in a mouse animal model using a bioluminescent clone of Y. pestis. Continue reading “Tracking the Progression of Plague Using Bioluminescence”