Peptide Mass Fingerprinting (PMF)

Motivated to learn more about the fur and animal hair found in our Predynastic mummy bundle, I popped up to Boston yesterday for a workshop entitled “Identifying collagen-based materials in cultural objects using peptide mass fingerprinting“.

The workshop was organized by a group at Harvard, including the Peabody Museum of Archaeology and Ethnology in collaboration with the Straus Center for Conservation at the Harvard Art Museums and the Harvard FAS Division of Science. The team received NCPTT funding for a project to develop a new application of an analytical technique called peptide mass fingerprinting (PMF).

PMF uses mass spectrometry to analyze very tiny samples of proteinaceous objects and identify the mammalian source to the species level. It actually can be used to analyze materials made of collagen and keratin, but the group at Harvard is focusing on collagen-based materials. The procedure essentially breaks up the protein into smaller peptides, and the mass of the peptides is measured using a mass spectrometer such as a MALDI-TOF. The peptide masses are compared to known reference samples, which allow for identification. This type of analysis falls under the category of proteomics, or the large-scale study of proteins, and it is sometimes referred to by this name as well.

The Harvard project is focused on applying this technique to objects made of gut, skin, sinew, and membrane from Alaska, the Northwest Coast, Northern California, and the High Plains. Another goal of the project is to bring this type of analysis, which typically takes place in large industrial or academic labs, to museum labs. You can learn more about the project on their blog.

The workshop included 3 presentations by the project’s primary analytical investigator/scientist Dr. Dan Kirby, project research associate Madeline Corona, and Kress fellow Ellen Promise. Between the 3 of them, they covered how PMF works, what it can tell you, and how it is applied to cultural artifacts, using a project on Alaskan kayaks as a case study.

After Q&A led by Peabody Museum conservator T. Rose Holdcraft, we were led on a tour of the Peabody conservation lab, where we were able to feast our eyes on some of the impressive Native Alaskan objects that they are investigating as part of the project.
A view of the Peabody Museum conservation lab, with several Native Alaskan skin and gut objects on view

A view of the Peabody Museum conservation lab, with several Native Alaskan objects on view

We also toured the impressive Mass Spectrometry and Proteomics Resource Lab, where we had a chance to see the Bruker MALDI TOF/TOF instrument and a demonstration of how samples are prepped for analysis.
The Bruker MALDI-TOF/TOF instrument and Madeline Corona demonstrating sample prep

The Bruker MALDI-TOF/TOF instrument and Madeline Corona demonstrating sample prep

The sample prep area showing the equipment used, including the MALDI plate (lower right)

The sample prep area showing the equipment used, including the MALDI plate (lower right)

Here at Penn, we are excited by this technique – not only for the minute sample size required (the samples used are just barely detectable to the naked eye) but also for its accessibility. We have a lot of animal-based materials in our collection and we are hoping to pursue using PMF to analyze these materials. Actually, we are already working to see if its possible to use this technique to identify the sources of the fur and basketry hair fibers from our Predynastic mummy, thanks to help from Smithsonian MCI fellow Caroline Solazzo, whose work focuses on keratin-based materials. PMF supposedly works on all types of samples, including those that are very old and/or are in poor condition, so we thought we’d put this to the test by starting with samples from our oldest Egyptian mummy (he’s well over 6000 years old). We will let you know how it seems to work.

A side note – a quick trip to Boston wouldn’t be complete without a stop at the Museum of Fine Arts. I spent most of my time there ogling the Ancient Egypt exhibits, admiring the massive, yet delicately decorated and inscribed coffin boards of Djehutynakht’s outer coffin (same time period and style as Ahanakht’s coffin)

The interior of the lid of Governor Djehutynakht's outer coffin (left) and detail of the false door (right)

The interior of the lid of Governor Djehutynakht’s outer coffin (left) and detail of the false door (right)

and many of the other treasures of this collection, such as this bead net dress made of faience and gold from the 4th Dynasty.
Detail of a 4th Dynasty beadnet dress (ca. 2551-2528 BCE)

Detail of a 4th Dynasty beadnet dress (ca. 2551-2528 BCE)

Breathtaking, really. I also found this shabti in a miniature coffin very charming.
Shabti of Queen Neferu with  miniature coffin, from Deir el-Bahri, tomb of Queen Neferu, 11th Dynasty (ca. 2061-2010 BCE)

Shabti of Queen Neferu with miniature coffin, from Deir el-Bahri, tomb of Queen Neferu, 11th Dynasty (ca. 2061-2010 BCE)

And while the MFA does not have conservators working in a gallery, as we are doing here at Penn, they do have some great “behind the scenes” galleries, one with interactives that engage visitors to think about conservation ethics and decision making. One of my favorites was an example using Maya Cylinder vases, examining condition issues and treatment decisions.

Some screen shots of the Maya vase example in the MFA's "behind the scenes" gallery

Some screen shots of the Maya vase example in one of the MFA’s “behind the scenes” galleries

All in all, a great trip. We’ll keep you updated on the whole peptide mass fingerprinting technique and how we might be able to use this for our collection.

 

Elephant and giraffe hair? No problem!

There are many reasons why I love working at the Penn Museum, and this is one of them: just the other day, I was casually talking to some colleagues during a break, and mentioned that I’d love to get my hands on some elephant and giraffe hair to use as a reference to compare to some of the material included in our Predynastic mummy Bruce‘s bundle.

“What’s that you say?” quipped Egyptian Section Curator Dr. Jen Wegner. “Why it just so happens that we have a drawer with some elephant and giraffe hair down in storage!”. After working here for 9 months, this should come as no surprise to me. And what a delight – just the next day I ran down to storage and brought this drawer of goodies up to the lab.

Contents of the drawer, containing bits of elephant and giraffe hide, with the hair intact.

Contents of the drawer, containing bits of elephant and giraffe skins, with the hair intact

In addition to the animal skins, this drawer also contains a small woven basket, made of either elephant or giraffe hair and dating to the early 18th Dynasty, according to it’s catalog card.

Overall view of the small basket made of elephant or giraffe hair

Overall view of the small basket made of elephant or giraffe hair

These materials will be useful to compare to the animal skins and the basket that we have documented in Bruce’s bundle. We will provide updates as we learn more about our Predynastic mummy and the materials he was buried with.

 

The New Guy

by Lynn Grant

Molly Gleeson, the Project Conservator for In the Artifact Lab has been very busy over the last nine months, conserving lots of Egyptian artifacts and she’s finished treatments on a human mummy, an animal mummy and has done a lot of work on PUM I. So, as these projects finish up, it’s time to start some new ones – there’s never any shortage of projects for the Museum conservators. Earlier this month, we brought another of our human mummies out of storage and into the Artifact Lab. And what a mummy he is:

E 16229, a Predynastic mummy.

E 16229, a Predynastic mummy.


Not what you were expecting, right? No stiff upright form tightly wrapped in bandages. That’s because this is a very early mummy, probably dating to “4000-3600 BCE (or from the Badarian Period to Naqada IIB to use Egyptological time periods”, to quote Dr. Jane Hill, an Assistant Professor at Rowan University, who’s been studying this mummy. Dr. Hill will be presenting some of her initial findings at a mini seminar hosted by ARCE-PA (American Research Center in Egypt – Pennsylvania Chapter) and held at Penn Museum this Saturday, June 1st, open to the public.

Because Molly is going to be away at a conference this week, I’ve begun familiarizing myself with this ‘new’ mummy so I can talk about him to the seminar attendees and our other visitors. When I say ‘new’, he’s only new to the Artifact Lab. Not only is he at least 5600 years old, he’s been in our collections since 1898. He was donated to the Museum by Ethelbert Watts, a prominent Philadelphian who was serving as an Assistant American Consul in Cairo. His history in our collections is a little unclear: we know he was x-radiographed in 1932 and we have this undated early photograph from the Archives. Since this image comes from a glass plate negative, it could date anytime between 1898 and the early 1930s, when the Museum finally switched to film based photography.

An early photograph of the mummy from a glass plate negative

An early photograph of the mummy from a glass plate negative

We think he may have been on exhibition some time in the past but we haven’t tracked down those records yet. For at least the past few decades, he languished in a box in the Egyptian storerooms until Dr. Hill and Dr. Joe Wegner ‘excavated’ the box in 2011. Since then he’s been the subject of quite a lot of interest – Dr. Hill and her Rowan colleague Dr. Maria Rosado have been examining samples of materials associated with the mummy and sent samples for AMS/C14 dating.

Cool stuff about this mummy: he was buried in the flexed or contracted position, like many Predynastic mummies but he was also buried inside an animal skin bag, which had the animal’s hair left on the inside. He has a small, finely woven basket by his side and an animal skin cap covered by a basketry framework on his head.

Details of some of the items buried with the mummy

Details of some of the items buried with the mummy

Clearly, this guy has a lot to tell us and we’ll keep you posted on what’s up with Bruce (yes, Bruce – it gets hard to refer to the mummies by their accession number and so many get nicknames. This guy has been Bruce to us pretty much since he came out of his box. No disrespect meant; he’s a fascinating individual and I look forward to getting to know him better).