Nicotine extracted from ancient dental plaque for the first time

A team of scientists including researchers from Washington State University has shown for the first time that nicotine residue can be extracted from plaque, also known as "dental calculus," on the teeth of ancient tobacco users.

This is a 1945 picture of a Yokuts Native American woman smoking a pipe
[Credit: Clifford Relander]

Their research provides a new method for determining who was consuming tobacco in the ancient world and could help trace the use of tobacco and other intoxicating plants further back into prehistory.

"The ability to identify nicotine and other plant-based drugs in ancient dental plaque could help us answer longstanding questions about the consumption of intoxicants by ancient humans," said Shannon Tushingham, a WSU assistant professor of anthropology and co-author of a new study on the research in Journal of Archaeological Science Reports. "For example, it could help us determine whether all members of society used tobacco, or only adults, or only males or females."

A new source of information

Tracing the ancient spread of tobacco in the Americas has traditionally relied on the presence of pipes, charred tobacco seeds and the analysis of hair and fecal matter. However, these items are rare in the archeological record and are hard to link to particular individuals. As a result, tobacco use has been difficult to document archeologically.

On the other hand, dental plaque adheres to the surfaces of teeth and mineralizes over time, preserving a wide range of substances that are in the mouth. It is easy to link to particular individuals because it can be removed directly from teeth.

Nevertheless, dental plaque was largely ignored by archaeologists until recently.

However, using modern and highly sensitive instrumentation, scientists have found they can detect and characterize trace amounts of a wide variety of compounds, including proteins, bacterial DNA, starch grains and other plant fibers in dental plaque.

Because nicotine is detectable in the dental plaque of contemporary smokers, Tushingham and her collaborators wanted to find out if it also preserved in plaque taken from people who lived long ago.

She and David Gang, a professor in the WSU Institute of Biological Chemistry, Korey Brownstein, a graduate student in the WSU Molecular Plant Sciences Program, and Jelmer Eerkens, an anthropologist at the University of California, Davis, collaborated with members from the Ohlone tribe in San Francisco Bay to extract plaque from the teeth of eight individuals, buried between 6,000 and 300 years ago, and analyze it for nicotine.

Using ordinary dental picks, Eerkens and his team at UC Davis extracted the dental plaque from the ancient teeth and then sent it to Tushingham and Gang's labs at WSU for analysis. The WSU researchers used liquid chromatography-mass spectrometry to test the samples for nicotine and other plant-based drugs like caffeine and atropine, a muscle-relaxant.

Among the samples they analyzed, two tested positive for nicotine, demonstrating for the first time that the drug can survive in detectable amounts in ancient plaque. One of these individuals, an adult man, was also buried with a pipe. A surprise came from the molar of an older woman, which also tested positive for nicotine.

"While we can't make any broad conclusions with this single case, her age, sex, and use of tobacco is intriguing," Eerkens said. "She was probably past child-bearing age, and likely a grandmother. This supports recent research suggesting that younger adult women in traditional societies avoid plant toxins like nicotine to protect infants from harmful biochemicals, but that older women can consume these intoxicants as needed or desired."

While the researchers did not detect evidence of any other plant-based drugs in this particular study, they believe dental plaque could be used help trace the use and spread of other intoxicants as well.

"We think a wide variety of plant-based, intoxicating chemicals could be detected in ancient dental plaque," Brownstein said. "It really opens up a lot of interesting avenues of discovery."

Author: Will Ferguson | Source: Washington State University [February 27, 2018]

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Archaeologist uncovers hidden history of conquistadors in American South

Chris Rodning, the Paul and Debra Gibbons Professor in the Tulane School of Liberal Arts’ Department of Anthropology, unravels early entanglements between Native Americans and European explorers, revealing how their interactions shaped the history of the American South.

An image taken in June 2017 by a camera mounted on a drone displays the exposed remnants of Fort San Juan.
Excavations of this area of the site will be continued in June 2018 [Credit: Ryan Wallace]

“Native Americans’ responses to Spanish explorers and colonists form an important part of the story behind the history of European colonialism in North America,” said Rodning, who conducts archaeological research at Fort San Juan — the earliest known permanent European settlement in the interior United States, located near Morganton, North Carolina.

Since 2001, Rodning has collaborated with David Moore, an anthropology professor from Warren Wilson College, and Rob Beck, an associate professor of anthropology from the University of Michigan, to excavate the site.

“In 2013, we identified the archaeological footprint of the fort,” said Rodning, noting that the team has since focused on learning how the structure was built and where it was located in relation to a nearby Native American settlement called Joara.

In 1540, the conquistador Hernando de Soto traversed this part of western North Carolina.

“He threatened communities with violence, demanded food and sometimes attacked when they did not comply with his demands. He also pressed Native Americans into service as porters to carry supplies for his men,” said Rodning.

Hannah Hoover, a Tulane senior double majoring in anthropology and classical studies, digs dirt from excavation
squares at the Fort San Juan site and throws it up to sifters to screen the dirt in search of artifacts
[Credit: Christopher Rodning]

One generation after de Soto’s expedition, Spanish explorer Juan Pardo arrived with another group of soldiers and established Fort San Juan in 1566.

“When Pardo marched inland, the town of Joara was a much more powerful town than it had been 26 years previously,” said Rodning — possibly because of Joara’s previous interactions with de Soto.

At first, an alliance formed between Pardo and the people of Joara, but in 1568, warriors from Joara sacked the fort and burned the compound.

“Architectural materials and designs of burned houses at the site demonstrate evidence of the typical Native American style of architectural design and construction, but some wooden fragments also indicate that they were cut and shaped with metal tools. The significance of that is Native Americans didn’t have those types of metal tools,” said Rodning.

Rodning said that it’s likely that Native Americans gained access to these new tools from Spanish soldiers, or that Spanish soldiers participated in the construction and maintenance of houses where the men garrisoned at Fort San Juan lived.

Rodning said his team remains committed to the project in hopes of understanding how early moments and subsequent episodes of Spanish contact changed Native American communities in this region.

University Press of Florida published the group’s findings in a book called Fort San Juan and the Limits of Empire: Colonialism and Household Practice at the Berry Site in 2016.

Source: Tulane University [February 27, 2018]

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Infant skull binding shaped identity, inequality in ancient Andes

The idea of binding and reshaping a baby's head may make today's parents cringe, but for families in the Andes between 1100-1450, cranial modification was all the rage.

Starting around 1300, high-ranking members of a pre-Inca population increasingly had their heads bound into
a narrow, elongated shape during infancy [Credit: M. Velasco/Current Anthropology 2018]

Like Chinese foot binding, the practice may have been a marker of group identity. Its period of popularity in what is now Peru, before the expansion of the Inca empire, was marked by political upheaval, ecological stress and the emergence of new cultural practices. In a study published in Current Anthropology, Matthew Velasco, assistant professor of anthropology at Cornell University, explores how head-shaping practices may have enabled political solidarity while furthering social inequality in the region.

Velasco analyzed hundreds of human skeletal remains from multiple tombs in the Colca Valley of highland Peru and discovered that before 1300 most people did not have modified heads. He found that the number of individuals with cranial modifications increased over time, from 39.2 percent to 73.7 percent during the later portion of the Late Intermediate Period.

Above-ground tombs at the cemetery site of Yuraq Qaqa (Colca Valley, Peru)
[Credit: David Rodriguez Sotomayo]

Skeletal samples of two major ethnic groups showed that the Collaguas employed methods to make their heads assume a longer, narrower shape, while the Cavanas sought to make their heads wide and squat. Eventually, the elongated head shape of the Collaguas became the predominant style of modification in the upper Colca Valley. According to Velasco, this shift toward embodying a shared identity may have strengthened ties between groups engaged in protracted conflict with outsiders, including the Incas.

"The increased homogeny of head shapes suggests that modification practices contributed to the creation of a new collective identity and may have exacerbated emerging social differences," Velasco said. "Head shape would be an obvious signifier of affiliation and could have encouraged unity among elites and increased cooperation in politics."

About 300 years before the Inca arrived, low-ranking members of the Collagua people sometimes had their
heads flattened at the back during infancy (left). More often, their heads were not modified (right)
[Credit: M. Velasco/Current Anthropology 2018]

Whether head modification conferred distinct privileges and higher status is unclear, but Velasco found bio-archaeological evidence that modified females possessed greater access to diverse food options and were less likely to encounter violence. Cranial modification thus appears to be a factor in societal inequality, Velasco said.

One explanation for the cranial modifications is offered by a 16th-century Spanish colonial document Velasco examined, which described groups molding skulls into the shape of the volcano from their origin myth. "If this is true, then cranial modification reflects a deeply religious worldview and was fundamental to a person's being and existence, and not simply a fashion statement," Velasco said.

Author: Linda B. Glaser | Source: Cornell University [February 21, 2018]

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Laser technology takes Maya archaeologists where they've never gone before

With the help of airborne laser mapping technology, a team of archaeologists, led by University of Arizona professor Takeshi Inomata, is exploring on a larger scale than ever before the history and spread of settlement at the ancient Maya site of Ceibal in Guatemala.

On the left is an aerial image of an area of Ceibal. On the right is the same area, as mapped by LiDAR
[Credit: Takeshi Inomata/University of Arizona]

In a new paper published in the journal PLOS ONE, Inomata and his colleagues explain how they commissioned the use of LiDAR, or light detection and ranging, technology to map a significantly larger area of Ceibal than ever before recorded.

LiDAR provides highly accurate, detailed 3-D maps of ground surface topography. Over the course of just a few days at Ceibal, a small airplane, equipped with lasers powerful enough to peer through the dense jungle canopy, soared above the site, mapping -- with a less than 10-centimeter margin of error -- the shape, size and location of ancient Maya pyramids, platforms, ceremonial centers, roads, water reservoirs and other structures previously undocumented by archaeologists.

The resulting map covers 470 square kilometers that would have been extremely challenging for archaeologists to reach on foot, and includes the locations of more than 15,000 ancient Maya architectural remains. Previously, archaeologists had information on only about 8 square kilometers and fewer than 1,000 structures in the area.

"This kind of understanding was really unthinkable some years ago, and now suddenly we can have all these data," Inomata said. "The scale is completely different."

Inomata and his colleagues used the LiDAR data to reconstruct a timeline of growth and change at Ceibal, building upon what they already knew from previous excavations about when different styles of structures appeared between about 1,000 B.C. and A.D. 950.

At the top is an aerial image of a reconstructed temple at Ceibal. At the bottom is the same area, mapped by thousands
of individual laser points [Credit: Takeshi Inomata/University of Arizona]

"What we tried to do here was to set up a systematic method of analyzing this LiDAR data over a wide area, and then translate it into an interpretation of temporal sequences and social change," said Inomata, a professor and Agnese Nelms Haury Chair in Environment and Social Justice in the UA School of Anthropology.

Combining LiDAR and excavation data then allowed the archaeologists to reconstruct settlement patterns over a long period of time.

"Looking at the LiDAR image, you can see the specific types of architecture -- pyramids, long structures -- and we know from our excavations what time period they're from. So just looking at the shape of the structures, we can see this network of communities and ceremonial centers from specific periods," Inomata said.

Lasers Let Humans Explore Challenging Terrain

Mapping an archaeological site in a densely vegetated area such as the Guatemalan jungle is a daunting task -- one traditionally done on foot. Because of the challenging terrain, only about 1.9 square kilometers of Ceibal had been completely mapped previously -- by Harvard archaeologists in the 1960s -- while about 6 more kilometers were surveyed with less detail.

It was in that small area that Inomata and his colleagues have been conducting archaeological excavations for the last 13 years.

UA archaeologist Takeshi Inomata during an excavation at Ceibal
[Credit: Takeshi Inomata/University of Arizona]

Since joining the growing number of researchers who have used the LiDAR surveying method to help with interpretation of archaeological sites, Inomata and his team have gained access to data that would have been nearly impossible to obtain through on-foot surveys. The LiDAR survey, which was conducted by the University of Houston's National Center for Airborne Laser Mapping, even found a few things that the original on-the-ground mapping done in the 1960s missed.

"The maps that Harvard made were incredibly accurate, considering they were all ground survey, but with LiDAR we found a lot more buildings than were on the map previously, and their locations are very accurate," said paper co-author Melissa Burham, a UA graduate student in anthropology.

As a growing number of researchers turn to the LiDAR surveying method to aid in the interpretation of archaeological sites, Inomata and his team hope their colleagues in the field may follow a similar process to what they used at Ceibal, which they plan to apply again in their regional survey in the state of Tabasco in Mexico, where they will begin work in February.

"In archaeology, excavation is always important, but you can't excavate everything, so you look for patterns on a smaller scale that you can extrapolate over a larger region," said Burham, who co-authored the paper along with Inomata, UA anthropology professor Daniela Triadan and researchers from Guatemala and Japan. "That's really what this paper aims to do. This can help other people understand growth at other Maya centers and help with dating methods."

Source: University of Arizona [February 21, 2018]

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Acoustic imaging reveals hidden features of megathrust fault off Costa Rica

Geophysicists have obtained detailed three-dimensional images of a dangerous megathrust fault west of Costa Rica where two plates of the Earth's crust collide. The images reveal features of the fault surface, including long grooves or corrugations, that may determine how the fault will slip in an earthquake.

Perspective view of the shallow megathrust looking seaward towards the trench; the frontal prism has been cut away.
The color scales indicate depth below seafloor, and grey denotes the seafloor [Credit: Edwards et al., 2018]

The study, published in Nature Geoscience, focused on the Costa Rica subduction zone where the Cocos plate slowly dives beneath the overriding Caribbean plate. Variations in texture seen in different portions of the fault surface may explain why Costa Rica has complex, patchy earthquakes that do not seem to slip to shallow depths, unlike some other megathrust faults, said first author Joel Edwards, a Ph.D. candidate in Earth and planetary sciences at UC Santa Cruz.

"Our new imagery shows large variability in the conditions along the megathrust, which may be linked to a number of earthquake phenomena we observe in the region," Edwards said.

Megathrusts, the huge continuous faults found in subduction zones, are responsible for Earth's largest earthquakes. Megathrust earthquakes can generate destructive tsunamis and are a serious hazard facing communities located near subduction zones. Understanding the mechanisms at work along these faults is vital for disaster management around the globe.

Edwards worked with a team of geophysicists at UC Santa Cruz, the U.S. Geological Survey, the University of Texas-Austin, and McGill University to obtain 3-dimensional imagery of the fault interface using cutting-edge acoustic imaging technology. The long grooves, or corrugations, they observed along the interface are similar in size to those found along the base of fast-flowing glaciers and along some ocean ridges. The images also showed varying amounts of smoothness and corrugations on different portions of the fault.

"This study produced an unprecedented view of the megathrust. Such 3-D information is critical to our ability to better understand megathrust faults and associated hazards worldwide," said coauthor Jared Kluesner, a geophysicist at the USGS in Santa Cruz.

The acoustic dataset was collected in spring 2011 on the academic research vessel Marcus G. Langseth. The ship towed an array of underwater microphones and sound sources behind it as it made a series of overlapping loops over the area of the fault. The data were processed over the next 2 years and have since been used in a number of studies looking at different aspects of the subduction zone process. This particular study focused on the interface between the sliding plates, which serves as a record of slip and slip processes.

"The 3-D site selection was really good and the resulting acoustic dataset showed extraordinary detail," said Edwards, noting that coauthor Emily Brodsky, professor of Earth and planetary sciences, was the first to recognize the corrugations. Such features had been observed in exposed faults on land, but never before in a fault deep beneath the surface.

"I had an early rendition of the interface that vaguely showed long grooves, and during my qualifying exam, Brodsky saw them and asked, 'are those corrugations!?' I didn't know, but I knew they were real features. Slip-derived corrugations was a really neat hypothesis, and we dug into it after that," he said.

The area in this study had long been a target for drilling into the megathrust by the Costa Rica Seismic Project (CRISP). Coauthor Eli Silver, professor emeritus of Earth and planetary sciences at UC Santa Cruz, and others in the CRISP program decided to pursue a 3-D seismic study, which must precede any deep drilling, and the project was funded by the National Science Foundation in 2009. "At present, two drilling expeditions have been accomplished with shallower targets, and, though not yet scheduled, we are hopeful that the deep drilling will occur," Silver said.

Researchers hope to use similar imaging techniques on other subduction zones, such as the Cascadia margin along the northern U.S. west coast, where there is a long history of large megathrust earthquakes and related tsunamis. "Conducting this type of 3-D study along the Cascadia margin could provide us with key information along the megathrust, a plate boundary that poses a substantial hazard risk to the U.S. west coast," Kluesner said.

Author: Tim Stephens | Source: University of California - Santa Cruz [February 12, 2018]

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