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Large wildlife removal drives immune defence increases in rodents

Smithsonian Libraries
* Anthropogenic disturbances involving land use change, climate disruption, pollution and invasive species have been shown to impact immune function of wild animals. These immune changes have direct impacts on the fitness of impacted animals and, also, potentially indirect effects on other species and on ecological processes, notably involving the spread of infectious disease. Here, we investigate whether the selective loss of large wildlife can also drive changes in immune function of other consumer species. * Using a long-standing large-scale exclosure experiment in East Africa, we investigated the effects of selective removal of large wildlife on multiple measures of immune function in the dominant small rodent in the system, the East African pouched mouse, Saccostomus mearnsi. * We find support for a general increase in immune function in landscapes where large wildlife has been removed, but with some variation across immune parameters. These changes may be mediated in part by increased pathogen pressure in plots where large wildlife has been removed due to major increases in rodent density in such plots, but other factors such as changes in food resources are also likely involved. * Overall, our research reveals that the elimination of large-bodied wildlife - now recognized as another major form of global anthropogenic change - may have cascading effects on immune health, with the potential for these effects to also impact disease dynamics in ecological communities.

Toward clearer skies: Challenges in regulating transboundary haze in Southeast Asia

Smithsonian Libraries
Addressing transboundary environmental problems, such as pollution, and climate change, hinge on strategies that often require both mandatory and voluntary participation of affected nations. Using an unprecedented approach, the Singapore government recently passed a Transboundary Haze Pollution Act (THPA) that financially penalizes companies for smoke-haze affecting the city-state but originating from activities outside her political boundaries. This Act may set a precedent for future actions against proximate actors of environmental degradation but is fraught with substantial challenges in implementation. In attempting to hold agri-business companies accountable, the THPA must present indisputable evidence of fire burning activities and positively identify the initiator of these fires. We further argue that small amendments to the THPA, and other similar laws, may result in environmental co-benefits related to carbon emissions, ecosystem services and biodiversity preservation.

Global prevalence and distribution of genes and microorganisms involved in mercury methylation

Smithsonian Libraries
Mercury (Hg) methylation produces the neurotoxic, highly bioaccumulative methylmercury (MeHg). The highly conserved nature of the recently identified Hg methylation genes hgcAB provides a foundation for broadly evaluating spatial and niche-specific patterns of microbial Hg methylation potential in nature. We queried hgcAB diversity and distribution in >3500 publicly available microbial metagenomes, encompassing a broad range of environments and generating a new global view of Hg methylation potential. The hgcAB genes were found in nearly all anaerobic (but not aerobic) environments, including oxygenated layers of the open ocean. Critically, hgcAB was effectively absent in ~1500 human and mammalian microbiomes, suggesting a low risk of endogenous MeHg production. New potential methylation habitats were identified, including invertebrate digestive tracts, thawing permafrost soils, coastal "dead zones," soils, sediments, and extreme environments, suggesting multiple routes for MeHg entry into food webs. Several new taxonomic groups capable of methylating Hg emerged, including lineages having no cultured representatives. Phylogenetic analysis points to an evolutionary relationship between hgcA and genes encoding corrinoid iron-sulfur proteins functioning in the ancient Wood-Ljungdahl carbon fixation pathway, suggesting that methanogenic Archaea may have been the first to perform these biotransformations. A global metagenome assessment reveals a low risk of methylmercury production in humans and a high potential in Arctic permafrost. A global metagenome assessment reveals a low risk of methylmercury production in humans and a high potential in Arctic permafrost.

Parabrachial lesions in rats disrupt sodium appetite induced by furosemide but not by calcium deprivation

Smithsonian Libraries
An appetite for CaCl2 and NaCl occurs in young rats after they are fed a diet lacking Ca or Na, respectively. Bilateral lesions of the parabrachial nuclei (PBN) disrupt normal taste aversion learning and essentially eliminate the expression of sodium appetite. Here we tested whether similar lesions of the PBN would disrupt the calcium-deprivation-induced appetite for CaCl2 or NaCl. Controls and rats with PBN lesions failed to exhibit a calcium-deprivation-induced appetite for CaCl2. Nevertheless, both groups did exhibit a significant calcium-deprivation-induced appetite for 0.5 M NaCl. Thus, while damage to the second central gustatory relay in the PBN disrupts the appetite for 0.5 M NaCl induced by furosemide, deoxycorticosterone acetate, and polyethylene glycol, the sodium appetite induced by dietary CaCl2 depletion remains intact.

Burpee Foundation: Cultivating America’s Gardens

Smithsonian Libraries
For as long as he can remember, George Ball, Chairman and CEO of W. Atlee Burpee and Chairman of the Board of the Burpee Foundation, has been gardening. As a young boy, his grandmother would send him to the yard to weed, watching him from her rocking chair on the porch. As George recalls, at more »

Back to School at the Portrait Gallery

National Portrait Gallery
Students in the galleries

Ptolemic-Era Black Granite Sarcophagus Discovered in Alexandria

Smithsonian Magazine

A black granite sarcophagus was recently uncovered in the Sidi Gaber district of Alexandria, Egypt, reports Rob Waugh at Yahoo News UK. The most exciting part? A layer of mortar between the lid and the rest of the tomb indicates that the coffin hasn’t been opened in 2,000 years, which is rare in Egypt where looters have picked through tombs and burials for millennia.

The ancient sarcophagus was found by local authorities during standard archaeological excavations conducted before the construction of a new building on Al-Karmili Street. It was found approximately 16 feet below ground. A rough alabaster bust of a man, likely a depiction of the body in the coffin, was also discovered in the tomb, which is believed to date from the era of the Ptolemies, the Greek royal family dynasty that ruled for roughly three centuries from 305 to 30 B.C.E.

According to the Ministry of Antiquities, the tomb is about 8.6 feet long and more than 5 feet wide. Mostafa Waziri, general secretary-general of the Supreme Council of Antiquities, says it is the largest sarcophagus ever excavated in the city.

This is just the latest discovery in Alexandria, an ancient city written off by archaeologists for decades. According to Andrew Lawler at Smithsonian, researchers often ignored the fabled city founded by Alexander the Great and ruled over by his close advisor Ptolemy and his descendants after its namesake’s death. That’s because over the centuries a bustling, congested metro area of 5 million people has grown up over the ruins of marble palaces, monuments and other ancient works.

But over the last few decades, researchers have begun the painstaking work of urban archaeology, going layer by layer into the city’s past. In 2005, archaeologists uncovered the remains of the University of Alexandria, where ancient Greek mathematician Archimedes studied. The remains of the Pharos, a lighthouse built by the Ptolemies that was considered one of the Seven Wonders of the Ancient World also lies in Alexandria’s harbor. In fact, changes in the flow of the Nile River and rising sea levels mean that large chunks of the ancient city are currently underwater, a submerged time capsule ready for exploration.

Alexandria isn’t the only coastal Egyptian city giving up its secrets. In the early 2000s, researchers discovered the legendary city Thonis-Heracleion, the ancient port city at the mouth of the Nile destroyed by an earthquake just a few miles from Alexandria. Jack Shenker at The Guardian reports that over the past decade and a half, underwater archaeologists have used vacuum systems to suck sediment and artifacts off the seabed, and have uncovered incredible statues, sarcophagi and stele, including the Decree of Sais, a stele that lays out Egypt’s intricate tax law. In fact, only 5 percent of Thonis-Heracleion has been explored, meaning there are decades of discoveries still to come.

While it’s too soon to make predictions on the identity of the body inside the newly discovered sarcophagus in Alexandria, one thing is for certain: it won’t be the last discovery made along Egypt’s Mediterranean coast.

Comparison of Circulating Iron, Total Iron Binding Capacity, and Percent Transferrin Saturation in Wild and Captive Kori Bustards (Ardeotis Kori)

Smithsonian Libraries
The kori bustard (Ardeotis kori) is one of the largest extant flighted birds and is displayed in zoos primarily in North America and Europe. In captivity, kori bustard diets are primarily based on animal proteins, whereas in the wild these birds eat a wide variety of plants, insects, and small vertebrate prey. The purpose of this study was to compare circulating iron, total iron binding capacity, and percent transferrin saturation levels in apparently healthy wild and captive kori bustards. Adult captive kori bustards had slightly higher percent transferrin saturation levels than juvenile captive birds, although this finding was not statistically significant. This information can be referenced as a guide for the assessment of nutrition and health in captive birds.
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