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Find video protocols related to scientific articles indexed in Pubmed.
Intraskeletal isotopic compositions (?(13) C, ?(15) N) of bone collagen: Nonpathological and pathological variation.
Am. J. Phys. Anthropol.
PUBLISHED: 12-11-2013
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Paleodiet research traditionally interprets differences in collagen isotopic compositions (?(13) C, ?(15) N) as indicators of dietary distinction even though physiological processes likely play some role in creating variation. This research investigates the degree to which bone collagen ?(13) C and ?(15) N values normally vary within the skeleton and examines the influence of several diseases common to ancient populations on these isotopic compositions. The samples derive from two medieval German cemeteries and one Swiss reference collection and include examples of metabolic disease (rickets/osteomalacia), degenerative joint disease (osteoarthritis), trauma (fracture), infection (osteomyelitis), and inflammation (periostitis). A separate subset of visibly nonpathological skeletal elements from the German collections established normal intraindividual variation. For each disease type, tests compared bone lesion samples to those near and distant to the lesions sites. Results show that normal (nonpathological) skeletons exhibit limited intraskeletal variation in carbon- and nitrogen-isotope ratios, suggesting that sampling of distinct elements is appropriate for paleodiet studies. In contrast, individuals with osteomyelitis, healed fractures, and osteoarthritis exhibit significant intraskeletal differences in isotope values, depending on whether one is comparing lesions to near or to distant sites. Skeletons with periostitis result in significant intraskeletal differences in nitrogen isotope values only, while those with rickets/osteomalacia do not exhibit significant intraskeletal differences. Based on these results, we suggest that paleodiet researchers avoid sampling collagen at or close to lesion sites because the isotope values may be reflecting both altered metabolic processes and differences in diet relative to others in the population. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.
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Carbon and nitrogen isotopic survey of northern peruvian plants: baselines for paleodietary and paleoecological studies.
PLoS ONE
PUBLISHED: 01-16-2013
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The development of isotopic baselines for comparison with paleodietary data is crucial, but often overlooked. We review the factors affecting the carbon (?(13)C) and nitrogen (?(15)N) isotopic compositions of plants, with a special focus on the carbon and nitrogen isotopic compositions of twelve different species of cultivated plants (n?=?91) and 139 wild plant species collected in northern Peru. The cultivated plants were collected from nineteen local markets. The mean ?(13)C value for maize (grain) was -11.8±0.4 ‰ (n?=?27). Leguminous cultigens (beans, Andean lupin) were characterized by significantly lower ?(15)N values and significantly higher %N than non-leguminous cultigens. Wild plants from thirteen sites were collected in the Moche River Valley area between sea level and ?4,000 meters above sea level (masl). These sites were associated with mean annual precipitation ranging from 0 to 710 mm. Plants growing at low altitude sites receiving low amounts of precipitation were characterized by higher ?(15)N values than plants growing at higher altitudes and receiving higher amounts of precipitation, although this trend dissipated when altitude was >2,000 masl and MAP was >400 mm. For C(3) plants, foliar ?(13)C was positively correlated with altitude and precipitation. This suggests that the influence of altitude may overshadow the influence of water availability on foliar ?(13)C values at this scale.
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The effects of phenotypic plasticity on photosynthetic performance in winter rye, winter wheat and Brassica napus.
Physiol Plant
PUBLISHED: 11-29-2011
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The contributions of phenotypic plasticity to photosynthetic performance in winter (cv Musketeer, cv Norstar) and spring (cv SR4A, cv Katepwa) rye (Secale cereale) and wheat (Triticum aestivum) cultivars grown at either 20°C [non-acclimated (NA)] or 5°C [cold acclimated (CA)] were assessed. The 22-40% increase in light-saturated rates of CO? assimilation in CA vs NA winter cereals were accounted for by phenotypic plasticity as indicated by the dwarf phenotype and increased specific leaf weight. However, phenotypic plasticity could not account for (1) the differential temperature sensitivity of CO? assimilation and photosynthetic electron transport, (2) the increased efficiency and light-saturated rates of photosynthetic electron transport or (3) the decreased light sensitivity of excitation pressure and non-photochemical quenching between NA and NA winter cultivars. Cold acclimation decreased photosynthetic performance of spring relative to winter cultivars. However, the differences in photosynthetic performances between CA winter and spring cultivars were dependent upon the basis on which photosynthetic performance was expressed. Overexpression of BNCBF17 in Brassica napus generally decreased the low temperature sensitivity (Q??) of CO? assimilation and photosynthetic electron transport even though the latter had not been exposed to low temperature. Photosynthetic performance in wild type compared to the BNCBF17-overexpressing transgenic B. napus indicated that CBFs/DREBs regulate not only freezing tolerance but also govern plant architecture, leaf anatomy and photosynthetic performance. The apparent positive and negative effects of cold acclimation on photosynthetic performance are discussed in terms of the apparent costs and benefits of phenotypic plasticity, winter survival and reproductive fitness.
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Isotopic paleoecology of Clovis mammoths from Arizona.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-24-2011
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The causes of megafaunal extinctions in North America have been widely debated but remain poorly understood. Mammoths (Mammuthus spp.) in the American Southwest were hunted by Clovis people during a period of rapid climate change, just before the regional onset of Younger Dryas cooling and mammoth extirpation. Thus, these mammoths may provide key insights into late Pleistocene extinction processes. Here we reconstruct the seasonal diet and climatic conditions experienced by mammoths in the San Pedro Valley of Arizona, using the carbon ((13)C/(12)C) and oxygen ((18)O/(16)O) isotope compositions of tooth enamel. These records suggest that Clovis mammoths experienced a warm, dry climate with sufficient summer rainfall to support seasonal C(4) plant growth. Monsoon intensity may have been reduced relative to the preceding time period, but there is no isotopic evidence for severe drought. However, it is possible that the "Clovis drought", inferred from stratigraphic evidence, occurred suddenly at the end of the animals lives and thus was not recorded in the enamel isotopic compositions. Unlike mammoths that lived before the Last Glacial Maximum, Clovis mammoths regularly increased C(4) grass consumption during summer, probably seeking seasonally green grasslands farther from the river valley. This predictable seasonal behavior may have made mammoths easier to locate by Clovis hunters. Furthermore, Clovis mammoths probably had no previous experience of such sudden climatic change as is believed to have occurred at the time of their extinction.
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Evidence of latitudinal migration in tri-colored bats, Perimyotis subflavus.
PLoS ONE
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Annual movements of tri-colored bats (Perimyotis subflavus) are poorly understood. While this species has been considered a regional migrant, some evidence suggests that it may undertake annual latitudinal migrations, similar to other long distance North American migratory bat species.
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Stable isotope biogeochemistry of seabird guano fertilization: results from growth chamber studies with maize (Zea mays).
PLoS ONE
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Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues (diet, habitat use, migration) in ecology, geology, archaeology, and related disciplines. A crucial component to these studies is a thorough understanding of the range and causes of baseline isotopic variation, which is relatively poorly understood for nitrogen (?(15)N). Animal excrement is known to impact plant ?(15)N values, but the effects of seabird guano have not been systematically studied from an agricultural or horticultural standpoint.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.