Human paleodiet and animal utilization strategies during the Bronze Age in northwest Yunnan Province, southwest China

<div><p>Reconstructing ancient diets and the use of animals and plants augment our understanding of how humans adapted to different environments. Yunnan Province in southwest China is ecologically and environmentally diverse. During the Neolithic and Bronze Age periods, this region was occupied by a variety of local culture groups with diverse subsistence systems and material culture. In this paper, we obtained carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopic ratios from human and faunal remains in order to reconstruct human paleodiets and strategies for animal exploitation at the Bronze Age site of Shilinggang (ca. 2500 Cal BP) in northwest Yunnan Province. The δ¹³C results for human samples from Shilinggang demonstrate that people’s diets were mainly dominated by C₃-based foodstuffs, probably due to both direct consumption of C₃ food and as a result of C₃ foddering of consumed animals. Auxiliary C₄ food signals can also be detected. High δ¹⁵N values indicate that meat was an important component of the diet. Analysis of faunal samples indicates that people primarily fed pigs and dogs with human food waste, while sheep/goats and cattle were foddered with other food sources. We compare stable isotope and archaeobotanical data from Shilinggang with data from other Bronze Age sites in Yunnan to explore potential regional variation in subsistence strategies. Our work suggests that people adopted different animal utilization and subsistence strategies in different parts of Yunnan during the Bronze Age period, probably as local adaptations to the highly diversified and isolated environments in the region.</p></div

Isotopic value distributions for domesticated animals showing groups with different husbandry strategies.

<p>Isotopic value distributions for domesticated animals showing groups with different husbandry strategies.</p

Isotopic composition and quality indicators of human samples from Shilinggang, Yunnan.

<p>The samples marked in bold italics were found to be contaminated, and were not included in further statistical analysis. Context locations are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177867#pone.0177867.g002" target="_blank">Fig 2a</a>. Among the sample context codes, TNnWn (where n is an Arabic numeral) refers to excavation unit; Mn (where n is an Arabic numeral) refers to the grave number. “Ind.” stands for indeterminate sex.</p

Isotopic composition and quality indicators of animal samples from Shilinggang, Yunnan.

<p>Samples marked in bold italics were found to be contaminated, and were not included in further statistical analysis. Context locations are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177867#pone.0177867.g002" target="_blank">Fig 2a</a>. Among the sample context codes, TNnWn (where n is an Arabic numeral) refers to excavation unit; circles with a number inside refer to the stratigraphic layer.</p

The location of Shilinggang and other sites mentioned in the text.

<p>DEM (digital elevation model) data was downloaded from Geospatial Data Cloud (<a href="http://www.gscloud.cn/" target="_blank">http://www.gscloud.cn/</a>), and map features in the figure were modified from Li et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177867#pone.0177867.ref028" target="_blank">28</a>].</p

Comparison of human isotopic signatures for adult vs. child samples.

<p>Comparison of human isotopic signatures for adult vs. child samples.</p

Scatter diagram of human and animal collagen carbon and nitrogen values from Shilinggang.

<p>Analytical error is so small that it is contained within the symbols.</p

Image_2_Comparative transcriptomics reveal different genetic adaptations of biofilm formation in Bacillus subtilis isolate 1JN2 in response to Cd2+ treatment.jpg

Biofilm plays important roles in the life cycle of Bacillus species, such as promoting host and object surface colonization and resisting heavy metal stress. This study utilized transcriptomics to evaluate the impacts of cadmium on the components, morphology, and function of biofilms of Bacillus subtilis strain 1JN2. Under cadmium ion stress, the morphology of the B. subtilis 1JN2 biofilm was flattened, and its mobility increased. Moreover, differential gene expression analysis showed that the main regulator of biofilm formation, Spo0A, decreased in expression under cadmium ion stress, thereby inhibiting extracellular polysaccharide synthesis through the SinI/SinR two-component regulatory system and the AbrB pathway. Cadmium ion treatment also increased the SigD content significantly, thereby increasing the expression of the flagella encoding and assembly genes in the strain. This promoted poly-γ-glutamic acid production via the DegS/DegU two-component regulatory system and the conversion of biofilm extracellular polysaccharide to poly-γ-glutamic acid. This conferred cadmium stress tolerance in the strain. Additionally, the cadmium ion-mediated changes in the biofilm composition affected the colonization of the strain on the host plant root surface. Cadmium ions also induced surfactin synthesis. These findings illustrate the potential of Bacillus species as biocontrol strains that can mitigate plant pathogenic infections and heavy metal stress. The results also provide a basis for the screening of multifunctional biocontrol strains.</p

Plan map of northern Shilinggang and stratigraphic column from unit TN6W3.

<p>a) Plan map of the northern part of Shilinggang. Rectangular excavation units are labeled starting with the letter T. Features include burials (labeled with the letter “M”), pits (labeled with the letter “H”), and building foundations (labeled with the letter “F”). The features shown in Fig 2a are modified from Li et al. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177867#pone.0177867.ref028" target="_blank">28</a>]. b) Photograph of stratigraphic profile in unit TN6W3 (center right of plan map in Fig 2a). Circles around numbers indicate stratigraphic levels.</p

Additional file 1: of Attitudes towards suicide in urban and rural China: a population based, cross-sectional study

Appendix 1. Scale of Public Attitudes about Suicide (SPAS) (translated from the original Chinese). (DOCX 16 Kb