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This study aims to elucidate both the impact of copper on the structure of the gills and hepatopancreas and the induction of metallothionein (MT) during waterborne copper exposure in juvenile Macrobrachium rosenbergii. Structural observations were performed with light microscopy, and the MT titrations were performed with the cadmium saturation assay. The structural changes that occurred in the gills and hepatopancreas appeared to result from copper accumulation, and the degree of damage observed in both tissues was relevant to the elevated waterborne copper concentration. Exposure to copper concentrations ranging from 0.01 mg/L to 0.4 mg/L for 7 days resulted in profound structural changes including the accumulation of hemocytes in the hemocoelic space; swelling and fusion of the lamellae; abnormal gill tips; and hyperplastic, necrotic, and clavate-globate lamellae in the gills. Similarly, hemocytic infiltration in the interstitial sinuses, an increased number of hemocytes, thickening and ruptures of the basal laminae, and necrosis of the tubules were observed in the hepatopancreas. The MT measurements showed no significant differences in MT contents between the control group and the group treated with 0.01 mg/L waterborne copper. The maximum MT content was observed at the level of 0.4 mg/L waterborne copper.

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The Han Chinese are the largest ethnic group in the world, and their origins, development, and expansion are complex. Many genetic studies have shown that Han Chinese can be divided into two distinct groups: northern Han Chinese and southern Han Chinese. The genetic history of the southern Han Chinese has been well studied. However, the genetic history of the northern Han Chinese is still obscure. In order to gain insight into the genetic history of the northern Han Chinese, 89 human remains were sampled from the Hengbei site which is located in the Central Plain and dates back to a key transitional period during the rise of the Han Chinese (approximately 3,000 years ago). We used 64 authentic mtDNA data obtained in this study, 27 Y chromosome SNP data profiles from previously studied Hengbei samples, and genetic datasets of the current Chinese populations and two ancient northern Chinese populations to analyze the relationship between the ancient people of Hengbei and present-day northern Han Chinese. We used a wide range of population genetic analyses, including principal component analyses, shared mtDNA haplotype analyses, and geographic mapping of maternal genetic distances. The results show that the ancient people of Hengbei bore a strong genetic resemblance to present-day northern Han Chinese and were genetically distinct from other present-day Chinese populations and two ancient populations. These findings suggest that the genetic structure of northern Han Chinese was already shaped 3,000 years ago in the Central Plain area.

BackgroundThe Tarim Basin in western China, known for its amazingly well-preserved mummies, has been for thousands of years an important crossroad between the eastern and western parts of Eurasia. Despite its key position in communications and migration, and highly diverse peoples, languages and cultures, its prehistory is poorly understood. To shed light on the origin of the populations of the Tarim Basin, we analysed mitochondrial DNA polymorphisms in human skeletal remains excavated from the Xiaohe cemetery, used by the local community between 4000 and 3500 years before present, and possibly representing some of the earliest settlers.ResultsXiaohe people carried a wide variety of maternal lineages, including West Eurasian lineages H, K, U5, U7, U2e, T, R*, East Eurasian lineages B, C4, C5, D, G2a and Indian lineage M5.ConclusionOur results indicate that the people of the Tarim Basin had a diverse maternal ancestry, with origins in Europe, central/eastern Siberia and southern/western Asia. These findings, together with information on the cultural context of the Xiaohe cemetery, can be used to test contrasting hypotheses of route of settlement into the Tarim Basin.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0237-5) contains supplementary material, which is available to authorized users.