Pleistocene climate change promoted rapid diversification of aquatic invertebrates in Southeast Australia

ABSTRACT: BACKGROUND: The Pleistocene Ice Ages were the most recent geohistorical event of major global impact, but their consequences for most parts of the Southern hemisphere remain poorly known. We investigate a radiation of ten species of Sternopriscus, the most species-rich genus of epigean Australian diving beetles. These species are distinct based on genital morphology but cannot be distinguished readily by mtDNA and nDNA because of genotype sharing caused by incomplete lineage sorting. Their genetic similarity suggests a Pleistocene origin. RESULTS: We use a dataset of 3858 bp of mitochondrial and nuclear DNA to reconstruct a phylogeny of Sternopriscus using gene and species trees. Diversification analyses support the finding of a recent rapid speciation event with estimated speciation rates of up to 2.40 species per MY, which is considerably higher than the proposed average rate of 0.16 species per MY for insects. Additionally, we use ecological niche modeling and analyze data on habitat preferences to test for niche divergence between species of the recent Sternopriscus radiation. These analyses show that the species can be characterized by a set of ecological variables referring to habitat, climate and altitude. CONCLUSIONS: Our results suggest that the repeated isolation of populations in glacial refugia might have led to divergent ecological adaptations and the fixation of morphological traits supporting reproductive isolation and therefore may have promoted speciation. The recent Sternopriscus radiation fulfills many characteristics of a species flock and would be the first described example of an aquatic insect species flock. We argue that the species of this group may represent a stage in speciation past the species flock condition because of their mostly broad and often non-overlapping ranges and preferences for different habitat types.     

Ancient mitochondrial DNA evidence for prehistoric population movement: the Numic expansion

The mitochondrial DNA of modern Native Americans has been shown to fall into one of at least five haplogroups (A, B, C, D, or X) whose frequencies differ among tribal groups. The frequencies of these five haplogroups in a collection of ancient individuals from Western Nevada dating to between approximately 350-9,200 years BP were determined. These data were used to test the hypothesis, supported by archaeological and linguistic data, that the current inhabitants of the Great Basin, the Numic speakers, are recent immigrants into the area who replaced the previous non-Numic inhabitants. The frequency distributions of haplogroups in the ancient and modern Native Americans differed significantly, suggesting that there is a genetic discontinuity between the ancient inhabitants and the modern Numic speakers, providing further support for the Recent Numic Expansion hypothesis. The distribution of mitochondrial haplogroups of the ancient inhabitants of the Great Basin is most similar to those of some of the modern Native American inhabitants of California.     

Distribution of mtDNA haplogroup X among Native North Americans.

Mitochondrial DNA (mtDNA) samples of 70 Native Americans, most of whom had been found not to belong to any of the four common Native American haplogroups (A, B, C, and D), were analyzed for the presence of Dde I site losses at np 1715 and np 10394. These two mutations are characteristic of haplogroup X which might be of European origin. The first hypervariable segment (HVSI) of the non-coding control region (CR) of mtDNA of a representative selection of samples exhibiting these mutations was sequenced to confirm their assignment to haplogroup X. Thirty-two of the samples exhibited the restriction site losses characteristic of haplogroup X and, when sequenced, a representative selection (n = 11) of these exhibited the CR mutations commonly associated with haplogroup X, C --> T transitions at np 16278 and 16223, in addition to as many as three other HVSI mutations. The wide distribution of this haplogroup throughout North America, and its prehistoric presence there, are consistent with its being a fifth founding haplogroup exhibited by about 3% of modern Native Americans. Its markedly nonrandom distribution with high frequency in certain regions, as for the other four major mtDNA haplogroups, should facilitate establishing ancestor/descendant relationships between modern and prehistoric groups of Native Americans. The low frequency of haplogroups other than A, B, C, D, and X among the samples studied suggests a paucity of both recent non-Native American maternal admixture in alleged fullblood Native Americans and mutations at the restriction sites that characterize the five haplogroups as well as the absence of additional (undiscovered) founding haplogroups.     

敦煌西湖湿地鸟类栖息地重要性模糊综合评判

根据2007～2008年在甘肃敦煌西湖国家级自然保护区进行的湿地鸟类调查种类和数量数据,运用模糊综合评判法对保护区内的8块湿地进行了湿地鸟类栖息地重要性评价. 评判中隶属度的确定采用最佳因子值法,并分春、秋两种最佳因子值进行评判.结果表明:(1)春季各湿地均比秋季的重要性程度高,春季是管理的重点;(2)春秋两季南湖湿地重要性(0.938和0.966)都要远大于其它的湿地.春季盐池湾、羊水海子、南大湖的结果较相近,重要性程度次之,可持有相同程度的管理水平.党河水库、墩子湾、马圈湾、南园湖的重要性程度较低,只需一般水平的管理;(3)秋季各湿地水平除了南湖外普遍较低,羊水海子和盐池湾的重要性(0.340和0.269)相对较高些,但也只需一般水平的管理.     

The relation between mitogen activated protein kinase (MAPK) pathway and different genes expression in patients with beta Thalassemia

Backgroundβ-thalassemia is an inherited hemoglobinopathy resulting in quantitative changes in the β-globin chain. Understanding the molecular basis of that disorder requires studying the expression of genes controlling the pathways that affect the erythropoietic homeostasis especially the MAPK pathway. The MAPKs are a family of serine/threonine kinases that play an essential role in connecting cell-surface receptors to DNA in the nucleus of the cell.Aimto study the effect of expression of GNAI2, DUSP5 and ARRB1 genes on MAPK signaling pathway in pediatric patients with beta thalassemia.MethodsForty children with beta thalassemia major (TM), forty children with beta thalassemia intermedia (TI) and forty age and gender matched healthy controls were enrolled in this study. Detection of GNAI2, DUSP5 and ARRB1 mRNA expression was done by real time polymerase chain reaction (RT-PCR).Resultsrevealed increased expression of ARRB1 (Arrestin Beta 1) gene, and decreased expression of both GNAI2 (Guanine nucleotide-binding protein G (i) subunit alpha-2) and DUSP5 (Dual specificity protein phosphatase 5) genes in both patient groups than control groups respectively.ConclusionsChange in the rate of expression of ARRB1, GNAI2 and DUSP5 may have a role in the pathogenesis of abnormal hematopoiesis in cases of β thalassemia through affecting the MAPK pathway.     

多基因模型在肝细胞癌预后中的应用

利用较少分子信息预测肝细胞癌类型对患者的个性化治疗十分关键。探索已知的与肝细胞癌预后相关的信号通路,共发现41个关键基因。随后,运用机器学习的方法对其构建风险预测模型,并在4个肝细胞癌数据集上进行验证。结果显示,该模型能将肝细胞癌患者分成两个预后差异显著的类型:癌症基因图谱(The cancer genome atlas,TCGA)数据集交叉验证的平均log rank P值为0.03;其他测试数据集的log rank P 值分别为0.000 38、0.002 1和0.01。生物信息学分析显示肝细胞癌的预后与细胞周期等信号通路显著相关,并筛选出12个潜在的肝细胞癌分子标志物。研究结果表明,基于41个基因构建的肝细胞癌预后模型具有较好的稳健性和准确的风险预测能力。     

犁头霉11α-羟基化制备16β-甲基-11α,17α,21-三羟基孕甾-1,4-二烯-3,20-二酮

选育到一株对16β-甲基,17α,21-二羟基孕甾-1,4-二烯-3,20-二酮(Ⅱa)11α-羟基化活性强的犁头霉A28菌株,并发现底物21-乙酰化(Ⅱb)可明显提高11α-羟基化的能力.在适宜的转化条件下,Ⅱb投料浓度0.5%,产物16β-甲基-11α,11α,21-三羟基孕甾-1,4-二烯-3,20-二酮(Ⅲ)收率为73%,结构经波谱分析确认.     

Ancient DNA from the Schild site in Illinois: Implications for the Mississippian transition in the Lower Illinois River Valley

Archaeologists have long debated whether rapid cultural change in the archaeological record is due to in situ developments, migration of a new group into the region, or the spread of new cultural practices into an area through existing social networks, with the local peoples adopting and adapting practices from elsewhere as they see fit (acculturation). Researchers have suggested each of these explanations for the major cultural transition that occurred at the beginning of the Mississippian period (AD 1050) across eastern North America. In this study, we used ancient DNA to test competing hypotheses of migration and acculturation for the culture change that occurred between the Late Woodland (AD 400–1050) and Mississippian (AD 1050–1500) periods in the Lower Illinois River Valley. We obtained sequences of the first hypervariable segment of the mitochondrial genome (mtDNA) from 39 individuals (17 Late Woodland, 22 Mississippian) interred in the Schild cemetery in western Illinois, and compared these lineages to ancient mtDNA lineages present at other sites in the region. Computer simulations were used to test a null hypothesis of population continuity from Late Woodland to Mississippian times at the Schild site and to investigate the possibility of gene flow from elsewhere in the region. Our results suggest that the Late Woodland to Mississippian cultural transition at Schild was not due to an influx of people from elsewhere. Instead, it is more likely that the transition to Mississippian cultural practices at this site was due to a process of acculturation. Am J Phys Anthropol 156:434–448, 2015. © 2014 Wiley Periodicals, Inc.     

Imaging herpes simplex virus type 1 amplicon vector-mediated gene expression in human glioma spheroids

Vectors derived from herpes simplex virus type 1 (HSV-1) have great potential for transducing therapeutic genes into the central nervous system; however, inefficient distribution of vector particles in vivo may limit their therapeutic potential in patients with gliomas. This study was performed to investigate the extent of HSV-1 amplicon vector-mediated gene expression in a three-dimensional glioma model of multicellular spheroids by imaging highly infectious HSV-1 virions expressing green fluorescent protein (HSV-GFP). After infection or microscopy-guided vector injection of glioma spheroids at various spheroid sizes, injection pressures and injection times, the extent of HSV-1 vector-mediated gene expression was investigated via laser scanning microscopy. Infection of spheroids with HSV-GFP demonstrated a maximal depth of vector-mediated GFP expression at 70 to 80 μm. A > 80% transduction efficiency was reached only in small spheroids with a diameter of < 150 μm. Guided vector injection into the spheroids showed transduction efficiencies ranging between < 10 and > 90%. The results demonstrated that vector-mediated gene expression in glioma spheroids was strongly dependent on the mode of vector application-injection pressure and injection time being the most important parameters. The assessment of these vector application parameters in tissue models will contribute to the development of safe and efficient gene therapy protocols for clinical application.