零口战国墓颅骨的人类学特征

本文对陕西省临潼县零口村遗址发掘出土的战国秦墓颅骨的人类学特征进行了研究。该组颅骨的种族特征可归入现代亚洲蒙古人种的东亚人种范畴。在若干近代和古代对比组中 ,零口组的基本体质类型与近代华北组、新石器时代的宝鸡组和关中合并组、青铜时代的上马组和殷墟中小墓②组最为接近。     

Morphological and Molecular Characterization of Punctodera Stonei Brzeski, 1998 (Nematoda: Heteroderidae) from Virginia,USA

In August of 2021, several cysts with juveniles and eggs were discovered during a vegetation survey conducted at the Arlington National Cemetery, Virginia. Eight soil samples were collected from the rhizosphere region of the common grass (Festuca arundinacea L.) and processed at the Mycology and Nematology Genetic Diversity and Biology Laboratory (MNGDBL). Cysts were light to dark brown in color, and oval to pear-shaped without bullae in young cysts but present in older cysts and with prominent vulval cone. The juveniles had slightly concave stylet knobs projecting sometimes anteriorly, tail tapering gradually to a narrowly rounded terminus, and hyaline tail terminus conspicuous at least twice the length of stylet. The molecular analysis included the analysis of three gene sequence fragments: D2–D3 of 28S rRNA, ITS rRNA, and COI. The nematode species was identified by both morphological and molecular means as Stone''s cyst nematode, Punctodera stonei. Detection of P. stonei in Virginia represents a new record of this species in the United States, and a second report after Canada in North America.     

我国东北土壤有机碳、无机碳含量与土壤理化性质的相关性

根据黑龙江、吉林、辽宁省和内蒙古地区相关历史资料数据,分析了我国东北表层土壤(0-50 cm)土壤相关理化性质与有机碳、无机碳的相关性,得到如下结论:土壤全氮、碱解氮、全磷、速效磷、速效钾、K⁺离子交换量、Fe₂O₃、P₂O₅、总孔隙度均与土壤有机碳含量呈显著正相关(R²=0.10-0.94, n=38-345, P<0.0001),但与土壤无机碳含量则大多呈显著负相关(R²=0.11-0.30, n=37-122, P<0.01);与此相反,土壤pH值、容重与土壤有机碳呈负相关(R²=0.36-0.42,n=41-304, P<0.0001),而与无机碳呈显著正相关(R²=0.29-0.31,n=39-125, P <0.01)。表层土壤有机碳、无机碳与土壤理化性质呈相反变化趋势的结果说明,由于土壤利用方式变化所导致的土壤理化性质改变对土壤无机碳和有机碳可能具有相反影响。在研究土壤碳平衡过程中,应该充分考虑这种关系所导致的相互补偿作用,即有机碳的增加,可能意味着无机碳的减少,或者反之。目前研究中普遍忽略无机碳的变化,可能导致生态系统碳收支计算显著偏差,所获得的经验拟合方程有利于对我国东北地区土壤碳平衡研究产生的这种偏差进行粗略估计。     

气候变化对东北沼泽湿地潜在分布的影响

东北地区是我国沼泽湿地分布最广泛的地区。为研究沼泽湿地对气候变化的响应,选取了对沼泽湿地分布可能存在影响的26个环境因子,利用最大熵(Maximum Entropy, MaxEnt)模型模拟了沼泽湿地基准气候条件下的潜在分布,并预测了气候变化情景下2011-2040 年、2041-2070 年和2071-2100 年3个研究阶段东北沼泽湿地潜在分布。研究结果表明:最大熵模型预测精度较高(平均AUC(Aera Under Curve)为(0.826±0.005))。基准气候条件下东北沼泽潜在分布区主要为大小兴安岭和三江平原地区。随着时间的推进,东北地区沼泽湿地原有潜在分布面积明显减少,而新增潜在分布面积较少,总面积呈现急剧减少趋势。至2071-2100年,原有沼泽湿地潜在分布面积将减少99.80%,新增潜在分布面积仅2.48%,总潜在分布面积减少97.32%。空间分布上,东北沼泽湿地潜在分布呈现由东向西迁移,南北向中心收缩的趋势。研究结果可为东北地区沼泽湿地保护政策的制定提供参考。     

Effects of Forest Regrowth and Urbanization on Ecosystem Carbon Storage in a Rural–Urban Gradient in the Southeastern United States

Forest regrowth after cropland abandonment and urban sprawl are two counteracting processes that have influenced carbon (C) sequestration in the southeastern United States in recent decades. In this study, we examined patterns of land-use/land-cover change and their effect on ecosystem C storage in three west Georgia counties (Muscogee, Harris, and Meriwether) that form a rural–urban gradient. Using time series Landsat imagery data including MSS for 1974, TM for 1983 and 1991, and ETM for 2002, we estimate that from 1974 to 2002, urban land use in the area has increased more than 380% (that is, 184 km²). Most newly urbanized land (63%) has been converted from forestland. Conversely, cropland and pasture area has decreased by over 59% (that is, 380 km²). Most of the cropland area was converted to forest. As a result, the net change in forest area was small over the past 29 years. Based on Landsat imagery and agricultural census records, we reconstructed an annual gridded data set of land-cover change for the three counties for the period 1850 to 2002. These data sets were then used as input to the Terrestrial Ecosystem Model (TEM) to simulate land-use effects on C fluxes and storage for the study area. Simulated results suggest that C uptake by forest regrowth (approximately 23.0 g C m⁻² y⁻¹) was slightly greater than the amount of C released due to deforestation (approximately 18.4 g C m⁻² y⁻¹), thus making the three counties a weak C sink. However, the relative importance of different deforestation processes in this area changed significantly through time. Although agricultural deforestation was generally the most important C-release process, the amount of C release attributable to urbanization has increased over time. Since 1990, urbanization has accounted for 29% of total C loss from the study area. We conclude that balancing urban development and forest protection is critically important for C management and policy making in the southeastern United States.     

Post-translational modifications in MeHg-induced neurotoxicity

Mercury (Hg) exposure remains a major public health concern due to its widespread distribution in the environment. Organic mercurials, such as MeHg, have been extensively investigated especially because of their congenital effects. In this context, studies on the molecular mechanism of MeHg-induced neurotoxicity are pivotal to the understanding of its toxic effects and the development of preventive measures. Post-translational modifications (PTMs) of proteins, such as phosphorylation, ubiquitination, and acetylation are essential for the proper function of proteins and play important roles in the regulation of cellular homeostasis. The rapid and transient nature of many PTMs allows efficient signal transduction in response to stress. This review summarizes the current knowledge of PTMs in MeHg-induced neurotoxicity, including the most commonly PTMs, as well as PTMs induced by oxidative stress and PTMs of antioxidant proteins. Though PTMs represent an important molecular mechanism for maintaining cellular homeostasis and are involved in the neurotoxic effects of MeHg, we are far from understanding the complete picture on their role, and further research is warranted to increase our knowledge of PTMs in MeHg-induced neurotoxicity.     

三维技术对安徽白鹭洲战国墓M566墓主容貌的复原

2011年安徽白鹭洲发现战国时期保存完整的楚国贵族墓葬,因墓主人头发和发簪保存完好、墓主身份显赫而备受关注。该头骨保存完整,具有亚洲蒙古人种的特征,根据骨骼的形态推测其为女性,年龄为35-39岁。为展现该地区战国贵族妇女的容貌、丰富该地区考古多样性提供研究材料。本文首先使用高分辨率CT对该个体的头骨及下颌骨进行了扫描和重建,然后采用基于偏最小二乘回归的颅面复原方法实现生前容貌基本形态的复原。最后,结合考古资料,利用三维模型处理软件对面貌复原模型及其发饰进行了三维建模和纹理贴图等处理,提高了颅面复原模型的真实感,生动形象地再现战国贵族女性面部的形态特征。     

Selective antibacterial activity of the cationic peptide PaDBS1R6 against Gram-negative bacteria

Infections caused by Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa foremost among them, constitute a major worldwide health problem. Bioinformatics methodologies are being used to rationally design new antimicrobial peptides, a potential alternative for treating these infections. One of the algorithms used to develop antimicrobial peptides is the Joker, which was used to design the peptide PaDBS1R6. This study evaluates the antibacterial activities of PaDBS1R6 in vitro and in vivo, characterizes the peptide interaction to target membranes, and investigates the PaDBS1R6 structure in contact with mimetic vesicles. Moreover, we demonstrate that PaDBS1R6 exhibits selective antimicrobial activity against Gram-negative bacteria. In the presence of negatively charged and zwitterionic lipids the structural arrangement of PaDBS1R6 transits from random coil to α-helix, as characterized by circular dichroism. The tertiary structure of PaDBS1R6 was determined by NMR in zwitterionic dodecylphosphocholine (DPC) micelles. In conclusion, PaDBS1R6 is a candidate for the treatment of nosocomial infections caused by Gram-negative bacteria, as template for producing other antimicrobial agents.