Scientists unlock secrets of ancient Egyptian materials with proteomics
Scientists unlock secrets of ancient Egyptian materials with proteomics
科学家利用蛋白质组学揭开古埃及材料的秘密
The precise composition of ancient Egyptian paints, binders, adhesives, and similar materials used to make artifacts is largely unknown, in part because a full analysis would require taking samples that would damage those valuable artifacts. The development of cutting-edge, non-destructive techniques has been helping to unlock those secrets, aiding conservation efforts.
古埃及文物所使用的颜料、粘合剂、胶水及类似材料，其精确成分在很大程度上仍是未解之谜。部分原因在于，进行全面分析需要提取样本，而这会损坏这些珍贵的文物。随着尖端无损检测技术的发展，科学家们正逐步揭开这些秘密，并助力文物保护工作。
Most recently, researchers have used mass spectrometry-based proteomics to analyze the glues and adhesives in a broad set of Egyptian artifacts, according to a new paper published in the journal Science Advances. They found plenty of expected sources, such as animal collagens and egg proteins, but also plant proteins, specifically from sesame and drumstick tree (moringa) cereals.
根据发表在《科学进展》（Science Advances）杂志上的一篇新论文，研究人员最近利用基于质谱的蛋白质组学技术，分析了一系列古埃及文物中的胶水和粘合剂。他们不仅发现了许多预料之中的成分，如动物胶原蛋白和蛋类蛋白质，还发现了植物蛋白，特别是来自芝麻和辣木（drumstick tree）的蛋白质。
As previously reported, the ancient Egyptians had a highly formalized (and easily recognizable) painting style, and there has been considerable interest in gaining insights into the specific pigments and painting techniques employed. Common pigments included hematite and realgar for red; goethite and orpiment for yellow; Egyptian blue; Egyptian green; carbon-based black; and calcite, gypsum, anhydrite, and huntite for white.
正如之前报道的那样，古埃及人拥有高度程式化（且极易辨认）的绘画风格，人们对深入了解其所使用的特定颜料和绘画技术一直抱有浓厚兴趣。常见的颜料包括：用于红色的赤铁矿和雄黄；用于黄色的针铁矿和雌黄；埃及蓝；埃及绿；碳基黑色；以及用于白色的方解石、石膏、硬石膏和水菱镁矿。
Many pigments available to ancient Egyptian artists have elemental markers detectable by X-ray fluorescence imaging. Macro-XRF imaging in particular has previously been used (in combination with hyperspectral imaging) to study a Greco-Roman painted funerary portrait from the second century CE, as well as to determine the remnants of color on marble at Delphi in Greece. In 2023, scientists used a portable MA-XRF imaging device to study ancient Egyptian paintings, part of a broader project investigating tomb chapels in the Theban Necropolis.
古埃及艺术家使用的许多颜料都含有可通过X射线荧光成像检测到的元素标记。特别是宏观X射线荧光（Macro-XRF）成像技术，此前曾（结合高光谱成像）被用于研究公元二世纪的一幅希腊-罗马彩绘葬礼肖像，以及确定希腊德尔斐大理石上的色彩残留。2023年，科学家们使用便携式MA-XRF成像设备研究了古埃及绘画，这是调查底比斯墓地墓室更广泛项目的一部分。
Mass spectrometry-based proteomics is a relative newcomer to the field and is capable of providing a thorough and very detailed characterization of any protein residues present in a given sample, as well as any accumulated damage. The technique is so sensitive that less sample material is needed compared to other methods. And unlike, say, gas chromatography-mass spectrometry, it’s also capable of characterizing all proteins present in a sample (regardless of the complexity of the mixture), rather than being narrowly targeted to predefined proteins.
基于质谱的蛋白质组学是该领域的一个相对较新的技术，它能够对样本中存在的任何蛋白质残留及其累积损伤进行全面且极其详细的表征。该技术非常灵敏，与其他方法相比，所需的样本量更少。此外，与气相色谱-质谱联用技术不同，它能够表征样本中存在的所有蛋白质（无论混合物多么复杂），而不是仅仅针对预定义的蛋白质。
For this latest study, the authors took tiny samples from several Egyptian artifacts housed in different collections in Sweden, the UK, and Denmark, dating between 1425 BCE to 400 CE. These included painted wooden coffins, wall painting fragments from a tomb, painted plaster used to make a mummy bust, and painted limestone architectural elements. In addition to those samples, the team also analyzed blank negative control samples and examined the chemical damage to all detected proteins in order to exclude the possibility of laboratory contamination from the final results.
在这项最新研究中，作者从瑞典、英国和丹麦不同收藏机构的几件古埃及文物中提取了微小样本，这些文物的年代跨度从公元前1425年到公元400年。其中包括彩绘木棺、墓葬壁画碎片、用于制作木乃伊半身像的彩绘石膏以及彩绘石灰岩建筑构件。除了这些样本外，研究小组还分析了空白阴性对照样本，并检查了所有检测到的蛋白质的化学损伤，以排除实验室污染对最终结果的影响。
The results confirmed that ancient Egyptians frequently used cow glue, as well as collagens derived from sheep, goats, horses, donkeys, and antelope. Those materials were most likely prepared by boiling animal skin and connective tissue. These weren’t just found in adhesive samples, but also in samples of paint and ground layers, suggesting that Egyptians chose their materials based on ready availability.
结果证实，古埃及人经常使用牛胶，以及从绵羊、山羊、马、驴和羚羊身上提取的胶原蛋白。这些材料很可能是通过煮沸动物皮和结缔组织制成的。这些成分不仅存在于粘合剂样本中，还存在于颜料和底漆层样本中，这表明古埃及人选择材料是基于其易获取性。
“No notable correlation was observed between the choice of the animal species/part and the object type, the nature of the application, the color, the chronology, the geographical origin, or the use context (funerary or palatial),” the authors wrote.
作者写道：“在动物物种/部位的选择与物体类型、应用性质、颜色、年代、地理来源或使用背景（葬礼或宫廷）之间，没有观察到显著的相关性。”
The team also detected the presence of distinctive seed proteins from sesame and moringa, both of which were common at the time in ancient Egypt; the oils extracted from those seeds were high quality and hence used for cooking, medicine, insect repellant, cosmetics, and mummification. Sesame proteins were found in a red sample from a coffin fragment and a tomb wall painting fragment, and moringa proteins were detected on a coffin sample. It’s possible they were residual byproducts of the seed processing, but more research combining complementary techniques is needed to better define how (and why) sesame and moringa may have been used.
研究小组还检测到了来自芝麻和辣木的独特种子蛋白，这两种植物在当时的古埃及都很常见；从这些种子中提取的油品质很高，因此被用于烹饪、医药、驱虫、化妆品和木乃伊制作。在来自棺材碎片和墓葬壁画碎片的红色样本中发现了芝麻蛋白，而在一个棺材样本上检测到了辣木蛋白。它们可能是种子加工后的残留副产品，但需要结合更多互补技术进行研究，以更好地界定芝麻和辣木是如何（以及为何）被使用的。
One possible clue lies in the fact that the moringa tree in particular held a special symbolic significance to ancient Egyptians. It was considered a manifestation of the god Ptah, believed to be the patron of craftsmen, and finding traces on a coffin…
一个可能的线索在于，辣木树对古埃及人具有特殊的象征意义。它被认为是工匠守护神普塔（Ptah）神的化身，而在棺材上发现其痕迹……