In 1950, Morgan, Morton and Parker described one of the first totally defined media that did not depend largely on animal products or extracts as nutritive sources. This medium supported the growth of primary chick embryo heart cells. It has since become known as Medium 199. Its current use is with the addition of serum in virus and vaccine production, and in the culture of many non-transformed cells. It is also used in combination with less complex media. Medium 199 modified with Hanks’ Balanced Salts is designed for use with cells maintained in ambient (non-CO2) atmospheric conditions. M2852 differs from the original formulation by containing all L-amino acids. The original formulation contained 10 DL-amino acids, which are less biologically active on a per gram basis than the corresponding L-amino acids.||Appearance: White, homogeneous, free flowing powder||Solubility: Colorless, clear, complete||pH: As Reported||Endotoxin: ≤1Eu/mlImportant Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

USbio全称United States Biological，位于麻省斯万普斯科特(Swampscott, MA)。全美**的抗原抗体和生化试剂供应商，目前向全球六十余个国家的科研工作者提供约50,000种抗体、抗原和生化试剂，以质量**闻名。主要产品种类包括：抗体、生化试剂、基因克隆相关产品、培养基、生长因子等细胞因子、分子生物学试剂。美国US Biological公司是生物化学和生物学试剂的专业生产商，产品服务于免疫学，分子生物学，分子遗传学，体外诊断，组织培养等科研领域。产品精确度高，质量稳定，产品数量巨大，提供70,000多种抗体、抗原和生化试剂等。