Purification System for Polybasic Amphiphiles (PAs)

低膜通透性和广泛的外排是细菌防御机制，它们协同减少化合物在革兰氏阴性菌中的积累，导致内在耐药性，从而阻止抗菌剂达到(预期)生物效果(S)。多元两亲性(PAS)是一类新兴的被称为佐剂的“增效剂分子”，它通过增加外膜通透性和减少外排来拯救抗菌素在GNB中的耐药性。由于对人体的毒性和选择性的担忧，PAS作为治疗药物的来源被制药行业广泛忽视。然而，有许多以PA为基础的批准用于人类的药物的例子，包括基于多粘菌素和氨基糖苷类的抗生素以及大环内酯类阿奇霉素。此外，以PA为基础的抗菌肽(长春花素)在人类感染部位被释放，作为第一道防线，表明PAS在人类中的责任可以被最小化/抑制。*与非碱性两亲分子不同，PA是一种挑战分子的纯化方法。多胺是高极性分子，(取决于pH值)以中性、混合或多电离(聚阳离子)形式共存。目前，我的团队使用过时的低压反相闪光层析法反相提纯PAS。这项技术导致(I)低纯度水平和(Ii)少量积累(通常是10个活跃的研究合作)，将其研究时间的30%花费在纯化上。为了解决这些挑战，帮助学生提高竞争力，并使用各种固相反相萃取技术对学生进行现代净化技术培训，需要一套自动化的PA高压净化系统，以便能够快速获得半制备规模(5-50 mg)的高纯度(95%)的PA。*拟议的多元两亲化合物纯化系统预计将做出重大贡献，包括在与细菌系统的生物化学、生物有机化学和微生物学相关的广泛领域的潜在突破。这些研究收集的信息将对制定化学战略产生直接和直接的强烈影响，以解除全球细菌防御机制的武装并消除全球细菌的抗药性，其多种应用包括食品和水安全、兽医保健、农业和安全。*****

Low membrane permeability and extensive efflux are bacterial defence mechanisms which synergistically reduce compound accumulation in Gram-negative bacteria (GNB) resulting in intrinsic resistance that prevent antibacterial agents from achieving their (intended) biological effect(s). Polybasic amphiphiles (PAs) are an emerging class of “potentiator molecules” termed adjuvants that rescue antibacterials from resistance in GNB by enhancing outer membrane permeability and reducing efflux. PAs have been widely neglected by the pharmaceutical industry as a source of therapeutics because of perceived toxicity and selectivity concerns in humans. However, there are multiple examples of PA-based approved drugs for human use including the polymyxin- and aminoglycoside-based classes of antibiotics as well as the macrolide azithromycin. In addition, PA-based antimicrobial peptides (cathelicidins) are released at the site of human infection as a first line of defense indicating that the liabilities of PAs can be minimized/suppressed in humans. ******In contrast to non-basic amphiphiles, PAs are challenging molecules to purify. PAs are highly polar molecules that (depending on pH) coexist in neutral, mixed or polyionized (polycationic) forms. Currently my group purifies PAs by reverse-phase using outdated low-pressure reverse phase flash chromatography. This technique results in (i) low purity levels and (ii) accumulation of small quantities (typically 10 active research collaborations) to spend up to 30 % of their research time on purification. To resolve these challenges, to help students to become more competitive and to train students in modern purification techniques using various solid phase reverse phase extraction techniques, an automated high-pressure purification system for PAs is required to enable rapid access to PAs with high purity ( 95%) on semi-preparative scale (5-50 mg). ******The proposed purification system for polybasic amphiphiles is expected to make significant contributions, including potential breakthroughs in a wide variety of areas associated with biological chemistry of bacterial systems, bioorganic chemistry and microbiology. The information gathered by these studies will have immediate, direct strong impacts on the development of chemical strategies to disarm bacterial defence mechanisms and counter antimicrobial resistance in GNB with multiple applications including food and water safety, veterinary health, agriculture and security. *****