A self-penetrating and chemically stable zinc (ii)-organic framework as multi-responsive chemo-sensor to detect pesticide and antibiotics in water

Guided by the self-penetrating features can improve the stability of metal organic frameworks (MOFs), an unprecedented 3D self-penetrated framework, {[Zn (tptc)_0.5(bimb)]·H₂O}_n ( NUC-6 , here NUC corresponding to North University of China), with 3D (4,4)-c {8⁶} net, was designed. Benefit from the high chemical stability and excellent luminescent property, NUC-6 can be act as an efficient multi-response chemo-sensor in detecting dichloronitroaniline pesticide and nitrofuran antibiotics in water with the detection limits are 116 ppb for DCN pesticide, 16 ppb for NFT antibiotic, and 12 ppb for NTZ antibiotic. Besides, the mechanisms of luminescence quenching were revealed from the viewpoint of internal filter effect (IFE) and photo-induced electron transfer (PET), implied by the optical spectroscopy and quantum chemical calculation. This work provides a promising strategy to design stable MOFs by improving the self-penetrating features and to expand their practical applications in the detection of organic pollutants in aqueous medium.     

Antivitamins B12—Some Inaugural Milestones

The recently delineated structure- and reactivity-based concept of antivitamins B₁₂ has begun to bear fruit by the generation, and study, of a range of such B₁₂-dummies, either vitamin B₁₂-derived, or transition metal analogues that also represent potential antivitamins B₁₂ or specific B₁₂-antimetabolites. As reviewed here, this has opened up new research avenues in organometallic B₁₂-chemistry and bioinorganic coordination chemistry. Exploratory studies with antivitamins B₁₂ have, furthermore, revealed some of their potential, as pharmacologically interesting compounds, for inducing B₁₂-deficiency in a range of organisms, from hospital resistant bacteria to laboratory mice. The derived capacity of antivitamins B₁₂ to induce functional B₁₂-deficiency in mammalian cells and organs also suggest their valuable potential as growth inhibitors of cancerous human and animal cells.     

Determination of sulfa antibiotic residues in river and particulate matter by field-amplified sample injection-capillary zone electrophoresis

In the present research, field-amplified sample injection–CZE (FASI–CZE) coupled with a diode array detector was established to determine trace level sulfa antibiotic. Sulfathiazole, sulfadiazine, sulfamethazine, sulfadimethoxine, sulfamethoxazole, and sulfisoxazole were selected as analytes for the experiments. The background electrolyte solution consisted of 70.0 mmol/L borax and 60.0 mmol/L boric acid (including 10% methanol, pH 9.1). The plug was 2.5 mmol/L borax, which was injected into the capillary at a pressure of 0.5 psi for 5 s. Then the sample was injected into the capillary at an injection voltage of –10 kV for 20 s. The electrophoretic separation was carried out under a voltage of +19 kV. The capillary temperature was maintained at 20˚C throughout the analysis, and six sulfonamides were completely separated within 35 min. Compared with pressure injection-CZE, the sensitivity of FASI-CZE was increased by 6.25–10.0 times, and the LODs were reduced from 0.2–0.5 to 0.02–0.05 μg/mL. The method was applied to the determination of sulfonamides in river water and particulate matter samples. The recoveries were 78.59–106.59%. The intraday and interday precisions were 2.89–7.35% and 2.77–7.09%, respectively. This provides a simpler and faster method for the analysis of sulfa antibiotic residues in environmental samples.     

Ensuring robustness in the quality of antibiotic susceptibility test discs for four novel antibiotics

Antibiotic susceptibility test (AST) discs are used as an in-vitro diagnostic tool to select the appropriate antibiotic to treat an infection. Generally, the concentration of the drug loaded on to the AST discs is measured by studying its activity against quality control organisms. This methodology has several limitations—it is time consuming, requires trained manpower, has a wider acceptance criteria of zone of inhibitions—causing ambiguity in judging smaller variations in drug concentration. To overcome these issues, we have developed and validated high-performance liquid chromatographic (HPLC) methods for the determination of strength of AST discs for in-house researched antibiotics, namely Levonadifloxacin/WCK 771, Nafithromycin/WCK 4873, Cefepime-Tazobactam/WCK 4282, and Cefepime-Zidebactam/WCK 5222. The drugs were extracted from the AST discs using an appropriate solvent. The developed methods are simple, accurate, precise, reproducible, rugged, and robust. They are efficient in terms of time, and can be easily conducted in a quality control laboratory during release as well as stability evaluation of AST disc. Application of HPLC methods for the determination of strength of AST discs ensures flawless quality and, consequently, a better selection of drugs to treat bacterial infections in clinics.     

Development and validation of a sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method for quantitative analysis of bambermycin in livestock and aquatic products: Implications for food safety control and regulatory enforcement

A sensitive and accurate analytical method was developed and validated to detect bambermycin, a commonly used antibiotic in animal feed and livestock. The presence of bambermycin residues in food products can pose health risks to consumers, emphasizing the need for a sensitive and accurate analytical method. A reversed-phase analytical column was utilized with a mobile phase comprising 0.005 mol/L ammonium acetate in 5% acetonitrile (A) and 0.005 mol/L ammonium acetate in 95% acetonitrile (B) to achieve effective chromatographic separation. Quantitative determination of bambermycin in various samples, including beef, pork, chicken, milk, eggs, flatfish, eel, and shrimp, was performed using ultra-high-performance liquid chromatography-tandem mass spectrometry. Sample extraction involved a mixture of methanol and a 25% ammonium hydroxide solution, followed by low-temperature purification and phospholipid removal utilizing a Phree cartridge. The method exhibited a satisfactory recovery rate ranging from 69% to 100%. Validation results demonstrated the reliability, robustness, and accuracy of the method, exhibiting good linearity, precision, and recovery. This validated method can be applied for routine analysis of bambermycin residues, assisting in the development of effective monitoring and control measures to ensure the safety of livestock and aquatic products.     

Citronellol-Based Long-Lasting Antibacterial Cotton Fabrics without Bacterial Resistance

Antibacterial cotton helps prevent the growth and spread of harmful microorganisms, reduces the risk of infection, and has a prolonged service life by reducing bacterial degradation. However, most antibacterial agents used are toxic to humans and the environment. Citronellol-poly(N,N-dimethyl ethyl methacrylate) (CD), a highly effective antibacterial polymer, is synthesized from natural herbal essential oils (EOs). CD exhibited efficient, rapid bactericidal activity against Gram-positive, Gram-negative, and drug-resistant bacteria. Citronellol's environmental benignity makes CDs less hemolytic. Notably, negligible drug resistance developed after 15 bacterial subcultures. The CD-treated cotton fabric displayed better antibacterial performance than AAA-grade antibacterial fabric, even after repeated washing. This study extends the practical application of EOs to antibacterial surfaces and fabrics, which is promising for use in personal care products and medical settings.     

基质辅助激光解析/电离飞行时间质谱(MALDI-TOF MS)在微生物鉴定中的应用*

基质辅助激光解析/电离飞行时间质谱(MALDI-TOF MS)是一种新型软电离生物质谱,具有检测速度快、操作简便、结果准确等优点,目前已成为可靠的微生物快速鉴定技术。就工作流程而言,与常规生化方法相比,MALDI-TOF MS可以将微生物鉴定的时间缩短为一天甚至更短。对于具有抗生素耐药性的微生物,使用MALDI-TOF MS鉴定也有很好的准确性。在病毒鉴定中,MALDI-TOF MS也可以发挥作用,已有报道将MALDI-TOF MS和机器学习(ML)分析方法结合来检测鼻拭子中SARS-CoV-2。此外,MALDI-TOF MS还可用于细菌的无光谱库鉴定。目前,MALDI-TOF MS正通过与其他技术(例如傅里叶红外光谱FTIR)相结合进一步扩大微生物鉴定范围。     

一种新型噁唑烷酮类抗生素的合成

以2,4-二溴吡啶为原料,经Weinreb酰胺酰化、Noyori不对称氢转移反应、脱Boc保护基、环化、Suzuki偶联、磷酸单酯化及成盐共七步反应制得一种新型噁唑烷酮类抗生素【【(3R,3aS)-7-{6-[(S)3-甲基-2-噁唑烷酮-5-基]吡啶-3-基}-1-氧-1,3,3a,4-四氢苯并[b]噁唑[3,4-d][1,4]噁嗪-3-基】甲基】磷酸单酯二钠盐,其结构经~1H NMR,~(13)C NMR和HR-MS(ESI)确征,总收率7%,纯度99.7%。     

The Discovery of 2‐Aminobenzimidazoles That Sensitize Mycobacterium smegmatis and M. tuberculosis to β‐Lactam Antibiotics in a Pattern Distinct from β‐Lactamase Inhibitors

A library of 2‐aminobenzimidazole derivatives was screened for the ability to suppress β‐lactam resistance in Mycobacterium smegmatis. Several non‐bactericidal compounds were identified that reversed intrinsic resistance to β‐lactam antibiotics in a manner distinct from β‐lactamase inhibitors. Activity also translates to M. tuberculosis, with a lead compound from this study potently suppressing carbenicillin resistance in multiple M. tuberculosis strains (including multidrug‐resistant strains). Preliminary mechanistic studies revealed that the lead compounds act through a mechanism distinct from that of traditional β‐lactamase inhibitors.     

Monitoring the Reaction of the Body State to Antibiotic Treatment against Helicobacter pylori via Infrared Spectroscopy: A Case Study

The current understanding of deviations of human microbiota caused by antibiotic treatment is poor. In an attempt to improve it, a proof-of-principle spectroscopic study of the breath of one volunteer affected by a course of antibiotics for Helicobacter pylori eradication was performed. Fourier transform spectroscopy enabled searching for the absorption spectral structures sensitive to the treatment in the entire mid-infrared region. Two spectral ranges were found where the corresponding structures strongly correlated with the beginning and end of the treatment. The structures were identified as methyl ester of butyric acid and ethyl ester of pyruvic acid. Both acids generated by bacteria in the gut are involved in fundamental processes of human metabolism. Being confirmed by other studies, measurement of the methyl butyrate deviation could be a promising way for monitoring acute gastritis and anti-Helicobacter pylori antibiotic treatment.