Real-Time Monitoring of the Evaporation and Fission of Electrospray-Ionized Polystyrene Beads and Bacterial Pellets at Elevated Temperatures.

This study uses real-time monitoring, at microsecond time scales, with a charge-sensing particle detector to investigate the evaporation and fission processes of methanol/micrometer-sized polystyrene beads (PS beads) droplets and bacterial particles droplets generated via electrospray ionization (ESI) under elevated temperatures. By incrementally raising capillary temperatures, the solvent, such as methanol on 0.75 µm PS beads, experiences partial evaporation. Further temperature increase induces fission, and methanol molecules continue to evaporate until PS ions are detected after this range. Similar partial evaporation is observed on 3 µm PS beads. However, the shorter period of the fission temperature range is necessary compared to 0.75 µm PS beads. For the spherical-shaped bacterium, Staphylococcus aureus, the desolvation process shows a similar fission period as compared to 0.75 µm PS beads. Comparably, the rod-shaped bacteria, Escherichia coli EC11303, and E. coli strain W have shorter fission periods than S. aureus. This research provides insights into the evaporation and fission mechanisms of ESI droplets containing different sizes and shapes of micrometer-sized particles, contributing to a better understanding of gaseous macroion formation.

Rapid Quantification of Polyhydroxybutyrate Polymer from Single Bacterial Cells with Mass Spectrometry.

Polyhydroxyalkanoate (PHA) is one of the biocompatible and biodegradable plastics that can be produced and accumulated as granules inside microorganisms. In this study, a new approach to rapidly quantify a short-chain-length PHA, polyhydroxybutyrate (PHB), produced from genetically engineered Escherichia coli containing phaCAB is presented. The mass of each bacterial cell was measured using a laser-induced radio frequency (rf) plasma charge detection quadrupole ion trap mass spectrometer (LIRFP CD QIT-MS), and then, the PHB contents were determined by calculating the change in cellular mass. The quantitative results showed that the PHB contents measured by LIRFP CD QIT-MS were consistent with those by reference analysis, gas chromatography (GC). The PHB content of each bacterial sample can be obtained within 20 min from sampling using LIRFP CD QIT-MS while GC analysis takes 2 days. In addition, LIRFP CD QIT-MS does not use any hazardous chemicals in cellular mass quantification as compared to GC. This indicates that LIRFP CD QIT-MS has potential in routine monitoring of PHB production.

Ionization of Submicrometer-Sized Particles by Laser-Induced Radiofrequency Plasma for Mass Spectrometric Analysis.

A laser-induced rf plasma (LIRFP) ion source was developed to ionize submicrometer-sized particles for the first time. The LIRFP ion source can increase the charge of those particles to several thousand charges via charge exchange reactions so that those particles can be trapped and analyzed with a charge detection quadrupole ion trap-mass spectrometer (CD QIT-MS). Different reagent gases for charge exchange reaction were investigated, viz. argon, nitrogen, oxygen, methane, helium, krypton, xenon, argon/methane (with ratios of 10:1 and 2:1), argon/nitrogen (with a ratio of 1:1), nitrogen/oxygen (10:1), krypton/methane (10:1), and air. The average charge of 0.75 µm polystyrene particles could reach 1631 using an argon/methane mixture with a ratio of ∼10:1. The average charges for freeze-dried Escherichia coli EC11303, Escherichia coli strain W, and Staphylococcus aureus were 842, 1112, and 971, respectively, with a mass-to-charge ratio ( m/ z) range from 107 to 108; and the average masses were 3.5 × 1010 Da, 6.0 × 1010 Da, and 5.6 × 1010 Da, respectively. The average mass and charge of the vaccinia virus were ∼9.1 × 109 Da and ∼708 with a m/ z of ∼107. This LIRFP CD QIT-MS method was rapid with only 20 min for each sample measurement.

[Study on material basis of Mahuang Fuzi Xixin decoction for anti-inflammation and immune suppression based on combined method of serum pharmacochemistry and serum pharmacology].

To investigate me material basis of Mahuang Fuzi Xixin decoction (MFXD) for anti-inflammation and immune-suppression based on the combined method of serum chemical and serum pharmacological. The LC-MS/MS fingerprints of MFXD, drug-containing serum and blank serum were compared to define the components in plasma. Histamine, ß-hexosaminidase released from RBL-2H3 cell infulenced by drug-containing serum at different time points were measured by ELISA. The effect of drug-containing serum on lipopolysaccharide-induced splenocyte proliferation at different time points were determined by MTT. A correlation analysis was made on components of MFXD and pharmacological indexes based the stepwise regression method. After the intragastrical administration with MFXD, 32 components were discovered in rat serum, including 27 prototype components (10 from Mahuang, 13 from Fuzi and four from Xixin) and five unknown components. Compared with blank serum, drug-containing serum could reduce the release of histamine from RBL-2H3 induced by antigen at different time points (P < 0.05); except the 4-hour drug-containing serum, all of the remaining drug-containing serums could inhibit the RBL-2H3 mastocyte degranulation induced by antigen at different time points (P < 0.05). Drug-containing serum could significantly lipopolysaccharide-induced mouse splenocyte proliferation at 15 and 30 min (P < 0.05). A regression analysis was made on the chemical data of components absorbed into blood and pharmacological indexes, i. e. release rate of histamine, release rate of ß-hexosaminidase and inhibition rate of splenocyte. This suggested the close correlations among methyl pseudo-ephedrine, pseudoephedrine and histamine released from RBL-2H3 induced by antigen; pseudoephedrine, hypaconine, methyl pseudoephedrine and ß-hexosaminidase released from RBL-2H3 induced by antigen; as well as benzoyl hypaconine, benzoylaconine, 14-benzoyl-10-OH-mesaconine, mesaconine and lipopolysaccharide-induced mouse splenocyte proliferation. Methylpseudoephedrine, pseudoephedrine, benzoyl hypaconine, benzoylaconine and mesaconine may be part of material basis of MFXD on anti-inflammation and immune suppression.

[Comparative analysis of volatile oils of Mahuang Fuzi Xixin decoction and its major constituted herbs by GC-MS].

OBJECTIVE: To evaluate the correlativity between volatile oils of Mahuang Fuzi Xixin decoction and its major constituted herbs in composition and proportion. METHODS: The chemical compositions of volatile oils obtained by wet distillation from Mahuang Fuzi Xixin decoction and its major constituted herbs (Herba Ephedrae, processed Radix Aconiti Lateralis, Herba Asari) were analyzed by GC-MS. RESULTS: 44 volatile components of Mahuang Fuzi Xixin decoction were identified, which mainly derived from its constituted herbs Mahuang and Xixin. 68, 8, 39 volatile components were respectively identified from volatile oils of Herba Epherae, processd Radix Aconiti Lateralis and Herba Asari. There were apparent changes in composition and proportion between volatile oils of Mahuang Fuzi Xixin decoction and its major constituted herbs. CONCLUSION: There are apparent changes not only in quantity but also in quality between decoction and its major constituted herbs. Meanwhile any changes in composition may lead to a change in efficacy.

Pharmacokinetic studies of multi-bioactive components in rat plasma after oral administration of Xintiantai â extract and effects of guide drug borneol on pharmacokinetics.

Objective: To investigate the in vivo pharmacokinetic characteristics of 17 bioactive components including ginsenoside Rg1, Rb1, Rd, berberine, epiberberine, jatrorrhizine, palmatine, columbamine, coptisine, evodiamine, dehydroevodiamine, rutaecarpine, limonin, hyperin, curcumin, demethoxycurcumin and bisdemethoxycurcumin in rat plasma after oral administration of Xintiantai I extract powder (XI) and Xintiantai I without guide drug borneol extract powder (XI without borneol), and study the compatibility effects of guide drug borneol on the pharmacokinetics. Methods: A UHPLC-MS/MS method was established and fully validated for the comparative pharmacokinetics of 17 bioactive components. The pharmacokinetics parameters of 17 bioactive components after oral administration of XI and XI without borneol were calculated by the software of DAS 3.0 and intercompared. Results: The specificity, linearity, lower limit of quantification (LLOQ), precision, accuracy, extraction recovery rates, matrix effects, and stability of the UHPLC-MS/MS assay were good within the acceptance criteria from FDA guidelines. Guide drug borneol can significantly increase AUC of G-Rd, palmatine, hyperin, curcumin, demethoxycurcumin, bisdemethoxycurcumin and C max of 16 bioactive components except for dehydroevodiamine (P < 0.05), decrease T max of G-Rd, berberine, columbamin, coptisine, limonin and MRT of 17 bioactive components in XI group (P < 0.05). Conclusion: Guide drug borneol enhanced the absorption of G-Rd, palmatine, hyperin, curcumin, demethoxycurcumin and bisdemethoxycurcumin.