Bacterial membrane vesicles: orchestrators of interkingdom interactions in microbial communities for environmental adaptation and pathogenic dynamics.

Bacterial membrane vesicles (MVs) have attracted increasing attention due to their significant roles in bacterial physiology and pathogenic processes. In this review, we provide an overview of the importance and current research status of MVs in regulating bacterial physiology and pathogenic processes, as well as their crucial roles in environmental adaptation and pathogenic infections. We describe the formation mechanism, composition, structure, and functions of MVs, and discuss the various roles of MVs in bacterial environmental adaptation and pathogenic infections. Additionally, we analyze the limitations and challenges of MV-related research and prospect the potential applications of MVs in environmental adaptation, pathogenic mechanisms, and novel therapeutic strategies. This review emphasizes the significance of understanding and studying MVs for the development of new insights into bacterial environmental adaptation and pathogenic processes. Overall, this review contributes to our understanding of the intricate interplay between bacteria and their environment and provides valuable insights for the development of novel therapeutic strategies targeting bacterial pathogenicity.

Pyrolysis and thermal-oxidation characterization of organic carbon and black carbon aerosols.

In this study, the pyrolytic behaviors and the thermal-oxidation decomposition characteristics of organic carbon (OC), pyrolytically generated elemental carbon (PEC) and black carbon (BC) particles have been studied in inert and air atmosphere respectively, in order to develop a new PEC correction method for the determination of BC by using thermal oxidation method. Our results indicated that: 1) a part of OC can be removed by heating it at 400°C in inert atmosphere and another part of OC was charred to form PEC, whereas, the weight of BC particles approximately keeps no change in the same conditions. 2) PEC and BC began to decompose at a similar temperature in air atmosphere. However, the decomposition rate of PEC is quite different from that of BC in air atmosphere and the difference varied with the temperature. As maximum, the decomposition rate of PEC is 5.64 times faster than that of BC particles at 500°C in air atmosphere. Based on the difference of the decomposition rate between PEC and BC, a new method of PEC correction was developed for the thermal oxidation method. With the help of the new PEC correction method and thermal analyzer, we successfully determined OC and BC concentrations in actual soot sample and artificial soot samples. The results obtained with our PEC correction method are consistent well with the real value or those analyzed with thermal-optical method, suggesting that the novel PEC correction method have a high accuracy.

Chemical characterization and source identification of polycyclic aromatic hydrocarbons in aerosols originating from different sources.

To obtain the characteristic factors or signatures of particulate polycyclic aromatic hydrocarbons (PAHs) to help identify the sources of particulate PAHs in the atmosphere, different carbonaceous aerosols were generated by burning different fossil fuels and biomass under different conditions in the laboratory, and the chemical characteristics of 14 PAHs were studied in detail. The results showed that (1) carbonaceous aerosols derived from domestic burning of coal, diesel fuel, and gasoline have much higher concentrations of PAHs than those derived from domestic burning of biomass; (2) carbonaceous aerosols derived from domestic burning of diesel fuel/gasoline have similar PAH components as those derived from high-temperature combustion of diesel fuel/gasoline, although the former have much higher concentrations of PAHs than the latter, suggesting that the burning temperature obviously affects the emitting amount of particulate PAHs, but only slightly influences the PAHs components; and (3) the ratios of benzo[b]fluoranthene/acenaphthylene, benzo[b]fluoranthene/fluorene, dibenzo[a,h]anthracene/acenaphthylene, dibenzo[a,h]anthracene/fluorine, and benzo[b]fluoranthene/benzo[k]fluoranthene in carbonaceous aerosols are sensitively dependent on their sources, indicating that these ratios are suitable for use as characteristic factors or signatures of particulate PAHs in the atmosphere.