The pulmonary toxicology after H2S inhalation was studied with bronchoaleveolar lavage (BAL),ultracentrifuge.and optical and electron microscopy in rats.The changes of the activities of lactate dehydrogenase,alkaline phosphatase,acid phosphatase and angiotension converting enzyme in BAL fluid were used as indicators of cellular damages.those of leucocytic count as the indicator of inflammatory response,and those of the concentration of protein and Evans blue as the indicator of the alterations of vascular permeability.In addition,the effects of H2S on lipid peroxidation,natural antioxidative system and energy substances and the changes of phospholipid concentration in BAL fluid were also studied.The results were as follows:(1)Inhalation of H2S exerted a severe cytotoxic effect on the lung tissues resulting in damages on various types of cells and a severe edematogenic effect on lung parenchyma.(2)The development of pulmonary edema in H2S intoxication resulted from a combination of different pathogenic factors.(3)The biochemical changes and their recovery occurred earlier than those of the pathological changes.The effecacy of 6 categories of drugs including 25 medicaments against H2S intoxication was e-valuated in mice,and 10 drugs were found prophylactically effective.The effects of various methe-moglobin-forming substances and some other drugs were also investingated in their treatment for H2S intoxication in rabbitsand dogs.It was concluded that methemoglobin-forming substances could be used as specific antidotes but could not prevent or diminish the lung damages due to H2S inhalation unless they were administered in association with dexamethasone,vitamin E,and anisodamine.Eventually,a postulated scheme of the medical treatment for H2S intoxication was presented.

The effects of 4-DMAP and NaNO2 on the hemodynamics of dogs suffering from acute hemorrhage complicated with cyanide poisoning were studied. It was found that the administration of 4-DMAP could brought about an increase of the cardiovascular functions in the experimental animals. Although the increase was temporal and not very impressive, it played an important role to prevent the dogs from developing cardiovascular collapse during the period of observation. On the other hand, the administration of NaNO2 resulted in a transient excitation for 1-2 minutes and then a prolonged and progressive depression of the cardiovascular functions, and all the experimental animals died from cardiovascular failure within 13-19 minutes after NaNO2 injection.The results of this study indicate that 4-DMAP as a therapeutic agent for acute hemorrhage complicated with cyanide poisoning is superior to NaNO2 since the former can produce an excitation of the cardiovascular functions while the latter a progressive depression and eventually a failure of the cardiovascular functions.

Through introducing mutations into ribosomes by obtaining spontaneous drug resistance of microorganisms, ribosome engineering technology is an effective approach to develop mutant strains that overproduce secondary metabolites. In this study, ribosome engineering was used to improve the yield of butenyl-spinosyns produced by Saccharopolyspora pogona by screening streptomycin resistant mutants. The yields of butenyl-spinosyns were then analyzed and compared with the parent strain. Among the mutants, S13 displayed the greatest increase in the yield of butenyl-spinosyns, which was 1.79 fold higher than that in the parent strain. Further analysis of the metabolite profile of S13 by mass spectrometry lead to the discovery of Spinosyn α1, which was absent from the parent strain. DNA sequencing showed that there existed two point mutations in the conserved regions of rpsL gene which encodes ribosomal protein S12 in S13. The mutations occurred a C to A and a C to T transversion mutations occurred at nucleotide pair 314 and 320 respectively, which resulted in the mutations of Proline (105) to Gultamine and Alanine (107) to Valine. It also demonstrated that S13 exhibited genetic stability even after five passages.
Genetic Engineering ; Macrolides ; metabolism ; Point Mutation ; Ribosomal Proteins ; genetics ; Ribosomes ; metabolism ; Saccharopolyspora ; metabolism

The fcl gene encodes GDP-fucose synthase, which catalyzes two-step differential isomerase and reductase reactions in the synthesis of GDP-L-fucose from GDP-D-mannose. It also participates in the biosynthesis of amino sugar and ribose sugar, and is one of the key enzymes to regulate the metabolism of sugar and nucleotides in organisms. The presence of fcl gene in Saccharopolyspora pogona was found through sequencing result of genome. The mutant S. pogona-fcl and S. pogona-Δfcl were constructed by gene engineering technology. The results showed that the gene had an effects on growth and development, protein expression and transcriptional level, insecticidal activity, and biosynthesis of butenyl-spinosyn of Saccharopolyspora pogona. The results of HPLC analysis showed that the yield of butenyl-spinosyn in S. pogona-Δfcl was 130% compared with that in S. pogona, which reduced by 25% in S. pogona-fcl. The results of determination of insecticidal activity showed that S. pogona-Δfcl had a stronger insecticidal activity against Helicoverpa armigera than that of S. pogona, while the S. pogona-fcl had a lower insecticidal activity against Helicoverpa armigera compared with S. pogona. Scanning electron microscopy (SEM) was used to observe the morphology of the mycelia. It was found that the surface of the S. pogona-Δfcl was wrinkled, and the mycelium showed a short rod shape. There was no significant difference in mycelial morphology between S. pogona-fcl and S. pogona. Aboved all showed that deletion of fcl gene in S. pogona hindered the growth and development of mycelia, but was beneficial to increase the biosynthesis of butenyl-spinosyn and improve insecticidal activity. Whereas the fcl gene over-expression was not conducive to the biosynthesis of butenyl-spinosyn and reduced their insecticidal activity. SDS-PAGE results showed that the difference of protein expression among the three strains was most obvious at 96 hours, which was identified by real-time fluorescence quantitative polymerase chain reaction, the results showed that there were significant differences of related genes in transcriptional levels among the three strains. Based on the results of the study, a network metabolic control map was constructed to analyze the effect of fcl gene on growth and the regulation pathway of butenyl-spinosyn biosynthesis, which provided an experimental basis for revealing the regulation mechanism of butenyl-spinosyn biosynthesis and related follow-up studies.
Bacterial Proteins ; Genetic Engineering ; Insecticides ; Macrolides ; Saccharopolyspora