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Summary A heavy metal-accumulating strain of aCitrobacter sp. was unable to accumulate lead from trimethyl lead, but trimethyl lead did not affect the ability of the strain to accumulate cadmium.  相似文献   
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Lynne Cohen 《CMAJ》1985,132(2):184-185
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Q fever, caused by Coxiella burnetii, is a serious zoonotic disease in humans with a worldwide distribution. Many species of animals are capable of transmitting C. burnetii, and consequently all veterinary workers are at risk for this disease. An effective Q fever vaccine has been readily available and used in Australia for many years in at-risk groups, and the European Centre for Disease Prevention and Control has recently also called for the use of this vaccine among at-risk groups in Europe. Little is known about attitudes towards this vaccine and vaccine uptake in veterinary workers. This study aimed to determine the Q fever vaccination status of veterinarians and veterinary nurses in Australia and to assess and compare the knowledge and attitudes towards Q fever disease and vaccination of each cohort. An online cross-sectional survey performed in 2014 targeted all veterinarians and veterinary nurses in Australia. Responses from 890 veterinarians and 852 veterinary nurses were obtained. Binary, ordinal and multinomial logistic regression were used to make comparisons between the two cohorts. The results showed that 74% of veterinarians had sought vaccination compared to only 29% of veterinary nurses. Barriers to vaccination among those not vaccinated did not differ between cohorts, and included a lack of perceived risk, financial expense, time constraints, and difficulty in finding a vaccine provider. Poor knowledge and awareness of Q fever disease and vaccination were additional and notable barriers for the veterinary nursing cohort, suggesting veterinary clinics and veterinarians may not be meeting their legal responsibility to educate staff about risks and risk prevention. Further evaluation is needed to identify the drivers behind seeking and recommending vaccination so that recommendations can be made to improve vaccine uptake.  相似文献   
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Background

Cilia and flagella are often lost in anticipation of mitosis or in response to stress. There are two ways that a cell can lose its flagella: resorption or deflagellation. Deflagellation involves active severing of the axoneme at the base of the flagellum; this process is defective in Chlamydomonas fa mutants. In contrast, resorption has been thought to occur as a consequence of constitutive disassembly at the tip in the absence of continued assembly, which requires intraflagellar transport (IFT). Chlamydomonas fla mutants are unable to build and maintain flagella due to defects in IFT.

Results

fla10 cells, which are defective in kinesin-II, the anterograde IFT motor, resorb their flagella at the restrictive temperature (33°C), as previously reported. We find that in standard media containing ~300 microM calcium, fla10 cells lose flagella by deflagellation at 33°C. This temperature-induced deflagellation of a fla mutant is not predicted by the IFT-based model for flagellar length control. Other fla mutants behave similarly, losing their flagella by deflagellation instead of resorption, if adequate calcium is available. These data suggest a new model whereby flagellar resorption involves active disassembly at the base of the flagellum via a mechanism with components in common with the severing machinery of deflagellation. As predicted by this model, we discovered that deflagellation stimuli induce resorption if deflagellation is blocked either by mutation in a FA gene or by lack of calcium. Further support for this model comes from our discovery that fla10-fa double mutants resorb their flagella more slowly than fla10 mutants.

Conclusions

Deflagellation of the fla10 mutant at the restrictive temperature is indicative of an active disassembly signal, which can manifest as either resorption or deflagellation. We propose that when IFT is halted by either an inactivating mutation or a cellular signal, active flagellar disassembly is initiated. This active disassembly is distinct from the constitutive disassembly which plays a role in flagellar length control.
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