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• The degradation products of BDE-47 were qualitatively analyzed, and the degradation pathway was deduced. • Transcriptomes of Acinetobacter pittii with and without BDE-47 were sequenced and functional genes analyzed. • The function of 1,2-dioxygenase gene was preliminarily identified by cloning and expression. 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47) is one of the most widely distributed PBDEs. BDE-47 is also the most abundant in organisms and the most toxic to humans and animals. Herein, we have studied the pathway of BDE-47 degradation and gene involvement in Acinetobacter pittii GB-2. This degradation is dominated by hydroxylation, resulting in hydroxylated products 6-OH-BDE-47, 5-OH-BDE-47 and 2′-OH-BDE-28, and bromophenol products 2,4-DBP and 4-BP. Transcriptome sequencing results showed 359 differentially expressed genes (DEGs) induced by BDE-47, of which 159 were up-regulated and 200 were down-regulated. The up-regulated ones were mainly related to substance transport, degradation and cell stress. From these results, we suggest that 1,2-dioxygenase, phenol hydroxylase and monooxygenase are involved in BDE-47 degradation. The function of AntA gene was identified by constructing a prokaryotic expression vector. Our study contributes to understanding how the metabolism of strain GB-2 changes under BDE-47 stress conditions, and sheds light on the mechanism of BDE-47 degradation. [ABSTRACT FROM AUTHOR]

Abstract: Beijing’s mountainous areas have an important ecological significance because they are ecological conservation and water source protection areas of Beijing. The impact of precipitation on the vegetation coverage of Beijing’s mountainous areas is qualitatively analyzed using multi-temporal Landsat images obtained during the last 20 years. Firstly, the influence of external factors, such as phenology and relative radiometric correction, on the normalized difference vegetation index (NDVI) are removed by the normalization of remote sensing images for different periods. Then, the vegetation coverage is calculated using the method of the dimidiate pixel model. Finally, based on that, the relationship between precipitation in different seasons and change of vegetation coverage is discussed. The results indicate that the mean vegetation coverage has the same change trends with winter and summer precipitation, but an opposite change trend with spring precipitation. The paper provides a theoretical basis and data support for further research on driving models of natural vegetation restoration in Beijing’s mountainous areas. [Copyright &y& Elsevier]

The proton motive force ( pmf ) across the thylakoid membranes plays a key role for photosynthesis in fluctuating light. However, the mechanisms underlying the regulation of pmf in fluctuating light are not well known. In this study, we aimed to identify the roles of chloroplastic ATP synthase and cyclic electron flow (CEF) around photosystem I (PSI) in the regulation of the pmf in fluctuating light. To do this, we measured chlorophyll fluorescence, P700 parameters, and the electrochromic shift signal in the fluctuating light alternating between 918 (high light) and 89 (low light) μmol photons m −2  s −1 every 5 min. We found that the activity of chloroplastic ATP synthase ( g H + ), pmf , CEF activity, non-photochemical quenching (NPQ), and the P700 redox state changed rapidly in fluctuating light. During transition from low to high light, the decreased g H + and the stimulation of CEF both contributed to the rapid formation of pmf , activating NPQ and optimizing the redox state of P700 in PSI. During the low-light phases, g H + rapidly increased and the pmf declined sharply, leading to the relaxation of NPQ and down-regulation of photosynthetic control. These findings indicate that in fluctuating light the g H + and CEF are finely regulated to modulate the pmf formation, avoiding the over-accumulation of reactive intermediates and maximizing energy use efficiency. [ABSTRACT FROM AUTHOR]