Host proteasomal degradation generates amino acids essential for intracellular bacterial growth     

Price CT  Al-Quadan T  Santic M  Rosenshine I  Abu Kwaik Y 《Science (New York, N.Y.)》2011,334(6062):1553-1557

Legionella pneumophila proliferates in environmental amoeba and human cells within the Legionella-containing vacuole (LCV). The exported AnkB F-box effector of L. pneumophila is anchored into the LCV membrane by host-mediated farnesylation. Here, we report that host proteasomal degradation of Lys(48)-linked polyubiquitinated proteins, assembled on the LCV by AnkB, generates amino acids required for intracellular bacterial proliferation. The severe defect of the ankB null mutant in proliferation within amoeba and human cells is rescued by supplementation of a mixture of amino acids or cysteine, serine, pyruvate, or citrate, similar to rescue by genetic complementation. Defect of the ankB mutant in intrapulmonary proliferation in mice is rescued upon injection of a mixture of amino acids or cysteine. Therefore, Legionella promotes eukaryotic proteasomal degradation to generate amino acids needed as carbon and energy sources for bacterial proliferation within evolutionarily distant hosts.  相似文献   

Efficiency of sample-based indices for spatial pattern recognition of wild pistachio (<Emphasis Type="Italic">Pistacia atlantica</Emphasis>) trees in semi-arid woodlands     

Yousef Erfanifard  Joachim Saborowski  Kerstin Wiegand  Katrin M. Meyer 《林业研究》2016,27(3):583-594

The efficiency of sample-based indices proposed to quantify the spatial distribution of trees is influenced by the structure of tree stands, environmental heterogeneity and degree of aggregation. We evaluated 10 commonly used distance-based and 10 density-based indices using two structurally different stands of wild pistachio trees in the Zagros woodlands, Iran, to assess the reliability of each in revealing stand structure in woodlands. All trees were completely stem-mapped in a nearly pure (40 ha) and a mixed (45 ha) stand. First, the inhomogeneous pair correlation function [g(r)] and the Clark–Evans index (CEI) were used as references to reveal the true spatial arrangement of all trees in these stands. The sampled data were then evaluated using the 20 indices. Sampling was undertaken in a grid based on a square lattice using square plots (30 m × 30 m) and nearest neighbor distances at the sample points. The g(r) and CEI statistics showed that the wild pistachio trees were aggregated in both stands, although the degree of aggregation was markedly higher in the pure stand. Three distance- and six density-based indices statistically verified that the wild pistachio trees were aggregated in both stands. The distance-based Hines and Hines statistic (h _t ) and the density-based standardised Morisita (I _p ), patchiness (IP) and Cassie (C _A ) indices revealed aggregation of the trees in the two structurally different stands in the Zagros woodlands and the higher clumping in the pure stand, whereas the other indices were not sensitive enough.  相似文献   

Nasal colonization and antibiotic resistance patterns of Staphylococcus species isolated from healthy horses in Tripoli, Libya     

Aesha A. OTHMAN  Murad A. HIBLU  Mohamed Salah ABBASSI  Yousef M. ABOUZEED  Mohamed O. AHMED 《Journal of Equine Science》2021,32(2):61

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_{Molecular mechanisms involved in the evasion of Legionella from the killing effect of macrophages}     

HAN Li-hui  SUN Wen-sheng  JIA Xiao-qing  LIU Su-xia  WANG Xiao-yan  GAO Li-fen  CAO Ying-lin  Yousef Abu-kwaik 《园艺学报》2005,21(9):1665-1668

AIM: To explore the relationship between caspase activation and the evasion of Legionella from macrophage elimination through a Legionella-infected macrophage model. METHODS: After infected by Legionella, the activity of caspase 3 in macrophages was analyzed by confocal microscopy as well as fluorescence reader. Growth and replication of Legionella in macrophage was assayed. Replication of Legionella was analyzed again to see the effect of caspase 3 inhibition on the growth of Legionella after use of caspase 3 inhibitor. RESULTS: Both confocal microscopy and caspase 3 fluorescent substrate analysis showed that Legionella virulent strain had powerful capability of activating caspase 3 while the mutant non-virulent strain did not have this capability. The virulent strain highly replicated in macrophages and the replication was significantly inhibited by caspase 3 inhibitor. CONCLUSION: Our results indicate that the intracellular caspase 3 is activated shortly after infection by Legionella virulent strain. The evasion of Legionella from the elimination of macrophages may be mediated by caspase 3 activation to a great degree.  相似文献   

Equine fatigue syndrome.     

S W Ricketts  A Young  J F Mowbray  G E Yousef  J Wood 《The Veterinary record》1992,131(3):58-59

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Calorigenesis of cattle as influenced by hydrocortisone and environmental temperature   总被引：1，自引：0，他引：1  

M K Yousef  H D Johnson 《Journal of animal science》1967,26(5):1087-1093

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Isolation of radiolabeled isoflavones from kudzu (Pueraria lobata) root cultures     

Reppert A  Yousef GG  Rogers RB  Lila MA 《Journal of agricultural and food chemistry》2008,56(17):7860-7865

Isoflavones have potential for preventing and treating several chronic health conditions, such as osteoporosis, cardiovascular disease, and cancer. In this study, radiolabeled isoflavones were recovered from kudzu (Pueraria lobata) root cultures after incubation with uniformly labeled (14)C-sucrose in the culture medium for 21 days. Approximately 19% of administered label was recovered in the isoflavone-rich dried extracts of kudzu root cultures (90.2 microCi/g or 3.3 MBq/g extract). HPLC-PDA analysis revealed the predominant isoflavones isolated from kudzu root cultures to be puerarin, daidzin, and malonyl-daidzin. The average concentration of the major isoflavone puerarin in kudzu root cultures was 33.6 mg/g extract, with a specific activity of 63.5 microCi/g (2.3 MBq/g). The isolated isoflavones were sufficiently (14)C-labeled to permit utilization for subsequent in vivo metabolic tracking studies.  相似文献   

What are the drivers of the occurrence of illegal fishing and conservation barriers of sturgeons in the Caspian Sea?          下载免费PDF全文

Seyed Mostafa Aghilinejhad  Saeid Gorgin  Daan van Uhm  Ramtin Joolaie  Rasoul Ghorbani  Seyed Yousef Paighambari  Jahangir Mohammadi  Ali Jalali 《水产资源保护:海洋与淡水生态系统》2018,28(3):690-701

Calorigenesis of dairy cattle as influenced by thyroxine and environmental temperature   总被引：1，自引：0，他引：1  

M K Yousef  H D Johnson 《Journal of animal science》1966,25(1):150-156

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Effect of salinity on growth and yield of Desi and Kabuli chickpea cultivars     

Sohrabi Y  Heidari G  Esmailpoor B 《Pakistan journal of biological sciences: PJBS》2008,11(4):664-667

To evaluate the effects of different level of Na salinity (0, 3, 6 and 9 dS m(-1)) on growth, yield and yield component of Kabuli (Hashem and Jam) and Desi (Kaka and Pirooz) chickpea cultivars a factorial experiment based on randomized complete block design with four replications was carried out in Research Greenhouse of Mokrian Agricultural Extension Center near Mahabad, Iran at 2006. Seeds of four chickpea cultivars were grown under 0, 3, 6 and 9 dS m(-1) levels of salinity until maturity. Salinity reduced the plant growth, flower, pod and seed number and seed weight. As increase in salinity, the undesirable effect of Na+ was more pronounced and reached the highest value at 9 dS m(-1) in all cultivars. Four chickpea cultivar have different responses to salinity and the Kabuli cultivars seemed to have a greater capacity for salt tolerance compared to Desi cultivars. Hahshem cultivar has the highest salinity tolerance among all cultivars.  相似文献