Isolation and characterization of phosphate-solubilizing bacteria from rhizosphere of poplar on road verge and their antagonistic potential against various phytopathogens.

BACKGROUND: Phosphate-solubilizing bacteria (PSB) can solubilize insoluble phosphate compounds and improve phosphate availability in soil. Road verges are important in urban landscaping, but the population structure of PSB and their ecological functions in the road verge soil is still unclear. RESULTS: Twenty-one mineral PSB strains and 14 organic PSB strains were isolated from the rhizosphere of poplar on urban road verge. All the mineral PSB strains showed better solubilization to Ca3(PO4)2 than FePO4 or AlPO4. Among them, 7 strains showed high phosphate-solubilizing (PS) activities to Ca3(PO4)2 (150-453 mg/L). All the organic PSB strains displayed weak solubilization to lecithin. 16S rRNA gene-based phylogenetic analysis showed good species diversity of the PSB strains, which belongs to 12 genera: Bacillus, Cedecea, Cellulosimicrobium, Delftia, Ensifer, Paenibacillus, Pantoea, Phyllobacterium, Pseudomonas, Rhizobium, Sinorhizobium and Staphylococcus. Moreover, 8 PSB strains showed various degrees of growth inhibition against 4 plant pathogenic fungi, Fusarium oxysporum S1, F. oxysporum S2, Pythium deliense Meurs Z4, Phomopsis sp. AC1 and a plant pathogenic bacterium, Pectobacterium carotovorum TP1. CONCLUSIONS: The results indicated that these PSB strains could perform multiple ecological functions on road verge. The development and application of bio-agents based on the strains would provide a new strategy for maintaining and improving the ecosystem stability of road verges.

The analysis of cerebral angiography of the ischemic cerebrovaseular diseases / 中国医师进修杂志

Objective To study the nlanifestation and the clinical significance of the cerebral angiography of the isehemic cerebrovascular diseases.Methods Digital sublraction angiography(DSA)was taken in 312 patients with cerebral infarction and transient ischemic attack(TLA).The distribution of the lesion in the extra/intracranial arteries was compared.Results Cerebral angiography showed that the stenosis and occlusion was dominant in the intracranial arteries at the cerebral infarction in the internal carotid artery system and vertebrobasilar artery system[59.57%(56/94)and 61.90%(26/42)].TIA of internal carotid artery system was mainly because of stenosis of intracranial arteries (68.75%,22/32).TIA of vertebrobasilar artery system was mainly because of stenosis of extracranial arteries(61.70%,29/47).Conclusions The diseases of the intracranial arteries are the main causes of cerebral infarction(including internal carotid artery system and vertebrobasilar artery system) and TIA of internal carotid artery system. The diseases of the extracranial arteries are main causes of TIA of vertebrobasilar artery system.