Construction of an artificial microalgal-bacterial consortium that efficiently degrades crude oil.

Four oil component-degrading bacteria and one oil-tolerant microalgae, Scenedesmus obliquus GH2, were used to construct an artificial microalgal-bacterial consortium for crude-oil degradation. The bacterial strains included Sphingomonas GY2B and Burkholderia cepacia GS3C, along with a mixed culture, named GP3, containing Pseudomonas GP3A and Pandoraea pnomenusa GP3B. GY2B could only degrade polycyclic aromatic hydrocarbons, GS3C was able to degrade aliphatic chain hydrocarbons, and GP3 could utilize both saturated and aromatic hydrocarbons. In combination with unialgal or axenic algae, the bacteria showed different effects on oil degradation. Unialgal GH2 was not suitable for the consortium construction, as it could not cooperate well with GS3C and GP3. The axenic GH2 exhibited no oil-degrading ability; however, it significantly promoted the degradation ability of the oil component-degrading bacteria, especially for degrading biorefractory polycyclic aromatic hydrocarbons. Axenic S. obliquus GH2, combined with the four bacteria mentioned above, formed an optimal algal-bacterial consortium. The artificial consortium demonstrated an elevated efficiency in degrading both aliphatic and aromatic hydrocarbons of crude oil.

[Effects of contact lens wear on the corneal endothelium and sensitivity].

The corneal endothelium of 38 contact lens wearers (74 eyes) and 74 normal eyes for control was photographed and analyzed with specular microscopy and the graphic processing system. The central corneal sensitivity and thickness were also measured. The results showed that the frequency rate of hexagonal cells that reflected the changes in endothelial cell morphology and size, the coefficient of variation of cell area, and the ratio of largest to smallest cell areas differed significantly from those of the control eyes comparable in age and sex distribution. The central corneal sensitivity declined while the corneal thickness was not affected. The causes and clinical significance of endothelial changes were discussed.