No abstract

Concentrations of butyltins (BTs) in the liver and organochlorine compounds (OCs) in the blubber of Risso's dolphins collected off Taiji, Japan, in 1991 were determined. Mean and range concentrations (wet weight basis) of these compounds were 3.6 μg/g (0.55−6.0 μg/g) for BTs, 25 μg/g (1.7−120 μg/g) for PCBs, 17 μg/g (0.45−77 μg/g) for DDTs, 4.0 μg/g (0.19−16 μg/g) for CHLs, and 0.16 μg/g (0.008−0.74 μg/g) for HCHs. OCs concentrations increased with age in males in contrast to that in females, which showed a decreasing trend after maturity. On the other hand, no difference was observed in BT concentrations between male and female, which showed increasing levels until maturity (8−10 years) and then remained constant. It is suggested that, unlike OCs, BTs were less transferable to young ones in reproductive processes. Risso's dolphins showed higher biomagnification factor (about 6) than Steller sea lion (0.6), implying a slower excretion rate of BTs in cetaceans than in pinnipeds due to the lower degradation capacity of xenobiotics and the lack of physiological processes such as shedding of hair in cetaceans.

We constructed hybrid Pseudomonas strains in which the bphA1 gene (coding for a large subunit of biphenyl dioxygenase) is replaced with the todC1 gene (coding for a large subunit of toluene dioxygenase of Pseudomonas putida F1) within chromosomal biphenyl-catabolic bph gene clusters. Such hybrid strains gained the novel capability to grow on a wide range of aromatic hydrocarbons, and, more interestingly, they degraded chloroethenes such as trichloroethylene and cis-1,2-dichloroethylene very efficiently.

This model can be used for simulating the spatial recognition of the vitreous chamber during vitreous surgery. This model proved useful for initial training in port creation, central vitreous body resection, and membrane manipulation in the macular area.

The industrially important yeast Candida utilis is widely used in production of food and medical materials, but its host-vector system has not been well developed. We screened for compact and efficient ARSs to construct practically useful vectors. The C. utilis strain AHU3053 was found to be efficiently transformed by the conventional lithium acetate method and was used as the host. The C. utilis IAM4264 genomic library was constructed by inserting the partial Sau3AI digests in pRI51, which has a kanMX gene expressible in C. utilis. By examining 98 C. utilis G418-resistant transformants, five plasmids had the highest ARS activity. By trimming of the inserts, the 1490 and 552 bp fragments with transformation activity of over 10(3)/microg DNA were obtained from ARS3 and ARS4, respectively. Although several sequences identical to S. cerevisiae ARS consensus sequences (ACSs) were found in ARS3 and ARS4, our deletion analysis indicated that these were not essential for the activity. Because the minimal functional ARS fragment was also several-fold larger than that of S. cerevisiae, the C. utilis ARSs have some unique characteristics resembling the Sz. pombe ARSs. These ARSs were functional in other C. utilis strains tested and useful for constructing practical vectors.