Genetic Diversity-Area Relationships across Bird Species.

The genetic diversity-area relationship (GAR), compared with the extensively explored species-area relationship (SAR), remains poorly recognized despite the importance of understanding it for the development and application of biodiversity theory. It has been hypothesized that maintaining genetic diversity within a population is mechanistically similar to maintaining species diversity within a community, implying that GAR trajectories should behave mathematically as SAR ones. Here we test this prediction by fitting microsatellite heterozygosity and allelic richness in relation to distribution range size across bird species against eight well-known SAR models. The Monod model best described the data on resident and migratory species combined and especially the data on resident species only, showing that with increasing range size, genetic diversity across species rapidly increased up to a certain level and then tended toward an asymptote. None of the candidate models provided an adequate fit for the data on migratory species, likely because their breeding range size mostly is large in that a GAR curve has become flat. Our work takes the first step toward formulating GARs and applying them to predicting the effect of habitat fragmentation on genetic diversity.

Cloning vector system for Corynebacterium glutamicum.

A protoplast transformation system has been developed for Corynebacterium glutamicum by using a C. glutamicum-Bacillus subtilis chimeric vector. The chimera was constructed by joining a 3.0-kilobase cryptic C. glutamicum plasmid and the B. subtilis plasmid pBD10. The neomycin resistance gene on the chimera, pHY416, was expressed in C. glutamicum, although the chloramphenicol resistance gene was not. The various parameters in the transformation protocol were analyzed separately and optimized. The resulting transformation system is simple and routinely yields 10(4) transformants per microgram of plasmid DNA.

Cytotoxic and antitumor properties of bleomycin and several of its metal complexes.

This study examines the concentration-dependent cytotoxicity and antitumor activity of bleomycin (Blm) and Cu-, Zn-, Fe(III)-, and CoBlm using Ehrlich cells in culture and the Ehrlich ascites tumor. The order of activity in culture under several conditions is CuBlm approximately equal to Blm approximately equal to ZnBlm > Fe(III)Blm > CoBlm approximately equal to control. Short exposures of cells to drugs in the presence or absence of serum produced effects on cell proliferation similar to 48-h incubations. With Blm and CuBlm there was no obvious relationship between cytotoxicity and the modest short-term inhibition of DNA synthesis by the drugs. The antitumor experiments produced qualitatively similar results with the order of antitumor potency being CuBlm > Blm > ZnBlm approximately equal to FeBlm > CoBlm approximately equal to control tumor. The host toxicity produced by these drugs as measured by weight loss had the opposite ordering: CoBlm < FeBlm < ZnBlm < Blm < CuBlm. At therapeutically effective concentrations, FeFlm was significantly less toxic relative to ther other active agents.