Species-specific detection of hydrocarbon-utilizing bacteria

Rapid detection and quantitative assessment of specific microbial species in environmental samples is desirable for monitoring changes in ecosystems and for tracking natural or introduced microbial species during bioremediation of contaminated sites. In the interests of developing rapid tests for hydrocarbon-degrading bacteria, species-specific PCR primer sets have been developed for Pseudomonas aeruginosa, Stentrophomonas (Xanthomonas) maltophilia, and Serratia marsescens. Highly variable regions of the 16S rRNA gene were used to design these primer sets. The amplification products of these primer sets have been verified and validated with hemi-nested PCR and with ligase chain reaction (LCR) techniques, and have been applied to the analyses of environmental water samples. These species-specific primer sets were also chosen to amplify in conjunction with a universal set of PCR primers chosen from highly conserved neighboring sequences in the same gene. These multiplex or competitive PCR procedures enable testing with an internal marker and/or the quantitative estimation of the relative proportion of the microbial community that any one of these species occupies. In addition, this universal PCR primer set amplified the same size amplicon from a wide spectrum of procaryotic and eucaryotic organisms and may have potential in earth biota analyses.     

Investigation on carp, Cyprinus carpio L. gynogenesis

A reliable method for gynogenetic mass-production has been developed in carp ( Cyprinus carpio L.). The effect of different cold shock treatments applied after fertilization were examined. The yield of viable diploid gynogenetic animals could be significantly increased when the cold shock was applied 5 min or 15 min after fertilization. A negative correlation has been found between the effectiveness of these two treatments, so both were used on separate batches of eggs. By means of gynogenesis, the crossover frequency and map distance of the transferrin locus have been determined. Successful pilot experiments were made on grass carp ( Ctenopharyngodon idella Val.) and sheatfish ( Silurus glanis L.) with respect to gynogenetic mass production.     

Osteoclast cell-surface changes during the egg-laying cycle in Japanese quail

The medullary bone serves as a source of labile calcium mobilized during calcification of the egg shell in birds. Quantitative histological methods demonstrate that the numbers of medullary bone osteoclasts and nuclei per osteoclast remain unchanged during the egg cycle in the Japanese quail (Coturnix). Therefore, cyclic changes in bone resorption cannot be explained by modulations of osteoclasts from and into other bone cells, a mechanism previously suggested for certain species of birds. Rather, dramatic changes in osteoclast cell-surface features occur during the egg cycle, which might account for cyclic variations in resorptive activity. During egg shell calcification, osteoclasts with ruffled borders are closely apposed to bone surfaces; the cytoplasm is rich in vacuoles that contain mineral crystals and seem to derive from the ruffled border. At the completion of egg shell calcification, the ruffled borders and vacuoles move away from the bone surface, although the osteoclast remains attached to the bone along the filamentous or "clear" zone. Associated with the disappearance of the ruffled borders is the appearance of extensive interdigitated cell processes along the peripheral surface of the osteoclast away from the bone. These unusual structures, which may serve as a reservoir of membrane, largely disappear when ruffled borders and associated structures reappear. Therefore, in these hens, the osteoclasts modulate their cell surface rather than their population during the egg cycle.