Identification of cellular factors that recognize UV-damaged DNA in Drosophila melanogaster.

Using a gel electrophoresis DNA band-shift assay, we have identified 2 DNA-binding protein complexes in wild-type Drosophila embryonic cells which have high affinity for UV-irradiated, double-stranded DNA. Screening of Drosophila mutants deficient in DNA repair led to the identification of 5 mutants which lacked either one of the 2 protein complexes. Four excision repair-deficient mutants (mus-201, phr, mus-308 and mus-205) lacked one protein complex (Factor 2). The other protein complex (Factor 1) was not detectable in the post-replication repair-deficient mutant mus-104. These findings might suggest the possible involvement of these gene products in lesion recognition and repair of UV-induced photoproducts in DNA.     

Sulfated vizantin inhibits biofilm maturation by Streptococcus mutans

Streptococcus mutans is the main pathogen of dental caries and adheres to the tooth surface via soluble and insoluble glucans produced by the bacterial glucosyltransferase enzyme. Thus, the S. mutans glucosyltransferase is an important virulence factor for this cariogenic bacterium. Sulfated vizantin effectively inhibits biofilm formation by S. mutans without affecting its growth. In this study, less S. mutans biofilm formation occurred on hydroxyapatite discs coated with sulfated vizantin than on noncoated discs. Sulfated vizantin showed no cytotoxicity against the human gingival cell line Ca9-22. Sulfated vizantin dose-dependently inhibited the extracellular release of cell-free glucosyltransferase from S. mutans and enhanced the accumulation of cell-associated glucosyltransferase, compared with that observed with untreated bacteria. Sulfated vizantin disrupted the localization balance between cell-associated glucosyltransferase and cell-free glucosyltransferase, resulting in inhibited biofilm maturation. These results indicate that sulfated vizantin can potentially serve as a novel agent for preventing dental caries.     

Effect of Physical Training and Its Cessation on Percent Fat and Bone Density of Children with Obesity

GUTIN, BERNARD, SCOTT OWENS, TOMOKI OKUYAMA, SHARON RIGGS, MICHAEL FERGUSON, AND MARK LITAKER. Effect of physical training and its cessation on percent fat and bone density of children with obesity. Obes Res. Objective We determined the effect of 4-month periods of physical training (PT) and detraining on percent fat (percent fat) and bone density of children with obesity. Research Methods and Procedures Subjects were 79 7- to 11-year-old children with obesity; 34 were white, 44 were black, and 1 was Asian, 26 were male and 53 were female. They were randomly assigned to two groups: group 1 engaged in PT for the first 4 months, while group 2 engaged in PT during the second 4 months. Body composition was measured with dual energy absorptiometry, and diet was measured with 4 days of recall for each 4-month period. PT was offered 5 dayslweek for 40 minuteslsession, heart rate monitors were worn, and no dietary information was given; mean attendance was 80%, and mean heart rate per session was 157 bpm. Results Group by time interactions across the three time-points (from analysis of variance) were significant for percent fat (p = <0.001) and bone density (p = 0.045). Both groups declined in percent fat during the periods of PT, by an average of 1.6 %fat units; in the 4 months after cessation of PT, group 1 increased by 1.3 %fat. In both groups, bone density increased more during periods of PT (0.025 g/cm²) than during periods of no PT (0.010 g/cm²). No significant PT vs. no-PT differences were found for dietary intake of energy, macronutrients, or calcium. Discussion This study suggests that regular exercise, without dietary intervention, can enhance the body composition of children with obesity.     

Monogamous mating system and protandrous-like sexuality in the goby Trimma taylori

Ichthyological Research - The reproductive ecology of the gobiid Trimma taylori is investigated using combined field sampling and rearing experiments. In captivity this species maintains continuous...