Drawing lines at the sand: evidence for functional vs. visual reef boundaries in temperate Marine Protected Areas.

Marine Protected Areas (MPAs) can either protect all seabed habitats within them or discrete features. If discrete features within the MPA are to be protected humans have to know where the boundaries are. In Lyme Bay, SW England a MPA excluded towed demersal fishing gear from 206 km(2) to protect rocky reef habitats and the associated species. The site comprised a mosaic of sedimentary and reef habitats and so 'non reef' habitat also benefited from the MPA. Following 3 years protection, video data showed that sessile Reef Associated Species (RAS) had colonised sedimentary habitat indicating that 'reef' was present. This suggested that the functional extent of the reef was potentially greater than its visual boundary. Feature based MPA management may not adequately protect targeted features, whereas site based management allows for shifting baselines and will be more effective at delivering ecosystem goods and services.

Negative regulation of transactivation function but not DNA binding of NF-kappaB and AP-1 by IkappaBbeta1 in breast cancer cells.

The transcription factor NF-kappaB regulates the expression of genes involved in cancer cell invasion, metastasis, angiogenesis, and resistance to chemotherapy. In normal cells NF-kappaB is maintained in the cytoplasm by protein-protein interaction with inhibitor IkappaBs. In contrast, in cancer cells a substantial amount of NF-kappaB is in the nucleus and constitutively activates target genes. To understand the mechanisms of constitutive NF-kappaB activation, we have analyzed the function of IkappaBalpha and IkappaBbeta in breast cancer cells. In most cases, constitutive NF-kappaB DNA binding correlated with reduced levels of either IkappaBalpha or IkappaBbeta isoforms. Overexpression of IkappaBalpha but not IkappaBbeta1 resulted in reduced constitutive DNA binding of NF-kappaB in MDA-MB-231 cells. Unexpectedly, IkappaBbeta1 overexpression moderately increased 12-O-tetradecanoylphorbol-13-acetate- and interleukin-1-inducible NF-kappaB DNA binding. 12-O-Tetradecanoylphorbol-13-acetate- and interleukin-1-induced transactivation by NF-kappaB, however, was lower in IkappaBbeta1-overexpressing cells. Mutants of IkappaBbeta1 lacking the C-terminal casein kinase II phosphorylation sites, which form a stable complex with DNA bound NF-kappaB without inhibiting its transactivation in other cell types, repressed the transactivation by NF-kappaB in MDA-MB-231 cells. Consistent with the results of transient transfections, the expression of urokinase plasminogen activator, an NF-kappaB target gene, was reduced in IkappaBbeta1-overexpressing cells. These results suggest that depending on the cell type, IkappaBbeta1 represses the expression of NF-kappaB-regulated genes by inhibiting either DNA binding or transactivation function of NF-kappaB.

Sperm motility hyperactivation facilitates penetration of the hamster zona pellucida.

These experiments were conducted to determine whether or not sperm motility hyperactivation facilities penetration of the zona pellucida of the oocyte. Two approaches were used. For the first, hamster sperm were incubated for 4.0-4.25 h in a capacitating medium that contained either 2.9 or 25.0 mM sodium bicarbonate. In these media, sperm became equally capacitated as evidenced by their ability to undergo the acrosome reaction when exposed to lysophosphatidyl choline or intact zonae pellucidae; however, sperm became hyperactivated only in the medium containing 25.0 mM bicarbonate. When these sperm were added to cumulus-free oocytes in vitro, only 2 of 88 oocytes were penetrated by sperm preincubated in 2.9 mM bicarbonate, while 31 of 86 oocytes were penetrated by sperm in 25.0 mM bicarbonate. It was found that equal numbers of sperm were bound to the oocytes and that equal numbers were acrosome-reacted on the surface of the zonae in the two media. For the second approach, sperm were incubated in a capacitating medium containing 25 mM bicarbonate. When > 70% were hyperactivated, aliquots were added to three sets of oocytes. After 10 min had been allowed for sperm to attach and acrosome-react, inhibitors of hyperactivation were added and the sperm and oocytes were incubated for an additional 20 min before fixation and examination for zona penetration. In the dishes treated with the inhibitors verapamil or Cd2+, 1 of 42 and 0 of 42 oocytes were penetrated, respectively, compared with 25 of 40 in controls. Therefore, it appears that hyperactivation facilitates penetration of the hamster zona pellucida.