Restoration of the properties of carnitine palmitoyltransferase I in liver mitochondria during re-feeding of starved rats.

Platelet factor 4 is a small protein (Mr 7756) from the alpha-granules of blood platelets which binds strongly to and neutralizes the anticoagulant properties of heparin. From an analysis of X-ray crystallographic data a model for the binding of platelet factor 4 to heparin is proposed.     

Ethical issues and the family doctor

After noting several contemporary societal factors that contribute to increasing concern about bioethical issues in general, the author focuses on special problems that confront the general or family practitioner. These problems arise from the family physician's large number of potentially conflicting roles and relationships.     

Working of the genetic code

The genetic code is used differently by different kinds of species. Each type of genome has a particular coding strategy, that is, choices among degenerate bases are consistently similar for all genes therein. This uniformity in the selection between degenerate bases within each taxonomic group has been discovered by applying new methods to the study of coding variability. It is now possible to calculate relative distances between genomes, or genome types, based on use of the codon catalog by the mRNAs therein.     

A synthetic channel-forming peptide induces Cl(-) secretion: modulation by Ca(2+)-dependent K(+) channels

A synthetic Cl(-) channel-forming peptide, C-K4-M2GlyR, applied to the apical membrane of human epithelial cell monolayers induces transepithelial Cl(-) and fluid secretion. The sequence of the core peptide, M2GlyR, corresponds to the second membrane-spanning region of the glycine receptor, a domain thought to line the pore of the ligand-gated Cl(-) channel. Using a pharmacological approach, we show that the flux of Cl(-) through the artificial Cl(-) channel can be regulated by modulating basolateral K(+) efflux through Ca(2+)-dependent K(+) channels. Application of C-K4-M2GlyR to the apical surface of monolayers composed of human colonic cells of the T84 cell line generated a sustained increase in short-circuit current (I(SC)) and caused net fluid secretion. The current was inhibited by the application of clotrimazole, a non-specific inhibitor of K(+) channels, and charybdotoxin, a potent inhibitor of Ca(2+)-dependent K(+) channels. Direct activation of these channels with 1-ethyl-2-benzimidazolinone (1-EBIO) greatly amplified the Cl(-) secretory current induced by C-K4-M2GlyR. The effect of the combination of C-K4-M2GlyR and 1-EBIO on I(SC) was significantly greater than the sum of the individual effects of the two compounds and was independent of cAMP. Treatment with 1-EBIO also increased the magnitude of fluid secretion induced by the peptide. The cooperative action of C-K4-M2GlyR and 1-EBIO on I(SC) was attenuated by Cl(-) transport inhibitors, by removing Cl(-) from the bathing solution and by basolateral treatment with K(+) channel blockers. These results indicate that apical membrane insertion of Cl(-) channel-forming peptides such as C-K4-M2GlyR and direct activation of basolateral K(+) channels with benzimidazolones may coordinate the apical Cl(-) conductance and the basolateral K(+) conductance, thereby providing a pharmacological approach to modulating Cl(-) and fluid secretion by human epithelia deficient in cystic fibrosis transmembrane conductance regulator Cl(-) channels.     

Accommodating dynamic oceanographic processes and pelagic biodiversity in marine conservation planning

Pelagic ecosystems support a significant and vital component of the ocean's productivity and biodiversity. They are also heavily exploited and, as a result, are the focus of numerous spatial planning initiatives. Over the past decade, there has been increasing enthusiasm for protected areas as a tool for pelagic conservation, however, few have been implemented. Here we demonstrate an approach to plan protected areas that address the physical and biological dynamics typical of the pelagic realm. Specifically, we provide an example of an approach to planning protected areas that integrates pelagic and benthic conservation in the southern Benguela and Agulhas Bank ecosystems off South Africa. Our aim was to represent species of importance to fisheries and species of conservation concern within protected areas. In addition to representation, we ensured that protected areas were designed to consider pelagic dynamics, characterized from time-series data on key oceanographic processes, together with data on the abundance of small pelagic fishes. We found that, to have the highest likelihood of reaching conservation targets, protected area selection should be based on time-specific data rather than data averaged across time. More generally, we argue that innovative methods are needed to conserve ephemeral and dynamic pelagic biodiversity.     

Codon catalog usage and the genome hypothesis.

Frequencies for each of the 61 amino acid codons have been determined in every published mRNA sequence of 50 or more codons. The frequencies are shown for each kind of genome and for each individual gene. A surprising consistency of choices exists among genes of the same or similar genomes. Thus each genome, or kind of genome, appears to possess a "system" for choosing between codons. Frameshift genes, however, have widely different choice strategies from normal genes. Our work indicates that the main factors distinguishing between mRNA sequences relate to choices among degenerate bases. These systematic third base choices can therefore be used to establish a new kind of genetic distance, which reflects differences in coding strategy. The choice patterns we find seem compatible with the idea that the genome and not the individual gene is the unit of selection. Each gene in a genome tends to conform to its species' usage of the codon catalog; this is our genome hypothesis.     

Controlling the cortical actin motor

Actin is the essential force-generating component of the microfilament system, which powers numerous motile processes in eukaryotic cells and undergoes dynamic remodeling in response to different internal and external signaling. The ability of actin to polymerize into asymmetric filaments is the inherent property behind the site-directed force-generating capacity that operates during various intracellular movements and in surface protrusions. Not surprisingly, a broad variety of signaling pathways and components are involved in controlling and coordinating the activities of the actin microfilament system in a myriad of different interactions. The characterization of these processes has stimulated cell biologists for decades and has, as a consequence, resulted in a huge body of data. The purpose here is to present a cellular perspective on recent advances in our understanding of the microfilament system with respect to actin polymerization, filament structure and specific folding requirements.     

The surf zone: a semi-permeable barrier to onshore recruitment of invertebrate larvae?

The supply of larvae to the shore is important for population replenishment and intertidal community dynamics but its variability at most scales is not well understood. We tested the relationship between nearshore mussel larval abundance and intertidal settlement rates over several years at multiple spatiotemporal scales in Oregon and New Zealand. Abundance of competent larvae nearshore and intertidal recruitment rates were simultaneously quantified using collectors mounted at different depths on moorings 50-1100 m from shore, and at adjacent rocky intertidal sites. Total mussel larval abundance and oceanographic conditions were also measured in some locations. At all scales, abundance of nearshore mussel larvae was unrelated to intertidal recruitment rates. In the intertidal, patterns of mussel recruitment were persistent in space, with sites of consistently high or low recruitment. In contrast, nearshore competent larval abundance showed generally similar abundances among sites except for a high, and spatially-inconsistent, variability in Oregon during 1998 only. On moorings, recruitment tended to be greater on midwater collectors than shallower or deeper. Finally, on moorings larval abundance in traps and recruitment on collectors was unrelated. These results suggest that (1) among sites, the size of the nearshore larval pool is relatively uniform while onshore recruitment varies and is unrelated to larval abundance, (2) temporal variability in nearshore larval availability is not strongly expressed onshore, (3) vertical stratification of competent larvae nearshore is strong and may influence transport and recruitment, and (4) within-coast variability in onshore recruitment is strongly driven by processes occurring locally within the surf zone that need to be studied to understand coastal recruitment dynamics.