A touch of history and a peep into the future of the lipid-quinone known as coenzyme Q and ubiquinone

Coenzyme Q (ubiquinone), a fully substituted benzoquinone with polyprenyl side chain, participates in many cellular redox activities. Paradoxically it was discovered only in 1957, albeit being ubiquitous. It required a person, F. L. Crane, a place, Enzyme Institute, Madison, USA, and a time when D. E. Green was directing vigorous research on mitochondria. Located at the transition of 2-electron flavoproteins and 1-electron cytochrome carriers, it facilitates electron transfer through the elegant Q-cycle in mitochondria to reduce O-2 to H2O, and to H2O2, now a significant signal-transducing agent, as a minor activity in shunt pathway (animals) and alternative oxidase (plants). The ability to form Q-radical by losing an electron and a proton was ingeniously used by Mitchell to explain the formation of the proton gradient, considered the core of energy transduction, and also in acidification in vacuoles. Known to be a mobile membrane constituent (microsomes, plasma membrane and Golgi apparatus), allowing it to reach multiple sites, coenzyme Q is expected to have other activities. Coenzyme Q protects circulating lipoproteins being a better lipid antioxidant than even vitamin E. Binding to proteins such as QPS, QPN, QPC and uncoupling protein in mitochondria, QA and QB in the reaction centre in R. sphaeroides, and disulfide bond-forming protein in E. coli (possibly also in Golgi), coenzyme Q acquires selective functions. A characteristic of orally dosed coenzyme Q is its exclusive absorption into the liver, but not the other tissues. This enrichment of Q is accompanied by significant decrease of blood pressure and of serum cholesterol. Inhibition of formation of mevalonate, the common precursor in the branched isoprene pathway, by the minor product, coenzyme Q, decreases the major product, cholesterol. Relaxation of contracted arterial smooth muscle by a side-chain truncated product of coenzyme Q explains its effect of decreasing blood pressure. Extensive clinical studies carried out on oral supplements of coenzyine Q, initially by K. Folkers and Y. Yamamura and followed many others, revealed a large number of beneficial effects, significantly in cardiovascular diseases. Such a variety of effects by this lipid quinone cannot depend on redox activity alone. The fat-soluble vitamins (A, D, E and K) that bear structural relationship with coenzyme Q are known to be active in their polar forms. A vignette of modified forms of coenzyme Q taking active role in its multiple effects is emerging.

Graded IR Filters: Distinguishing Between Single and Multipoint NO2 center dot center dot center dot I Halogen Bonded Supramolecular Synthons (P, Q, and R Synthons)

The NO2 center dot center dot center dot I supramolecular synthon is a halogen bonded recognition pattern that is present in the crystal structures of many compounds that contain these functional groups. These synthons have been previously distinguished as P, Q, and R types using topological and geometrical criteria. A five step IR spectroscopic sequence is proposed here to distinguish between these synthon types in solid samples. Sets of known compounds that contain the P, Q, and R synthons are first taken to develop IR spectroscopic identifiers for them. The identifiers are then used to create graded IR filters that sieve the synthons. These filters contain signatures of the individual NO2 center dot center dot center dot I synthons and may be applied to distinguish between P, Q, and R synthon varieties. They are also useful to identify synthons that are of a borderline character, synthons in disordered structures wherein the crystal structure in itself is not sufficient to distinguish synthon types, and in the identification of the NO2 center dot center dot center dot I synthons in compounds with unknown crystal structures. This study establishes clear differences for the three different geometries P, Q, and Rand in the chemical differences in the intermolecular interactions contained in the synthons. Our IR method can be conveniently employed when single crystals are not readily available also in high throughput analysis. It is possible that such identification may also be adopted as an input for crystal structure prediction analysis of compounds with unknown crystal structures.

Mechanical Properties And Constitutive Relationships Of 30Crmnsia Steel Heated At High Rate

In this paper, the mechanical behavior of 30CrMnSiA steel after heating at a high rate are investigated experimentally and theoretically, including a detailed discussion of the effects of strain rate and temperature. Two constitutive models are presented to describe the mechanical response of this material after heating at a high rate, and verified by experimental results. (C) 2007 Elsevier B.V. All rights reserved.

Mechanical properties and constitutive relationships of 30CrMnSiA steel heated at high rate

In this paper, the mechanical behavior of 30CrMnSiA steel after heating at a high rate are investigated experimentally and theoretically, including a detailed discussion of the effects of strain rate and temperature. Two constitutive models are presented to describe the mechanical response of this material after heating at a high rate, and verified by experimental results. (C) 2007 Elsevier B.V. All rights reserved.

Species and size relationships within schools of yellowfin and skipjack tuna as indicated by catches in the Eastern Tropical Pacific Ocean

ENGLISH: Yellowfin tuna, Neothunnus macropterus, and skipjack tuna, Katsuwonus pelamis, are fished intensively off the west coast of the Americas in an area from about the California-Mexico border in the north to the Peru-Chile border in the south. The historical development of this fishery, and its expansion by the long-range California fleets of bait and purse-seine vessels, are well documented by Godsil (1938), Scofield (1951) and Shimada and Sehaefer (1956). The quarterly distribution of the tuna catches within this area has been reported for some recent years by Alverson (1959). SPANISH: Los atunes aleta amarilla, Neothunnus macropterus, y barrilete, Katsuwonus pelamis, son pescados con intensidad frente a la costa occidental del continente americano, en un área comprendida más o menos entre la frontera California-México en el norte y el límite Perú-Chile en el sur. El desarrollo histórico de esta pesquería y la expansión que le han dado las flotas californianas de largo radio de acción, formadas por los barcos de carnada y rederos, están bien documentados por Godsil (1938), Scofield (1951) y Shimada y Schaefer (1956). La distribución trimestral de las pescas de atún dentro de esta área ha sido tratada por Alverson (1959) con referencia a años recientes.

Spatial and seasonal relationships between Pacific harbor seals (Phoca vitulina richardii) and their prey, at multiple scales

Knowing where pinnipeds forage is vital to managing and protecting their populations, and for assessing potential interactions with fisheries. We assessed the spatial relationship between the seasonal distribution of Pacific harbor seals (Phoca vitulina richardii) outfitted with satellite transmitters and the seasonal distributions of potential harbor seal prey species in San Francisco Bay, California. Pearson’s correlation coefficients were calculated between the number of harbor seal locations in an area of the San Francisco Bay and the abundance of specific prey species in the same area. The influence of scale on the analyses was assessed by varying the scale of analysis from 1 to 10 km. There was consistency in the prey species targeted by harbor seals year-round, although there were seasonal differences between the most important prey species. The highest correlations between harbor seals and their prey were found for seasonally abundant benthic species, located within about 10 km of the primary haul-out site. Probable foraging habitat for harbor seals was identified, based on areas with high abundances of prey species that were strongly correlated with harbor seal distribution. With comparable local data inputs, this approach has potential application to pinniped management in other areas, and to decisions about the location of marine reserves designed to protect these species.

Diets of and trophic relationships among dominant marine nekton within the northern California Current ecosystem

In this study we analyzed the diets of 26 nekton species collected from two years (2000 and 2002) off Oregon and northern California to describe dominant nekton trophic groups of the northern California Current (NCC) pelagic ecosystem. We also examined interannual variation in the diets of three nekton species. Cluster analysis of predator diets resulted in nekton trophic groups based on the consumption of copepods, euphausiids, brachyuran larvae, larval juvenile fishes, and adult nekton. However, many fish within trophic groups consumed prey from multiple trophic levels—euphausiids being the most widely consumed. Comparison of diets between years showed that most variation occurred with changes in the contribution of euphausiids and brachyuran larvae to nekton diets. The importance of euphausiids and other crustacean prey to nekton indicates that omnivory is an important characteristic of the NCC food web; however it may change during periods of lower or higher upwelling and ecosystem production.