bluuebunny/crossref_metadata_2025 huggingface dataset:
N-Terminal Acetylation of Cellular Proteins Creates Specific Degradation Signals
Authors: Hwang Cheol-Sang , Shemorry Anna , Varshavsky Alexander
Published: January 2010

To Degrade or Not to Degrade

Regulating the turnover of proteins within the cell is of fundamental importance to almost every physiological process.

Hwang
et al.

(p.
973
, published online 28 January; see the Perspective by

Mogk and Bukau

) now find that acetylated N-terminal methionine (Met) is a degradation signal. This degron is recognized by
Saccharomyces cerevisiae
Doa10, a transmembrane E3 ubiquitin ligase that resides in the endoplasmic reticulum and inner nuclear membrane. The removal of N-terminal Met by Met-aminopeptidases generates N-terminal residues that are often N-terminally acetylated. Doa10 selectively binds to the resulting N-degrons, which may represent the most prevalent class of cellular protein degradation signals.
Generating a Prion with Bacterially Expressed Recombinant Prion Protein
Authors: Wang Fei , Wang Xinhe , Yuan Chong-Gang , Ma Jiyan
Published: January 2010

Recombinant Infectious Prions

Prion diseases are a group of fatal neurodegenerative disorders that include Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in cows. The prion hypothesis states that the infectious agent of these diseases is an aberrant conformational isoform of the normal prion protein (PrP
C
), a glycosylphosphatidylinositol-anchored cell surface protein enriched in the central nervous system. The final proof for the prion hypothesis is to convert bacterially expressed recombinant PrP into an infectious prion, but this has been difficult to achieve.

F. Wang
et al.

(p.
1132
, published online 28 January; see the Perspective by

Supattapone

) put recombinant PrP purified from bacteria into mice and obtained all the characteristics of the infectious agent in prion disease. The recombinant form is not only resistant to proteinase-K, but also shows infectivity in cultured cells and causes rapid disease progression in wild-type mice, yielding both the behavioral and the neuropathological symptoms.
Food Security: The Challenge of Feeding 9 Billion People
Authors: Godfray H. Charles J. , Beddington John R. , Crute Ian R. , Haddad Lawrence , Lawrence David , Muir James F. , Pretty Jules , Robinson Sherman , Thomas Sandy M. , Toulmin Camilla
Published: January 2010

Continuing population and consumption growth will mean that the global demand for food will increase for at least another 40 years. Growing competition for land, water, and energy, in addition to the overexploitation of fisheries, will affect our ability to produce food, as will the urgent requirement to reduce the impact of the food system on the environment. The effects of climate change are a further threat. But the world can produce more food and can ensure that it is used more efficiently and equitably. A multifaceted and linked global strategy is needed to ensure sustainable and equitable food security, different components of which are explored here.
Charged-Particle Probing of X-ray–Driven Inertial-Fusion Implosions
Authors: Li C. K. , Séguin F. H. , Frenje J. A. , Rosenberg M. , Petrasso R. D. , Amendt P. A. , Koch J. A. , Landen O. L. , Park H. S. , Robey H. F. , Town R. P. J. , Casner A. , Philippe F. , Betti R. , Knauer J. P. , Meyerhofer D. D. , Back C. A. , Kilkenny J. D. , Nikroo A.
Published: January 2010

Ignition Set to Go

One aim of the National Ignition Facility is to implode a capsule containing a deuterium-tritium fuel mix and initiate a fusion reaction. With 192 intense laser beams focused into a centimeter-scale cavity, a major challenge has been to create a symmetric implosion and the necessary temperatures within the cavity for ignition to be realized (see the Perspective by

Norreys

).

Glenzer
et al.

(p.
1228
, published online 28 January) now show that these conditions can be met, paving the way for the next step of igniting a fuel-filled capsule. Furthermore,

Li
et al.

(p.
1231
, published online 28 January) show how charged particles can be used to characterize and measure the conditions within the imploding capsule. The high energies and temperature realized can also be used to model astrophysical and other extreme energy processes in a laboratory settings.
Size at hatching determines population dynamics and response to harvesting in cannibalistic fish
Authors: van Kooten Tobias , Andersson Jens , Byström Pär , Persson Lennart , de Roos André M.
Published: January 2010

We hypothesize that size at hatching strongly affects population dynamics of cannibalistic fish species and is a crucial determinant of how populations respond to selective removal of large individuals (harvesting). We use a mechanistic mathematical model to study the relation between hatching size and response to harvesting mortality, using Eurasian perch ( Perca fluviatilis ) as a model organism. We show how hatching size determines dynamics through its effect on the relative strength of cannibalistic mortality and resource competition as mechanisms of population regulation. In populations with intermediate and large hatching size, cannibalistic mortality is an important determinant of population dynamics, and harvesting destabilizes population dynamics. When hatching size is small, population stability is less sensitive to this type of harvesting. Populations hatching at small size are regulated by competition, and harvesting large individuals affects such populations less. Harvesting can also induce the growth of very large individuals, absent in unharvested populations. Our results show that harvesting in cannibalistic lake fish populations can strongly alter population dynamics in ways that can only be anticipated on the basis of mechanistic knowledge about how populations are regulated.
Site fidelity of the declining amphibianRana sierrae(Sierra Nevada yellow-legged frog)
Authors: Matthews Kathleen R. , Preisler Haiganoush K.
Published: January 2010

From 1997 to 2006, we used mark–recapture models to estimate the site fidelity of 1250 Sierra Nevada yellow-legged frogs ( Rana sierrae ) in Kings Canyon National Park, California, USA, during their three main activity periods of overwintering, breeding, and feeding. To quantify site fidelity, the tendency to return to and reuse previously occupied habitats, we used multistrata models (with water bodies as the strata) and potential function analyses. The probability of returning to previously used water bodies during all activity periods was typically greater than 80% and always greater than the probability of moving to other water bodies. Site fidelity models (with lake-specific movement transitions) were favored over those models that held movement transitions equal between lakes. Potential function analyses demonstrated that frogs were most strongly attracted to their original capture lakes rather than moving to the nearest available breeding or overwintering lake. Under current disturbances in high-elevation Sierra Nevada lakes (exotic trout, climate change), site fidelity is problematic because frogs return to lakes subject to drying or those with fish rather than dispersing to other lakes. Future recovery of declining species will need to focus efforts towards restoring habitats when animals maintain strong site fidelity even when their habitats deteriorate.
A temporal perspective on population structure and gene flow in Atlantic salmon (Salmo salar) in Newfoundland, Canada
Authors: Palstra Friso P. , Ruzzante Daniel E.
Published: January 2010

Studying population structure and gene flow patterns on temporal scales facilitates an evaluation of the consequences of demographic, physical, and environmental changes on the stability and persistence of populations. Here, we examine temporal genetic variation within and among Atlantic salmon ( Salmo salar ) rivers in Newfoundland and Labrador, Canada, using samples collected over a period of six decades (1951–2004). Our objective was to evaluate temporal changes in population connectivity associated with the closure of a commercial marine fishery. Despite demographic instability, we find that population structure remained temporally stable over more than 50 years. However, age structure can affect results when not taken into consideration, particularly in populations of large effective size where genetic drift is not strong. Where weak signals of genetic differentiation did not complicate analyses, contemporary migration was often asymmetric, yet low, suggesting patterns of intermittent gene flow. Nevertheless, we find some links between changes in population dynamics and contemporary gene flow. These findings may therefore imply that management decisions impacting the contemporary population dynamics of individual Atlantic salmon rivers can also affect the genetic stability of this species as a whole.
The hyporheic assemblage of a recently formed stream following deglaciation in Glacier Bay, Alaska, USA
Authors: McDermott Michael J. , Robertson Anne L. , Shaw Peter J. , Milner Alexander M.
Published: January 2010

Many studies focus on the recovery of stream communities following disturbances such as high flows (secondary succession); relatively few examine community composition in streams undergoing primary succession and even fewer detail the hyporheic community in such streams. We examined the composition and temporal distribution of invertebrates in the shallow hyporheic sediments of Stonefly Creek, a recently deglaciated stream in Glacier Bay, Alaska, USA, whose lower reaches became ice free in the late 1970s. We used modified polyvinyl chloride wells at four contrasting sites over two years in this stream and collected data on stream temperature, discharge, and suspended solids. A diverse assemblage of 19 taxa was found, including cyclopoid and harpacticoid Copepoda, Ostracoda, Cladocera, tardigrades, and macroinvertebrates, but the nature and extent of the goods and services provided by the hyporheos of this young stream to the whole river ecosystem are unclear. The hyporheic assemblage differed strongly between sites and years and was significantly more abundant and diverse where there was minimal disturbance by redd-digging salmon. This study gives an insight into the development of the hyporheos in a primary successional context and our findings are also relevant to new streams created during river engineering.
Mixed effects models for fish growth
Authors: Weisberg Sanford , Spangler George , Richmond Laurie S.
Published: January 2010

Fish growth in a particular year has both intrinsic and environmental components. Intrinsic growth can depend on both the age and size of the fish and on particular characteristics of the individual fish. The environmental component is the influence of external conditions such as food supply on the growth increment. In this article, we present mixed-effects models as an alternative to fixed-effects linear models for incremental fish growth used previously in the literature and show how these models overcome many of the shortcomings of the fixed-effects approach. In addition, widely available software allows for fitting these models and for elaboration of them to learn about the effects of additional factors such as temperature, species interactions, management practices, the introduction of an invasive species, or other known environmental variables. Finally, we provide a connection with the more usual modeling of size-attained data through the use of growth functions such as the von Bertalanffy.
New and regenerated primary production in a productive reservoir ecosystem
Authors: Domine Leah M. , Vanni Michael J. , Renwick William H.
Published: January 2010

The concept of new and regenerated production has been used extensively in marine ecosystems but rarely in freshwaters. We assessed the relative importance of new and regenerated phosphorus (P) in sustaining phytoplankton production in Acton Lake, a eutrophic reservoir located in southwestern Ohio, USA. Sources of nutrients to the euphotic zone, including watershed loading, fluxes from sediments, and excretion by sediment-feeding fish (gizzard shad, Dorosoma cepedianum ), were considered sources of new P input that support new primary production and were quantified over the course of a growing season. Regenerated production was estimated by the difference between new and total primary production. New production represented 32%–53% of total primary production, whereas regenerated production represented 47%–68% of total primary production. P excretion by gizzard shad supplied 45%–74% of new P and 24% of P required for total production. In summary, fluxes of P from the watershed and those from sediment-feeding fish need to be considered in strategies to reduce eutrophication in reservoir ecosystems.
Reduced hatchery rearing density increases social dominance, postrelease growth, and survival in brown trout (Salmo trutta)
Authors: Brockmark Sofia , Johnsson Jörgen I.
Published: January 2010

Hatchery fish reared for conservation or supplementation often have difficulties adapting to natural conditions, resulting in poor performance in the wild. In a standard hatchery, fish are confined at high densities, which creates a social environment different from that experienced after release. Here we investigated how rearing density influences social dominance, postrelease growth, and survival in brown trout ( Salmo trutta ). Fish were reared at three density treatments: conventional hatchery density, half of conventional hatchery density, and natural density. Four months after hatching, dominance status was determined, and 36 fish from each treatment were released into an enclosed stream and recaptured after 36 days. Trout reared at natural density had higher dominance status and grew faster, both in the hatchery and in the natural stream, than trout from higher densities. Moreover, trout reared at natural density were twice as likely to survive in the stream as trout from higher densities. These novel results suggest that more natural rearing densities would facilitate the development of adaptive behaviour in hatchery salmonids and, thereby, their contribution to natural production.
Ontogenetic changes in the feeding habits of the abalone Haliotis discus hannai: field verification by stable isotope analyses
Authors: Won Nam-Il , Kawamura Tomohiko , Takami Hideki , Noro Tadakatsu , Musashi Tatsuya , Watanabe Yoshiro
Published: January 2010

The ontogenetic changes in the feeding habits of the abalone Haliotis discus hannai were elucidated for the first time in natural habitats using stable isotope analyses. Abalone individuals were grouped into three developmental stages: small juveniles (<10 mm shell length (SL)), large juveniles (10–50 mm SL), and adults (>50 mm SL). The inferences of natural diets indicated that benthic diatoms, small red macroalgae and (or) juvenile brown macroalgae, and adult brown macroalgae were the primary food sources for small juveniles (6.5 ± 1.0 mm SL), large juveniles (23.7 ± 6.1 mm SL), and adults (81.8 ± 14.3 mm SL), respectively. The changes of δ13C in abalone were similar among three sampling stations and were explained by ontogenetic changes in feeding habits. The decrease of δ13C in abalone (≤20 mm SL) indicated a transition from diatom feeding to juvenile brown macroalgae and (or) small red macroalgae feeding, whereas the subsequent increase of δ13C (>20 mm SL) represented a feeding transition to adult brown macroalgae. These results prove the hypothesis of the ontogenetic changes in the feeding habits of the abalone H. discus hannai.
Geographic effects on American eel (Anguilla rostrata) life history characteristics and strategies
Authors: Jessop B. M.
Published: January 2010

Latitudinal variability in length and age at maturity and annual growth rate for the American eel ( Anguilla rostrata ) along the Atlantic coast of North America was examined with respect to life history strategies and theory. Maturing (silver phase) female lengths and ages increased with increasing latitude (and distance) from the Sargasso Sea spawning site, as did male ages but not lengths. Growth rates for females (and males) declined with increasing latitude south of 44°N latitude, approximately the entrance to the Cabot Strait, but were constant or increased within the Gulf of St. Lawrence and St. Lawrence River, depending on the analysis method. The growing season and the number of degree-days ≥ 10 °C declined with increasing latitude. Female growth rates adjusted for the number of degree-days were approximately constant south of 44°N but increased further north, suggesting countergradient variation in growth. The temperature–size rule (increase in body size at lower temperatures) evidently applies to American eel females, but not males. No current life history model provides a satisfactory explanatory mechanism for the temperature–size rule and for anguillid life history strategies. A genetic link is proposed between increasing age (length) at elver and silver eel stages with increasing distance from the spawning area.
Diapausing zooplankton eggs remain viable despite exposure to open-ocean ballast water exchange: evidence from in situ exposure experiments
Authors: Gray Derek K. , MacIsaac Hugh J.
Published: January 2010

To reduce the transfer of nonindigenous species, regulations require transoceanic ships to exchange ballast with ocean water before discharging into the Great Lakes. Although ballast water exchange (BWE) is effective for live freshwater animals, laboratory experiments provide mixed results with regards to its impact on diapausing zooplankton eggs. We conducted an in situ test of the effectiveness of BWE for treating diapausing eggs in ballast sediments. Incubation chambers containing ballast sediment were placed in ballast tanks of cargo vessels transiting from North America to Europe. Each vessel had paired ballast tanks, one of which remained filled with Great Lakes water (control), while the second was exchanged with mid-ocean water. Laboratory viability tests were then conducted to compare viability of eggs recovered from sediments placed in both treatments, as well as identical sediments that remained at the laboratory in cold storage. No significant differences in egg viability were detected between treatments, but more species hatched from sediment that remained in cold storage. Results indicate that physical conditions in ballast tanks may affect egg viability, but saltwater exposure does not eliminate the risk of species introductions via diapausing eggs. Strategies that minimize sediment accumulation in ballast tanks can reduce the risk of species introductions via diapausing eggs.
An SSR-based genetic linkage map of the model grassBrachypodium distachyon
Authors: Garvin David F. , McKenzie Neil , Vogel John P. , Mockler Todd C. , Blankenheim Zachary J. , Wright Jonathan , Cheema Jitender J.S. , Dicks Jo , Huo Naxin , Hayden Daniel M. , Gu Yong , Tobias Christian , Chang Jeff H. , Chu Ashley , Trick Martin , Michael Todd P. , Bevan Michael W. , Snape John W.
Published: January 2010

The grass species Brachypodium distachyon (hereafter, Brachypodium) has been adopted as a model system for grasses. Here, we describe the development of a genetic linkage map of Brachypodium. The genetic linkage map was developed with an F2population from a cross between the diploid Brachypodium lines Bd3-1 and Bd21. The map was populated with polymorphic simple sequence repeat (SSR) markers from Brachypodium expressed sequence tag (EST) and bacterial artificial chromosome (BAC) end sequences and conserved orthologous sequence (COS) markers from other grass species. The map is 1386 cM in length and consists of 139 marker loci distributed across 20 linkage groups. Five of the linkage groups exceed 100 cM in length, with the largest being 231 cM long. Assessment of colinearity between the Brachypodium linkage map and the rice genome sequence revealed significant regions of macrosynteny between the two genomes, as well as rearrangements similar to those reported in other grass comparative structural genomics studies. The Brachypodium genetic linkage map described here will serve as a new tool to pursue a range of molecular genetic analyses and other applications in this new model plant system.
Analysis of ITS1 and ITS2 sequences in Ensis razor shells: suitability as molecular markers at the population and species levels, and evolution of these ribosomal DNA spacers
Authors: Vierna Joaquín , Martínez-Lage Andrés , González-Tizón Ana M.
Published: January 2010

Internal transcribed spacer 1 and 2 (ITS1 and ITS2) sequences were analysed in Ensis razor shells (Mollusca: Bivalvia: Pharidae). We aimed to (1) test ITS1 and ITS2 as molecular markers at the population level in the successful alien E. directus (Conrad, 1843); (2) test these spacers at the species level in E. directus and three other Ensis species, E. siliqua (L., 1758), E. macha (Molina, 1782), and E. magnus (Schumacher, 1817); and (3) analyse the evolutionary processes that may be shaping Ensis ITS1 and ITS2 extant variation. In E. directus, despite the intragenomic divergence detected, ITS1 and ITS2 were informative in differentiating the geographic areas considered (Denmark and Canada) by means of both the insertion-deletion polymorphism and the nucleotide polymorphism. In this species, the 5.8S ribosomal gene (5.8S) showed scarce polymorphism. At the species level, maximum parsimony and maximum likelihood analyses revealed that ITS1 and ITS2 may be suitable to reconstruct Ensis phylogenetic relationships. Finally, the evolutionary models that best fit the long-term evolution of Ensis ITS1–5.8S–ITS2 are discussed. A mixed process of concerted evolution, birth-and-death evolution, and selection is chosen as an option that may reconcile the long-term evolution of Ensis ITS1–5.8S–ITS2 and 5S ribosomal DNA.
Evolutionary distribution of light-harvesting complex-like proteins in photosynthetic eukaryotes
Authors: Neilson Jonathan A.D. , Durnford Dion G.
Published: January 2010

Light-harvesting-like (LIL) proteins are low-molecular-mass membrane proteins related to the light-harvesting complexes, which form the dominant antenna system in most photosynthetic eukaryotes. To analyze the LIL protein family, we mined a number of publicly available databases to identify members of this family in a broad range of organisms. LIL proteins are diverse, having one to three predicted transmembrane helices. One- and two-helix LIL proteins were found in all the major photosynthetic eukaryote lineages (glaucophytes, red algae, and green algae) and are particularly well conserved in the green algae and land plants. In most cases, however, these proteins are not conserved between major lineages, and in some cases appear to have evolved independently. Three-helix LIL proteins are well conserved within the gymnosperms and angiosperms, but are much more divergent, and have been duplicated multiple times, in the green algae and bryophytes. We also identified a novel LIL protein in two Micromonas strains that contains a fourth hydrophobic region. This analysis identifies conserved members of the LIL protein family, signifying their importance to photosynthetic eukaryotes. It also indicates that classification of these proteins based on structural characteristics alone inadequately reflects the evolutionary history observed in this complex protein family.
Microsatellites inBrassicaunigenes: relative abundance, marker design, and use in comparative physical mapping and genome analysis
Authors: Parida Swarup K. , Yadava Devendra K. , Mohapatra Trilochan
Published: January 2010

Microsatellites present in the transcribed regions of the genome have the potential to reveal functional diversity. Unigene sequence databases are the sources of such genic microsatellites with unique flanking sequences and genomic locations even in complex polyploids. The present study was designed to assay the unigenes of Brassica napus and B. rapa for various microsatellite repeats, and to design markers and use them in comparative genome analysis and study of evolution. The average frequency of microsatellites in Brassica unigenes was one in every 7.25 kb of sequence, as compared with one in every 8.57 kb of sequence in Arabidopsis thaliana . Trinucleotide motifs coding for serine and the dinucleotide motif GA were most abundant. We designed 2374 and 347 unigene-based microsatellite (UGMS) markers including 541 and 58 class I types in B. napus and B. rapa, respectively, and evaluated their use across diverse species and genera. Most of these markers (93.3%) gave successful amplification of target microsatellite motifs, which was confirmed by sequencing. Interspecific polymorphism between B. napus and B. rapa detected in silico for the UGMS markers was 4.16 times higher in 5′ untranslated regions than in coding sequences. Physical anchoring of Brassica UGMS markers on the A. thaliana genome indicated their significance in studying the evolutionary history of A. thaliana genomic duplications in relation to speciation. Comparative physical mapping identified 85% of Brassica unigenes as single copy and gave clues for the presence of conserved primordial gene order. Complex chromosomal rearrangements such as inversions, tandem and segmental duplications, and insertions/deletions were evident between A. thaliana and B. rapa genomes. The results obtained have encouraging implications for the use of UGMS markers in comparative genome analysis and for understanding evolutionary complexities in the family Brassicaceae.
Identification and characterization of the critical physically demanding tasks encountered by correctional officers
Authors: Jamnik Veronica K. , Thomas Scott G. , Shaw Jim A. , Gledhill Norman
Published: January 2010

The purpose of this investigation was to identify the critical tasks encountered by correctional officers (COs) on the job and to conduct a comprehensive assessment and characterization of the physical demands of these tasks. These are the first steps in developing a fitness screening test for COs in compliance with recent legislation. The most important, physically demanding, and frequently occurring tasks were identified using Delphi methodology, focus groups, and questionnaire responses from 190 experienced front-line COs. These tasks were structured into emergency response scenarios for which a physical and physiological characterization was conducted to verify their relative physical demands analysis. Oxygen consumption and the forces exerted by COs were quantified while they were responding and then controlling and restraining inmates. The female COs used less force than the male COs did to control and restrain the same inmates (body control = 46 vs. 60 kg, wrist hold = 32 vs. 49 kg, and arm retraction = 37 vs. 47 kg) and did not exert their maximal strength during their control and restraint activities. The mean oxygen consumption of the female and male COs while performing the on-the-job tasks was similar (39.5 vs. 38.5 mL·kg–1·min–1). We concluded that the essential components of a fitness screening protocol for CO applicants are cell search, expeditious response, body control, arm restraint, inmate relocation, and an assessment of aerobic fitness. The criterion performance standards for completing these tasks in a circuit were set at the job performance level of safe and efficient female COs.
Reducing dietary sodium intake: the Canadian context
Authors: Barr Susan I.
Published: January 2010

Sodium is a required nutrient; Adequate Intakes for adults range from 1200 to 1500 mg·day–1, depending on age. The Tolerable Upper Intake Level (UL) for sodium is 2300 mg·day–1 for adults, based on the relationship between sodium intake and increased blood pressure. Elevated blood pressure, which is prevalent among Canadians, is, in turn, a major risk factor for stroke, cardiovascular disease, and renal disease. Sodium intake is not the only determinant of blood pressure; other modifiable risk factors include relative mass, physical activity, overall dietary quality, and alcohol consumption. However, because >90% of adult Canadian men and two thirds of Canadian women have sodium intakes above the UL, Health Canada’s Working Group on Dietary Sodium Reduction has been charged with developing, implementing, and overseeing a strategy to reduce Canadians’ sodium intakes. It is estimated that ∼75% of dietary sodium is added during food processing; in addition to taste and palatability, sodium also has functional roles in food manufacturing and preservation, although the amounts used often exceed those required. Because of the central role of processed foods in sodium intake, the strategy proposed by Health Canada’s Working Group includes voluntary reduction of sodium in processed foods and foods sold in food service establishments. It will also include an education and awareness campaign, and research and surveillance. Initiatives to reduce sodium in other parts of the world have demonstrated that it will be challenging to reduce sodium intake to the recommended range and will likely require many years to accomplish.
Canadian Society for Exercise Physiology position stand: The use of instability to train the core in athletic and nonathletic conditioning
Authors: Behm David G. , Drinkwater Eric J. , Willardson Jeffrey M. , Cowley Patrick M.
Published: January 2010

The use of instability devices and exercises to train the core musculature is an essential feature of many training centres and programs. It was the intent of this position stand to provide recommendations regarding the role of instability in resistance training programs designed to train the core musculature. The core is defined as the axial skeleton and all soft tissues with a proximal attachment originating on the axial skeleton, regardless of whether the soft tissue terminates on the axial or appendicular skeleton. Core stability can be achieved with a combination of muscle activation and intra-abdominal pressure. Abdominal bracing has been shown to be more effective than abdominal hollowing in optimizing spinal stability. When similar exercises are performed, core and limb muscle activation are reported to be higher under unstable conditions than under stable conditions. However, core muscle activation that is similar to or higher than that achieved in unstable conditions can also be achieved with ground-based free-weight exercises, such as Olympic lifts, squats, and dead lifts. Since the addition of unstable bases to resistance exercises can decrease force, power, velocity, and range of motion, they are not recommended as the primary training mode for athletic conditioning. However, the high muscle activation with the use of lower loads associated with instability resistance training suggests they can play an important role within a periodized training schedule, in rehabilitation programs, and for nonathletic individuals who prefer not to use ground-based free weights to achieve musculoskeletal health benefits.
A role for Cdc48/p97 and Aurora B in controlling chromatin condensation during exit from mitosisThis paper is one of a selection of papers published in this special issue entitled 8th International Conference on AAA Proteins and has undergone the Journal's usual peer review process.
Authors: Meyer Hemmo , Drozdowska Alicja , Dobrynin Grzegorz
Published: January 2010

During cell division, chromosomes condense so that the replicated chromatids can be segregated by the mitotic spindle. While condensation is governed by cyclin-dependent kinase 1 (Cdk1) during mitotic entry and early mitosis, it is still poorly understood how condensation is maintained during anaphase after Cdk1 inactivation, and how decondensation is triggered in telophase. Here, we review recent reports that point to a novel role of Aurora B kinase in maintaining condensation and preventing premature nuclear envelope formation during exit from mitosis. Timely decondensation and nuclear envelope formation at the end of mitosis may then be triggered by two mechanisms. One is removing Aurora B phosphorylation marks from chromatin by specific phosphatases. The other is removing and inactivating Aurora B kinase itself by the ubiquitin system. We have recently provided evidence that the AAA ATPase Cdc48/p97 plays a central role in the inactivation of Aurora B, as it extracts ubiquitinated Aurora B from chromosomes and thus reduces chromatinassociated Aurora B activity.
DnaA, ORC, and Cdc6: similarity beyond the domains of life and diversityThis paper is one of a selection of papers published in this special issue entitled 8th International Conference on AAA Proteins and has undergone the Journal's usual peer review process.
Authors: Kawakami Hironori , Katayama Tsutomu
Published: January 2010

To initiate chromosomal DNA replication, specific proteins bind to the replication origin region and form multimeric and dynamic complexes. Bacterial DnaA, the eukaryotic origin recognition complex (ORC), and Cdc6 proteins, most of which include an AAA+(-like) motif, play crucial roles in replication initiation. The importance of ATP binding and hydrolysis in these proteins has recently become recognized. ATP binding of Escherichia coli DnaA is required for the formation of the activated form of a DnaA multimer on the replication origin. The ATP–DnaA multimer can unwind duplex DNA in an origin-dependent manner, which is supported by various specific functions of several AAA+ motifs. DnaA–ATP hydrolysis is stimulated after initiation, repressing extra initiations, and sustaining once-per-cell cycle replication. ATP binding of ORC and Cdc6 in Saccharomyces cerevisiae is required for heteromultimeric complex formation and specific DNA binding. ATP hydrolysis of these proteins is important for the efficient loading of the minichromosome maintenance protein complex, a component of the putative replicative helicase. In this review, we discuss the roles of DnaA, ORC, and Cdc6 in replication initiation and its regulation. We also summarize the functional features of the AAA+ domains of these proteins, and the functional divergence of ORC in chromosomal dynamics.
Comparison of the multiple oligomeric structures observed for the Rvb1 and Rvb2 proteinsThis paper is one of a selection of papers published in this special issue entitled 8th International Conference on AAA Proteins and has undergone the Journal's usual peer review process.
Authors: Cheung Kevin L. Y. , Huen Jennifer , Houry Walid A. , Ortega Joaquin
Published: January 2010

The Rvb1 and Rvb2 proteins are 2 members of the AAA+ family, involved in roles as diverse as chromatin remodeling, transcription, small nucleolar RNA maturation, cellular transformation, signaling of apoptosis and mitosis. These proteins are capable of playing a role in such diverse cellular activities because they are components of different macromolecular assemblies. In the last few years, there has been a number of groups reporting on the structure of purified Rvbs. The reported results have been rather controversial, because there are significant differences observed among the published structures in spite of the high degree of homology among these proteins. Surprisingly, contradictions are observed not only between structures representing the Rvb proteins from different species, but also between protein structures from the same species. This review describes the available Rvb structures from different species and also makes a comparative analysis of them. Finally, we identify some aspects of these structural studies worth pursuing in additional investigations to ensure that the reported structures reflect physiologically relevant conformations of the Rvb1–Rvb2 complex.
Cryo electron microscopy structures of Hsp100 proteins: crowbars in or out?This paper is one of a selection of papers published in this special issue entitled 8th International Conference on AAA Proteins and has undergone the Journal's usual peer review process.
Authors: Wendler Petra , Saibil Helen R
Published: January 2010

Independent cryo electron microscopy (cryo-EM) studies of the closely related protein disaggregases ClpB and Hsp104 have resulted in two different models of subunit arrangement in the active hexamer. We compare the EM maps and resulting atomic structure fits, discuss their differences, and relate them to published experimental information in an attempt to discriminate between models. In addition, we present some general assessment criteria for low-resolution cryo-EM maps to offer non-structural biologists tools to evaluate these structures.
1D and 2D NMR investigations of the interaction between oppositely charged polymers and surfactants
Authors: McLachlan Aleisha A. , Marangoni D. Gerrard
Published: January 2010

Proton chemical shifts and two-dimensional COSY and NOE spectroscopy (NOESY) experiments have been used to examine the interaction of various oppositely charged surfactant and polyelectrolyte systems, namely, the cationic surfactant dodecyltrimethyammonium bromide (DTAB) and a series of alkanediyl-α,ω-bis(alkyldimethylammonium bromide) surfactants (Gem 12-s-12, where s is the length of the methylene spacer group) with the anionic polyelectrolyte poly(styrene sulfonate) or PSS. In all cases, we observe substantial aromatic-solute-induced chemical shifts (ASIS) in the surfactant peaks of the polymer/surfactant complexes versus that of the pure surfactant spectra. In the case of the DTAB/PSS system, the chemical-shift changes as a function of changing ratio of surfactant to polymer are interpreted in terms of structural changes that occur in the complex with increasing polymer concentration. For the Gem 12-s-12/PSS systems, the interaction of these gemini surfactants with the anionic polyelectrolyte, as deduced from the interpretation of the1H ASIS shifts and the NOESY cross peaks, is dependent on the length of the methylene spacer. From the NOESY experiments, we observed significant NOESY cross peaks that correlated well with the expected mechanism of interaction as observed in the literature for the single-tailed surfactant/polymer system. NMR techniques are shown to provide information on the molecular arrangement of these molecules in aqueous solution.
1,3-Dibromo-5,5-dimethylhydantoin as an efficient homogeneous catalyst for the synthesis of 2-arylthiazolines and 2-arylimidazolines
Authors: Hojati Seyedeh Fatemeh , Mohammadpoor-Baltork Iraj , Maleki Behrooz , Gholizadeh Mostafa , Shafiezadeh Fatemeh , Haghdoust Mahnaz
Published: January 2010

A simple, facile, and efficient procedure for the synthesis of 2-arylthizolines and 2-arylimidazolines has been developed by the simple condensation of nitriles with 2-aminoethanethiol or ethylenediamine catalyzed by 1,3-dibromo-5,5-dimethylhydantoin under solvent-free conditions. Selective preparation of bisthiozolines and monoimidazolines from dinitriles and also selective conversion of arylnitriles to their corresponding 2-arylthiazolines or imidazolines in the presence of alkylnitriles can be considered as considerable advantages of this method.
Task-specific ionic-liquid-catalyzed efficient synthesis of indole derivatives under solvent-free conditions
Authors: Das Sudarshan , Rahman Matiur , Kundu Dhiman , Majee Adinath , Hajra Alakananda
Published: January 2010

A sulfonic-acid-functionalized ionic liquid is used as a Brønsted acid catalyst for the efficient synthesis of indole derivatives in good-to-high yields at room temperature under solvent-free conditions. The catalyst can be reused for ten consecutive runs without significant loss of activity.
Circular dichroism and fluorescence spectroscopic study on the interaction of bisdemethoxycurcumin and diacetylbisdemethoxycurcumin with human serum albumin
Authors: Mohammadi Fakhrossadat , Bordbar Abdol-Khalegh , Mohammadi Khosro , Divsalar Adeleh , Saboury Ali Akbar
Published: January 2010

The interactions of bisdemethoxycurcumin (BDMC) as a bioactive constituent of turmeric and diacetylbisdemethoxycurcumin (DABC) as a novel synthetic derivative of curcumin with human serum albumin (HSA) have been investigated by fluorescence and circular dichroism (CD) spectroscopy. The binding parameters, including the number of substantive binding sites and the binding constants, have been estimated from the analysis of fluorescence measurements. The estimated binding parameters indicated that BDMC has higher affinity than DABC to bind HSA, suggesting the essential role of the phenolic OH groups of BDMC, which are acetylated in DABC. It was found that the binding site for BDMC and DABC is located in the vicinity of Trp-214 in subdomain IIA, which is the same as binding site for curcumin (CUR). The minor changes on the far-UV circular dichroism spectra resulted in partial changes in the calculated secondary structure contents of HSA. The negligible alteration in the secondary structure of HSA indicated that ligand-induced conformational changes are localized in the binding site and do not involve considerable changes in the protein folding. The visible CD spectra indicated that the optical activity observed during the ligand binding is due to induced-protein chirality.
Renoprotective and blood pressure-lowering effect of dietary soy protein via protein kinase C βII inhibition in a rat model of metabolic syndrome
Authors: Palanisamy Nallasamy , Viswanathan Periyasamy , Ravichandran Mambakkam Katchapeswaran , Anuradha Carani Venkataraman
Published: January 2010

We studied whether substitution of soy protein for casein can improve insulin sensitivity, lower blood pressure (BP), and inhibit protein kinase C βII (PKCβII) activation in kidney in an acquired model of metabolic syndrome. Adult male rats were fed 4 different diets: (i) starch (60%) and casein (20%) (CCD), (ii) fructose (60%) and casein (20%) (FCD), (iii) fructose (60%) and soy protein (20%) (FSD), and (iv) starch (60%) and soy protein (20%) (CSD). Renal function parameters, BP, pressor mechanisms, PKCβII expression, oxidative stress, and renal histology were evaluated after 60 days. FCD rats displayed insulin resistance and significant changes in body weight, kidney weight, urine volume, plasma and urine electrolytes accompanied by significant changes in renal function parameters compared with CCD rats. Elevated BP, plasma angiotensin-converting enzyme (ACE) activity, renal oxidative stress, and reduced nitrite (NO) and kallikrein activity were observed. Western blot analysis revealed enhanced renal expression of membrane-associated PKCβII in the FCD group. Histology showed fatty infiltration and thickening of glomeruli while urinary protein profile revealed a 5-fold increase in albumin. Substitution of soy protein for casein improved insulin sensitivity, lowered BP and PKCβII activation and restored renal function. Antioxidant action, inhibitory effect on ACE and PKCβII activation, and increased availability of kinins and NO could be contributing mechanisms for the benefits of dietary soy protein.
Acute hypertensive pulmonary edema: a new paradigm
Authors: Ford Lincoln E.
Published: January 2010

Although acute hypertensive pulmonary edema is sometimes regarded as the most severe form of heart failure, at the peak of symptoms, hearts perform well above resting levels and cannot be said to be failing. Another characteristic of the condition, the rapidity of its onset and reversal when properly treated, suggests positive feedback as a causal mechanism. It is proposed that the syndrome results from a feedback loop with increased sympathetic tone as the efferent output, increased pulmonary vascular pressure as the stimulus to increased sympathetic tone, and positive feedback occurring because elevated sympathetic tone constricts systemic veins, thereby transferring blood from peripheral veins to the pulmonary vasculature. Evidence for the proposed mechanism derives from all the empirical treatments that have evolved. All remove blood from the pulmonary circuit, and all but the oldest, bloodletting, do so by transferring blood from the pulmonary circuit to the peripheral veins.
Caveolin-1 exists and may function in cardiomyocytes
Authors: Cho Woo Jung , Chow Ava K. , Schulz Richard , Daniel Edwin E.
Published: January 2010

Whether ventricular cardiac myocytes of mouse contain caveolin-1 is disputed. It has been claimed to be exclusively in nearby endothelial cell profiles. Recently, matrix metalloproteinase-2 (MMP-2) was reported to be present in mouse ventricular cardiac myocytes, colocalized with caveolin-1, and caveolin-1 knockout was found to cause the loss of MMP-2 from mouse ventricular cardiac myocytes and affect their functioning. To resolve this dispute, we labeled cardiac myocytes with caveolin-1 and endothelial cells with caveolin-2. Caveolin-2 is agreed to be present exclusively in endothelial cells. The results showed that mouse ventricular myocytes were labeled with caveolin-1 antibodies independently of any caveolin-2 labeling, and endothelial cells were labeled with both caveolin-1 and caveolin-2 antibodies. This confirms that caveolin-1 is present in mouse ventricular cardiac myocytes as well as endothelial cells. Previous evidence confirms that loss of caveolin-1 affects the function of mouse ventricular cardiac myocytes and suggests that MMP-2 may be involved.
Population genetic structure of long-tailed pygmy rice rats (Oligoryzomys longicaudatus) from Argentina and Chile based on the mitochondrial control region
Authors: González-Ittig Raúl E. , Rossi-Fraire Hernán J. , Cantoni Gustavo E. , Herrero Eduardo R. , Benedetti Rosendo , Gallardo Milton H. , Gardenal Cristina N.
Published: January 2010

The rodent Oligoryzomys longicaudatus (Bennett, 1832) (Rodentia, Cricetidae) inhabits southern forests of Argentina and Chile, a region severely affected by glaciations during the Pleistocene–Holocene periods. We evaluate here the diversity of the mitochondrial control region to characterize the genetic structure of this species from forests and bushy areas of seven populations from Argentina and four populations from Chile. Statistical analyses showed shallow haplotype trees and mismatch distributions compatible with recent range expansions. The presence of “private” haplotypes indicates that current levels of gene flow among populations of each country would be low to moderate. Significant differences in haplotype frequencies were detected between eastern and western populations, indicating that the Andes mountains would be an effective geographic barrier for gene flow despite the existing valleys that could act as corridors for dispersion. A single clade containing all the haplotypes was recovered in the phylogenetic trees, suggesting postglacial dispersion from a single refugium during the Last Glacial Maximum. The higher effective size and levels of polymorphism in populations from Chile suggest that the refugium was located in this country. The asymmetric gene flow from Chile to Argentina may reflect a recent colonization of the eastern populations.